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.
