Geomechanical properties of the terrigenous reservoirs in the oil fields of Western Ural

UDK: 551.31
DOI: 10.24887/0028-2448-2017-4-32-35
Key words: elastic modulus, Poisson ratio, Biot coefficient, hydraulic fractures, static and dynamic parameters
Authors: Yu.A. Kashnikov, D.V. Shustov, A.E. Kukhtinskii (Perm National Research Polytechnic University, RF, Perm), S.A. Kondratiev (PermNIPIneft Branch of LUKOIL-Engineering LLC in Perm, RF, Perm)
The program and results of the study of geomechanical properties of the terrigenous reservoirs in the oil fields of West Ural is presented. The study was performed using PIK-UIDK/PL triaxial apparatus (made in Russia) which is used to determine static and dynamic geomechanical parameters and reservoir properties (permeability) in reservoir conditions. More than 150 samples were tested in this study. Correlations between static and dynamic properties were established based on the results of conducted tests. In particular, the dependences of static elastic modulus, uniaxial compressive strength and Biot coefficient on the compressional wave velocity were found. It is noted that there is no correlation between static and dynamic Poisson ratio according to the results of this study and many other Russian and foreign studies. However, the correlation between the static Poisson ratio and the data fr om gamma ray logs was found which shows that Poisson ratio is connected with rock shaliness. The parameters of the Hoek-Brown strength criterion were determined. The correlation between these parameters and the compressional wave velocity was found. The results of Biot and Skempton coefficients determination are presented. The conclusions about the features of the geomechanical parameters are made. The established dependencies were compared with the log data in the interval wh ere hydraulic fracturing was performed. It is noted that the Biot coefficient values calculated using well log data are on average 0.05 higher than the values determined in laboratory conditions. This is due to not only the difference in acoustic signal frequencies between well logging equipment and PIK-UIDK/PL system but also due to the discrepancy of laboratory experiment conditions and conditions the conditions in the well.

References

1. Economides M., Oligney R., Valko P., Unified fracture design. Bridging the gap between theory and practice, Orsa Press, Alvin, Texas, 2002, 262 p.

2. Timonov A.V., Sudeev I.V., Pestrikov A.V. et al., A new methodology of simulation of hydraulic fracturing at the development of Priobskoye field (In Russ.), Neftyanoe khozyaystvo = Oil Industry, 2012, no. 3, pp. 58–61.

3. Kashnikov Yu.A., Ashikhmin S.G., Kukhtinskiy A.E. et al., Determination of fracture toughness of oil fields rocks (In Russ.), Neftyanoe khozyaystvo = Oil Industry, 2015, no. 10, pp. 86–89.

4. Zoback M., Reservoir geomechanics, Cambridge: Cambridge University Press, 2007.

5. Fjaer E., Static and dynamic moduli of weak sandstones, Proceedings of the 37th U.S. Symposium on Rock Mechanics (USRMS), June 7–9, 1999.

6. Fjaer E., Holt R.M., Harsrud P. et al., Petroleum related rock mechanics Hugaru: Elsevier, 2008, 515 p.

7. Hoek E., Martin C.D., Fracture initiation and propagation in intact rock – A review, Journal of Rock Mechanics and Geotechnical Engineering, 2014, V. 6, pp. 287–300.

8. Dobrynin V.M., Deformatsii i izmeneniya fizicheskikh svoystv kollektorov nefti i gaza (Deformations and changes in the physical properties of oil and gas collectors), Moscow: Nedra Publ., 1970, 239 p.

The program and results of the study of geomechanical properties of the terrigenous reservoirs in the oil fields of West Ural is presented. The study was performed using PIK-UIDK/PL triaxial apparatus (made in Russia) which is used to determine static and dynamic geomechanical parameters and reservoir properties (permeability) in reservoir conditions. More than 150 samples were tested in this study. Correlations between static and dynamic properties were established based on the results of conducted tests. In particular, the dependences of static elastic modulus, uniaxial compressive strength and Biot coefficient on the compressional wave velocity were found. It is noted that there is no correlation between static and dynamic Poisson ratio according to the results of this study and many other Russian and foreign studies. However, the correlation between the static Poisson ratio and the data fr om gamma ray logs was found which shows that Poisson ratio is connected with rock shaliness. The parameters of the Hoek-Brown strength criterion were determined. The correlation between these parameters and the compressional wave velocity was found. The results of Biot and Skempton coefficients determination are presented. The conclusions about the features of the geomechanical parameters are made. The established dependencies were compared with the log data in the interval wh ere hydraulic fracturing was performed. It is noted that the Biot coefficient values calculated using well log data are on average 0.05 higher than the values determined in laboratory conditions. This is due to not only the difference in acoustic signal frequencies between well logging equipment and PIK-UIDK/PL system but also due to the discrepancy of laboratory experiment conditions and conditions the conditions in the well.

References

1. Economides M., Oligney R., Valko P., Unified fracture design. Bridging the gap between theory and practice, Orsa Press, Alvin, Texas, 2002, 262 p.

2. Timonov A.V., Sudeev I.V., Pestrikov A.V. et al., A new methodology of simulation of hydraulic fracturing at the development of Priobskoye field (In Russ.), Neftyanoe khozyaystvo = Oil Industry, 2012, no. 3, pp. 58–61.

3. Kashnikov Yu.A., Ashikhmin S.G., Kukhtinskiy A.E. et al., Determination of fracture toughness of oil fields rocks (In Russ.), Neftyanoe khozyaystvo = Oil Industry, 2015, no. 10, pp. 86–89.

4. Zoback M., Reservoir geomechanics, Cambridge: Cambridge University Press, 2007.

5. Fjaer E., Static and dynamic moduli of weak sandstones, Proceedings of the 37th U.S. Symposium on Rock Mechanics (USRMS), June 7–9, 1999.

6. Fjaer E., Holt R.M., Harsrud P. et al., Petroleum related rock mechanics Hugaru: Elsevier, 2008, 515 p.

7. Hoek E., Martin C.D., Fracture initiation and propagation in intact rock – A review, Journal of Rock Mechanics and Geotechnical Engineering, 2014, V. 6, pp. 287–300.

8. Dobrynin V.M., Deformatsii i izmeneniya fizicheskikh svoystv kollektorov nefti i gaza (Deformations and changes in the physical properties of oil and gas collectors), Moscow: Nedra Publ., 1970, 239 p.



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