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川西坳陷彭州地区雷口坡组天然裂缝 发育特征与形成期次

作    者:夏 宇1, 邓虎成1,2, 王园园1, 何建华1, 解馨慧1, 滕 娟1
单    位:1成都理工大学能源学院; 2成都理工大学产业技术学院
基金项目:本文受四川省教育厅省属高校科研创新团队“非常规油气地质研究”资助
摘    要:
利用野外露头、岩心、薄片及地球化学等资料对四川盆地川西坳陷彭州地区雷口坡组天然裂缝发育特征及形成期次开展了研究。研究区宏观裂缝按成因可划分构造裂缝和和非构造裂缝,构造裂缝包括张性裂缝、剪性裂缝和破碎状裂缝,非构造裂缝主要为风化网状裂缝。宏观裂缝以构造裂缝为主,主要为剪性裂缝和张性裂缝,其中的垂直裂缝、高角度裂缝的发育密度和有效性较高。微裂缝充填程度高,有效性较差,对储层的影响较小。研究区雷口坡组主要发育4期构造裂缝和1期风化裂缝,构造裂缝形成于印支中—晚期、燕山早—中期、燕山晚期和喜马拉雅期,风化裂缝发育在印支早期。印支期裂缝在燕山中晚期烃源岩大规模排烃之前已被方解石、石膏等充填,对油气开发高产的意义不大;燕山中晚期—喜马拉雅期形成的垂直裂缝和高角度裂缝对彭州地区雷口坡组气藏开发具有重要意义。这项研究为进一步综合评价研究区储层特征、明确天然气富集规律提供了依据。
关键词:裂缝特征; 裂缝期次; 雷口坡组; 彭州地区; 四川盆地

Development characteristics and formation stages of natural fractures of the Triassic Leikoupo Formation in Pengzhou area of Western Sichuan Basin

Author's Name: XIA Yu, DENG Hucheng, WANG Yuanyuan, HE Jianhua, XIE Xinhui, TENG Juan
Institution: 
Abstract:
Based on outcrop, core, thin section and geochemical data, the development characteristics and formation stages of natural fractures of Leikoupo Formation in Pengzhou area of Western Sichuan Depression, Sichuan Basin were studied. The macro fractures in the study area can be divided into structural fractures and non-structural fractures according to their genesis. The structural fractures include tensile fractures, shear fractures and broken fractures, while the non-structural fractures are mainly weathering fractures. The macro fractures are mainly structural fractures (shear fractures and tensile fractures), in which the vertical fractures and high angle fractures have higher development density and effectiveness. Micro fracture has high filling degree, poor effectiveness and so has little influence on reservoir. The Leikoupo Formation in the study area mainly developed four stages of structural fractures and one stage of weathering fractures. The structural fractures were formed in the middle to late Indosinian, early to middle Yanshanian, late Yanshanian and Himalayan, and the weathering fractures were developed in the early Indosinian. The Indosinian fractures have been filled with calcite and gypsum before the large-scale expulsion of hydrocarbon from the source rocks in the middle and late Yanshanian, which is of little significance to the enrichment of oil and gas. The vertical fractures and high angle fractures formed in the middle and late Yanshanian and Himalayan are of great significance to the gas development of Leikoupo Formation in Pengzhou area. This study provides a basis for further comprehensive evaluation of reservoir characteristics and gas enrichment in the study area.
Keywords: fracture characteristics; fracture genesis; Leikoupo Formation; Pengzhou area; Sichuan Basin
投稿时间:2021-03-31  
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