A newly derived nonlinear flow numerical simulator was used to study on the diamond-shape inverted nine-spot well pattern based on laboratory experiment and actual field data. The optimum artificial fracture penetration ratio, flow conductivity, and condition of converting the corner-wells to injection wells were presented on the basis of 37 concept model well plans. Finally, the formation pressure gradient distributions of different well plans were provided and analyzed.

The permeability variation characteristic of non-Darcy flow was measured by laboratory physical simulation experiment, and a newly developed non-Darcy flow numerical simulator was used to perform an integrated study on XPJ low permeability reservoir. The primary goal is to perform a non-Darcy flow numerical study on actual low permeability reservoir. Six well plans were designed based on the properly history matched geological model. The optimal opportunity for well adjustment was identified. Finally, a comprehensive comparison and analysis of the reservoir oil saturation, pressure gradient and dimensionless permeability distribution were provided. The result shows that the effective permeability of low permeability reservoir varies with the driving pressure gradient; adjusting the well pattern at the field composite water-cut of 60% is the optimal recommended well adjustment plan in XPJ reservoir; the nonlinear flow region is larger than that of quasi-linear flow and the capture of fluid flow characteristic in low velocity and low pressure gradient condition is essential to evaluate the low permeability reservoir performance.

A nonlinear flow reservoir mathematical model was established based on the flow characteristic of low-permeability reservoir.The well-grid equations were deduced and the dimensionless permeability coefficient was introduced to describe the permeability variation of nonlinear flow.The nonlinear flow numerical simulation program was compiled based on black-oil model.A quarter of five-spot well unit was simulated to study the effect of nonlinear flow on the exploitation of low-permeability reservoir.The comprehensive comparison and analysis of the simulation results of Darcy flow,quasi-linear flow and nonlinear flow were provided.The dimensionless permeability coefficient distribution was gained to describe the nonlinear flow degree.The result shows that compared with the results of Darcy flow,when considering nonlinear flow,the oil production is low,and production decline is rapid.The fluid flow in reservoir consumes more driving energy,which reduces the water flooding efficiency.Darcy flow model overstates the reservoir flow capability,and quasi-linear flow model overstates the reservoir flow resistance.The flow ability of the formation near the well and artificial fracture is strong while the flow ability of the formation far away from the main streamline is weak.The nonlinear flow area is much larger than that of quasi-linear flow during the fluid flow in low-permeability reservoir.The water propelling speed of nonlinear flow is greatly slower than that of Darcy flow in the vertical direction of artificial fracture,and the nonlinear flow should be taken into account in the well pattern arrangement of low-permeability reservoir.

A newly derived FV (fluidity variation) flow mathematical model was established to describe the fluid flow in low-permeability reservoir based on laboratory flow experiments. The numerical stimulation program was compiled and used to simulate an inverted nine-spot well pattern. A comprehensive comparison and analysis of Darcy flow and FV flow were provided, which has verified the development characteristics of low-permeability reservoir. The FV flow numerical simulation technique could anticipate the dynamic fluid flow characteristics in - low permeability reservoir more exactly.