石油与天然气地质 ›› 2020, Vol. 41 ›› Issue (3): 474-483.doi: 10.11743/ogg20200304

• 油气地质 • 上一篇    下一篇

四川盆地涪陵地区海相页岩天然裂缝特征及对页岩气的影响

田鹤1,2, 曾联波1,2, 徐翔1,2, 舒志国4, 彭勇民3, 毛哲1,2, 罗兵4   

  1. 1. 油气资源与探测国家重点实验室 中国石油大学(北京), 北京 102249;
    2. 中国石油大学(北京)地球科学学院, 北京 102249;
    3. 中国石化 石油勘探开发研究院, 北京 100083;
    4. 中国石化 江汉油田分公司 勘探开发研究院, 湖北 武汉 430223
  • 收稿日期:2019-05-15 修回日期:2020-04-06 发布日期:2020-06-16
  • 通讯作者: 曾联波(1967-),男,博士、教授,应力场分析,裂缝性储层和非常规油气储层评价与预测。E-mail:lbzeng@sina.com。 E-mail:lbzeng@sina.com
  • 作者简介:田鹤(1993-),男,博士研究生,应力场分析、非常规储层裂缝形成、分布及预测。E-mail:th1556243165@gmail.com。
  • 基金资助:
    国家自然科学基金项目(U1663203)。

Characteristics of natural fractures in marine shale in Fuling area,Sichuan Basin, and their influence on shale gas

Tian He1,2, Zeng Lianbo1,2, Xu Xiang1,2, Shu Zhiguo4, Peng Yongmin3, Mao Zhe1,2, Luo Bing4   

  1. 1. State Key Laboratory of Petroleum Resources and Prospecting, China University of Petroleum(Beijing), Beijing 102249, China;
    2. College of Geosciences, China University of Petroleum(Beijing), Beijing 102249, China;
    3. Petroleum Exploration and Production Research Institute, SINOPEC, Beijing 100083, China;
    4. Research Institute of Exploration and Development of Jianghan Oilfield Branch Company Ltd., SINOPEC, Wuhan, Hubei 430223, China
  • Received:2019-05-15 Revised:2020-04-06 Published:2020-06-16

摘要: 不同类型裂缝对页岩气富集和保存的影响不同,因而在页岩气储层天然裂缝研究时,需要进行分类评价和预测。利用野外露头、岩心、薄片和FMI成像测井资料,对四川盆地涪陵地区五峰组-龙马溪组海相页岩天然裂缝的成因类型、发育特征、主控因素及不同类型天然裂缝对页岩气富集与保存的影响进行了探讨。涪陵地区五峰组-龙马溪组页岩天然裂缝在地质成因上分为构造裂缝、成岩裂缝及异常高压裂缝3种类型,其中构造裂缝包括层内张开裂缝、穿层剪切裂缝及顺层剪切裂缝;成岩裂缝包括页理缝和收缩裂缝。研究区以构造裂缝和页理缝为主,构造裂缝的发育程度受构造、岩石力学层厚度及脆性矿物含量等因素的控制;页理缝主要受页理发育程度、脆性矿物含量、异常流体压力、有机质含量及其热演化程度的控制。不同成因类型的天然裂缝对页岩气影响明显不同,其中层内张开裂缝和页理缝在页岩层内发育,裂缝规模小,为页岩气富集提供良好的储集空间;穿层剪切裂缝和顺层剪切裂缝发育规模大,主要影响页岩气的保存条件;收缩裂缝和异常高压裂缝的发育程度低,有效性差,对页岩气的影响较小。

关键词: 岩石力学, 保存条件, 页岩气, 构造裂缝, 成岩裂缝, 五峰组, 龙马溪组, 涪陵地区, 四川盆地

Abstract: Fractures of various types show different impacts on shale gas enrichment and preservation.Therefore,categorized evaluation and prediction are quite necessary in studying the natural fractures in shale gas reservoirs.A wealth of outcrop,coring and thin section observation,as well as FMI logging interpretation is applied to the discussion of the genetic types,development characteristics,and main controlling factors of natural fractures in marine shale,and the impact of various types of natural fractures on shale gas enrichment and preservation in the Wufeng-Longmaxi Formations,Fuling area,Sichuan Basin.The natural fractures in the study area can be divided into tectonic,diagenetic and abnormally high-pressure fractures in terms of geological origin.In turn,the tectonic fractures can be subdivided into intra-layer aperture fractures,cross-layer shear fractures,layer-parallel shear fractures,whereas diagenetic fractures mainly include lamellar fractures and constricted fractures.The shale formation of the study area is dominated by tectonic and lamellar fractures.The development of tectonic fractures is mainly controlled by structural position,rock mechanical stratigraphy thickness and brittle mineral content.While the development of the lamellar fractures is determined by laminae development,brittle mineral content,abnormal high pressure in fluids,and content and thermal evolution stage of organic matter.Natural fractures of various origins have different influence on shale gas.The aperture fractures and lamellar fractures developed within the shale formation are small in scale,providing better reservoir space for shale gas accumulation.The larger-scale cross-layer shear fractures and layer-parallel shear fractures mainly impact the preservation conditions of shale gas.The underdevelopment of constricted and abnormally high-pressure fractures provides poor effective porosity and thus has little influence on shale gas enrichment and preservation.

Key words: rock mechanics, preservation condition, shale gas, tectonic fracture, diagenetic fracture, Wufeng Formation, Longmaxi Formation, Fuling area, Sichuan Basin

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