非达西渗流效应对考虑原油压缩系数低渗透油藏直井产能的影响

Impact of Non-Darcy Percolation Effect on Vertical Well Productivity Considering Oil Compressibility in Low-permeability Oil Reservoirs

由于低渗透油藏普遍具有低孔、低渗特征，导致其油水渗流存在非线性和流态的多变性，使得流体的渗流不再符合经典的达西定律。考虑启动压力梯度、原油压缩系数和基于岩石本体有效应力理论的应力敏感效应的综合影响，推导出修正的低渗透油藏直井产能方程；并以某低渗透油藏为例，研究启动压力梯度、原油压缩系数应力敏感效应对其产能的影响。结果表明．低渗透油井中启动压力梯度比应力敏感和原油压缩系数对产能的影响强烈得多，建议低渗透油藏直井产能预测时必须充分考虑启动压力梯度的影响。

The nonlinearity of water/oil percolation and multi-variability of fluidal exists in low-permeability oil reservoirs due to the reservoirs with low porosity. As a result, the oil percolation is inconsistent with the traditional Darey law. Considering the comprehen- sive influences of start-up pressure gradient, oil compressibility and stress sensitivity based on the theory of rock primary effective stress, the revised vertical well productivity equation of low permeability oil reservoir is deduced. The influence of start-up pressure gradient, oil compressibility and stress sensitivity effects on the productivity are studied based on the real data from a low-permeabil- ity oil reservoir. Results indicate file impact of start-up pressure gradient on the productivity is much stronger than that of stress sen- sitivity and oil compressibility. We suggest that start-up pressure gradient effect should be taken full consideration into into account in correctly predicting the productivity of vertical well in low permeability oil reservoirs.