微裂缝性特低渗透油藏产能研究

Productivity of Micro-fractured Ultra-low Permeability Reservoirs

在综合考虑流体和多孔介质压力敏感性及启动压力梯度的基础上,建立了微裂缝性特低渗透油藏平面径向稳态渗流的数学模型,采用拟压力变换求解得到了产能解析公式。并通过与已有公式的对比证明了该产能公式的正确性和更具普遍适用性。采用应用算例,分析了启动压力梯度、变形系数、井距等对产能、采油指数、非线性因子的非线性影响关系。结果表明,启动压力梯度、变形系数和井距越小、生产压差越大产量越高,但对于具体油藏条件,存在最优的井距和生产压差使得采油指数和非线性因子达到最高,此时的非线性因素影响降到最低,开发效果达到最佳。

Based on the motion equation combining the pressure-sensitive effect and threshold pressure gradient, an integrate mathematical model of stable percolation in radio direction for micro-fractured ultra-low permeability reservoirs was established. And the analytical solution was used by pseudo-pressure transformation. Compared with the known formula, the correctness and universal validity were confirmed. The nonlinear influence of some factors on productivity, productivity index, and nonlinear factor are analyzed by using examples, these factors include the threshold pressure gradient, deformity coefficient, well spacing, and producing pressure drop. Some vital conclusions are acquired as following: the smaller the threshold pressure gradient, deformity coefficient, well spacing are, the larger the producing pressure drop is, the higher productivity would be obtained.