基于脆性随钻解释的页岩气地质导向应用  

Geosteering Application of Brittleness Based on Interpreting While Drilling in Shale Gas Reservoirs

作　　者：李特社 夏宏泉[1] 陈颖杰[2] 

机构地区：[1]西南石油大学油气藏地质及开发工程国家重点实验室 [2]中国石油西南油气田公司勘探事业部

出　　处：《国外测井技术》2015年第6期31-34,40,共5页World Well Logging Technology

基　　金："973"项目"中国南方海相页岩气高效开发的基础研究"子课题:页岩气水平井钻完井关键基础研究(编号:2013CB228003)

摘　　要：页岩储层通常需要经过大型分段多级压裂才能产气。脆性指数作为岩石力学评价的一个新参数,对页岩储层后期压裂改造有着重要影响。岩石脆性的强弱受地层岩性及其孔隙度大小影响,声波、密度和中子测井值能综合反映地层岩性和孔隙度大小。本文从脆性指数影响因素分析出发,考虑测井响应特征与岩石脆性的关系,基于统计回归法分析了页岩脆性指数与密度、中子等测井值的相关性,研究认为中子测井值能够很好地反映页岩脆性高低,由此建立了利用随钻中子测井值计算页岩脆性指数的方法和模型。将其计算结果用于CW地区多口水平井的地质导向钻井效果分析中,发现脆性指数配合常规地质导向参数进行产层导向,指导钻头沿目标层最佳部位钻进,能明显提高优质页岩储层钻遇率。Shale reservoirs usually need large segment multistage fracturing to produce gas.The brittleness index,as an important parameter of reservoir rock mechanics evaluation,plays a key role in the later fracturing of shale gas reservoir.Brittleness is influenced by the lithology and porosity which can be reflected by sonic,density and neutron log value.Considering the relationship between conventional logging response characteristics and brittleness,this article analyzes the correlation of shale brittleness index and density,neutron value and so on by statistical regression method.It is suggested that neutron value can well reflect the level of shale brittleness in the research.Herefore,a model is established for calculating the brittleness index with LWD neutron curves.This method has been used in geosteering analysis of several horizontal wells in CW area.The results indicate that combination of brittleness index with conventional geosteering parameters can guide the bit drilling in productive layers and greatly improve the drilling-encounter ratio of superior gas reservoir.

关 键 词：页岩 脆性指数 孔隙度 中子测井值 地质导向 

分 类 号：TE243[石油与天然气工程—油气井工程]