石油与天然气地质 ›› 2021, Vol. 42 ›› Issue (6): 1295-1306.doi: 10.11743/ogg20210605

• 油气地质 • 上一篇    下一篇

四川盆地及其周缘五峰组-龙马溪组页岩裂缝发育特征及其控储意义

王濡岳1,2,3(), 胡宗全1, 周彤1, 包汉勇4, 吴靖5, 杜伟1, 何建华6, 王鹏威1, 陈前1   

  1. 1. 中国石化 石油勘探开发研究院, 北京 100083
    2. 页岩油气富集机理与有效开发国家重点实验室, 北京 100083
    3. 中国石化 页岩油气勘探开发重点实验室, 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
    5. 山东科技大学 地球科学与工程学院, 山东 青岛 266500
    6. 成都理工大学 能源学院, 四川 成都 610059
  • 收稿日期:2021-07-26 出版日期:2021-12-28 发布日期:2021-12-16
  • 作者简介:王濡岳(1990-), 男, 博士、高级工程师, 非常规油气地质与油气勘探规划。E-mail: wry1990@vip.qq.com
  • 基金资助:
    国家自然科学基金项目(41902134);国家自然科学基金项目(42172165);中国石油化工股份有限公司科技开发部项目(P20046-1)

Characteristics of fractures and their significance for reservoirs in Wufeng-Longmaxi shale, Sichuan Basin and its periphery

Ruyue Wang1,2,3(), Zongquan Hu1, Tong Zhou1, Hanyong Bao4, Jing Wu5, Wei Du1, Jianhua He6, Pengwei Wang1, Qian Chen1   

  1. 1. Petroleum Exploration and Production Research Institute, SINOPEC, Beijing 100083, China
    2. State Key Laboratory of Shale Oil and Gas Enrichment Mechanisms and Effective Development, Beijing 100083, China
    3. Key Laboratory of Shale Gas and Oil Exploration & Production, SINOPEC, Beijing 100083, China
    4. Exploration and Development Research Institute of Jianghan Oilfield Branch Company, SINOPEC, Wuhan, Hubei 430223, China
    5. College of Earth Science and Engineering, Shandong University of Science and Technology, Qingdao, Shandong 266500, China
    6. College of Energy, Chengdu University of Technology, Chengdu, Sichuan 610059, China
  • Received:2021-07-26 Online:2021-12-28 Published:2021-12-16

摘要:

利用岩心、测井、扫描电镜和相关样品物性分析等手段,探讨了四川盆地周缘五峰组-龙马溪组页岩裂缝类型、发育特征、分布规律及其对页岩气富集与保存的影响。结果表明:①页岩裂缝发育受沉积、成岩、构造与压力演化等因素共同影响。低角度滑脱缝与层理缝充填程度低,对储层孔隙度和渗透率均有贡献;高角度裂缝和水平层间缝通常被充填,裂缝有效性较低。低角度裂缝对高角度裂缝穿层性的调节对页岩气的富集与保存具有重要意义。②页岩微裂缝以非构造成因为主,上部低有机质高粘土层段层理缝与大尺度层间微裂缝发育程度低,小尺度粘土粒间孔缝发育,宜采用"密切割"和"高砂比"等储层改造工艺技术以提高缝网控制储量。底部硅质页岩层理缝、层间微裂缝和刚性矿物粒缘缝发育程度高,裂缝力学性质薄弱,它们与密集发育的低角度及小尺度高角度裂缝共生形成了有利的天然缝网系统。③中-浅埋深下层理缝和层间微裂缝渗透率显著高于基质,利于储层改造与页岩气的渗流。深层条件下裂缝与基质渗透率均较低且大致相当,储层渗流能力与压裂改造效果是影响深层页岩气高效开发的重要因素。

关键词: 产能, 物性, 保存, 裂缝, 页岩气, 五峰组-龙马溪组, 四川盆地

Abstract:

An integration of core and scanning electron microscopy (SEM) observation, FMI logging, and physical property analysis, is applied to discuss the types, characteristics and distribution of fractures and their effects on gas enrichment and preservation in the shale of Wufeng Formation-Longmaxi Formations in the Sichuan Basin and on it speriphery. The results show that: (1) the development of shale fractures results from a combination of factors including sedimentation, diagenesis, tectonic and pressure evolution. Low angle slip fractures and bedding-parallel fractures at low level of filling are conducive to reservoir porosity and permeability development. High angle fractures and horizontal interlayer fractures are usually fully filled, leading to low effectiveness as fluid pathways. The modification of low angle fractures on the layer-transecting capacity of high angle fractures is of great significance to the enrichment and preservation of shale gas. (2) The micro-fractures of shale are mainly non-structural. The upper organic-lean interval with high clay mineral content, is of low developmental degree of bedding-parallel and large-scale inter-layer micro-fractures; instead, the small-scale inter-clay particle micro-fractures are well-developed. In this case, the new hychaulic fracturing technologies of dense cluster spacing and high proppant concentration should be adopted to improve fracture network-controlled reserves. However, the bedding-parallel fractures, interlayer micro-fractures and rigid grain-edge fractures with weak mechanical properties are abundant in the lower siliceous shale interval; in addition, the coexistence of intensive low angle fractures and small-scale high angle fractures results in a favorable natural fracture network system. (3) The permeability of the bedding-parallel fractures and interlayer micro-fractures in shale intervals of shallow to middle burial depth, is significantly higher than that of the matrix, favorable for reservoir stimulation and seepage of shale gas. In contrast, permeability of fractures and matrix are both low and roughly equivalent for shale intervals of deep burial. Therefore, the reservoir seepage ability and hychaulic fracturing effect are essential factors for efficient development of deep shale gas.

Key words: productivity, physical property, preservation, fracture, shale gas, Wufeng-Longmaxi Formations, Sichuan Basin

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