地学前缘 ›› 2016, Vol. 23 ›› Issue (2): 63-74.DOI: 10.13745/j.esf.2016.02.008

• 页岩岩石力学性质与裂缝研究 • 上一篇    下一篇

页岩储层构造应力场模拟与裂缝分布预测方法及应用

丁文龙,曾维特,王濡岳,久凯,王哲,孙雅雄,王兴华   

  1. 1. 中国地质大学(北京) 能源学院, 北京 100083
    2. 中国地质大学(北京) 海相储层演化与油气富集机理教育部重点实验室, 北京 100083
    3. 中国地质大学(北京) 页岩气资源战略评价国土资源部重点实验室, 北京 100083
    4. 海南省地质调查院, 海南 海口 570206
    5. 北京京能油气资源开发有限公司, 北京 100022
    6. 山东科瑞控股集团有限公司, 山东 东营 257000
  • 收稿日期:2015-09-15 修回日期:2015-11-10 出版日期:2016-03-15 发布日期:2016-03-15
  • 作者简介:丁文龙(1965—),男,教授,博士生导师,长期从事石油构造分析与控油气作用、非常规油气构造和裂缝及其与含气性关系研究等方面的教学与科研工作。E-mail:dingwenlong2006@126.com
  • 基金资助:

    国家自然科学基金面上项目(41372139,41072098);国家油气重大专项专题(2016ZX05046 - 003,2011ZX05018 - 001 - 002,2011ZX05033 - 004)

Method and application of tectonic stress field simulation and fracture distribution prediction in shale reservoir.

  • Received:2015-09-15 Revised:2015-11-10 Online:2016-03-15 Published:2016-03-15

摘要:

裂缝是页岩气富集高产的关键因素。页岩储层相对于其他类储层,其塑性相对较强,非构造裂缝比较发育。构造裂缝除了高角度的张性裂缝以外,还发育有较多近水平的层理缝和低角度构造滑脱缝等。针对页岩储集层的特点和裂缝发育特征,从地质成因的角度,明确了页岩储层构造应力场模拟数值模拟与裂缝分布预测的方法,其核心在于建立模拟地区目的层的精确地质模型、力学模型和计算模型。利用页岩的单轴和三轴压缩变形试验和声发射古、今地应力测试结果进行应力场数值模拟,获得研究区构造应力场分布,将应力场模拟果与实际地质资料对比分析,进一步检验校正已建立地质模型的合理性;在此基础上,针对富有机质页岩主要发育张裂缝和剪裂缝的特殊性,分别采用格里菲斯、库伦摩尔破裂准则计算页岩储层张破裂率、剪破裂率,依据张裂缝与剪裂缝所占的比例关系,求取页岩储层的综合破裂率,据此分别定量表征页岩储层中张裂缝、剪裂缝和构造裂缝的发育程度及分布特征;并在全面考虑影响页岩储层裂缝发育程度的综合破裂率、脆性矿物含量、有机碳含量多种主控因素的基础上,进一步提出了页岩“裂缝发育系数”作为最终判别指标,综合定量表征页岩储层裂缝的发育程度和预测裂缝的分布,页岩裂缝发育系数越大,裂缝发育程度则越高。该方法在我国渝东南地区下志留统龙马溪组页岩储层裂缝分布预测中得到了有效应用。此不仅为页岩气甜点优选提供了一种新的技术方法,而且模拟成果对页岩气水平井和压裂改造方案的设计具有重要的参考价值。

关键词: 渝东南地区, 龙马溪组, 页岩储层, 构造应力场模拟, 裂缝预测

Abstract:

Fracture is a key factor for the enrichment and high production of shale gas. Compared with other types of reservoirs, shale reservoir is characterized by a relatively strong ductility and multitypes of structural and nonstructural fractures such as high dipangle tensionshear fracture, low dipangle slip fracture and bedding fracture. According to the characteristics of shale reservoirs and fractures from the perspective of geological origin, a method of tectonic stress field simulation and fracture distribution prediction was put forward and effectively applied in the Lower Silurian Longmaxi shale in the southeastern Chongqing area, the emphasis of which is the establishment of accurate geological, mechanical and mathematical Models. By the use of uniaxial and triaxial compression and acoustic emission tests, the paleostress, presentday stress and mechanical data were obtained to conduct a numerical simulation of the tectonic stress field. The rationality of the established models was examined and calibrated by the comparison of the simulation results and actual geological data. For the particular existence of tension and shear fractures in shale, Griffith and MohrCoulomb criteria were respectively used to calculate the tension and shear rupture rates. According to the proportions of the tension and shear fractures, a comprehensive rupture rate was introduced. By the combination of the comprehensive rupture rate and other dominant controlling factors of fractures, such as total organic carbon (TOC) and brittle mineral contents, the fracture developmental coefficient was proposed as an ultimate evaluating index to characterize the developmental degree and distribution of fractures. This method not only provides a new technical approach for the optimization of ‘sweet spot’, but also has important reference value for the design of horizontal wells and fracturing programs.

Key words: southeast Chongqing area, Longmaxi Formation, shale reservoir, tectonic stress field simulation, fracture prediction

中图分类号: