Логин:
Пароль:
Регистрация
Забыли свой пароль?

A geomechanical analysis of the influence of orientation and placement of jet slots on terrigenous reservoir permeability

UDK: 622.245.422.4
DOI: 10.24887/0028-2448-2018-6-132-135
Key words: hydro-geomechanics of reservoir rocks, stress strain state of rocks, producing oil well, perforation work
Authors: S.G. Ashikhmin (Perm National Research Polytechnic University, RF, Perm), S.E. Chernyshov (Perm National Research Polytechnic University, RF, Perm), Yu.A. Kashnikov (Perm National Research Polytechnic University, RF, Perm), D.I.M. Macdonald (University of Aberdeen, United Kingdom, Aberdeen)

The paper presents the results of a geomechanical analysis of the effects of the placement and orientation of jet slot channels on the wellbore area permeability of terrigenous reservoir in producing oil wells in the Perm region. Various scenarios for the formation of jet slot channels in the reservoir were outlined and assessed; the stress-strain state of the rocks was determined; and the effect of "unloading" on the permeability of rocks and the stability of the slot channels was assessed. The unloading of the rock mass near the jet slots was estimated from changes of average effective pressure. It was established that the best placement scheme for jet slot channels is a system of four slot channels with a phasing of 90°. The height difference between jet slots channels does not appear to be significant, because the slot channels interact with each other very weakly in the vertical direction.

The influence of unloading of the rocks on the permeability of the reservoir at a pressure drawdown of 5 MPa was calculated. Functional dependence of all-round effective pressure on the permeability was based on the results of rock tests of the terrigenous reservoirs of the Shershnevskoye oil field. It is demonstrated that without additional work, reservoir permeability is significantly reduced during well exploration under specified conditions; however, the abrasive jet perforation effectively contributes to preservation of the initial permeability. It was also found that jet slot channels in the productive layers with the correct physicomechanical properties and the depression of 5 MPa are stable, since zones of inelastic deformations are very rare.

Thus, in addition to increasing the filtration area in the well-bore–reservoir system, the abrasive jet perforation ensures the preservation of the reservoir permeability due to unloading of rocks from the operating stresses. The additional positive effect of the proposed technology is the possibility of azimuth orientation of the jet slots channels for different stress scenarios.

References

1. Khristianovich S.A., Kovalenko Yu.F., Kulinich Yu.V., Karev V.I., Increase the productivity of oil wells using the geoloosening (In Russ.), Neft' i gaz Evraziya, 2000, no. 2, pp. 90–94.

2. Klimov D.M., Karev V.I., Kovalenko Yu.F., Rol' napryazheniy v formirovanii ekspluatatsionnykh svoystv skvazhin (The role of stress in the formation of the operational properties of wells), Collected papers “Aktual'nye problemy mekhaniki. Mekhanika deformiruemogo tverdogo tela” (Actual problems of mechanics. Mechanics of a deformable solid), Moscow: Nauka Publ., 2009, pp. 470–476.

3. Charlez F.R., Rock mechanics. Petroleum applications, 1997, V. 2.

4. Fjaer E. et al., Petroleum related rock mechanics, Elseveir, 2008, 515 p.

5. Krysin N.I., Ryabokon' E.P., Turbakov M.S. et al., Improvement of devices of abrasive jet perforation in oil wells (In Russ.), Neftyanoe khozyaystvo = Oil Industry, 2016, no. 8, pp. 129–131.

6. 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.

7. Kashnikov Yu.A., Ashikhmin S.G., Mekhanika gornykh porod pri razrabotke mestorozhdeniy uglevodorodnogo syr'ya (Rock mechanics in the development of hydrocarbon deposits), Moscow: Nedra Publ., 2007, 467 p.

8. Sonich V.P., Cheremisin N.A., Baturin Yu.E., Effect of reducing reservoir pressure in reservoir properties (In Russ.), Neftyanoe khozyaystvo = Oil Industry, 1997, no. 9, pp. 52–57.

9. Bulychev N.S., Mekhanika podzemnykh sooruzheniy (Mechanics of underground structures), Moscow: Nedra Publ., 1982, 270 p.

