Study on the Theory of Effective Displacement in Low Permeability Reservoir

Abstract

Taking displacing pressure gradient and threshold pressure gradient into account, we have carried on a research of effective displacement theory in low permeability formation. Based on displacing pressure gradient expression of different production diverging/converging, we get displacing pressure gradient engraving when formational pressure, injection pressure, bottom hole producing pressure, and inter well distance is changing. And analyze its regular as well. On the basis of experimental result, establishing the relationship between threshold pressure gradient and displacing pressure gradient, and analyze the critical value of different pay zones for effective displacement. Study has shown that if we want to drive low permeability formation it is necessary that the displacing pressure gradient is larger than the threshold pressure gradient. It is the optimal choice for low permeability formations effective displacement that the well spacing should be smaller. It can achieve a goal that effective driving low permeability reservoir by the adjustment of taking measures and the injection-production pressure systems modulation. The study has important guiding significance for the development of low permeability formation, and it has got effective verification in oil field test.