Rapid assessment of clay content based on NMR-relaxometry results

UDK: 552.52:539.26
DOI: 10.24887/0028-2448-2020-9-93-95
Key words: nuclear magnetic resonance (NMR), clay content, relaxation times, residual water saturation, effective porosity coefficient
Authors: A.V. Churkov (Rosneft-NTC LLC, RF, Krasnodar), A.A. Rogozin (Rosneft-NTC LLC, RF, Krasnodar), V.M. Yatsenko (Rosneft Oil Company, RF, Moscow), T.S. Ignatieva (Rosneft-NTC LLC, RF, Krasnodar

Nowadays, complicated due to the increased content of clay matter structure reservoirs have been involved in the development and operation by Rosneft Oil Company. Sometimes widely used in laboratory practice (capillarimetry, routine petrophysical studies) core analysis methods treatment faces a number of significant difficulties and limitations including in extreme cases the complete impossibility of their using in the case of weakly consolidated, highly clay and oil source rocks. It is obvious that the complex terrigenous reservoirs core samples researching process faces certain difficulties, such as partial or complete destruction of samples under repeated exposure, violation of the integrity of the pore space, etc. Integration of research methods in this case is problematic. At the same time, even under such non-trivial conditions, the existing and currently developing method of laboratory NMR-relaxometry is quite capable to solving the problems of determining both the standard set of filtration – reservoir properties and specific ones-determining capillary-bound, structural (bound in clays) and free fluid, phase composition of the saturating fluid and the parameters associated with the above.

The employees of Rosneft together with employees of the laboratory complex Rosneft-NTC LLC (a subsidiary of Rosneft Oil Company) considered the possibility of using the NMR-relaxometry method for the rapid assessment of clay content of terrigenous rocks. Based on the results obtained, it can be concluded that a single experiment is applicable by the method of NMR-relaxometry where along with the determination of the above petrophysical parameters, the clay content of the rocks is estimated without additional involvement of particle size analysis data, which helps to reduce time and effort required to laboratory studies.

References

1. Metodicheskie rekomendatsii po issledovaniyu porod-kollektorov nefti i gaza fizicheskimi i petrograficheskimi metodami (Guidelines for the research of oil and gas reservoir rocks by physical and petrographic methods), Moscow: Publ. of VNIGNI, 1978, 381 p.

2. Coates G.R., Xiao L., Prammer M.G., NMR logging principles and applications, Houston: Hullibarton Energy Services, 1999, 335 p.

3.  Dzhafarov I.S., Syngaevskiy P.E., Khafizov S.F., Primenenie metoda yaderno-magnitnogo rezonansa dlya kharakteristik sostava i raspredeleniya plastovykh flyuidov (Application of nuclear magnetic resonance to determine the composition and distribution of reservoir fluids), Moscow: Khimiya Publ., 2002, 439 p.

4. Omel'yanyuk M.V., Pakhlyan I.A., Rogozin A.A., Justification of the combined technology for enhanced oil recovery in case of Maikop sediments (In Russ.), Neftyanoe khozyaystvo = Oil Industry, 2019, no. 9, pp. 114 - 116.

5. Shumskayte M.Y., Opredelenie petrofizicheskikh parametrov peschano-glinistykh obraztsov kerna i tipizatsiya plastovykh flyuidov metodom YaMR-relaksometrii (Determination of petrophysical parameters of sandy-clayey core samples and typification of formation fluids by NMR-relaxometry): thesis of candidate of technical science, Novosibirsk, 2017.

6. Kharisov R.F., NMR relaxometry as a method for studying fluid filtration in a pore medium based on the results of assessing the type and volume of clay minerals (In Russ.), Vestnik nedropol'zovatelya Khanty-Mansiyskogo AO, 2014, V. 26, URL: http://www.oilnews.ru/26-26/yamr-relaksometriya-kak-metod-izucheniya-filtracii-flyuida-v-porovoj-sre...

7. Tugarova M.A., Porody-kollektory: Svoystva, petrograficheskie priznaki, klassifikatsii (Reservoir rocks: Properties, petrographic features, classifications), St. Petersburg: Publ. of  SPbSU, 2004, 36 p.

Nowadays, complicated due to the increased content of clay matter structure reservoirs have been involved in the development and operation by Rosneft Oil Company. Sometimes widely used in laboratory practice (capillarimetry, routine petrophysical studies) core analysis methods treatment faces a number of significant difficulties and limitations including in extreme cases the complete impossibility of their using in the case of weakly consolidated, highly clay and oil source rocks. It is obvious that the complex terrigenous reservoirs core samples researching process faces certain difficulties, such as partial or complete destruction of samples under repeated exposure, violation of the integrity of the pore space, etc. Integration of research methods in this case is problematic. At the same time, even under such non-trivial conditions, the existing and currently developing method of laboratory NMR-relaxometry is quite capable to solving the problems of determining both the standard set of filtration – reservoir properties and specific ones-determining capillary-bound, structural (bound in clays) and free fluid, phase composition of the saturating fluid and the parameters associated with the above.

The employees of Rosneft together with employees of the laboratory complex Rosneft-NTC LLC (a subsidiary of Rosneft Oil Company) considered the possibility of using the NMR-relaxometry method for the rapid assessment of clay content of terrigenous rocks. Based on the results obtained, it can be concluded that a single experiment is applicable by the method of NMR-relaxometry where along with the determination of the above petrophysical parameters, the clay content of the rocks is estimated without additional involvement of particle size analysis data, which helps to reduce time and effort required to laboratory studies.

References

1. Metodicheskie rekomendatsii po issledovaniyu porod-kollektorov nefti i gaza fizicheskimi i petrograficheskimi metodami (Guidelines for the research of oil and gas reservoir rocks by physical and petrographic methods), Moscow: Publ. of VNIGNI, 1978, 381 p.

2. Coates G.R., Xiao L., Prammer M.G., NMR logging principles and applications, Houston: Hullibarton Energy Services, 1999, 335 p.

3.  Dzhafarov I.S., Syngaevskiy P.E., Khafizov S.F., Primenenie metoda yaderno-magnitnogo rezonansa dlya kharakteristik sostava i raspredeleniya plastovykh flyuidov (Application of nuclear magnetic resonance to determine the composition and distribution of reservoir fluids), Moscow: Khimiya Publ., 2002, 439 p.

4. Omel'yanyuk M.V., Pakhlyan I.A., Rogozin A.A., Justification of the combined technology for enhanced oil recovery in case of Maikop sediments (In Russ.), Neftyanoe khozyaystvo = Oil Industry, 2019, no. 9, pp. 114 - 116.

5. Shumskayte M.Y., Opredelenie petrofizicheskikh parametrov peschano-glinistykh obraztsov kerna i tipizatsiya plastovykh flyuidov metodom YaMR-relaksometrii (Determination of petrophysical parameters of sandy-clayey core samples and typification of formation fluids by NMR-relaxometry): thesis of candidate of technical science, Novosibirsk, 2017.

6. Kharisov R.F., NMR relaxometry as a method for studying fluid filtration in a pore medium based on the results of assessing the type and volume of clay minerals (In Russ.), Vestnik nedropol'zovatelya Khanty-Mansiyskogo AO, 2014, V. 26, URL: http://www.oilnews.ru/26-26/yamr-relaksometriya-kak-metod-izucheniya-filtracii-flyuida-v-porovoj-sre...

7. Tugarova M.A., Porody-kollektory: Svoystva, petrograficheskie priznaki, klassifikatsii (Reservoir rocks: Properties, petrographic features, classifications), St. Petersburg: Publ. of  SPbSU, 2004, 36 p.



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