考虑变渗透率模量的压敏油藏产能计算模型

摘要

For stress-sensitive media, the permeability modulus changes with the effective stress. When the pressure changes in a large range, the deliverability analyzing method considering constant permeability modulus can not effectively evaluate the dynamic deliverability characteristic of pressure-sensitive reservoirs. Therefore, in light of the seepage laws of the reservoirs, a productivity evaluating model considering variable permeability modulus is established. In addition, by means of Newton-Raphson method, the solution of this model is resolved. The study results prove that when the bottom-hole flowing pressure is much higher, the production considering variable permeability modulus is little different from the one considering constant permeability modulus, but when the bottom-hole flowing pressure is rather lower, the production considering constant permeability modulus may lead to abnormally evaluate the influences of the stress-sensitivity action. As the variable permeability modulus can better characterize the pressure-sensitivity features, so it must be proposed to consider the effects of the variable permeability modulus on the productivity of pressure-sensitivity oil reservoirs.%对于压敏介质,渗透率模量随着有效应力变化而变化,在压力变化范围较大时,基于常渗透率模量的产能分析方法不能够有效评价压敏油藏的产能动态特征.因此,针对压敏油藏的渗流规律,建立了考虑变渗透率模量的产能计算模型,并用Newton-Raphson方法对模型进行求解.结果表明:当井底流压较大时,考虑变渗透率模量计算的产量与常渗透率模量计算的产量差别不大,但是当井底流压较小时,用常渗透率模量计算的产量可能会过高或过低地估计应力敏感作用对油井产量的影响.由于变渗透率模量能更好地表征压力敏感特征,因此建议在应用中必须考虑变渗透率模量对压敏油藏产能的影响.