The Research On Numerical Simulation Of Low Permeability Reservoir

With the development of modern oil industry, the exploitation of low permeability reservoir has been paid more and more attention in recent years. Compared with medium and high permeability reservoirs, the low permeability reservoir has different seepage flow characteristics, which are as follows: The flow of the fluid does not obey Darcy`s Law; The starting pressure gradient exists in transfusion; The stress sensitivity influence can not neglect.This paper, based on widespread investigation and study, considered starting pressure gradient and stress sensitivity influence, makes some research on numerical simulation of low permeability reservoir. Specifically, it is considered that oil and water have the same starting pressure gradient, which has the relationship with absolute permeability and water saturation. At the same time, it is also considered that the absolute permeability will vary, because of stratum elastoplasticity distortion. On this basis, First, a two-dimensional mathematical model of oil-water two-phase is set up, which is solved with the IMPES numerical method and whose computation function is realized by programming. Using this program, the production characteristics, the factors affecting the deliverability and the different injection pattern were studied. The result indicates that starting pressure gradient,stress sensitivity,oil/water viscosity ratio and capillary pressure have obvious effect to the deliverability of low permeability reservoir, row well pattern and reverse nine-spot pattern are better than five-spot pattern, skewed four-spot injection pattern and reverse seven-spot pattern. Second, based on the black oil model, a three-phase three-dimensional numerical simulator is established, in which the key work is improving the production-calculating part compared with the two-phase program. And using it, do some works about history matching and production forecasting for a certain block.