Research on transformation of water-flooding mode in low permeability reservoirs

 

WU Zhongbao1, LI Li1, ZHANG Jialiang2, YAN Yiqun1, WANG Junwen1, ZHANG Yuan1

1. PetroChina Research Institute of Petroleum Exploration & Development, Beijing 100083, China;

2. Explortion and Production Research Institute, CNPC Dangang Oilfield Company, Tianjin 300270, China

Abstract: When the low permeability reservoirs are developed with conventional water-flooding technology, producers will have low efficiency, low oil and liquid production, and poor economic effects. Conventional water-flooding development technology cannot meet the requirements of economic and effective development of low permeability reservoirs. Although the development mode of depletion recovery after SRV of tight oil can improve the initial productivity of single well, due to the characteristics of small sand body, low formation pressure coefficient, high viscosity of crude oil and low gas oil ratio, there are still defects of rapid production decline, low cumulative oil production and low recovery factor. There is an urgent need to adjust development ideas and change water-flooding development mode. Therefore, this paper innovatively puts forward three development ideas for low permeability reservoirs, namely the transformation from radial displacement to linear displacement, transformation from continuous water injection to imbibition oil recovery such as asynchronous injection and production, water injection huff & puff, producer-injector exchange, and transformation from increasing producing reserves by shortening producer-njector spacing to increasing fracture-controlled reserves by SRV. A brand-new development model of “SRV + effective displacement + imbibition oil recovery” is established and applied to GD6 X1 Block in the Dagang Oilfield, receiving remarkable preliminary implementation effects.