Evaluation And Optimization Of Water-releasing And Locking Agents In Tight Sandstone Gas Reservoirs

In the development process of tight sandstone gas reservoirs,the phenomenon of water lock is a common phenomenon,which leads to the reduction of production and cannot be efficiently developed for such gas reservoirs.Therefore,it is of great significance to find an efficient water-locking agent to relieve water-locking damage and increase the production of such gas reservoirs.This paper firstly analyzes the causes of water lock and deepens the mechanism of water lock by studying the geological characteristics of reservoir pores,water content and wettability in the study area.Then,the existing water retarding agent evaluation method was optimized,and the problems of salting out,serious water sensitivity problem,inaccurate establishment of irreducible water saturation by centrifugal method,and unintuitive determination of water saturation by weighing were improved.The evaluation method of water-releasing agent was optimized.Through the optimized evaluation method of water-releasing agent,the interfacial properties of several water-releasing agents were evaluated,and then the water-releasing performance of these water-releasing agents was evaluated,and the effect of these water-releasing agents was evaluated.In order to further optimize the water-releasing agent,the formulation of the water-releasing agent was optimized through the optimization experiment of the water-releasing agent.After selecting a good formula,the concentration of the water-releasing agent was optimized to determine the formula the optimum concentration.The experimental results show that the water-locking agent of this formula has better water-locking performance than a single water-releasing agent,which is of great significance to the improvement of the production of tight sandstone gas reservoirs.