Optimization Research On Horizontal Well Volume Fracturing For Chepai Che210 Oil Reservoir

For tight oil reservoirs with low permeability and a large number of natural fractures,natural fractures are usually closed before hydrofracturing.It is difficult for fluids to flow directly from the fractures to the bottom of the wells.Horizontal well volume hydrofracturing is an effective method for reservoir reformation forming stimulated reservoir volume(SRV)fracturing area.It can allow artificial fractures to connect natural fractures and secondary fractures.Finally it will increase the contact area between fractures and reservoirs,and greatly increase recovery.The research reservoir which called ChePai is a typical low-porosity and low-permeability tight reservoir.Horizontal well volume hydrofracturing is used to increase production on this area.Firstly,the paper evaluates the geological characteristics of the well area and analyzes the feasibility of volume fracturing through rock brittleness,ground stress characteristics and natural fractures.Then basing on dual porosity and trilinear flow model,use eclipse software to establish dual-permeability model and divide it into SRV area and non-SRV area.For SRV area,a grid-local encryption method is used to define the complex fracture network.Thirdly,design standard orthogonal experiment which contains 16 models and simulate oil production.Through intuitive analysis and analysis of variance method analyze the sensitivity of fracturing series,fracture length,single-stage SRV zone width,single-stage cluster number,and diversion network conductivity.Through the factor analysis select the optimal value for the above parameters.Finally,compare the optimized fracturing model with the production formula,and optimize the fracturing process parameters to meet the requirements of the SRV area.The optimized fracturing program has great application in the ChePai reservoir.The research results can be used as a reference for volume fracturing optimization in similar oil reservoirs.