The Research On Numerical Simulation Of Low Permeability Reservoir

The sharp increase of oil and gas resources consumption all over the world lead to the sharp decrease of medium-high permeability reservoirs.Low-permeability reservoirs have been found in succession.However,low-permeability reservoirs have the feature of "three low".Its porous flow rules is correspond to the Darcy's law in fact,and the porous flow rules is nonlinear.Therefore,the research of a new numerical simulation program which is to be corresponded to the porous flow in low-permeability reservoir is necessary.Based on detailed investigation of flow in low permeability reservoirs and numerical simulation technology,taking stress sensitivity and starting pressure gradient into consideration,this research makes a reasonable mathematical description of these two factors and establishes a mathematical model which correspond to three-phase three-dimensional low permeability reservoir.This research uses the IMPES method to solve the equation and uses Fortran language to program.To develop a proper three-phase three-dimensional numerical simulation program for low permeability reservoir,first of all,this research tests the rationality of the program,and uses the self-made program and ECLIPSE to simulate the conventional ideal reservoir model.The simulation results are very consistent,so the program is completely correct.Secondly,this research considers the influence of starting pressure gradient factor and stress sensitive factor for the low permeability reservoir numerical simulation separately.We find that the influence of starting pressure gradient on productivity is relatively large.The daily oil production and recovery degree of oil reservoir decrease with the increasing of the starting pressure gradient.The stress sensitive factor has large impact to production capacity too.With the increasing of the stress sensitivity coefficient,the damage of low permeability reservoir permeability increased.The daily oil production and recovery degree is gradually reduced.Finally,we consider both starting pressure gradient and stress sensitivity factor to make numerical simulation of low permeability reservoir.We find that the influence of them to production capacity is greater,and the impact of starting pressure gradient on the production capacity is bigger than stress sensitivity factor.