10. Kashnikov Yu.A., Shustov D.V., Kukhtinskiy A.E., Kondrat'ev S.A., Geomechanical properties of the terrigenous reservoirs in the oil fields of Western Ural (In Russ.), Neftyanoe khozyaystvo = Oil Industry, 2017, no. 4, pp. 32–35.

The paper presents the results of a geomechanical analysis of the effects of the placement and orientation of jet slot channels on the wellbore area permeability of terrigenous reservoir in producing oil wells in the Perm region. Various scenarios for the formation of jet slot channels in the reservoir were outlined and assessed; the stress-strain state of the rocks was determined; and the effect of "unloading" on the permeability of rocks and the stability of the slot channels was assessed. The unloading of the rock mass near the jet slots was estimated from changes of average effective pressure. It was established that the best placement scheme for jet slot channels is a system of four slot channels with a phasing of 90°. The height difference between jet slots channels does not appear to be significant, because the slot channels interact with each other very weakly in the vertical direction.

The influence of unloading of the rocks on the permeability of the reservoir at a pressure drawdown of 5 MPa was calculated. Functional dependence of all-round effective pressure on the permeability was based on the results of rock tests of the terrigenous reservoirs of the Shershnevskoye oil field. It is demonstrated that without additional work, reservoir permeability is significantly reduced during well exploration under specified conditions; however, the abrasive jet perforation effectively contributes to preservation of the initial permeability. It was also found that jet slot channels in the productive layers with the correct physicomechanical properties and the depression of 5 MPa are stable, since zones of inelastic deformations are very rare.

Thus, in addition to increasing the filtration area in the well-bore–reservoir system, the abrasive jet perforation ensures the preservation of the reservoir permeability due to unloading of rocks from the operating stresses. The additional positive effect of the proposed technology is the possibility of azimuth orientation of the jet slots channels for different stress scenarios.

References

1. Khristianovich S.A., Kovalenko Yu.F., Kulinich Yu.V., Karev V.I., Increase the productivity of oil wells using the geoloosening (In Russ.), Neft' i gaz Evraziya, 2000, no. 2, pp. 90–94.

2. Klimov D.M., Karev V.I., Kovalenko Yu.F., Rol' napryazheniy v formirovanii ekspluatatsionnykh svoystv skvazhin (The role of stress in the formation of the operational properties of wells), Collected papers “Aktual'nye problemy mekhaniki. Mekhanika deformiruemogo tverdogo tela” (Actual problems of mechanics. Mechanics of a deformable solid), Moscow: Nauka Publ., 2009, pp. 470–476.

3. Charlez F.R., Rock mechanics. Petroleum applications, 1997, V. 2.

4. Fjaer E. et al., Petroleum related rock mechanics, Elseveir, 2008, 515 p.

5. Krysin N.I., Ryabokon' E.P., Turbakov M.S. et al., Improvement of devices of abrasive jet perforation in oil wells (In Russ.), Neftyanoe khozyaystvo = Oil Industry, 2016, no. 8, pp. 129–131.

6. 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.

7. Kashnikov Yu.A., Ashikhmin S.G., Mekhanika gornykh porod pri razrabotke mestorozhdeniy uglevodorodnogo syr'ya (Rock mechanics in the development of hydrocarbon deposits), Moscow: Nedra Publ., 2007, 467 p.

8. Sonich V.P., Cheremisin N.A., Baturin Yu.E., Effect of reducing reservoir pressure in reservoir properties (In Russ.), Neftyanoe khozyaystvo = Oil Industry, 1997, no. 9, pp. 52–57.

9. Bulychev N.S., Mekhanika podzemnykh sooruzheniy (Mechanics of underground structures), Moscow: Nedra Publ., 1982, 270 p.

10. Kashnikov Yu.A., Shustov D.V., Kukhtinskiy A.E., Kondrat'ev S.A., Geomechanical properties of the terrigenous reservoirs in the oil fields of Western Ural (In Russ.), Neftyanoe khozyaystvo = Oil Industry, 2017, no. 4, pp. 32–35.



Attention!
To buy the complete text of article (a format - PDF) or to read the material which is in open access only the authorized visitors of the website can. .

Mobile applications

Read our magazine on mobile devices

Press Releases

16.07.2019
08.07.2019
04.07.2019
SPE 2019
ТАТАРСТАНСКИЙ НЕФТЕГАЗОХИМИЧЕСКИЙ ФОРУМ