Laboratory studies of polymer compositions for well-kill under increased fracturing

Abstract

Workovers in conditions of increased fracturing is often accompanied by complications even at the stage of well killing operations. During the well killing process, significant gas breakthroughs and fluid loss are observed at this field, which requires significant usage of blocking compositions and increases the well service costs. It is necessary to conduct laboratory studies in order to develop a blocking composition for reliable isolation of highly permeable intervals of formations, which does not adversely affect the reservoir properties of the reservoir and satisfy the safety requirements for work. In this work, the physical, chemical and rheological properties of the carcass and gel forming compositions are studied, which are crosslinked systems prepared on the basis of soluble silicates. Well killing technology involves their sequential injection into the well. The compositions under consideration showed the manufacturability of their use in a wide range of reservoir temperatures, which consists in the possibility of their injection into a typical well and selling into the bottomhole formation zone due to the low viscosity and slowed down crosslinking speed. The use of a destructor allows almost completely eliminating the negative impact of this technology on the filtration characteristics of the bottomhole formation zone after well killing process. The studies carried out in this work showed the effectiveness of the use of blocking polymer compositions, and also opened up new areas for further research, namely, the need for a cycle of laboratory and field tests of the compositions considered, which will allow us to choose and justify the optimal technological and economic parameters of the operation. The results can be applied to increase the well killing efficiency of oil and gas wells in conditions of increased fracturing during well service operations.