Synthesis and Study on a Type of New Salt-Resistant and Slow-Expansion Gel Particles for Deep Water Control

Abstract

Abstract Enhancing the development of low permeability reservoirs is an important investigation direction for increasing crude oil production in China. Currently, prolonged water or polymer flooding in oil fields exacerbates reservoir heterogeneity. Leading to premature water breakthrough and high water cut significantly hindering efficient oil field development. It is difficult for oilfield production to control the preferential water pathways within the low permeability reservoir and expand the utilization degree of the deep remaining oil. The reservoir control agent represented by polymer gel particles can effectively control the preferential water pathways, expand the sweep range of injected water, and achieve oil field production and efficiency. However, inherent drawbacks of polymer gel particles, such as poor performance of salt resistance and water absorption, high initial hydration expansion rates and low post-expansion rates, present a challenge for in-depth migration and water control. To solve the above problems, in this paper, we prepared a gel particle with excellent salt resistance and water absorption performance, which can delay swelling as well. In order to enhance the salt resistance and water absorption of the gel particles, a zwitterionic monomer methacrylamide propyl-N, N-dimethylpropane sulfonate (with anti-polyelectrolyte effect) with salt resistance performance was synthesized. The method of the composite crosslinking was used to delay the expansion of the gel particles. The salt-resistant and slow-expansion gel particles with low primary expansion ratio and higher secondary expansion performance were prepared and optimized. The results showed that the preparation of the particles was successful and the mechanism of delaying expansion was revealed. The deep migration and deep plugging performance of the gel particles were further studied through a multi-point pressure measurement experiment of sand pipe. This paper solves the problems of poor salt resistance, water absorption ability and fast expansion speed of polymer gel particles. The results shown here provide theoretical guidance and technical support for in-depth water control of low permeability reservoirs.