The Study On The Flowing Law And Optimization Of Well Network In Low-permeability Reservoir

With the continuous improvement of exploration technique and the reforming of engineering in petroleum reservoir and China’s energy development strategy,the exploitation of reserve volume in low and extremely low permeable reservoir has become an important potential for the stable development of China’s petroleum industry in the future.The reserve volume in low and extremely low permeable reservoir is abundant,so it will be the main resource base in the increasing reserve volume for a long time in the future.As a result,the exploration of low permeable reservoir can not be ignored and the research on the mechanism of fluid flow through porous medium,development plan and development technique in low permeable reservoir has an important significance.In the paper,the reservoir geologic characteristic of micro-pore structure,the oil-water micro-flooding,the starting pressure gradient and the oil-water relative permeability curves of Shanshan 6#in Xinjiang Oilfield were studied.From a large number of core experiments,the relationships between the threshold pressures and the ratio of gas permeability of rock to the viscosity of fluids are obtained.The parameters modifying the shape of velocity-pressure gradient are also obtained.Then the empirical figure for determining the min-and max-threshold pressures are built,the feature of the threshold pressures and the depicting way of single flowing are also obtained.In addition,the optimization of the well spacing was another important part.The economic limit density of wells is 19.6 wells/km2 and the most economical density is 6.25wells/km2.The technical limited spacing is 441m(corresponding to the well density 19.1 wells/km)under current injection and pressure conditions.But well spacing(520m)in the area currently is greater than the technical limited well spacing.Therefore,the infill is a good way to establish a more effective displacement system.In the case of considering the optimal oil displacement efficiency and the best economic efficiency,the reasonable injection pressure is 21.1MPa from well calculation.