In the article actual different-scale lithological, petrophysical and geochemical investigations of the Bazhenov rocks are considered. The authors stated hierarchy levels of structure model including nano-, micro-, rock layer and zones. New methods of investigation are described, specifically ‘microstructure’ modeling. As a result, it was found that the rocks of Bazhenov formation have two types of kerogen distribution on microstructure level. The first type is characterized by even kerogen distribution as tiny aggregates in mineral intergrain space. In the second type kerogen gathered in restricted aggregates lenticular-layer shape.The main components are silica, clay, carbonate and kerogen. The rock layer consists of these components and it is a base of section zone determination.Section zones are different in texture and contents of rocks included, and in porosity types, reservoir types that give an opportunity for hydrocarbon potential evaluation. The lower zone has intercalation of kerogen-clay and clay-kerogen silicite, the upper part has an interval build of kerogen-clay-carbonate and clay-carbonate-kerogen silicite. In the lower part of middle zone clay-kerogen and kerogen-clay silicite are prevalent, in the upper part of zone interval of kerogen-clay-carbonate and clay-carbonate-kerogen silicite are found. In the upper zone of section kerogen-clay-carbonate and clay-carbonate-kerogen silicite are prevalent.

References

1. Postnikov A.V., Postnikova O.V., Olenova K.Yu. et al., New methodological

aspects of lithological research of rocks Bazhenov formation (In Russ.),

Neftyanoe khozyaystvo = Oil Industry, 2015, no. 10, pp. 23–27.

2. Khasanov I.I., Rock color analysis using digital images of core material

(In Russ.), Geologiya nefti i gaza = The journal Oil and Gas Geology, 2014,

no. 5, pp. 33–39.

3. Gutman I.S., Postnikov A.V., Postnikova O.V. et al., Methodical approach to

vertical zonation of Bazhenov formation in relation to resources evaluation

(In Russ.), Nedropol'zovanie XXI vek, 2016, no. 6, pp. 80–87.

The idea of Bazhenov formation rocks wettability evolution held from hydrophilic mudstones to hydrophobic rocks. In addition, the conclusion of hydrophobicity was often based on solid organic matter in large quantities contained in Bazhenov formation rocks cannot be hydrophilic. Usual petrophysical studies in these rocks are concerned with great difficulties, so we have to find some innovative solutions. In this case, the five wells core material was tested on lyophilic properties by adsorption of water vapor. The results were very surprising: the entire section is either hydrophilic or neutral.

The problem of wettability determination is that the hydrophobization ratio is defined, in fact, as the difference amount of adsorbed water. Therefore, it can be assumed that a significant kerogen presence in the organic-matrix will produce stable values near zero of hydrophobic coefficient by adsorption method. In other words, the amount of water adsorbed on the extracted and not extracted surface will not differ radically, i.e. hydrophobic ratio will indicate surface hydrophilicity, while possible real hydrophobicity

To solve this problem the core material of two wells was complex investigated by nuclear magnetic resonance (NMR) with different fluid saturation: water and kerosene. The incremental spectra analyzed jointly to identify the preferential wettability by the spectrum shift to the short relaxation times. For easy comparison, the wettability coefficient based on the mean log times was designed to characterize the position of the spectra from each other. As a result, the distributions of wettability coefficient were obtained for two wells of the same deposit. One of it was corresponded to the adsorption method, the other - neutral or light-hydrophobic wetting throughout the section. In this case, an effect of organic matter influence is presented. Organic matter can be either solid or liquid. The amount of free organic material increases with the degree of organic matrix maturity that revealed in the different wells, even in a single field.

The estimation of kerogen content in mineral matrix of Bazhenov formation rocks was made by NMR and X-ray diffraction methods in comparison with results of geochemical technique. This model will clarify petrophysical data interpretation of NMR logging.

References

1. Gurari F.G., Gurari I.F., Formation of oil deposits in the shales of the

Bazhenov suite in Western Siberia (In Russ.), Geologiya nefti i gaza, 1974,

no. 5, pp. 36–40.

2. Kollektory nefti bazhenovskoy svity Zapadnoy Sibiri (Oil collectors of

Bazhenov suite in Western Siberia): edited by Dorofeeva T.V., Leningrad:

Nedra Publ., 1983, 132 p.

3. Bredikhin N.P., Informativnost’ nazemnykh geokhimicheskikh i geofizicheskikh

(neseysmicheskikh) metodov pri poiskakh zalezhey slantsevoy nefti

v bazhenovskoy svite (Informative ground geochemical and geophysical

(non-seismic) survey in search of shale oil deposits in the Bazhenov suite),

Collected papers “Problemy geologii i osvoeniya nedr” (Problems of geology

and mineral resources development), Proceedings of XX International

Symposium name of M.A. Usov, Tomsk, 4 – 8 April 2016, Tomsk: Publ. of TPU,

2016, Part 1, pp. 290–291.

4. Gudok N.S., Bogdanovich N.N., Martynov V.G., Opredelenie fizicheskikh

svoystv neftevodosoderzhashchikh porod (Determination of the physical

properties of oil-and-water-containing rocks), Moscow: Nedra Publ., 2007,

592 p.

5. Vasil’ev A.L., Pichkur E.B., Mikhutkin A.A. et al., The study of pore space

morphology in kerogen from Bazhenov formation (In Russ.), Neftyanoe

khozyaystvo = Oil Industry, 2015, V. 10, pp. 28–31.

6. Shlykov V.G., Rentgenovskiy analiz mineral’nogo sostava dispersnykh

gruntov (X-ray analysis of the mineral composition of fine-grained soil),

Moscow: GEOS Publ., 2006, 176 p.

7. Foley I., Farooqui S.A., Kleinberg R.L., Effect of paramagnetic ions on

NMR relaxation of fluids at solid surfaces, Journal of Magnetic Resonance,

1996, Ser. A 123, no. 1, pp. 95–104.

8. Metodicheskoe rukovodstvo po kolichestvennoy i ekonomicheskoy otsenke

resursov nefti, gaza I kondensata Rossii (Methodological guidelines

for the quantitative and economic evaluation of resources of oil, gas and

condensate of Russia): edited by Kleshchev K.A., Kontorovich A.E., Krylov

N.A., Mironychev Yu.P., Moscow: Publ. of VNIGNI, VNIGRI, VNIIGaz, IGNG

SO RAN, SNIIGGiMS, 2000, 189 p.

9. Coates G.R., Xiao L., Prammer M.G., NMR logging principles and applications,

Houston: Hullibarton Energy Services, 1999.

10. Berry L.G., Mason B., Mineralogy: Concepts, descriptions determinations,

Freeman and Company, San Francisco and London, 1959, 612 p.

Pyrolysis investigations of organic matter in the rocks are the basis for geochemical characteristics of source rocks and determination of modeling parameters for generation processes in the petroleum basins. Data obtained on Rock-Eval (Vinci Technologies), HAWK (Wildcat Technologies) instruments and other pyrolyzer modifications contains information on amount of organic carbon in the rocks, hydrocarbon generation during thermal history and the maturity of organic matter. The standard interpretation of Rock-Eval pyrolysis data is not suitable for Bazhenov formation in the rocks rich in organic material (amount of organic carbon reaches 20%), which has low porosity and low permeability, and contains a significant amount of adsorbed petroleum hydrocarbons. Pyrolitic peak S₂ contains products of the kerogen cracking, but also it is complicated by the presence of agglomerates which consist of resins, asphaltenes and paraffin-naphthenic hydrocarbons, and subdivides into S_2a and S_2b peaks before and after extraction (S_2ex). A qualitative characteristics and quantity of liquid and gaseous pyrolitic products estimation by combining pyrolysis, extraction with organic solvents and pyrolysis after extraction for Bazhenov formation of Western Siberia are proposed. Comparison of pyrolysis and chemical-bituminological data for Bazhenov formation allows receiving more accurate information on petroleum generative potential of kerogen and distribution of groups of the hydrocarbon components (where hydrocarbon gases play an important role) in the sedimentary sequence. The ratio of gas, light and heavy petroleum hydrocarbons and heteroatomic compounds are different in the sedimentary sections characterized by different maturity of organic matter. Increasing of organic matter thermal maturity in a range from immature to the end of oil window zone is accompanied by decreasing of the kerogen cracking products from 90 to 10-25%. In extractable compounds the catagenetic maturation shows decrease in proportion of the asphaltenes and increase of light hydrocarbons.

References

1. Espitalie J., Bordenave M.L., Rock-Eval pyrolysis, In: Applied Petroleum Geochemistry:

edited by Bordenave M.L., Paris: Technip ed., 1993, pp. 237–361.

2. Lopatin N.P., Emets T.P., Piroliz v neftegazovoy geologii (Pyrolysis in oil and

gas geology), Moscow: Nauka Publ., 1987, 143 p.

3. Goncharov I.V., Kharin V.S., Using pyrolysis in an inert atmosphere during the

study of organic matter of rocks (In Russ.), Problemy nefti i gaza Tyumeni, 1982,

V. 56, pp. 8–10.

4. Safranov T.A., Comparative characteristics of pyrolytic and chemical-bi tuminous

parameters of sedimentary rocks (In Russ.), Geologiya nefti i gaza =

The journal Oil and Gas Geology, 1991, no. 7, рр. 26–29.

