各向异性稠油油藏SAGD产能公式校正

Correction of SAGD productivity formula in anisotropic heavy oil reservoir

蒸汽辅助重力泄油(SAGD)的Butler产能模型假设油藏均质各向同性,在没有考虑垂向渗透率的影响时,导致SAGD产能计算结果较实际值偏高。通过对比常规水平井产能公式的各向异性校正方法,并采用多元非线性回归拟合对SAGD产能公式中的平均渗透率进行了校正。该方法将SAGD数值模拟结果反推得到解析公式中平均渗透率的值,从而建立其与水平和垂直渗透率的对应关系,再通过回归即得各向异性油藏中渗透率的表达式。实例计算表明,校正后的SAGD产能解析公式其结果更接近真实值。

Butler productivity formula for steam assisted gravity drainage （SAGD） assumes that the reservoir is homogeneous and isotropie, without considering the impact of the vertical permeability, which causes that the SAGD production capacity result is higher than the actual value. This paper compared the correction methods of productivity formula for conventional horizontal well in anisotropy reservoir, and carried out the average permeability correction of SAGD productivity formula by using nonlinear regression fitting. The SAGD numerical simulation result was applied to push back the value of the average permeability in the analytical formula, in order to establish the corresponding relations among the average permeability, horizontal permeability and vertical permeability, and finally obtain the expression of permeability in anisotropy reservoir through the regression. The application result shows that the calculation result of the corrected SAGD productivity formula is closer to the true value.