石油与天然气地质 ›› 2022, Vol. 43 ›› Issue (4): 1005-1012.doi: 10.11743/ogg20220420

• 方法技术 • 上一篇    下一篇

页岩气“双甜点”参数测井评价方法

刘双莲1,2()   

  1. 1.页岩油气富集机理与有效开发国家重点实验室,北京 100101
    2.中国石化 石油工程技术研究院,北京 100101
  • 收稿日期:2022-01-05 修回日期:2022-05-01 出版日期:2022-07-14 发布日期:2022-07-14
  • 作者简介:刘双莲(1970—),女,博士、高级工程师,非常规储层评价与测井解释。E?mail: liusl.sripe@sinopec.com
  • 基金资助:
    中国石化科技部项目(PE19012-2)

Logging evaluation of “double sweet spot” in shale gas reservoirs

Shuanglian Liu1,2()   

  1. 1.State Key Laboratory of Shale Oil and Gas Enrichment Mechanisms and Effective Development, Beijing 100101, China
    2.Research Institute of Petroleum Engineering, SINOPEC, Beijing 100101, China
  • Received:2022-01-05 Revised:2022-05-01 Online:2022-07-14 Published:2022-07-14

摘要:

页岩气储层的地质与工程“双甜点”评价常困于3点:① 含气饱和度计算精度低,定量评价方法还不成熟;② 可压裂性评价方法虽多,但操作困难,局限性大;③地质与工程评价弱关联,一体化融合不充分。针对上述难点,开展了3方面探索:① 根据含气原理,基于测井曲线与含气敏感关系的次序重构,建立了表征地质“甜点”的含气丰度曲线;② 根据脆性指数、岩石力学参数及地应力差异系数与压裂的相关性,提出表征工程“甜点”的综合可压指数;③ 根据生产数据,基于测试层产能分级,建立了表征地质-工程一体化的评价图版。本研究提高了页岩气层的定性判别和可压性评价精度,地质-工程一体化评价图版能准确区分高、中、低产气层及干层,并被生产测试及产出剖面所验证。实践表明,该技术在四川盆地及其周缘深、浅层具有良好通用性和可靠性,推广应用前景广阔。

关键词: 含气丰度, 可压指数, 甜点, 地质-工程一体化, 页岩气, 储层评价, 四川盆地

Abstract:

Evaluation of “double sweet spot” in shale gas reservoirs, i.e. shale gas sweet spot that are both geologically and engineeringly feasible, is challenging due to insufficient accuracy of gas saturation calculation, limitations of fracability assessment methods (though quite a few), and inadequate integration between the geological and engineering assessments. In view of these, a gas abundance curve representing the geological “sweet spot” is established to tackle the accuracy problem through a sequential reconstruction of the sensitivity relationship between logging curves and gas bearing property based on gas bearing principles. A comprehensive fracability index representing the engineering “sweet spot” is developed to enhance the usability of the fracability assessment methods based on the correlation of rock brittleness index, mechanic parameters and in-situ stress difference coefficients to fracturing. And a geology-engineering evaluation chart is also proposed to better integrate the two aspects based on the production data and productivity classification of layers tested. This study improves the accuracy of qualitative identification and fracability assessment of shale gas sweet spots. The chart has been proven to be effective in recognizing high- medium- and low-potential gas pay zones as well as dry layers. Practices show that the technology is applicable and reliable in assessing shallow/deep layers in the Sichuan Basin and its periphery.

Key words: gas abundance, compressibility index, sweet spot, geology-engineering integration, shale gas, reservoir assessment, Sichuan Basin

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