5. Batalin O.Yu., Vafina N.G., Forms of free-hydrocarbon capture by kerogen

(In Russ.), Mezhdunarodnyy zhurnal prikladnykh i fundamental'nykh issledovaniy,

2013, no. 10, pp. 418–425.

6. Kostenko O.V., Blocking nature of distribution of high-molecular compounds

of bitumoid in pore system of Bazhenov formation (West Siberian basin)

(In Russ.), Neftegazovaya geologiya. Teoriya i praktika, 2014, no. 1, pp. 1–13.

7. Litvinets I.V., Prozorova I.V., Yudina N.V., Influence of the inhibiting additiveson

the process of the formation of paraffin deposits in the petroleum dispersal

systems (In Russ.), Neftepererabotka i neftekhimiya, 2015, no. 3, pp. 45–51.

8. Kozlova E.V., Fadeeva N.P., Kalmykov G.A. et al., Geochemical technique

of organic matter research in deposits enriched in kerogen (the Bazhenov

formation, West Siberia) (In Russ.), Vestnik MGU. Seriya 4. Geologiya = Moscow

University Geology Bulletin , 2015, no. 5, pp. 44–54.

Fast continuous non-contact profiling of rock thermal conductivity tensor components (along and perpendicular to the bedding) and volumetric heat capacity on cores within the intervals of the Bazhenov formation depths has been performed for 8 wells drilled in Krasnoleninskiy arch (Palyanovskoye field), Priobskoye upland (South Priobskoye field), Nizhnevartovskiy arch (Orekhovo-Ermakovskoye and Yuzhnoye oilfields), and Vyngoyakhskiy bank (Vyngoyakhskoye oilfield) of West Siberia. The profiling has been done in core storages at full set of recovered cores from Bazhenov fm. without preliminary machining process and any core destruction, with full preservation of core collections. Spatial resolution of thermal conductivity profiling is about 1-2 mm, it provides detalization of the structure of thin geological objects like Bazhenov fm. The total volume of the studied core collections was about 2400 cores, that significantly exceeds the volume of previously studied cores from low-permeable reservoirs. Thermal core logging data has been converted to detailed profiles of total organic carbon, sonic velocities, elastic moduli (Young’s modulus and Poisson’s ratio), natural radioactivity, density, and acoustic anisotropy (Tomsen’s parameter) with the help of the original techniques of thermal core logging data processing. Obtained data set of Bazhenov fm. rock properties is important for basin and petroleum system modeling, hydrodynamic modeling of thermal EOR methods, efficiency assessment, design and optimization of hydrocarbon recovery methods, geology structure investigations, estimation of petroleum reserves, and geomechanical modeling. Continuous high-resolution thermal profiling can replace or complement core scratching for heterogeneity rock analysis and for geomechanical properties estimation.

References

1. Popov E.Yu., Kalmykov G.A., Stenin V.P. et al., Thermal

properties of rocks from Bazhenov suite (In Russ.), Neftyanoe

khozyaystvo = Oil Industry, 2015, no. 10, pp. 32–37.

2. Popov E.Yu., Chekhonin E.M., Popov Yu.A. et al., Novel

approach to Bazhenov fm. investigations through thermal

core profiling (In Russ.), Nedropol'zovanie XXI vek,

2016, no. 6, pp. 52–61

3. Popov Yu., Beardsmore G., Clauser C., Roy S., ISRM Suggested methods for

determining thermal properties of rocks from laboratory tests at atmospheric

pressure, Rock Mechanics and Rock Engineering, 2016, no. 49(10),

pp. 4179–4207.

4. Popov E.Yu., Contactless measurements of thermal conductivity and thermal

diffusivity of full-size kern without samples optical characteristics alignment

(in Russ.), Izvestiya vuzov. Geologiya i razvedka, 2015, no. 4, pp. 48-52.

5. Bekasova N.B., Popov Yu.A., Romushkevich R.A., Teploprovodnost’ osadochnykh

porod Barentsevomorskogo regiona. Apatity (The thermal conductivity

of sedimentary rocks of the Barents Sea region. Apatites), Publ. of KNTs

AN SSSR, 1990, 48 р.

6. Popov Yu.A., Romushkevich R.A., Popov E.Yu., Teplofizicheskie issledovaniya

porod razreza Tyumenskoy sverkhglubokoy skvazhiny (Thermophysical study of

rocks of Tyumen superdeep well column), Collected papers “Tyumenskaya

sverkhglubokaya skvazhina” (Tyumen superdeep well), Perm’: Publ. of KamNIIKIGS,

Nedra, 1997, pp. 163–175.

7. Clauser, C.: Geothermal Energy, in Landolt-B􀀀rnstein, GroupVIII “Advanced

Material and Technologies”, Vol. 3 “Energy Technologies”, Subvol. C “Renewable

Energies”: edited by Heinloth, K., Springer Verlag, Heidelberg-Berlin, 2006,

pp. 480–595.

8. Popov E.Yu., Gabova A.V., Karpov I.A. et al., Svyaz’ teploprovodnosti i estestvennoy

radioaktivnosti porod bazhenovskoy svity po dannym gammakarotazha,

gamma-spektrometrii i teplofizicheskogo karotazha na kerne (Relations

between thermal conductivity and the natural radioactivity of Bazhenov

suite rocks according to gamma logging, gamma-ray spectrometry and thermophysical

logging at the core), Proceedings of Geomodel 2016 - 18th Science

and Applied Research Conference on Oil and Gas Geological Exploration

and Development 2016, DOI: 10.3997/2214-4609.201602271.

9. Gurari F.G., Matvienko N.I., Paleogeografiya bazhenovskoy svity po raspredeleniyu

v ney urana (Paleogeography of Bazhenov suite on the distribution of

uranium in it), Collected papers “Perspektivy neftegazonosnosti yugo-vostoka

Zapadnoy Sibiri” (Prospects of oil and gas potential of the southeast of Western

Siberia), Proceedings of SNIIGGiMS, 1980, V. 275, pp. 81–90.

10. Armstrong P., Ireson D., Chmela B. et al., The promise of elastic anisotropy,

Oilfield Review, 1994, no. 6, pp. 36–47.

11. Eremeev A.A., Mikhal’tseva I.V., Dentification and evaluation of elastic

properties of the rocks having a transverse isotropy with a vertical axis (TIV

anisotropy) by long-spaced sonic logs (In Russ.), Karotazhnik, 2013, V. 234,

no. 12, pp. 20–32.

12. Popov Yu.A., Mikhal’tseva I.V., Chekhonin E.M. et al., Povyshenie kachestva

izucheniya anizotropii porod putem sochetaniya akusticheskogo karotazha i

izmereniy teploprovodnosti na kerne (Improving the quality of studying

anisotropy of rocks through a combination of acoustic logging and thermal

conductivity measurements on core), Proceedings of Geomodel 2015 - 17th

Science and Applied Research Conference on Oil and Gas Geological Exploration

and Development, Gelendzhik, 2015, DOI: 10.3997/2214-

4609.201413949.

13. Schn J.H., Physical properties of rocks: Fundamentals and principles of

petrophysics, Developments in Petroleum Science, Elsevier, 2015, V. 65, 499 p.

14. Chekhonin E., Popov E., Popov Y. et al., Prediction of geomechanical properties

from thermal conductivity of low-permeable reservoirs, Geophysical Research

Abstracts, 2016, V. 18.

15. Chang C., Zoback M.D., Khaksar A., Empirical relations between rock

strength and physical properties in sedimentary rocks, Journal of Petroleum Science

and Engineering, 2006, no. 15, pp. 223–237.

The article concerns the problem of quantitative hydrocarbons evaluation of Bazhenov formation itself. Geological features of formation are defined basing on integrated multy-scale study. The formation has complex mineral a lithological composition and void media and it has vertical heterogeneity. Three zonal intervals could be allocated for studied area using lithological, geophysical, petrophysical and geochemical data. In the context of development by proven technology, the most important objects are fine-grained siliceous and carbonate layers located in middle and lower zonal intervals and layers with high concentration of pelecypod shells in middle interval.

Differentiation of estimation target in reliance on dominated petroleum occurrence forms is crucial for the concerning formation. Different approaches should be implemented for similar to traditional reservoirs intervals, for rocks containing petroleum in isolated porosity, and for source rocks. Quantitive reserves and resources estimations of kerogen-containing rocks based on pyrolytic parameters should be controlled by volumetric method of evaluation. Objective reserves values could be obtained using pyrolysis before and after extraction and consider dependence between parameters and sample volume.

Volumetric method should be applied for the traditional reservoirs within Bazhenov formation, and it is possible to use pyrolytic estimates for stimulated rocks. We recommend that reserves categories should be defined for the both types of rocks in accordance with RF Classification (2013), but with some specifications described in the article.

References

1. Postnikov A.V., Postnikova O.V., Olenova K.Yu. et al., Different-scale investigations

of geological heterogeneity of Bazhenov formation in terms of

hydrocarbon potential evaluation (In Russ.), Neftyanoe khozyaystvo = Oil

Industry, 2017, no. 3, pp. 8–11.

