夏盐11井区剩余油分布特征与挖潜对策研究

Study on Characteristics of Remaining Oil Distribution and Countermeasures for Potential Tapping in Well Block Xiayan 11

针对新疆油田夏盐11井区层内、层间非均质性强,产量持续下降,注水开发后油藏剩余油分布规律不清楚,持续稳产能力较差的问题,利用数值模拟、油藏工程方法及动态监测资料开展了非均质性强油藏不同类型剩余油分布规律研究,明确了下步挖潜对策。研究结果表明:夏盐11井区剩余油挖潜潜力区可分为3种,Ⅰ类为注采井网不完善控制型剩余油,剩余油饱和度高,平均大于45%,油层厚度不小于4.5 m,主要发育水下分流河道,挖潜对策为储层改造提高低渗区域的物性;Ⅱ类为井间滞留型剩余油,剩余油饱和度较高,平均为20%~45%,油层厚度为3.0~4.5 m,主要发育河口坝,挖潜对策为油水井补孔、完善注采井网;Ⅲ类为水淹程度较高型剩余油,剩余油饱和度较低,平均小于20%,油层厚度不超过2 m,剩余油分布零散,挖潜对策为老井补孔和水井分注,同时进行注水井调剖,对低产井进行重复压裂、补孔。该研究可为同类型非均质性油藏开发提供参考。

In response to the problems of strong intra-and inter-reservoir heterogeneity,continuous decrease in production,unclear pattern of remaining oil distribution after development with water flooding,and poor capability of sustainable and stable production in Well Block Xiayan 11,Xinjiang Oilfield,the distribution pattern of different types of remaining oil in highly heterogeneous reservoir was studied by numerical simulation,reservoir engineering methods and dynamic monitoring,and countermeasures for further potential tapping were defined.The results of the study showed that,there were three types of remaining oil potential tapping areas in Well Block Xiayan 11,specifically,typeⅠwas the remaining oil controlled by the imperfect injection-production well pattern,featured by high remaining oil saturation(more than 45%on average)and reservoir thickness of no less than 4.5 m and mainly developed with underwater distributary channels,and the potential tapping countermeasure was to improve the physical properties of low-permeability areas by reservoir stimulation;typeⅡwas remaining oil restricted between wells,featured by high remaining oil saturation(20%to 45%on average)and reservoir thickness of 3.0 to 4.5 m and mainly developed with estuary dams,and the potential tapping countermeasure was to re-perforate the oil-water wells and improve the injection-production well pattern;typeⅢwas remaining oil with high flooding level,and featured by low remaining oil saturation(less than 20%on average),reservoir thickness of no more than 2 m and scattered remaining oil distribution,and the potential tapping countermeasures included re-perforation of old wells,separate injection of water wells,profile control of water injection wells,and repeated fracturing and re-perforation of low-production wells.The study provides a reference for the development of similar heterogeneous reservoirs.