大庆油田萨南开发区三类油层三元复合驱注入参数数值模拟优化

Numerical simulation optimization of injection parameters of ASP flooding for ClassⅢreservoirs in Sanan development area of Daqing Oilfield

大庆萨南开发区三元复合驱开发对象已由以河道砂沉积为主的高孔、高渗的一、二类油层转为储层物性较差的以席状砂沉积为主的中孔、中渗的三类油层,原来适合一、二类油层三元复合驱的注入参数不再适合三类油层三元复合驱开发的需要,提高采收率幅度降低,与数值模拟预测差距大。从三类油层地质特征出发,明确了影响三元复合驱数值模拟预测的4项关键参数,通过室内实验和矿场测试,确定了4项参数取值范围。采用正交化方法设计78个方案,应用新参数进行数值模拟,优化出适合三类油层的三元复合驱主、副段塞表面活性剂质量分数和段塞用量并应用在8个三元复合驱工业化区块,平均提高采收率18百分点,应用于L区块比化学驱预测方案多提高采收率6.00百分点。研究成果为大庆长垣油田三类油层和其他油田同类油层三元复合驱优质高效开发提供了参考和借鉴。

The object of ASP flooding in Daqing Sanan development area has changed from ClassⅠand ClassⅡreservoirs with high porosity and permeability and mainly channel sand sediments to ClassⅢreservoirs with poor reservoir quality and with mainly medium-porosity and medium-permeability sheet sand sediments.Original injec-tion parameters of ASP flooding suitable for ClassⅠand ClassⅡreservoirs are no longer suitable for ASP flooding development of ClassⅢreservoirs,with incremental recovery reduced,being much different from numerical simu-lation prediction.Based on geological characteristics of ClassⅢreservoirs,4 key parameters affecting numerical simulation prediction of ASP flooding are defined,and the value ranges of the 4 key parameters are determined by laboratory experiments and field tests.By using orthogonalization method,78 schemes are designed.The new pa-rameters are used in numerical simulation to optimize the surfactant mass fraction and slug size of the main and aux-iliary slugs for ClassⅢreservoirs,with application in 8 commercial ASP flooding blocks,getting oil recovery aver-agely increased by 18 percentage points,among which application in Block L getting 6.00 percentage points higher than that of chemical flooding prediction scheme.The research provides reference for high quality and efficient de-velopment of ClassⅢreservoirs in Daqing Placanticline oilfield and other similar reservoirs.