Investigation and Application of Reversible Temporary Plugging Steering Agent for Acidification

Abstract

Abstract In order to solve the problems of insolubility of conventional plant gum type solid steering agents and the need to return after stratified acidification to unblock the formation, two chemically reversible temporary plugging agents were developed in this paper. The variation of viscosity of liquid steering agent and the dissolution of particles of solid-liquid combination steering agent were evaluated indoors. The liquid steering agent single-pipe core blocking experiment and double-pipe core splitting rate experiment were carried out, and the indoor over-hole plate pressure measurement experiments of different types of steering agents were conducted. And the two steering agents were applied in the field. The results show that the viscosity of liquid steering agent can change with the pH value, showing the characteristics of becoming viscous in acid and decomposing in water, which can increase the injection pressure by 1.95MPa after plugging the core in the indoor experiment, and can increase the construction pressure by 1.4MPa in the field application. What’s more, the pressure of solid-liquid combination steering agent indoor over pore plate is 3 times of liquid temporary plugging agent, and the construction pressure can be increased by 3.0 MPa. Both of the above temporary plugging agents can be dissolved by themselves in the process of water injection after the measure, and the plugging of the reservoir can be released without returning to the drainage. Meanwhile, it can also meet the needs of different pressure difference layer section for diversion acidification.