2. Gutman I.S., Potemkin G.N., Balaban I.Yu. et al., Volumetric control for

hydrocarbon resources estimations based on geochemical laboratory

measurements (In Russ.), Neftyanoe khozyaystvo = Oil Industry, 2016, no. 9,

pp. 12–17.

3. Kozlova E.V., Spasennykh M.Yu., Kalmykov G.A. et al., Balance of the petroleum

hydrocarbon compounds in pyrolyzed organic matter of the

Bazhenov formation (In Russ.), Neftyanoe khozyaystvo = Oil Industry, 2017,

no. 3, рр. 18–21.

4. Alekseev A.D., Antonenko A.A., Zhukov V.V. et al., The differentiated approach

of the reserves estimation for source rock formations (In Russ.),

SPE 182074-RU, 2016.

5. Gutman I.S., Postnikov A.V., Postnikova O.V. et al., Methodical approach

to vertical zonation of bazhenov formation in relation to resources evaluation

(In Russ.), Nedropol'zovanie XXI vek, 2016, no. 6, pp. 80–87.

6. Petersil'e V.I., Komar N.V., The algorithm for shale oil reserves assessment

with volumetric methods (In Russ.), Geologiya nefti i gaza = The journal Oil

and Gas Geology, 2016, no. 5, pp. 95–101.

7. Strizhnev K.V., Zagranovskaya D.E., Zhukov V.V., Selection of promising oil

and gas bearing area formations for unconventional reservoirs Bazhenov

suite (In Russ.), Nedropol'zovanie XXI vek, 2015, no. 1, pp. 46–51.

Laboratory experiment in combustion tube was conducted to evaluate the potential of the high-pressure air injection method and to determine the main parameters of combustion process in the source rocks of the Bazhenov formation. This study is designed for physical modeling of oil recovery from the reservoir in high-pressure combustion tube. Core pack consisted of rock samples of various forms from several fields in Western Siberia and was saturated with dead oil from selected Bazhenov formation producing wells. Oil ignited readily after preheating of ignition zone of combustion tube up to 200 °C. During the process, gas composition was monitored to assess the intensity of the oxidation reactions. Produced oil samples composition was analyzed and pyrolysis analysis of rock chips prior to and after the chemical and thermal exposure was done. As a result, several exothermic peaks in each of the tube sections were observed, which might corresponds to the combustion of initial oil, synthetic oil and kerogen. Due to the combustion front propagation, the total residual oil saturation in the core pack was 2%. Minimal residual oil saturation was observed in zones that the combustion front has passed through. Maximum oil saturation corresponds to the areas in front of the combustion front. Conversion of kerogen was observed ahead of the combustion front. The maximum temperature that was achieved as a result of the exothermic combustion reactions, was 463 °C. Results indicated a high potential of high-pressure air injection based method for the development of Bazhenov formation deposits.

References

1. Sarathi P.S., In-situ combustion handbook – Principles and practices, National

Petroleum Technology Office, U.S. Department of Energy, Tulsa, Oklahoma,

1999.

2. Moore R.G. et al., Observation and design considerations for in-situ combustion,

Proceedings of 48th Annual Technical Meeting of The Petroleum Society

in Calgary, Alberta, Canada, 1997, 8 – 11 June.

3. Kovscek A.R. et al., Improving predictability of in situ combustion enhanced

oil recovery, SPE 165577-PA, 2013.

4. URL: http://www.vniineft.ru/activities/physical-chemical-process-research/

5. Bondarenko T.M., Mukhametdinova A.Z., Popov E.Yu. et al., Analysis of

changes in Bazhenov formation rock properties as a result of high-pressure air

injection based on laboratory modelling data (In Russ.), Neftyanoe

khozyaystvo = Oil Industry, 2017, no. 3, pp. 40–44.

6. Peters K.E., Guidelines for evaluating petroleum source rock using programmed

pyrolysis, AAPG Bull., 1986, V. 70, no. 3, pp. 318–329.

7. Burzhe Zh. Surio P., Kombarnu M., Termicheskie metody povysheniya nefteotdachi

(Thermal methods of enhanced oil recovery), Moscow: Nedra

Publ., 1988, 422 p.

To assess the effectiveness of high-pressure air injection into layers of the Bazhenov formation and to analyze changes in properties of rocks under chemical and thermal exposure during experiment, the main experiment of air injection in the combustion tube and a number of additional studies of samples packed were carried out. A series of additional experiments included: a study of cylindrical samples in NMR relaxometer to obtain saturation profiles along the core samples prior to and after the experiment in the combustion tube; thermal conductivity measurements for evaluation of their changes as a result of the combustion front propagation through the samples; measurements of porosity and permeability of the cylindrical samples to assess changes in reservoir properties under chemical and thermal exposure. Integration of studies listed above has allowed to determine the dynamics of the physical and chemical state of rock samples prior to and after exposure. Porosity and permeability of samples after combustion front propagation significantly increased, while the porosity of some samples reached 32%, and permeability reached 5.77 mD. The results of measurements of the thermal properties indicated the displacement and oxidation of hydrocarbons in the cylindrical samples. Due to the low thermal conductivity of air that fills the voids formed, thermal conductivity of samples decreased. Due to the cracking thermal conductivity anisotropy of the samples increased. By analyzing saturation profiles one can assess the progress of the combustion front propagation through the samples. In all samples studied, a decrease of NMR porosity indicated the organic matter conversion.

References

1. Bondarenko T.M., Popov E.Yu., Cheremisin A.N. et al., Laboratory modeling

of high-pressure air injection in oil fields of Bazhenov formation (In Russ.),

Neftyanoe khozyaystvo = Oil Industry, 2017, no. 3, pp. 34–39.

2. Popov Y.A. et al., Continuous core thermal properties measurements

and analysis, 47th US Rock Mechanics, Geomechanics Symposium 2013,

ARMA 13-391, V.4, pp. 2991–2999.

3. Popov Y.A. et al., ISRM suggested methods for determining thermal properties

of rocks from laboratory tests at atmospheric pressure, Rock mechanics

and rock engineering, 2016, V. 49, pp. 4179–4207.

4. Nicot B. et al., Estimating saturations in organic shales using 2D NMR,

2016-V57N1A2 SPWLA Journal Paper, 2016.

During thermal impact with water or overheated steam on formation, kerogen thermal conversion can be initiated in the rock containing solid organic matter. At the first stage of this transformation liquids and gases, formed during the conversion, occupy the former kerogen volume. Subsequently water substitutes hydrocarbons in the pore volume. So the sophisticated process of rock pore space transformation occurs with changing porosity and permeability and it essentially depends on heating rate and exposure periods. Porosity and permeability are some of the most crucial and sensitive parameters of rock in numerical modelling of thermal enhanced oil recovery (EOR) methods. Experimental studies were conducted first on crushed and then on cylindrical Bazhenov formation core samples to obtain porosity and permeability changes at different exposure periods. The influence of heating rates and sizes of rock chips on the amount of hydrocarbons produced in the tests was evaluated. Time dependencies of porosity and permeability of Bazhenov formation cores were obtained from the tests conducted at 350 °С and 25 MPa. The experiments show that application of hydrothermal treatment method allows to improve filtration properties of Bazhenov formation cores. The results are to be applied to the numerical model of reservoir development with thermal EOR. It was determined that the results of the experiments conducted on cylindrical core samples significantly differ from the observed effects among crushed cores, both in terms of changes in porosity and permeability characteristics and the amount of the recovered synthetic hydrocarbons.

References

1. Kontorovich A.E., Burshteyn L.M., Kazanenkov V.A. et al., The Bazhenov suite

is the main reserve of unconventional oil in Russia (In Russ.), Georesursy.

Geoenergetika. Geopolitika, 2014, no. 2, http://oilgasjournal.ru/vol_10/kontorovich.

html.

2. Bychkov A.Yu., Kalmykov G.A., Bugaev N.A. et al., Experimental investigations

of hydrocarbon fluid recovery from hydrothermally treated rocks of the

Bazhenov formation, Moscow University Geology Bulletin, 2015, V. 70, no. 4,

pp. 299–304.

3. Le-Doan T.-V., Bostrom N.W., Burnham A.K. et al., Experimental study of

green river oil shale pyrolysis, SPE 168715, 2013.

4. Jin Lu, Wang Yuhe, Li Yinghui, The consideration of pore size distribution in

organic-rich unconventional formations may increase oil production and reserve

by 25 %, Eagle Ford case study, SPE-178507, 2015.

5. Tiwari P., Deo M., Lin C.L., Miller J.D., Characterization of oil shale pore structure

before and after pyrolysis by using X-ray micro CTP, Fuel, 2013, V. 107,

pp. 547–554.

6. Erofeev A.A., Mitrushkin D.A., Meretin A.S. et al., Simulation of thermal recovery

methods for development of the Bazhenov formation, SPE-182131-

MS, 2016.

7. Development of laboratory and petrophysical techniques for evaluating

shale reservoirs. GRI-95/0496, Final technical report, Chicago: Gas Research

Institute, 1996.

8. Bondarenko T., Popov E., Cheremisin A. et al., Experimental assessment of

the hydrocarbons yeilds from bazhenov shale formation by kerogen conversion

in the presence of supercritical water, Proceedings of International Symposium

of the Society of Core Analyst, Snow Mass, Colorado, USA, 21–26 August

2016.

