Title

Evolution of montmorillonite and its related clay minerals and their effects on shale gas development

单位

(1.西南石油大学石油与天然气工程学院,四川成都610500;2.油气藏地质及开发工程国家重点实验室,四川成都610500;3.中国石油化工股份有限公司石油物探技术研究院,江苏南京211103;4.大港油田公司第三采油厂,天津300380)

Organization

(1.School of Oil & Natural Gas Engineering,Southwest Petroleum University,Chengdu 610500,China;2.State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation,Chengdu 610500,China;3.Sinopec Geophysical Research institute,Nanjing 211103,China;4.Dagang Oilfield Company,Tianjin 300380,China)

摘要

按照分布特征—演化规律—工程应用的思路揭示了蒙脱石及相关黏土矿物对页岩气高效开发的影响。首先归纳总结、分析对比了不同地区蒙脱石及相关黏土矿物含量的差异性,发现其复杂多变的分布特征蕴含着一定的变化规律;然后系统分析了蒙脱石及相关黏土矿物的沉积环境及其在不同埋深条件下赋存特征的差异性,揭示了蒙脱石及相关黏土矿物的时空演变规律——蒙脱石在富含K⁺的碱性环境下易于转化为伊利石,在富含Fe²⁺和Mg²⁺的碱性环境下易于转化为绿泥石,在酸性环境下形成高岭石,随着地层埋藏深度的增加,可以进一步演变出伊-蒙混层发育带、高岭石异常高值带及伊利石-绿泥石发育带;最后依据蒙脱石易于水化膨胀造成页岩气产出困难的特性和蒙脱石及相关黏土矿物的演变规律,形成对优质页岩储层分布范围预测、页岩气开发过程中钻井液及压裂液配方研制的有益认识,从而有利于更好地识别及开发页岩气。

Abstract

The effects of montmorillonite and its related clay minerals on shale gas development were assessed in this study.First,the differences in content of the montmorillonite and its related clay minerals in various areas were analyzed,and certain variation patterns in changeable distribution features were found.Next,the sedimentary environment and differences in occurrence characteristics for montmorillonite and its related clay minerals under different buried depth conditions were analyzed to reveal the spatio-temporal evolution of montmorillonite and its related clay minerals.Montmorillonite transforms into illite in an alkaline environment rich in K+,converts into chlorite under alkaline conditions rich in Fe²⁺ and Mg²⁺,and forms kaolinite in acidic environments.With changes in strata burial depth,montmorillonite can be divided into a mixed illite-montmorillonite zone,a zone with abnormally high values of kaolinite,and an illite-chlorite development zone.Finally,given that the characteristics of montmorillonite(i.e.,easy hydration expansion) can result in difficult shale gas production,the evolution law of montmorillonite and its related clay minerals is useful to form a reference scheme for the formulation development of drilling and fracturing fluids in shale gas reservoir development,and for predicting the distribution of high quality shale gas reservoirs.

关键词：

蒙脱石; 黏土矿物; 分布特征; 演变规律; 页岩气开发;

Keywords:

montmorillonite,; clay minerals,; distribution characteristic,; evolution law,; shale gas development;

基金项目

国家重点基础研究发展计划(973计划)项目(2014CB239201)和国家科技重大专项课题(2017ZX05035003)联合资助。

DOI

10.3969/j.issn.1000-1441.2018.03.003

蒙脱石与相关黏土矿物的演变规律及其对页岩气开发的影响