基于元素俘获测井的页岩脆性评价方法及应用  

Method and Application of Shale Brittleness Evaluation Based on Elemental Capture Spectroscopy Logging

作　　者：郭聪[1,2] 张冲[1,2] 朱林奇[1,2] 黄雨阳 程媛 

机构地区：[1]油气资源与勘探技术教育部重点实验室(长江大学),武汉430100 [2]非常规油气湖北省协同创新中心(长江大学),武汉430100

出　　处：《矿物岩石地球化学通报》2017年第6期1040-1047,共8页Bulletin of Mineralogy, Petrology and Geochemistry

基　　金：国家自然科学基金项目(41404084);油气资源与勘探技术教育部重点实验室(长江大学)开放基金项目(K2017-01);湖北省自然科学基金项目(2013CFB396)

摘　　要：准确计算页岩储集层的脆性指数对后期的压裂改造有重大影响,利用元素俘获能谱(ECS)测井资料能计算出页岩地层矿物组分含量进而再评价出脆性指数。以某地区五峰组-龙马溪组AA1井为例,选择八元体积模型,用带约束条件的最小二乘法求解反演出各矿物组分的质量含量,借助骨架密度中间值,将矿物的质量含量转换为矿物的体积含量后,同时考虑有机质的影响,用石英和碳酸盐2种脆性矿物所占的比例来表征目标区块的脆性指数。结果表明,带约束条件的最小二乘法计算得到的矿物含量精度较高,反演的结果和全岩分析数据吻合度高;用考虑有机质影响校正的脆性指数计算模型能准确的计算出页岩地层的脆性指数。利用ECS测井资料进行页岩地层脆性评价的方法简单易行,效果良好,对页岩气储集层后期压裂改造能提供有力的帮助。Accurate calculation of the brittle index of the shale reservoir has a significant effect on the evaluation of later fracture and reconstruction. Elemental capture spectroscopy（ECS） logging data can be used to calculate the mineral compo- sitions of the shale and then evaluate the brittleness index. Taking the well AA1 in the Wufeng and Longmaxi formations as an example, we select eight element volume model and least square method with restraint condition to invert mineral quali- ty contents, and then calculate virtue of matrix density. The brittleness index of the target block is characterized by the proportion of quartz and carbonate and the contents of organic components. The results show that the least squares method with restraint condition can accurately calculate the mineral contents, which is consistent well with the calculation results from whole rock analysis data. The calculation model considering the influence of organic matter can accurately calculate the brittleness index. The method of evaluating the brittleness of shale formation by ECS logging data is simple and effec- tive, and it can be helpful to the later transformation and fracturing of shale gas reservoir.

关 键 词：ECS测井 矿物组分 脆性指数 页岩气储集层 总有机碳含量(TOC) 

分 类 号：P618.13[天文地球—矿床学] P631.81[天文地球—地质学]