石油与天然气地质 ›› 2021, Vol. 42 ›› Issue (4): 973-980.doi: 10.11743/ogg20210417

• 方法技术 • 上一篇    下一篇

“断缝体”概念、地质模式及其在裂缝预测中的应用——以四川盆地川西坳陷新场地区须家河组二段致密砂岩气藏为例

刘振峰(), 刘忠群, 郭元岭, 季玉新, 李王鹏, 林恬, 陈天胜, 金武军   

  1. 中国石化 石油勘探开发研究院, 北京 100083
  • 收稿日期:2020-10-23 出版日期:2021-08-28 发布日期:2021-08-27
  • 作者简介:刘振峰(1974-), 男, 研究员, 石油物探。E-mail: liuzf.syky@sinopec.com
  • 基金资助:
    国家科技重大专项(2016ZX05002-005);中国石化科技部项目(P17020-4);中国石化科技部项目(P18089-2);中国石化科技部项目(P20056-3)

Concept and geological model of fault-fracture reservoir and their application in seismic fracture prediction: A case study on the Xu 2 Member tight sandstone gas pool in Xinchang area, Western Sichuan Depression in Sichuan Basin

Zhenfeng Liu(), Zhongquan Liu, Yuanling Guo, Yuxin Ji, Wangpeng Li, Tian Lin, Tiansheng Chen, Wujun Jin   

  1. Petroleum Exploration and Production Research Institute, SINOPEC, Beijing 100083, China
  • Received:2020-10-23 Online:2021-08-28 Published:2021-08-27

摘要:

裂缝是致密油气藏“甜点”形成的关键要素。由于裂缝尺度和地震资料信息承载尺度之间的巨大差异,以及对规模有效裂缝地质发育模式认识的不足,不同的裂缝预测方法在实践中的应用成效非常有限。在梳理近年来致密油气地质研究领域“断缝体”概念的基础上,对“断缝体”的内涵进行了归纳,建立了四川盆地新场地区须家河组二段致密砂岩气藏“断缝体”地质发育模式,以此模式为指导,分析了“断缝体”组构单元及背景围岩的地球物理响应特征,计算和筛选了基于梯度结构张量的混沌属性和最大似然属性进行“断缝体”的预测,形成了新场地区须二段致密砂岩气藏“断缝体”预测技术方案。在方案实施过程中,利用人工断层解释结果及电成像裂缝解释结果确定了相应的地震属性阈值,用最大似然属性(>0.15)刻画断层滑动面,用混沌属性的不同阈值范围刻画滑动破碎带(0.18~1.00)和诱导裂缝带(0.05~0.18)。通过该方案的实施,获取了新场地区须二段致密砂岩气藏主要目的层段的断层滑动面、滑动破碎带及诱导裂缝带数据体及相应的裂缝预测成果。从预测结果和电成像测井解释结果对照分析来看,由于预测过程考虑了“断缝体”的地质发育模式,预测结果的地质意义较为明晰,与实际情况吻合度较高,表明“断缝体”概念及其地质模式在地震裂缝预测实践中具有重要的应用价值。

关键词: 地震预测, 致密砂岩, 断缝体, 须家河组, 新场地区, 四川盆地

Abstract:

Fractures are one of the factors crucial for the formation of sweet spots in tight oil & gas reservoirs.Due to the great difference between the geological scale of fractures and the resolution of seismic data, and the vague understanding on development patterns of effective fractures of large scale, the effectiveness of seismic prediction methods of fractures is very limited.Based on the concept of fault-fracture reservoir put forward by some geological researchers in recent years, we summarize the connotation of fault-fracture reservoir, and establish a geological model showing their development in the tight sandstone gas pool of the second member of Xujiahe Formation (hereinafter referred to as Xu 2 Member) in Xinchang area.Furthermore, under the guide of the newly established geological model, we discuss the compositional units and geophysical response features of enclosing rocks, calculate and screen the gradient structure tensor (GST)-based chaotic attributes (chaos) and the maximum likelihood attributes for fault-fracture reservoir prediction, and put forward the technical scheme in predicting fault-fracture reservoirs in the Xu 2 Member tight sandstone pool in Xinchang area.In application of the scheme, artificial fault interpretation and electrical imaging logging are used to determine the threshold values of the GST-based chaotic attributes (chaos) and the maximum likelihood attributes.Besides, the threshold values of seismic attributes are calibrated according to the interpretation results of electrical imaging logging and artificial faults, the maximum likelihood attributes (greater than 0.15) are applied to describe the sliding surface of faults, various ranges of threshold values of chaotic attributes are applied to depict the sliding breaking zone (chaos attribute, 0.18-1.0) and induced fracture zone (chaos attribute, 0.05-0.18), and corresponding prediction results are obtained for major target sequences in the study area as guided by the geological model.The comparison of prediction results and electrical imaging log data shows the prediction is in high consistency with the actual situation, and its geological significance is obvious, indicating the concept of fault-fracture reservoir and its geological model are of application value in the practice of seismic fracture prediction.

Key words: seismic prediction, tight sandstone, fault-fracture reservoir, Xujiahe Formation, Xinchang area, Sichuan Basin

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