松辽盆地三肇凹陷致密储层地质评价

Geological Evaluation of Tight Reservoirs in Sanzhao Sag, Songliao Basin

摘要: 致密油藏采用压裂方式投入开发后，以孔隙结构为基础的致密储层分类评价标准不再适用。针对致密储层体积压裂或缝网压裂的开发特点，在致密储层地质评价时采用脆性指数和单井控制储量两项参数评价储层，并以投产连续生产两年的累积产油量检验该方法评价结果的准确性。根据两项评价参数，把研究区致密储层分为三类，I类储层脆性指数和储层单井控制储量都高，II类储层脆性指数高、单井控制指数低或脆性指数低，单井控制储量高，III类储层脆性指数和单井控制储量都低，该分类标准符合率达到85%。研究区扶杨油层整体开发效果较差是由普通压裂的压裂工艺和致密储层的脆性指数较低共同决定的；压裂开发的致密油藏单井产能受脆性指数和单井控制储量的共同控制，两者具有互补的作用；采用综合多项地质参数于一体的单井控制储量评价致密储层，不仅实现了降维，而且取得了较好的评价效果。

Abstract: After a tight reservoir is developed by fracturing, the classification and evaluation criteria of tight reservoir based on pore structure are no longer applicable. In view of the development characteristics of volume fracturing or fracturing with fracture networks in tight reservoirs, brittleness index and single well controlled reserves are adopted to evaluate the reservoir in geological evaluation of tight reservoirs, and the accuracy of the evaluation results of this method is tested by cumulative oil production after two years of continuous production. According to the evaluation of two parameters, the dense reservoir in the study area is divided into three categories, I reservoir: high brittleness index and single well controlled reserves, II reservoir: high brittleness index and low single well controlled reserves, or low brittleness index and high single well controlled reserves, III reservoir: low brittleness index and single well controlled reserves. The classification standards coincidence rate reaches 85%. The poor overall development effect of Fuyu and Yangdachengzi reservoir in the study area is determined by the common fracturing technology and the low brittleness index of tight reservoir. Single well productivity of fractured tight reservoir is controlled by brittleness index and controlled reserves of single well and the two factors have complementary effect. The single well controlled reserves evaluation of tight reservoir with integrated multiple geological parameters not only realizes dimension reduction, but also obtains good evaluation effect.