应用多孔介质双重有效应力理论,采用变围压应力敏感性实验研究东濮凹陷文东油田沙三中深层高压低渗砂岩油藏储层应力敏感性,建立储层物性参数的应力敏感性定量解释模型.研究表明,双重有效应力理论可以更真实地反映低渗透油藏储层岩石的应力敏感性.由应力敏感性模型计算目前渗透率是原始渗透率的85%左右,采油指数为初始采油指数的12%,采液指数为初始采液指数的35%.含水率小于20%时,驱油效率、水驱采出程度随含水率增加而急骤上升,注水利用率最大;含水率在20%~80%,随含水率增加,驱油效率、水驱采出程度缓慢上升,注水利用率下降;含水率大于80%时,含水率上升速度加快,驱油效率和采出程度上升速度加快,需要大量注水改善开发效果.应力敏感性模型的计算结果与水驱开发特征曲线吻合较好.
According to the theory of dual effective stress of porous medium, the stress-dependent sensitivity of deep section high pressure and low permeability sandstone reservoir of the third member of Shahejie formation in the Wendong Oil field, Dongpu Sag was studied by changing confining pressure stress sensitivity experiment, and then the quantitative model on stress sensitivity of reservoir physical property was built. The results indicated that the theory of dual effective stress can more really reflect the stress-dependent sensitivity of low permeability sandstone reservoir. From the model on stress sensitivity, it's concluded the now permeability is 85% of the original one, the oil productivity index is 12% of the original one, and the liquid productivity index is 35%. When the water cut is less than 20%, the oil displacement efficiency and water drive ratio of total oil produced to OOIP increase quickly with its increase, the water injection efficiency reaches to the great, However when the water cut is between 20% and 80%, they increases slowly, the utilization factor of water injection decreases, When the water cut is greater than 80%, its rise velocity speeds up, they continue to increase, and it's needed to inject much water to improve development effect. The calculation results of the quantitative model on stress sensitivity coincide with the water flooding characteristic curve.