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Algorithm design for locating fracture initiation during multistage refrac in horizontal wells by using iFrac technology

UDK: 622.276.66
DOI: 10.24887/0028-2448-2020-4-49-53
Key words: re-fracking, iFrac, flow diverting, fracture initiation in series, horizontal well
Authors: M.A. Kuznetsov (Slavneft-Megionneftegas PJSC, RF, Megion), I.I. Letko (Slavneft-Megionneftegas PJSC, RF, Megion), K.R. Ibragimov (Slavneft-Megionneftegas PJSC, RF, Megion), A.F. Mingazov (Slavneft-Megionneftegas PJSC, RF, Megion), M.S. Antonov (RN-BashNIPIneft LLC, RF, Ufa; Ufa State Petroleum Technological University, RF, Ufa), O.V. Evseev (RN-BashNIPIneft LLC, RF, Ufa), A.N. Voronina (RN-BashNIPIneft LLC, RF, Ufa), K.R. Kadyrova (RN-BashNIPIneft LLC, RF, Ufa)

The article describes the comparative characteristics of different repeated hydraulic fracturing technologies in horizontal wells such as one-stage conventional re-fracturing, SpotFrac technology, fracking with diverting agents, and iFrac. We present the results of efficiency analysis of re-fracturing technologies tests in horizontal wells performed by specialists of Slavneft-Megionneftegas in 2015–2018. The successful execution of multistage refracking in horizontal well is justified using estimation of additional in-situ stresses caused by injection of propping agent. First stage fracture creating and propping results in closure pressure increasing in the fracture initiating area. This effect depends proportionally on the fracture geometry and can allow initiating the subsequent fractures in other ports in a horizontal well. Also, an algorithm is proposed to determine the sequential stimulation intervals in horizontal well on each stage of re-fracking and to estimate the number of re-stimulated fracturing ports. This algorithm includes such stages as stress field calculation along the horizontal wellbore and fracture design. All calculations are performed using corporate software RN-GeoSim, RN-GRID, RN-KIN. The algorithm of fracture initiating intervals determination is tested on the well No. 1 of the oilfield in Western Siberia. We show that the same fracturing port was stimulated two times during three fracturing stages. Verification of calculations is made using mini-frac data and the accuracy of calculations is about 1 %.

References

1. http://www.petrogastech.ru/ru/services/neftegazovyy-servis/zakanchivanie-skvazhin/

2. Afanas'ev I.S., Baykov V.A., Kolonskikh A.V. et al., Development of ultra low-permeability oil reservoirs (In Russ.), Neftyanoe khozyaystvo = Oil Industry, 2014, no. 5, pp. 82–86.

3. Fedorov A.I., Davletova A.R., Pisarev D.Yu., Determination of closure pressure for hydraulic fractures using instruments of geomechanical modeling (In Russ.), Neftyanoe khozyaystvo = Oil Industry, 2014, no. 11, pp. 50–53.

4. Khalturin E.A., Improving the technology of multistage fracturing and re-fracturing in lateral wells (In Russ.), Neftyanoe khozyaystvo = Oil Industry, 2017, no. 9, pp. 44–46.

5. Fedorov A.I., Davletova A.R., Kolonskikh A.V., Toropov K.V., Justification of the necessity to consider the effects of changes in the formation stress state in the low permeability reservoirs development (In Russ.), Nauchno-tekhnicheskiy vestnik OAO “NK “Rosneft'”, 2013, no. 2(31), pp. 25–29. 

6. USSR Patent no. 1782294, MKI F04 D 13/12, Vkhodnoe ustroystvo skvazhinnogo nasosa (Well pump input device), Inventors: Chudin V.I., Popov V.I.

7. Salimov V.G., Nasybullin A.V., Salimov O.V., Prikladnye zadachi tekhnologii gidravlicheskogo razryva plastov (Applied problems of hydraulic fracturing technology), Kazan': FEN Publ., 2018, 380 p.

8. RN-BashNIPIneft: high-tech software, development course (In Russ.), Neftyanoe khozyaystvo = Oil Industry, 2019, no. 12, pp. 84–85.

The article describes the comparative characteristics of different repeated hydraulic fracturing technologies in horizontal wells such as one-stage conventional re-fracturing, SpotFrac technology, fracking with diverting agents, and iFrac. We present the results of efficiency analysis of re-fracturing technologies tests in horizontal wells performed by specialists of Slavneft-Megionneftegas in 2015–2018. The successful execution of multistage refracking in horizontal well is justified using estimation of additional in-situ stresses caused by injection of propping agent. First stage fracture creating and propping results in closure pressure increasing in the fracture initiating area. This effect depends proportionally on the fracture geometry and can allow initiating the subsequent fractures in other ports in a horizontal well. Also, an algorithm is proposed to determine the sequential stimulation intervals in horizontal well on each stage of re-fracking and to estimate the number of re-stimulated fracturing ports. This algorithm includes such stages as stress field calculation along the horizontal wellbore and fracture design. All calculations are performed using corporate software RN-GeoSim, RN-GRID, RN-KIN. The algorithm of fracture initiating intervals determination is tested on the well No. 1 of the oilfield in Western Siberia. We show that the same fracturing port was stimulated two times during three fracturing stages. Verification of calculations is made using mini-frac data and the accuracy of calculations is about 1 %.

References

1. http://www.petrogastech.ru/ru/services/neftegazovyy-servis/zakanchivanie-skvazhin/

2. Afanas'ev I.S., Baykov V.A., Kolonskikh A.V. et al., Development of ultra low-permeability oil reservoirs (In Russ.), Neftyanoe khozyaystvo = Oil Industry, 2014, no. 5, pp. 82–86.

3. Fedorov A.I., Davletova A.R., Pisarev D.Yu., Determination of closure pressure for hydraulic fractures using instruments of geomechanical modeling (In Russ.), Neftyanoe khozyaystvo = Oil Industry, 2014, no. 11, pp. 50–53.

4. Khalturin E.A., Improving the technology of multistage fracturing and re-fracturing in lateral wells (In Russ.), Neftyanoe khozyaystvo = Oil Industry, 2017, no. 9, pp. 44–46.

5. Fedorov A.I., Davletova A.R., Kolonskikh A.V., Toropov K.V., Justification of the necessity to consider the effects of changes in the formation stress state in the low permeability reservoirs development (In Russ.), Nauchno-tekhnicheskiy vestnik OAO “NK “Rosneft'”, 2013, no. 2(31), pp. 25–29. 

6. USSR Patent no. 1782294, MKI F04 D 13/12, Vkhodnoe ustroystvo skvazhinnogo nasosa (Well pump input device), Inventors: Chudin V.I., Popov V.I.

7. Salimov V.G., Nasybullin A.V., Salimov O.V., Prikladnye zadachi tekhnologii gidravlicheskogo razryva plastov (Applied problems of hydraulic fracturing technology), Kazan': FEN Publ., 2018, 380 p.

8. RN-BashNIPIneft: high-tech software, development course (In Russ.), Neftyanoe khozyaystvo = Oil Industry, 2019, no. 12, pp. 84–85.



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