Testing of preformed particles polymer gel technology on core filtration models to limit water inflows

Abstract

In order to reduce watering of wells and equalize their injectivity profiles, the prospects of introducing PPG technology in Russian fields are considered, in which preformed particles polymer gel are pumped into the injection well. These particles, being a supersorbent based on polyacrylamide, absorb water, become elastic, which allows them to shrink and tear in narrow filtration channels. When the polymer is filtered along permeable layers saturated with water, polymer particles accumulate in waterlogged intervals and thus they form a polymer plug, which redistributes the filtration flows and increases the coverage of the formation by the process of oil displacement.More than 4000 downhole operations have been carried out in the fields of China and the USA using PPG technology by now. In domestic fields in Western Siberia, there is limited experience in applying a similar technology in high-temperature formations with low mineralization of formation water. Due to the absence of hydrolytic processes in polyacrylamide, well-known domestic compositions are not applicable due to the low absorption capacity in the conditions of low-temperature deposits with increased mineralization of formation water.The authors synthesized a polymer based on polyacrylamide by block polymerization, which allows to obtain a high absorption capacity, including for low-temperature formations with high mineralization of formation water, which is typical for Perm Territory fields.Filtration experiments were carried out on core models with the composition developed by the authors, this composition focused on low formation temperatures and high mineralization of formation water. As a result of the experiments, it was found that the swollen particles of the gel are able to pass into fractures with a diameter less than their own size at least 20 times. With a significant increase in the viscosity of the dispersion medium, the stability of the suspension increases. Particles of polymer gel have the necessary strength for injection in the field conditions. The fracture permeability during polymer injection decreases by several times and becomes comparable with the permeability of pore collectors.