9. Vol'f A.A., Petrov A.A., Features of internal burning process initiation in low

permeability kerogen containing rocks (In Russ.) , Neftyanoe khozyaystvo = Oil

Industry, 2006, no. 4, pp. 56–58.

This article aims to overview the prototype software for multi-stage hydraulic fracturing (MHF) design treatment. It includes HF simulator and reservoir simulator. Both of them are adapted for Bazhenov formation features such as high geological heterogeneity, vertical stress anisotropy, natural fractures, and extremely low permeability. Technological process features are also considered. As multistage hydraulic fracturing is of interest the issue of stress shadow effect and pressure distribution within the wellbore are considered.

The core of MHF module is based on cell-based pseudo-3D model with equilibrium-height growth regime, which is chosen for its reasonable accordance between accuracy and speed of numerical calculation. The hydraulic fracturing module allows setting an arbitrary design treatment (fluid and proppant properties, pumping schedule), lithology and well construction. Fracture geometry, mechanics of flow with proppant must be taken into account for proper fracture design and evaluation of packed fracture width profile. During the treatment, concentration of proppant near the fracture tip often increases causing tip screen out and making further fracture growth impossible. These aspects of fracture growth are implemented in MHF module. Once the fracture growth (with its sequent closure) is simulated, the MHF geometry may be transferred into the module for reservoir simulation in a straightforward way to calculate the inflow.

Thereby, the software allows following the HF design treatment workflow: both modules may be used in a joint way. In this article two cases are discussed: single fracture growth modelling and multi-stage hydraulic fracturing modelling.

References

1. Yew C.H., Weng Xiaowei. Mechanics of hydraulic

fracturing. – Gulf Professional Publishing, 2015,

pp. 65–67. – http://dx.doi.org/10.1016/B978-0-12-

420003-6.09995-X.

2. Dontsov E.V., Peirce A.P., Proppant transport in hydraulic

fracturing: crack tip screen-out in KGD and P3D

models, International Journal of Solids and Structures,

2015, V. 63, pp. 206–218.

3. Crouch S.L., Starfield A.M., Boundary element methods

in solid mechanics: With applications in rock,

Boston: George Allen & Unwin, 1983.

4. Economides M.J., Nolte K.G., Reservoir stimulation,

Houston: John Wiley&Son, 2000.

5. Lecampion B., Desroches J., Simultaneous initiation

of multiple transverse hydraulic fractures froma a horizontal

well, ARMA 2014-7110, 2014.

6. Weng X., Kresse O., Chohen C. et al.,Modelling of hydraulic

fracture network propagation in a naturally

fractured formation, SPE 140253, 2011.

7. Baikov V.A., Davletbaev A.Y., Ivaschenko D.S., Non-

Darcy flow numerical simulation and pressure/Rate

transient analysis for ultra-low permeable reservoirs,

SPE 171174-MS, 2014.

This work is devoted to estimate the potential impact of tertiary methods for unconventional low-permeable hydrocarbon system on the example of the Bazhenov formation. Carbone dioxide (CO₂) or water injection under high temperature, pyrolysis in inert atmosphere and thermal front produced by the combustion of fluid are considered as tertiary methods. Experiments have shown that after the injection of CO₂ at low temperatures (up to 300 °C) only hydrocarbon compounds desorption occurs. Significant improvement of the oil recovery with CO₂ injection can be achieved by application of CO₂ flood and cyclic injection. During experiments of heating rock samples in the presence of water in closed system “synthetic” oil can be produced. By varying the experimental conditions the maximum yield of oil achieved. The experimental studies show good opportunity to vary the composition of the recovered “synthetic” oil by changing temperature and exposure time in this method of solid organic matter conversion. An experiment of high-pressure air injection (combustion) into Bazhenov formation core model gets the maximal conversion value of the solid organic matter. Main condition to initiate the in-situ combustion is a preliminary broad fracturing in the low-permeable formation. A significant increase in porosity (up to 30%) in the samples was obtained in high air injection test. However, in the presence of oxygen uncontrolled temperature increase may occur resulting in combustion of some products (initial fuel and synthetic oil). Increasing of the porosity and permeability was also observed after pyrolysis in an inert atmosphere. Growth of cracks in the rock improves the properties of reservoir rocks, but after pyrolysis only gaseous hydrocarbon compounds were obtained.

Experiments carried out in this work shown a high potential of tertiary methods, particularly cracking in the presence of water or as a result of the combustion front, for the increase of oil production in Bazhenov formation and probably in other high-carbon formations. Experiments on rock samples heating in the presence of water or with the combustion front showed the role of experimental conditions on the process and demonstrated the necessity of parameters control in order to achieve a high yield of oil products from the rocks of the Bazhenov formation.

References

1. Asaulov S., Unconventional sources of hydrocarbons: shale bubble or shale

revolution (In Russ.), ROGTEC, 2013, V. 32, pp. 52–61.

2. Schmoker J.W., Method for assessing continuous type (unconventional) hydrocarbon

accumulations, In: National Assessment of United States Oiland Gas

Resources: Results, Methodology, and Supporting Data: edited by Gautier D.L.,

Dolton G.L., Takahashi K.I., Varnes K.L., Denver, Colorado: Digital Data Series, US

Geological Survey, 1995.

3. Iglauer S., Al-Yaseri M.S.A., Lebedev M., Permeability evolution in sandstone

due to injection of CO2-saturated brine or supercritical CO2 at reservoir conditions,

Proceedings of GHGT-12, 2014.

4. Y Zhang.P., Sayegh S.G., Huang S.S., Dong M., Laboratory investigation of enhanced

light oil recovery by CO2, Flue Gas Huff-n-puff Process, Journal of

Canadian Petroleum Technology, 2006, V. 45(2), pp. 24–32.

5. Yu W., Lashgari H., Sepehrnoori K., Simulation study of CO2 huff-n-puff process

in Bakken tight oil reservoirs, Proceedings of Western North American and

Rocky Mountain Joint Conference and Exhibition, 2014.

6. Kong B., Wang S., Chen S., Simulation and optimization of CO2 huff-and-puff

processes in tight oil reservoirs, SPE 179668-MS, 2016, DOI:10.2118/179668-MS.

7. Popov E.Yu., Myasnikov A.V., Cheremisin A.N. et al., Experimental and computational

complex for determination of the effectiveness of cyclic carbon

dioxide injection for tight oil reservoirs (In Russ.), SPE 181918, 2016.

8. Bychkov A.Yu., Kalmykov G.A., Bugaev I.A., Experimental investigations of hydrocarbon

fluid recovery from hydrothermally treated rocks of the Bazhenov

Formation (In Russ.), Vestnik Moskovskogo universiteta. Seriya 4. Geologiya =

Moscow University Geology Bulletin, 2015, no. 4, pp. 34–39.

9. Bushnev D.A., Burdel'naya N.S., Shanina S.N., Makarova E.S., Generation of

hydrocarbons and hetero compounds by sulfur-rich oil shale in hydrous pyrolysis

(In Russ.), Neftekhimiya = Petroleum Chemistry, 2004, V. 44, no. 6, pp. 449–458.

10. Kokorev V.I., Tekhniko-tekhnologicheskie osnovy innovatsionnykh metodov

razrabotki mestorozhdeniy s trudnoizvlekaemymi i netraditsionnymi zapasami

nefti (Technical and technological foundations of innovative methods for developing

deposits with hard-to-recover and unconventional oil reserves): thesis

of doctor of technical science, Moscow, 2010.

The geological service of Oil and Gas Production Department Komsomolskneft of Surgutneftegas OAO introduces new technologies, which often have no analogues in Russia. There are technologies of underbalanced drilling elongations and branches using coiled tubing equipment (continuous pipe) and drilling multilateral wells among them. Horizontally branched boreholes drilling allow to increase zonally the oil recovery factor, ensuring a more efficient inflow of oil from the reservoir and, in general, improving the quality of field development management.

The article presents new well construction technologies, used in Komsomolskneft, including at drilling additional boreholes in operated wells. Based on the existing experience in the construction of wells, a brief overview of the main designs and schemes of the used technologies is given: multilateral and multihole wells drilled using various methods of exposing producing horizons. The analysis of advantages and disadvantages of well designs used in the developed fields is performed. Recommendations are given on the choice of methods and their combinations, taking into account the geological features of the operation objects structure. The efficiency of construction of multilateral and multihole wells is substantiated due to reduction of the operating well stock, which is to construct on the developing fields. The actual data on yield of wells of various designs depending on the measure action duration are given.

For the effective operation of multi-layered objects, the field-geophysical data, obtained during the development of these objects, are necessary. The use of layout plans for, multiple-zone selective completion implies the possibility of creating a separate drawdown for each layer, up to a complete separation of one of them. This allows to keep separate account of well production for simultaneously working layers. If the layout plans of the simultaneous-separate operation are equipped with a multi-sensor system for registration of reservoir parameters, then apart separate accounting of production, it is possible real-time monitoring of the down hole equipment operation, the state of the bottom hole formation zone, as well as the operation of the layers at various drawdown creating on them.

