Fracture features and fault influence on gas accumulation in the Longmaxi Formation in Changning block, southern Sichuan Basin

IF 4.2 3区 工程技术 Q2 ENERGY & FUELS
{"title":"Fracture features and fault influence on gas accumulation in the Longmaxi Formation in Changning block, southern Sichuan Basin","authors":"","doi":"10.1016/j.ngib.2024.09.007","DOIUrl":null,"url":null,"abstract":"<div><div>The Lower Silurian Longmaxi Formation is a major horizon for shale gas development in the Changning block in Sichuan Basin. In this study, the fracture features in the Longmaxi Formation in the Changning block were investigated through outcrop observation, core description, inclusion testing, and Fullbore Formation MicroImage logging. The results showed that tectogenetic shear fractures dominated the Longmaxi Formation, with maximum principal stress in the SSW, NW, and NE directions. According to fracture features and stress analysis, three phases of faults were generated by tectonic movements after the buried depth reached a maximum in the study area: phase 1 nearly EW-trending faults formed in the middle-late Yanshanian, phase 2 NE-trending faults formed from the end of the Yanshanian to the early Himalayan, and phase 3 NW-trending faults formed from the middle Himalayan to the present. According to the regression analysis of the tested shale gas production and faults, the faults with a throw of &gt; 200 m could have a great effect on gas production, and high-yield wells were generally located over 1 km away from faults. Based on the dissection of tectonic styles and typical wells drilled in the Changning block, three shale gas accumulation models were established: wide gentle syncline + internal smalxl fault, subdued anticline + large fault, and slope + internal fault. The study reveals the mechanism of fault influence on shale gas accumulation in the Longmaxi Formation in the Changning block and provides a reference for efficient shale gas production in the Sichuan Basin.</div></div>","PeriodicalId":37116,"journal":{"name":"Natural Gas Industry B","volume":null,"pages":null},"PeriodicalIF":4.2000,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Natural Gas Industry B","FirstCategoryId":"1085","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S235285402400072X","RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"ENERGY & FUELS","Score":null,"Total":0}
引用次数: 0

Abstract

The Lower Silurian Longmaxi Formation is a major horizon for shale gas development in the Changning block in Sichuan Basin. In this study, the fracture features in the Longmaxi Formation in the Changning block were investigated through outcrop observation, core description, inclusion testing, and Fullbore Formation MicroImage logging. The results showed that tectogenetic shear fractures dominated the Longmaxi Formation, with maximum principal stress in the SSW, NW, and NE directions. According to fracture features and stress analysis, three phases of faults were generated by tectonic movements after the buried depth reached a maximum in the study area: phase 1 nearly EW-trending faults formed in the middle-late Yanshanian, phase 2 NE-trending faults formed from the end of the Yanshanian to the early Himalayan, and phase 3 NW-trending faults formed from the middle Himalayan to the present. According to the regression analysis of the tested shale gas production and faults, the faults with a throw of > 200 m could have a great effect on gas production, and high-yield wells were generally located over 1 km away from faults. Based on the dissection of tectonic styles and typical wells drilled in the Changning block, three shale gas accumulation models were established: wide gentle syncline + internal smalxl fault, subdued anticline + large fault, and slope + internal fault. The study reveals the mechanism of fault influence on shale gas accumulation in the Longmaxi Formation in the Changning block and provides a reference for efficient shale gas production in the Sichuan Basin.
四川盆地南部长宁区块龙马溪地层的断裂特征及其对天然气聚集的影响
志留系下统龙马溪地层是四川盆地长宁区块页岩气开发的主要地层。本研究通过对长宁区块龙马溪地层的露头观察、岩心描述、包裹体测试和全孔地层微成像测井,研究了龙马溪地层的断裂特征。结果表明,龙马溪地层以构造成因剪切断裂为主,最大主应力位于西南、西北和东北向。根据断裂特征和应力分析,研究区在埋藏深度达到最大值后,构造运动产生了三期断层:第一期近似EW向断层,形成于燕山期中晚期;第二期NE向断层,形成于燕山期末期至喜马拉雅早期;第三期NW向断层,形成于喜马拉雅中期至今。根据已测试页岩气产量与断层的回归分析,抛距在 200 米左右的断层对页岩气产量影响较大,高产井一般距离断层 1 公里以上。根据对长宁区块构造样式和典型钻井的剖析,建立了三种页岩气聚集模式:宽缓向斜+内部小断层、低缓向斜+大断层、斜坡+内部断层。该研究揭示了断层对长宁区块龙马溪地层页岩气聚集的影响机理,为四川盆地页岩气高效生产提供了参考。
本文章由计算机程序翻译,如有差异,请以英文原文为准。
求助全文
约1分钟内获得全文 求助全文
来源期刊
Natural Gas Industry B
Natural Gas Industry B Earth and Planetary Sciences-Geology
CiteScore
5.80
自引率
6.10%
发文量
46
审稿时长
79 days
×
引用
GB/T 7714-2015
复制
MLA
复制
APA
复制
导出至
BibTeX EndNote RefMan NoteFirst NoteExpress
×
提示
您的信息不完整,为了账户安全,请先补充。
现在去补充
×
提示
您因"违规操作"
具体请查看互助需知
我知道了
×
提示
确定
请完成安全验证×
copy
已复制链接
快去分享给好友吧!
我知道了
右上角分享
点击右上角分享
0
联系我们:info@booksci.cn Book学术提供免费学术资源搜索服务,方便国内外学者检索中英文文献。致力于提供最便捷和优质的服务体验。 Copyright © 2023 布克学术 All rights reserved.
京ICP备2023020795号-1
ghs 京公网安备 11010802042870号
Book学术文献互助
Book学术文献互助群
群 号:481959085
Book学术官方微信