Formation pressure prediction technology of infill point in low permeability oilfield

Abstract

Poor reservoir physical property which leads to low rate of water injection pressure decline after the shut-in because of drilling control is the main characteristic of Daqing peripheral oilfields. To reduce reservoir energy loss, ensure the effect of infilling well, it is necessary to study the formation pressure of infill well point. However, there is no formation pressure prediction formula for infill well point in low permeability reservoir. In this article, combined with detailed reservoir description results, the effective characteristics of formation with different permeabilities are analyzed, the range of effective displacement permeability are defined, and the formation pressure of infill well point is calculated based on reservoir engineering method. Meanwhile, according to the actual injection pressure, produced liquid volume and partial static pressure data, numerical simulation pressure prediction is presented to simulate infill well point pressure. Considering to both prediction results, formation pressure at infill well point can be determined. Field test verifies that the predicted pressure is close to the actual pressure with an error rate within ± 10%, wells with pressure coefficients less than 1.80mpa/100m can be drilled, and those with the pressure coefficients greater than 1.80mpa/100m, drilling should be processed after depressurization.