A layout plan is proposed for obtaining information on each operating layer with placement of pressure and temperature sensors in the well at the layers cap. This design will allow the operation of well that drill in three layers or more. At that it is assumed complete automation with the control station setting to close the valves with the necessary regularity and fixing separately the parameters of the layer operation in the automatic mode. The proposed layout plan allows to control and regulate the drawdown created on the layers. Well survey is conducted without down hole equipment lifting.

The technology of research on steady state and non-steady filtration modes with the use of the proposed layout plan is considered. The application of these technologies allows to determine the production rate and water cutting of well production for each layer at a given drawdown, the production indexes for layers and well at the joint operation of the layers, the layer conductivity, the permeability, the skin factor and the current reservoir pressures of the objects under study. This makes it possible to control the state of development of a multi-layer field at a qualitatively new level and with a large sweep ratio.

References

1. Tsiku Yu.K., Issledovanie i razrabotka metodov kontrolya i optimizatsii

vyrabotki zapasov mnogoplastovykh ob»ektov pri odnovremennorazdel’noy

ekspluatatsii (na primere Russkinskogo mestorozhdeniya) (Research

and development of methods of control and optimization of the

development of multilayer objects reserves during simultaneous-separate

operation (for example, Russkinskoye field)): thesis of candidate of technical

science, Moscow, 2015, 150 p.

2. Tsiku Yu.K., Zakharov I.V., Experience and prospects of simultaneouslyseparate

development of multilayer fields of Oil and Gas Production Department

Komsomolskneft (In Russ.), Neftyanoe khozyaystvo = Oil Industry,

2012, no. 8, pp. 52–54.

3. Fedorov V.N., Meshkov V.M., Lushpeev V.A., Technology of thermohydrodynamic

investigations of multilayer objects (In Russ.), Neftyanoe

khozyaystvo = Oil Industry, 2006, no. 4, pp. 80–82.

4. Kremenetskiy M.I., Ipatov A.I., Gulyaev D.N., Informatsionnoe obespechenie

i tekhnologii gidrodinamicheskogo modelirovaniya neftyanykh

i gazovykh zalezhey (Information support and technologies of hydrodynamic

modeling of oil and gas deposits), Moscow – Izhevsk: Publ. of Institute

of Computer Science, 2012, 896 p.

5. Kremenetskiy M.I., Ipatov A.I., Gidrodinamicheskie i promyslovo-tekhnologicheskie

issledovaniya skvazhin (Hydrodynamic and oil field and technological

research of wells), Moscow: MAKS Press Publ., 2008, 476 p.

6. Deeva T.A., Kamartdinov M.R., Kulagina T.E. et al., Gidrodinamicheskie

issledovaniya skvazhin: Analiz i interpretatsiya dannykh (Well test: analysis

and interpretation of data), Tomsk: Publ. of TPU, 2009, 240 p.

At present Oil and Gas Production Department Komsomolskneft of Surgutneftegaz OAO has a stock of injection wells, mainly located at far from the cluster pumping stations sites, intake capacity of which could not be increased by existing methods. One way to increase the intake capacity of such wells is to increase the pressure of the working agent injection into the stratum. However, the injection pressure increase from the cluster pumping stations throughout the whole system of high-pressure water conduits leads to a number of negative consequences. Owing to the low efficiency of the centralized system for maintaining reservoir pressure due to the considerable distance of the cluster sites from the cluster pumping stations, the pits are widely used in Komsomolskneft. At pit using the injected liquid is fed from a high-pressure water conduit to the annular space of the pit, at first it goes to the pump intake, then under increased pressure - to the input of the water distributing unit.

740 injection wells with a low intake capacity were covered by increased injection pressure in Komsomolskneft on 01.10.16. Cumulative additional oil production amounted to 1161.3 thousand tons.

The use of pits makes it possible to reduce the specific costs of electricity for pumping water into the stratum, investing capital in the construction of high-pressure water conduits, improve their reliability and environmental safety, and ensure compliance with the design parameters of field development. The disadvantage of this technology is the lack of mobility, large costs for implementation.

The proposed scheme is not the only way to increase the injection pressure used in the enterprise. The choice of this or that way of increasing the injection pressure depends on many factors and is determined by the calculation of the economic efficiency of the measures implementation.

References

1. Shchurov V.I., Tekhnika i tekhnologiya dobychi nefti (Technique and technology

of oil production), Moscow: Nedra Publ., 1983, 510 p.

2. Spravochnik po neftepromyslovomu oborudovaniyu (Handbook of oilfield

equipment): edited by Bukhalenko E.I., Moscow: Nedra Publ., 1983, 399 р.

The problems of constant duty operation of electric centrifugal pump units in marginal wells are considered. The causes of electric submersible pumps (ESP) units starvation are analyzed. The necessity of applying new technologies and technical solutions is shown. One of the rational ways is to use additional equipment: control stations with a frequency converter and AC electric motors for bringing wells on a stable production. The methods of bringing marginal wells (with production rate of less than 20 m³/day) and methods for selecting electric centrifugal pump units with AC electric motors are considered.

It is shown that the technique of maintaining a given frequency of the ESP unit does not always allow the well to be brought to a stable production, because the pump starvation occurred from insufficient thrust of the electric submersible installation.

The technique for calculating the running current, corresponding to the technological parameters of the well operation, on the basis of head and flow rate of ESP units is presented. The application of this technique allows to reduce the time of bringing the well to a stable production and to increase oil output.

If the electric submersible unit fails, it is suggested to use a technique, developed on the basis of a change in the pump head and flow rate depending on the engine shaft speed. The ESP units, supplied with the AC electric motor, have a head margin, which allows marginal wells operation using frequency regulation. According to this technique, knowing the inflow rate at a certain dynamic level, we can determine the type of pump to be lowered into the well. An example of equipment selection for three types of ESP units, equipped with AC electric motors, is given.

The possibility of applying the proposed methods is confirmed by the results of the tests, carried out at the Oil and Gas Production Department Komsomolskneft fields.

References

1. RITEK: Intensivnye tekhnologii neftedobychi (RITEK: Technology of intensive

oil extraction), URL: www.technopolisxxi.ru

2. Bogdanov A.A., Pogruzhnye tsentrobezhnye elektronasosy dlya dobychi

nefti (raschet i konstruktsii) (Submersible centrifugal pumps for oil production

(design and calculation)), Moscow: Nedra Publ., 1968, 270 p.

3. Bartenev I.A., Spravochnik mastera po prokatu elektropogruzhnykh ustanovok

(Handbook of master of rental of electrical submersible pumps),

Surgut: Neft’ Priob’ya Publ., 2005, 348 p.

4. Rukovodstvo po ekspluatatsii “Stantsii upravleniya Elekton-05” (Manual

for Elekton-05 control station), 2006.

5. Chukcheev O.A., Loktev A.V., Bolgov I.D., Thermal & pressure gauge

control system for starting up and operation of general purpose electric

centrifugal pump (In Russ.), Neftyanoe khozyaystvo = Oil Industry, 2003,

no. 6, pp. 75-77.

6. Mishchenko I.T., Skvazhinnaya dobycha nefti (Oil production), Moscow:

Neft’ i gaz Publ., 2007, 826 p.

Thick sequence of potassium salt occurrence with commercial value on a global scale is a feature of the geological structure of the north of the Perm region. Construction of the wells within Verkhnekamskoye potash-magnesium field (VPMF) requires compliance of the restrictions relating to the profile of the well, the drilling and cementing slurries in the range of their occurrence. Due to the fact that the Rostovitskoye oil field is located under the VPMF, a course of holes has a vertical section of almost 1000 meters, followed by a set of a zenith angle and then well goes under the protected zone of potash (a departure fr om the mouth well of more than 3000 m). The potential risks considering the peculiarities of the geological structure and the large distances during the well construction have been considered before the start of the design for the formation of the technological measures. As a result of the successful implementation of design solutions during the construction of exploration well No. 102 the high commercial speed (1449 m/months per 1 oil-rig) was achieved. The potential shortening of the well construction was identified according to the results of the drilling: choosing insulation technology of the full acquisitions areas, range of the bits for the silicified rocks drilling and boring heads, providing high mechanical speeds of the drilling and tunneling.

References

1. Sbornik normativnykh dokumentov, reglamentiruyushchikh poryadok

stroitel'stva glubokikh skvazhin pri osvoenii neftyanykh mestorozhdeniy na

ploshchadi zaleganiya kaliynykh soley Verkhnekamskogo mestorozhdeniya

(Permskiy kray) (Collection of normative documents regulating the procedure

for the construction of deep wells in the development of oil fields in the

area of Verkhnekamskoye potassium salts deposit (Perm Region)), Perm':

Publ. of PSTU, 2006, 91 р.

2. Meshcheryakov K.A., Yatsenko V.A., Il'yasov S.E., Okromelidze G.V.,

Drilling of small diameter wells as a way to reduce costs in the construction

of development and exploratory wells (In Russ.), Territoriya NEFTEGAZ, 2013,

no. 10, pp. 28–32.

3. Meshcheryakov K.A., Il'yasov S.E., Okromelidze G.V., Yatsenko V.A., Drilling of

the sidetrack from the small diameter well (In Russ.), Neftyanoe khozyaystvo =

Oil Industry, 2015, no. 8, pp. 45–47.

