Research and Application on Enhancing Water Drive Effect by Volume Fracturing of Injection Well in Ultra-low Permeability Reservoir

The ultra-low permeability reservoir is affected by poor reservoir physical properties, strong heterogeneity, injected water channeling along fractures and poor acidification effective, so it is difficult to establish an effective displacement system for conventional water injection. C1 reservoir of D area is taken as the research target, and the enhancing water drive effect is analyzed by analyzing of the volumetric fracturing mechanism of injection well as well as microseismic monitoring and water absorption profile testing. The experimental results of 8 Wells show that the original dominant flow direction is changed, the fracture width is increased, the corresponding relationship between oil and water Wells is improved, and the water flooding reserves is improved. The average annual accumulatively incremental oil production in a single well group was 297 tons by the method of hyperbolic decline, and the annual input-output ratio could reach 1:1.01. The corresponding monthly decline rate and monthly increasing index of water cut of the well group were significantly improved. The edge well is taken effectively at an average period of 55 days and the corner well is 29 days, which shows the interval period of corner well was short. The volume fracturing technology of water injection well provides guidance and reference for the development and adjustment of well group in high water in the same ultra-low permeability reservoir, which is of great significance for popularization.