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.
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