The paper presents the results of evaluation of the cement sheath safety in the interval of shaped charge perforation of reservoirs on the territory of the Perm Region. Various intervals of perforation are considered, pressure measurements at different distances from the perforation charges during cumulative perforation are performed, which made it possible to assess the cement stone safety behind the casing after the perforation job. To perform the calculations, the basic physicomechanical properties of the cement stone, which obtained using the most common recipes of cement slurries, were determined. With a minimum value of the compressive strength of selected recipes of cement slurries to prepare the cement stone samples (12.3 MPa), a significant zone of destroyed cement stone appears at the Shagirtsko-Gozhanskoye deposit, and at the Tanypskoye and Krasnoyarsko-Kuedinskoye deposits, the cement stone is completely destroyed during the shaped charge perforation. The results of estimation calculations showed that the massively applied technologies and methods of reservoir perforation do not ensure the safety of the wells casing, reduce its tightness, which leads to the occurrence of behind-the-casing flows and watering of the well production. In this regard, it is necessary, when designing and planning perforation works, to develop recommendations for the use of special perforation systems that allow to reduce the explosiveness, to reduce the density and the number of perforating charges, especially when forming the first holes in the well and where perforating operations have already been carried out earlier. Also, determine the change in the state of the cement stone behind the casing using scanning acoustic devices before and after the perforation of reservoirs.
1. Melekhin A.A., Krysin N.I., Tret'yakov E.O., Analysis of factors affecting the life time period of cement stone behind a casing string (In Russ.), Neftepromyslovoe delo, 2013, no. 9, pp. 77–82.
2. Chernyshov S.E., Kunitskikh A.A., Votinov M.V., Research of hydration dynamics and development of expanding additives to oil-well cement (In Russ.), Neftyanoe khozyaystvo = Oil Industry, 2015, no. 8, pp. 42–44.
3. Chernyshov S.E., Galkin S.V., Krisin N.I. et al., Efficiency improvement of abrasive jet perforation, SPE 177375-MS, 2015.
4. 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.
5. Bonett A., Pafitis D., Getting to the root of gas migration, URL: https://studylib.net/doc/8104375/getting-to-the-root-of-gas-migration
6. Savich A.D., El'kind S.Ya., Secondary opening of productive layers. Technics and techology (In Russ.), Karotazhnik, 2003, V. 106, pp. 120–134.
7. Samsykin A.V., Razrabotka kompozitsionnykh tamponazhnykh sostavov povyshennoy soprotivlyaemosti dinamicheskim vozdeystviyam dlya sokhraneniya germetichnosti krepi skvazhin (Development of composite grouting compositions with increased resistance to dynamic impacts to preserve the tightness of the lining of wells): thesis of candidate of technical science, Ufa, 2010.
8. Rastegar R. et al., Mitigating formation damage by using completion with built-in-casing perforations instead of perforation with explosive charges, SPE-174251-MS 2015.
9. Rahman M.A. et al., Quantifying the skin factor for estimating the completion efficiency of perforation tunnels in petroleum wells, Journal of Petroleum Science and Engineering, 2007, V. 58, pp. 99–110.
10. Grigoryan N.G., Vskrytie neftegazovykh plastov strelyayushchimi perforatorami (Opening of oil and gas reservoirs by perforating gun), Moscow: Nedra Publ., 1982, 263 p.
11. Kashnikov Yu.A., Ashikhmin S.G., Mekhanika gornykh porod pri razrabotke mestorozhdeniy uglevodorodnogo syr'ya (Rock mechanics in the development of hydrocarbon deposits), Moscow: Gornaya kniga Publ., 2019, 496 p.
12. Charlez F.Р., Rock mechanics. V2. Petroleum applications, Editions Technip, 1997, 661 p.
13. Fjaer E. et al., Petroleum related rock mechanics, Elseveir, 2008, 515 p.