致密油射孔簇有效性的测井评价方法

Log Evaluation Method for Effectiveness of Tight Oil Perforation Clusters

致密油通常都需要进行大型压裂改造才能获得产能,从国内外的资料显示,选取的射孔簇产液量并非均质的,大部分射孔簇产液量很低甚至为无效射孔簇,没有达到压裂效果,优化射孔簇成为生产急需解决的难题。通过在华北油田束鹿凹陷泥灰岩致密油储层进行深入研究,分析储层测井曲线及其响应特征,发现裂缝指数、电阻率比值、脆性指数、阵列声波渗透性指数及核磁共振孔隙结构指数等参数和储层特征及产能相关性较好,创建了测井综合评价参数评价射孔簇有效性,将射孔簇分为3类,并依据储层产能给出标准,测井综合评价参数大于800为高效射孔簇,100~800为有效射孔簇,小于100为无效射孔簇。将划分的射孔簇和工程施工参数(破裂压力、加砂量、注入量)和监测参数(示踪流量、微地震监测裂缝)等资料建立关系,发现有良好的相关性。研究认为,在油井压裂施工前,利用测井综合评价参数评价射孔簇有效性,可以实现优化射孔簇,顺利完成储层体积压裂改造。

Tight oil often requires large fracturing renovation to achieve production capacity, tne liquid output of the selected perforation clusters is not homogeneous. Most of the perforation clusters did not reach the fracturing effect and produced low yield without effective perforation clusters. How to optimize perforating cluster becomes urgent problem. In north China, through the research on tight oil reservoir of Shulu concave, Huabei oilfield, it is found that the fracture parameters, ratio of resistivity, brittleness index, array acoustic parameters such as permeability index, and porous structure exponent have better correlation with reservoir characteristics and reservoir capacity. Based on that, we created a logging comprehensive evaluation parameter to evaluate perforating cluster effectiveness. Perforation clusters can be divided into three types, according to reservoir capacity standard, the logging evaluation index is greater than 800 for efficient perforation clusters, 100~800 for effective perforation clusters and cluster is less than 100 as invalid perforation. The three types with operation parameters （fracture pressure, amount of sand, injection） and monitoring parameters （tracer flow, micro seismic monitoring crack） data, have good correlation. The evaluation of well logging parameter perforation cluster effectiveness can help us to realize optimization of perforation clusters operation.