4. Tuktarov D.Kh. et al., New records of drilling and multilateral wells completions

in Western Siberia (In Russ.), ROGTEC, 2016, no. 13, pp. 22–48.

5. German Muoz et al., Pushing the lim it for extended reach drilling: Delivering

the longest well in Saudi Arabia and the Worldwide Deepest 6 1/8-in. Section,

SPE 177816-MS, 2015.

6. Shtun S. et al., Integrated approach to drilling ERD wells with the innovative

reservoir-scale mapping while drilling technology on Korchagina field

(In Russ.), SPE 176536-RU, 2015.

The article is devoted to modeling the processes associated with the work of the vibration-percussion mechanism to eject stuck pipes due to small fragment rock (sand) while drilling and workover.

Extractable assembly in most cases is stuck with reservoir sand or gravel. Attempts to retrieve it by simple axial tension are ineffective. The reason for this – ‘self-braking effect’ of bodies which leads to the fact that the frictional force is greater than the axial force even for large quantities. Therefore, in practice downhole equipment is often drilled around extracting piecemeal. This technique requires a significant increase in time and cost of repair. Furthermore, the remaining part of the filter in the well cannot be removed because of the inability reconnection as they are in extensive cavity.

This article offers an alternative extraction confirmed with experimental studies and development testing. The self-braking mechanism of sand-stuck pipe under the action of axial tension is considered in the first place. The theoretical justification of the possibility of its removal from a medium depending on its physical characteristics is given. For example, it is theoretically possible to extract the assembly by axial force from the settled mud or well compressed sand. However, gravel filters are stuck with well compressed sand free of clay and extraction by the simple tension seems impossible. It is therefore proposed to impact the assembly with mechanical vibrations transforming gravel massif into a kind of liquid (false fluidization). In this regard, we studied the physical principles of the vibrator and vibrating hammer.  The difference between them is shown and theoretical explanation why a vibrator is less effective than vibrating hammer is given.  A mathematical model of the effect of a compression wave caused by the impact, on the stuck tool is offered as well as hydraulic calculation of vibrating hammer operation and its control parameters. The calculation is described with the help of well-known formulas for critical values of vibrating hammer parameters when its operation can cause destruction of the assembly the device.

References

1. Nadai A., Theory of flow and fracture of solids, New York, McGraw-Hill, 1950.

2. Dubrovskiy V.V., Spravochnik po bureniyu i oborudovaniyu skvazhin na vodu

(Handbook on drilling and equipment for water wells), Moscow: Nedra Publ.,

1972, 516 р.

3. URL: http://arsena-hotel.com/gruntovedenie/fiziko-mekhanicheskie_svoystva

4. Kunii D., Levenspiel O., Fluidization Engineering, 2nd ed., Butterworth-Heinemann,

USA, 1991.

5. Evdokimov I.N., Evdokimov I.N., Vedishchev I.A., Fizicheskie effekty pri burenii

neftyanykh i gazovykh skvazhin (Physical effects in oil and gas wells

drilling), Part 1. Effekt udara (Impact effect), Moscow: Publ. of Gubkin Russian

State University of Oil and Gas, 2001, 25 р.

6. Aleksandrov E.V., Sokolinskiy V.B., Prikladnaya teoriya i raschety udarnykh

sistem (Applied theory and calculations of percussion systems), Moscow:

Nauka Publ., 1969, 198 p.

7. Vol’mir A.S., Ustoychivost’ deformiruemykh sistem (The stability of deformable

systems), Part 1. Mekhanika (Mechanics), Moscow: Nauka Publ.,

1967, 984 p.

8. Timoshenko S.P., Teoriya kolebaniy v inzhenernom dele (Theory of oscillations

in engineering), Moscow: State technical and theoretical publishing,

1934, 360 p.

9. Biderman V.L., Teoriya mekhanicheskikh kolebaniy (The theory of mechanical

vibrations), Moscow: Vysshaya shkola Publ., 1980, 408 р.

10. Instruktsiya po raschetu obsadnykh kolonn dlya neftyanykh i gazovykh

skvazhin (Instructions on the design of casing for the oil and gas wells), Kuybyshev,

1989, 98 р.

The Sabanchinskoye oil field was discovered in 1963, commercial production started in 1973 with waterflooding. The carried out research allowed the several conclusions. In the Sabanchinskoye oil field characterized by complex geology and heterogeneity of oil reservoirs, a combined waterflooding system proved to be effective. This system involves perimeter waterflooding and regular waterflooding, in the latter, line drive waterflooding dominates. Line drive waterflooding of the Sabanchinskoye oil field Bobric formation makes it possible to maintain formation pressure at a level of ±10 % of the original in-situ pressure, to attain the planned oil recovery in the drilled blocks, and to develop oil reserves from bottom to surface. Application of various EOR methods improved displacement efficiency and allowed drainage of by-passed zones. The fourth stage of the field development witnessed decrease of effectiveness of production enhancement operations. This means that the waterflooding process has to be optimized, cyclic waterflooding has to be considered, operation modes need to be changed, and innovation technologies have to be applied on a field scale.

Cyclic waterflooding was carried out in one experimental and five pilot blocks of the Sabanchinskoye field Bobric formation. The injection volumes were changed, and the period of half-cycle was extended to 20 days. For two years of pilot production, 35000 tons of additional oil were extracted, produced water decreased by 885200 tons.

For the first time since 1984, the production decline curve was on the up, and from the year-earlier period (2014), oil production from the field increased.

References

1. Khisamov R.S., Khabibrakhmanov A.G., Yartiev A.F. et al., Sabanchinskoe

neftyanoe mestorozhdenie: istoriya, analiz razrabotki, perspektivy (Sabanchinskoye

oil field: the history, development analysis, perspectives),

Kazan’: Ikhlas Publ., 2016, 320 p.

2. Patent no. 2471971 RF, MPK E 21 V 43/20, Development method of nonhomogeneous

oil deposit, Inventors: Bakirov I.M., Idiyatullina Z.S.,

Bakirov A.I., Ramazanov R.G., Nasybullin A.V., Vladimirov I.V.

Traditionally effective differential pressure is determined to the maximum of an indicator diagram of flow rate fr om depression dependence. For reliable determination of the depression it is necessary to pass this maximum, significantly having lowered a flow rate and, therefore, to pass into the ultramundane condition of the formation permeability, i.e. to pass a point of no return, a skin factor. Irreversible decrease in the flow rate will remain also in case of the subsequent operation of a well. For elimination the skin factor is offered a new method of the maximum allowable depression determination not in the formation of the drilled exploitation well, and on the core, which is selected fr om this formation in earlier drilled next test hole and stored in the core storage (core storage time is unlimited). The method is implemented by removal of elastic waves distribution time dependence in the core sample fr om pore pressure in a hydropressure chamber with confining pressure, approximate to the reservoir under the conditions of its natural occurrence, and subsequent pressure estimating of the most admissible depression upon the formation on "memory" by a core pressure of the maximum paleo-immersion of formation layer in the period of their progressive epigenesis. Measurements are taken smoothly, reducing pore pressure to formation with a speed which isn't exceeding the speed of a relaxation rate of ultimate stress lim it in the core, of which judge by acoustic emission absence – acoustic noise from mutual sliding of grains with formation crackling in the course of a core plastic deformation, in case of which there is a repacking of grains to consolidation of formation pore space and corresponding reduction of its permeability. At first sharp reduction of a change gradient of this dependence in case of plasticity lim it achievement and acoustic issue emergence judge about the value of the maximum allowable depression. This plasticity lim it means the achievement by the core of the stress condition, corresponding to the maximum depth of a paleo-immersion of formation layer.

References

1. Pavlov S.D., Determination of pressure drawdown during the development

and well survey (In Russ.), Neftegazovye tekhnologii, 2002, no. 2, pp. 10–12.

2. Boganik V.N., Medvedev A.I., Chikishev A.Yu., Determining the optimal

reservoir drawdown during well operation (In Russ.), Tekhnologii TEK, 2004, no.

3, pp. 4–8.

3. Avchyan G.M., Fizicheskie svoystva osadochnykh porod pri vysokikh

davleniyakh i temperature (Physical properties of sedimentary rocks at high

pressures and temperatures), Moscow: Nedra Publ., 1972, 145 p.

4. Patent no. 2538563 RF, Optimal pressure drawdown determination

method, Inventors: Kosolapov A.F., Pustovit V.N.

5. Zhukov V.S., Laboratory modeling of reservoir pressure decline in the development

of oil and gas fields (In Russ.), Burenie i neft', 2006, no. 1, pp. 8–9.

Analysis of the status of the Lower Miocene development indicates the nonuniform oil reserves recovery in various areas of the reservoir. The oil recovery factor remains low, while the water-cut of the produced products increases. By means of increasing the displacing factor and areal sweep efficiency, the reservoir flooding technology based on polymer solutions allows significantly improve the production and economic performance of fields. The basis for the most implemented soluble polymers is polyacrylamide, which has limits in temperature (no higher than 90^oC) and salinity (for mediums with low salinity). The indicated properties prevent the polyacrylamide-based polymer solutions from wide implementation in oil-field practices under conditions of Vietsovpetro JV.

