中国地质2024，Vol.51Issue(3)：743-761,19.DOI:10.12029/gc20210125003
雪峰地区牛蹄塘组海相页岩脆性特征及影响因素
Brittleness characteristics and influencing factors of marine shale of Niutitang Formation in Xuefeng region:A case study of Well XZD-1
摘要
Abstract
[Objective]The brittleness evaluation of shale reservoir is of great significance for determining the favorable stratigraphic zone in shale gas exploration and development.[Methods]Based on the basic data of mineral composition,geophysical logging,rock mechanics experiment and fracture development characteristics of Lower Cambrian Niutitang Formation in Xuefeng region,the brittleness characteristics of Niutitang Formation shale are comprehensively analyzed and evaluated by mineral composition and rock mechanics parameter based on geophysical logging,and the influencing factors of shale brittleness are discussed.[Results]The results indicate that the brittle mineral composition based on the contents of quartz,feldspar,pyrite and carbonate is the most suitable method to evaluate the brittleness of Niutitang Formation shale in this region.Taking Well XZD-1 in this area as an example,the brittleness index of Niutitang Formation shale is 59.2%-93.8%,with an average value of 74.4%,which is influenced by sedimentary environment,diagenetic evolution,burial depth,tectonism and other factors.[Conclusion]The stable deep-water shelf basin facies sedimentary environment and late diagenetic evolution stage determine that the overall brittleness of Niutitang Formation shale in Xuefeng region is relatively high.In this sedimentary environment,biogenic brittle minerals such as siliceous and pyrite are more abundant.The content of brittle minerals is affected by the change in water depth during sedimentation,showing a trend of increasing first and then decreasing from bottom to top,gradually decreasing overall.This leads to a similar vertical variation law in shale brittleness and the development of natural fractures,and the three complement each other.Meanwhile,such brittle minerals have a good positive correlation with organic matter content,and their contribution to shale brittleness is much greater than that of organic matter to shale plasticity.In addition,the correlation between rock mechanics parameters and brittleness index indicates that the Young's modulus plays a more important role in the evaluation of Niutitang Formation shale brittleness in this area than the Poisson's ratio.关键词
脆性特征/影响因素/牛蹄塘组/页岩气/湘张地1井/雪峰地区/油气勘查工程Key words
brittleness characteristics/influencing factors/Niutitang Formation/shale gas/Well XZD-1/Xuefeng region/oil and gas exploration engineering分类
天文与地球科学引用本文复制引用
苗凤彬,彭中勤,汪宗欣,张保民,王传尚,巩磊..雪峰地区牛蹄塘组海相页岩脆性特征及影响因素[J].中国地质,2024,51(3):743-761,19.基金项目
中国地质调查局项目(DD20230323)、古生物与地质环境演化湖北省重点实验室基金项目(PEL-202307)及国家科技重大专项"中扬子高演化页岩气赋存机理与富集规律研究"(2016ZX05034001-002)联合资助. Supported by the project of China Geological Survey(No.DD20230323),Hubei Key Laboratory Foundation of Paleontology and Geological Environment Evolution(No.PEL-202307),National Science and Technology Major Project(No.2016ZX05034001-002). （DD20230323）
