低渗透断块油藏有效驱替压力系统研究

低渗透断块油藏由于存在启动压力梯度、含油面积小、形状复杂,很难建立有效的驱替压力系统,只有在渗流场压力梯度大于启动压力梯度的条件下,流体才能流动。所以在低渗透断块油藏开发中,建立有效的驱替压力系统尤为关键。通过实验数据的统计,拟合得到了永安地区低渗透储层启动压力梯度与流度的幂函数关系式。利用渗流力学理论,推导了存在启动压力梯度下油藏产能公式及注采井之间的压力梯度分布公式,建立了有效驱替压力系统的理论。同时给出多层开采时有效压力系统建立方法。

Research on the Effective Displacement Pressure System of Fault Block Oil Reservoirs With Low Permeability

Because of the low starting pressure gradient, small oil-bearing area and complex shapes, it is difficult to establish effective displacement pressure system for the fault block reservoirs with low permeability. Only under the condition that the seepage pressure gradient is larger than that of the threshold pressure, the fluid can flow. So in the development of fault-block oil reservoirs with low permeability, to establish effective displacement pressure system is particularly critical. In this paper, based on the statistical data, the relation formula of starting pressure gradient and mobility power function of Yong’an area was obtained by fitting. And the formulas of reservoir productivity and pressure gradient distribution between water injection wells were derived with the percolation mechanics theory; the effective displacement pressure system theory was established. At last, the method of establishing effective pressure system for multilayer production was put forward.