To improve the oil-displacing factor during Lower Miocene flooding at White Tiger field the radio irradiated polymer systems and methods for their rheological and physical properties control were developed. Using of radioactive irradiation new polymer was synthesized. Its viscosity is much higher than the viscosity of the initial polymer.

Study of the temperature influence on the new polymer solution viscosity under various concentrations revealed that the polymer system viscosity has a tendency to decrease under temperature rise. In that way, the viscosity lowers 2 times under low concentration and reduces 4 times under high concentration with temperature variation from 30 to 90^oC.

References

1. Ty Tkhan’ Ngia, Veliev M.M., Chan Kuok Khoy, Development of polymeric

water soluble compositions and methods of regulating their rheophysical

properties to increase the oil displacement efficiency by water flooding

the deposit of the lower miocene in the “White Tiger” field (In Russ.),

Problemy sbora, podgotovki i transporta nefti i nefteproduktov, 2015, no. 4

(102), pp. 66–75.

2. Al-Fariss T.F., Flow of polymer solutions through porous media, Ind. Eng.

Chem. Res., 1990, V. 29, pp. 2150–2151.

3. McCormick S.L., Blackmon K.P., Water-soluble copolymers. Copolymers

of acrylamide with sodium-3-acrylamido-3-methylbutanoate: synthesis

and characterization, J. Polym. Sci.: Part A: Polymer chemistry, 1986, V. 24,

pp. 2635–2645.

4. Modine A.D., Coats K.H., Wells M.W., A superposition method for representing

wellbore crossflow in reservoir simulation, SPE 20746-PA, 1992.

5. Chapiro A., Dulieu J., Mankowski Z., Schmitt N., Influence des solvants sur

la copolymerisation de l’acide acrylique avec l’acrylonitrile et l’acrylamide,

European Polymer Journal, 1989, V. 25, pp. 879–884.

6. Khue G.D., Donaruma L.G. et al., Modified acrylamide polymers for enhanced

oil recovery, J. Appl. Polym. Sci., 1985, V. 30, pp. 875–885.

7. Taylor K.S., Nasr-El-Din H.A., Acrylamide copolymers: A review of methods

for the determination of concentrationabd degree of hydrolysis, J. Petroleum

Science and Engineering, 1994, no. 12, pp. 9–23.

8. Ty Tkhan’ Ngia, Veliev M.M., Chan Kuok Khoy, Studies of radiation exposure

of water soluble polymer compositions in order to increase pool oil recovery

of the Lower Miocene of the “Bach Ho (White Tiger)” field (In Russ.),

Territoriya NEFTEGAZ, 2015, no. 12, pp. 110–117.

To assess development characteristics of Bazhenov formation the authors applied the new technology of hydraulic fracturing in wells, located in the South-Eastern part of Western Siberia. The new technology is based on use of composition, represented by 99.5% of fresh water and the other ingredients represented proppant decreased of friction, acid, clay stabilizer, etc. such a technology referred to as Slick Water. The peculiarity of the technology Slick Water is an injection of a large volume of water, reaching up to 900-1200 m³ at one stage of hydraulic fracturing. For experimental works we selected vertically drilled wells which discovered Bazhenov formation. In these wells according to the interpretation of well logging data we selected the most fragile intervals for the perforation before fracturing. Test results showed that Bazhenov formation reached the necessary maturity, formed liquid hydrocarbons, and can be developed. In the result of well No. 2 (area B) tests 6.7 m³ of oil and 402.5 m³ of water were produced, average watercut amounted to 98.3%, for well No. 1 (area A) 18 m³, 189.3 m³, 91.3% respectively. Wells performans demonstrated Bazhenov formation potential and the prospect of hydrocarbon production. We have to admit that at present in Russia there is no methodology to carry out the forecast distribution of zones of fracture in Bazhenov formation, for scheduling of drilling new wells, for which it is necessary to carry out a preliminary study of the distribution zones of fracture. Based on the results of the test we can conclude that in case of intermittent operation oil production rate will not exceed 2-3 tons if zones of abnormally high reservoir pressure are not drilled in.

References

1. Wright S., Pearson M., Griffin L. et al., Two Cs Drive Bakken Well Performance,

URL: http://www.aogr.com/magazine/frac-facts/two-cs-drivebakken-

well-performance-january-2013

2. Gladkov E.A., Well blasting operations in the development of low-permeability

reservoirs using multistage fracturing (In Russ.), Oil&Gas Journal

Russia, 2014, no. 11, pp. 18–20.

3. Gladkov E.A., Gladkova E.E., Karpova E.G., Application of «PLUG&PERF»

technology in the Western Siberia while developing low-permeable reservoirs

(In Russ.), Neftepromyslovoe delo, 2015, no. 5, pp. 30–33.

4. Gladkov E.A., Well blasting operations for Plug&Perf technology fracturing

in low-permeability reservoirs of the Western Siberia (In Russ.), Gornye

vedomosti, 2015, no. 1 (128), pp. 52–57.

5. Lanier Yeates J., Andrew M., Abrameit current issues in oil&gas shale development,

The 58-th Mineral Law Institute, URL: http://www.gordonarata.

com/720DE/assets/files/lawarticles/58thMLI.pdf)

6. URL: http://www.gofrac.com/services/slick-water.html

7. Bakhtina E.S., Perspektivy slantsevoy nefti bazhenovskoy svity Tomskoy

oblasti po dannym piroliticheskogo analiza Rock-Eval (Prospects for shale

oil of Bazhenov suite of Tomsk region according to Rock-Eval pyrolytic

analysis), Collected papers “Problemy geologii i osvoeniya nedr” (Problems

of geology and development of mineral resources), Proceedings of

XVIII International Symposium named after Academician M.A. Usov,

Tomsk: Publ. of TPU, 2014, pp. 258–259.

8. Goncharov I.V., Samoylenko V.V., Oblasov N.V., Fadeeva S.V., Catagenesis

of organic matter Bazhenov Formation rocks in the south-east of West

Siberia (Tomsk region) (In Russ.), Neftyanoe khozyaystvo = Oil Industry, 2013,

no. 10, pp. 32–37.

9. Gladkov E.A., Gladkova E.E., Changing the permeability and porosity of

deposits in during their development (In Russ.), Oil&Gas Journal Russia,

2011, no. 9, pp. 75–79.

10. Gladkov E.A., The need to consider the strain-metasomatic transformations

of hydrocarbon deposits in the process of their developing (In

Russ.), Neftyanoe khozyaystvo = Oil Industry, 2012, no. 2, pp. 46–49.

11. Gladkov E.A., Interaction of geo-mechanics and deformation -metasomathic

conversions of hydro-carbons’ (HC) pools (In Russ.), Burenie i

neft’, 2012, no. 2, pp. 54–56.

Last years, low oil prices make oil and gas companies to become more flexible and competitive. This situation leads to the creation of research centers, and conduct technical expertise to carry out the decisions taken by the design organizations for the additional ‘strength’ and metal structures for arrangement of oil and gas fields. The article considered the concept of adaptability of constructions and conclusions about the general conditions of technological design. Also it is shown the analysis of construction schemes of building structures. Preliminary evaluation of the constructions is based on comparing it with the specific quantity of metal of metal structural schemes of the same functionality. A detailed analysis is performed on the basis of the total cost of construction, including material costs, manufacturing design, logistics and installation cost. It is considered also criteria for the evaluation of the constructions solutions. The analysis of the optimal form of cross-sections for the design decisions was performed. We analyzed different ways of structures manufacture, such as the production at the site and prefabrication construction. The article presents the factors, which are affecting on the cost of construction forming in particular delivery costs of structures on the field and the cost of maintaining rotational camp. As a solution to the problem indicated in the article we determined the control of feasibility study of decisions taken by the design institute and the development of typical designs. The given method of calculation needs a few working time and it is based on the design and estimated pricing regulations and allow to solve the problem with high specific quantity of metal on the stage of design documentation development.

References

1. Sakhnovskiy M.M., Tekhnologichnost' stroitel'nykh svarnykh stal'nykh konstruktsiy

(Fabricability of engineering welded steel structure), Moscow - Kiev:

Budivel'nik Publ., 1980, 264 p.

2. Likhtarnikov Ya.M., Variativnoe proektirovanie i optimizatsiya stal'nykh konstruktsiy

(Variational design and optimization of steel structures), Moscow:

Stroyizdat Publ., 1979. – 318 р.

3. Muratov A.F., Povyshenie effektivnosti sterzhnevykh stroitel'nykh konstruktsiy

putem primeneniya ratsional'nykh form secheniy i marok staley (Increasing

the efficiency of framed building structures by applying rational shapes of

sections and steel grades): thesis of candidate of technical science, Nizhny

Novgorod, 2003, 235 р.

This paper presents the results of numerical investigation of stress-strain state of the vertical steel tanks with longitudinally oriented cracks. The paper studies the cracks in the wall of vertical steel tanks with specified volume of 5000, 10000, 20000 and 30000 m³. Surface non-through cracks are one of the main causes of tank failure. The prognostication of the crack critical dimensions requires analytical expression for the K-calibration function. K-calibration function is the dependence taking into account the change in dimensions of a defect and defect orientation angle relatively to generatix of the tank. The calculation of the stress-intensity factor (SIF) of a surface longitudinally oriented crack located in the tank wall was performed using finite element method. The cracks with various dimensions were studied by generating global finite-element model of the tank and a sub-model of the tank ring with a crack. Curve Fitting Toolbox Matlab software was implemented to derive analytical expressions for K-calibration function of cracks with different shape located in the wall of vertical steel tank. All expressions for the K-calibration function are described by a polynominal function that allows estimating the critical size of a defect. The new program is created for calculation critical and threshold crack depth. The work results could be interesting for oil industry engineers.

