Evaluation Of Deep Profile Control And Displacement Of DCA Microspheres In Low Permeability Reservoirs

Low-permeability reservoirs have the characteristics of strong heterogeneity,development of fractures,and dense matrix.There is a contradiction between injection and plugging strength in low-permeability reservoirs.In view of the urgent need for deep profile control technology in low permeability and non-homogeneous(fracture)reservoirs and the existing problems of deep profile control,a DCA microsphere has been developed for evaluation of profile adaptation in low permeability reservoirs.In this paper,DCA polymer microspheres are used as deep reservoir profile control agents to evaluate their basic properties.The experimental results show that DCA microspheres have controlled particle size and good dispersibility in formation water.The injectivity and sealing property of DCA microspheres in low-permeability reservoirs were evaluated by multi-pressure point core experiments.The results show that the incorporation of DCA microspheres on the ground is difficult.Based on this,it proposes the idea of DCA microsphere underground polymerization.The analysis of the experimental results shows that the microspheres have been successfully injected into the deep part of the core model to block,and the overall residual resistance coefficient that characterizes the profile control ability is distributed smoothly,and the overall blocking rate can reach over 70%.Three types of core models,namely the planar well model,the heterogeneous model and the fracture model,were used to evaluate the adaptability of the DCA microspheres to deep profile control in low permeability reservoirs.The experimental results show that the use of BA-DCA microsphere-BA profile control slug combination to increase the recovery rate than the single injection of DCA microspheres increased by 10% more.In the three models,composite slugs were used for deep profile control,which improved the recovery ratio by 9.43%-16.64% after water flooding.On this basis,the proposal of deep regulation-water plugging was put forward,and the enhanced oil recovery rate after plugging and plugging was combined to increase the recovery rate by 4.83%-6.02%.Based on the above results,this paper proposes a deep-adjusting method for low-permeability reservoir model using BA-DCA microsphere-BA as a composite slug,and gives a technical idea of the combination of deep-adjustment and water-blocking combined with enhanced recovery.