石油与天然气地质 ›› 2023, Vol. 44 ›› Issue (6): 1418-1429.doi: 10.11743/ogg20230607

• 油气地质 • 上一篇    下一篇

川东南盆缘复杂构造区綦江页岩气田的发现与启示

胡东风(), 魏志红, 刘若冰, 魏祥峰, 王威, 王庆波   

  1. 中国石化 勘探分公司,四川 成都 610041
  • 收稿日期:2023-06-25 修回日期:2023-08-17 出版日期:2023-12-01 发布日期:2023-12-20
  • 第一作者简介:胡东风(1964—),男,博士、教授级高级工程师,油气田勘探综合研究与技术管理。E?mail: hudf.ktnf@sinopec.com
  • 基金项目:
    国家自然科学基金企业创新发展联合项目(U19B6003-03)

Discovery of the Qijiang shale gas field in a structurally complex region on the southeastern margin of the Sichuan Basin and its implications

Dongfeng HU(), Zhihong WEI, Ruobing LIU, Xiangfeng WEI, Wei WANG, Qingbo WANG   

  1. Exploration Company,SINOPEC,Chengdu,Sichuan 610041,China
  • Received:2023-06-25 Revised:2023-08-17 Online:2023-12-01 Published:2023-12-20

摘要:

涪陵页岩气田发现以后页岩气勘探开始向川东南盆缘复杂构造区拓展,在复杂构造区发现了綦江页岩气。研究表明:①綦江页岩气田的地质特征总体上与涪陵页岩气田相似,表现为高总有机碳含量(平均2.62 %)、高孔隙度(平均4.53 %)和高含气量(平均5.43 m3/t),为典型的自生自储式连续型干气藏,其地表和地下条件均很复杂,埋藏深度跨度大,属于中深层-深层,气藏中深3 354 m;地温梯度偏低,平均为2.99 ℃/100 m;地层压力系数0.98~1.98,平均1.50,从常压到超高压都有分布;②建立了盆缘复杂构造区“大断裂带主体控制、深埋区富集”的盆缘鼻状断背斜页岩气富集模式,提出了“优质页岩发育、流体压力高、微裂缝发育、地应力低”是“甜点”目标评价的关键要素;③建立了适用的深层页岩气“甜点”预测和和复杂缝网体积压裂技术,为綦江页岩气田高产稳产提供了坚强的保障。2022年11月首期已提交丁山区块五峰组-龙马溪组页岩气探明地质储量1 459.68×108 m3

关键词: 发现历程, 气藏特征, 五峰组-龙马溪组, 綦江页岩气田, 盆缘, 川东南地区

Abstract:

Following the discovery of the Fuling shale gas field, shale gas exploration in the Sichuan Basin has expanded into the structurally complex region on its southeastern margin, where the Qijiang shale gas field has benn discovered. The findings achieved in the study are as follows. (1) The Qijiang shale gas field is generally similar to the Fuling shale gas field in terms of geological features, as shown with high total organic carbon (TOC) content (average:2.62 %), high porosity (average: 4.53 %), and high gas content (average:5.43 m3/t). It is a typical self-sourced dry gas reservoir of continuity. Furthermore, the Qijiang shale gas field exhibits complex surface and subsurface conditions, including a large burial depth range involving moderately deep to deep layers with a medium depth of 3 354 m, low geothermal gradients (average:2.99 ℃/100 m), and extensive formation pressure coefficient in a range of 0.98 to 1.98 (average:1.50) spanning normal to ultra-high pressure. (2) A shale gas enrichment model for basin-margin nose-like faulted anticlines in the structurally complex region is established featuring enrichment at deep burial areas as controlled by major fault zone, and this specifies that the shale gas enrichment in the anticlines, the critical features of shale gas sweet spots encompass high-quality shale, high fluid pressure, well-developed microfractures, and low in-situ stress. (3) Technologies applicable to deep shale gas reservoirs are developed, including sweet spot prediction technology and volume fracturing to form intricate fracture networks, providing a firm guarantee for high, stable gas flow in the Qijiang shale gas field. In November 2022, estimated shale gas in-place of 1 459.68×108 m3 from the Wufeng-Longmaxi formations in the Dingshan block was booked for the first time.

Key words: discovery process, gas reservoir characteristics, Wufeng-Longmaxi formations, Qijiang shale gas field, basin margin, southeastern Sichuan Basin

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