References

1. Evdokimov V.V., Basko E.M., About normalization of the permissible size of internal

defects in the welded joints of the wall with the technical diagnosis of

oil vertical storage tanks (In Russ.), Montazhnye i spetsial’nye raboty v

stroitel’stve, 2007, no. 6, pp. 24–27.

2. Khanukhov Kh.M., Analiz prichin avariy rezervuarov, proektnoe, normativnoe

i tekhnicheskoe obespechenie ikh bezopasnoy ekspluatatsii (Analysis of

the causes of tanks accidents, design, regulatory and technical support for

their safe operation), Proceedings of International scientific and practical

conference “Novye resheniya konstruktsiy, tekhnologii sooruzheniya i remonta

stal’nykh rezervuarov” (New solutions of designs, construction techniques

and repair of steel tanks), NEFTEGAZMASh, Samara, 2007, pp. 112–120.

3. Bolot in V.V., Resurs mashin i konstruktsiy (Source of machines and structures),

Moscow: Mashinostroenie Publ., 1990, 447 p.

4. Gallyamov A.K., Chernyaev K.V., Shammazov A.M., Obespechenie

nadezhnosti funktsionirovaniya sistemy nefteprovodov na osnove tekhnicheskoy

diagnostiki (Ensuring the reliability of oil pipelines on the basis of technical

diagnostics), Ufa: Vremya Publ., 1998, 597 p.

5. Shlyannikov V.N., Zakharov A.P., Gerasimenko A.A., The characteristics of

the cyclic crack resistance of steel St-3 under biaxial loading (In Russ.), Trudy

Akademenergo, 2013, no. 4, pp. 91–101.

6. Shlyannikov V., Tumanov A., Zakharov A., Gerasimenko A., Surface crack

growth subject to bending and biaxial tension-compression, Fracture and

Structural Integrity, 2016, V. 35, pp. 114–124.

7. Parton V.Z., Morozov E.M., Mekhanika uprugoplasticheskogo razrusheniya:

Osnovy mekhaniki razrusheniya (The mechanics of elastoplastic fracture:

Fundamentals of fracture mechanics), Moscow: LKI Publ., 2008, 352 p.

8. Pokrovskiy A.M., Chermoshentseva A.S., Estimating the survivability of a

stretched plate with a transverse semielliptical crack (In Russ.), Izvestiya vuzov.

Mashinostroenie, 2014, no. 3, pp. 42–46.

9. Pestrikov V.M., Morozov E.M., Mekhanika razrusheniya tverdykh tel (Fracture

mechanics of solid bodies), St. Petersburg: Professiya Publ., 2002, 320 p.

10. Cherepanov G.P., Mekhanika razrusheniya (Fracture mechanics), Izhevsk:

Publ. of Institute of Computer Science, 2012, 872 p.

11. Gerasimenko A.A., Prognozirovanie ostatochnogo resursa stal’nykh vertikal’nykh

rezervuarov po parametram tsiklicheskoy treshchinostoykosti v

usloviyakh dvukhosnogo nagruzheniya (Prediction of residual life of steel vertical

tanks in the parameters of crack resistance under cyclic biaxial loading):

thesis of candidate of technical science, St. Petersburg, 2014. 

The main cause of oil pollution of soils is the emergency situations within oil production, transportation and processing in the boundaries of industrial sites of chemical and petrochemical industries. Oil pollution leads to the deterioration of the agrophysic soil characteristics, namely to the dysfunction of the water, air, thermal, oxidation-reduction and nutrient regimens. Thus, it is necessary to develop the effective methods of oil pollution elimination which permit to restore the original state of soils.

The long-term investigations` results of the bioremediation of oil-polluted soils in the control conditions of bioreactor are presented in the current article (namely the change of the microbiocoenosis within the process and agrophysic characteristics of refined soils). Received data are the base for the bioreactor construction which allows providing the necessary aeration regimen for substratum, preventing substratum` blocking property, securing optimal conditions of vital functions for hydrocarbon microorganisms.

The application of the bioreactor technology permitted to reduce the bioremediation terms to 60±10 days in case of the soil pollution more than 90 g/kg, and to 20±5 days in case of pollution less than 40 g/kg. With the application of developed bioreactor the treatment efficiency made up 90,0±5% (in case of high level of soil pollution (more than 90 g/kg). In case of middle level pollution (less than 40 g/kg) the efficiency amounted to 70,0±10%.The realization of the developed bioreactor technology for the bioremediation is probable on any territory. This is determined by the bioremediation independence from the nature and climate factors of territory. Bioreactor technology is characterized by reduction of terms of bioremediation by increasing the rates of oxidation of hydrocarbons in a bioreactor in the 40-60 times.

References

1. Shagidullin R.R., Latypova V.Z., Ivanov D.V. et al., The rationing of allowable

residue of petroleum and its transformation products in soils (In Russ.),

Georesursy = Georesources, 2011, no. 5 (41), pp. 2–5.

2. Kireeva N.A., Mikrobiologicheskie protsessy v neftezagryaznennykh

pochvakh (Microbiological processes in the oil-contaminated soils), Ufa:

Gilem Publ., 1994, 159 p.

3. Oborin A.A., Neftezagryaznennye biogeotsenozy (Oil-contaminated

biogeocoenoses), Perm’: Publ. of PSU, 2008, 511 p.

4. Utility patent no. 51538 U1 RF, MPK B09C1/00, Poligon dlya mikrobiologicheskoy

ochistki nefteshlamov i neftezagryaznennogo grunta (Polygon

for microbiological treatment of oil sludge and oil-contaminated soil),

Inventors: Venyaminov A.V., Simak I.A., Surenkov V.V.

5. Shaydullina I.A., Yapparov A.Kh., Degtyareva I.D. et al., Recultivation of

oil-contaminated lands by example of leached black humus earth of

Tatarstan (In Russ.), Neftyanoe khozyaystvo = Oil Industry, 2015, no. 3,

pp. 102–105.

6. Nazar’ko M.D., Development of way restoration oily soils by means of the

combined biosorbent (In Russ.), Izvestiya vuzov. Pishchevaya tekhnologiya,

2011, V. 319, no. 1, pp. 108–110.

7. Mikrobiologische Bodensanierungsanlage, URL: http://www.bsi-itzehoe.

de

8. Gomes I.H., Dias-Ferreira C., Ribeiro A.B., Overview of in situ and ex situ

remediation technologies for PCB-contaminated soils and sediments and

obstacles for full-scale application, Science of the Total Environment, 2013,

V. 445–446, pp. 237–260.

9. Thaler P., Walter B., Ex-situ Behandlung kontaminierter Bden, Wien:

Umweltbundesamt GmbH, 2012, 89 p.

10. Patent no. 2479365 RF, MPK B09C1/10, Method and plant for microbiological

treatment of soils contaminated by heavy metals and oil products

(Versions), Inventors: Bel’kov V.M., Kholodilova E.S.

11. Utility patent no. 13798 U1 RF, MPK C02F3/04, Ustanovka bioremediatsii

shlamov (Unit for sludge bioremediation), Inventors: Yakusheva O.I., Garifutdinov

M.K., Galukhin V.A., Nikonorova V.N., Makarov V.M., Spiridonov

Yu.N., Kireev Yu.A., Kichigin V.P.

12. Dem’yanenko A.F., Mizgirev N.S., Microbiological soils treatment from oil

products in closed isothermal reactors (In Russ.), Vestnik VNIIZhT, 2005, no. 5,

рр. 40–43.

13. Zaborskaya E.A., Bioremediatsiya neftezagryaznennykh pochv s ispol’-

zovaniem bioreaktora s peremeshivayushchim ustroystvom (Bioremediation

of oil-contaminated soils using a bioreactor with a stirring device), Proceedings

of conference “Ekologicheskie problemy neftedobychi – 2014”

(Environmental problems of oil production - 2014), Ufa: Neftegazovoe delo

Publ., 2014, pp. 53–54.

14. Asonov A.M., Volkova K.R., Tereshchenko E.A., Regeneration of oil-firing

subsoil in a bioreactor (In Russ.), Vestnik Ural’skogo gosudarstvennogo universiteta

putey soobshcheniya, 2011, no. 2, pp. 44–53.

15. Nano G., Borroni A., Rota R., Combined slurry and solid-phase bioremediation

of diesel contaminated soils, Journal of Hazardous Materials,

2003, B100, pp. 79–94.

16. Puskas K., Al-Awadhi N., Abdullah F., Remediation of oil-contaminated

sandy soil in a slurry reactor, Environment International, 1995, V. 21, no. 4,

pp. 413–421.

17. Bekoski V.P. et al., Ex situ bioremediation of a soil contaminated by

mazut (heavy residual fuel oil) – A field experiment, Chemosphere, 2011,

no. 83, pp. 34–40.