石油与天然气地质 ›› 2023, Vol. 44 ›› Issue (1): 34-45.doi: 10.11743/ogg20230103

• 油气地质 • 上一篇    下一篇

四川盆地安岳气田震旦系台缘带和台内地区天然气成藏差异性及勘探领域

李剑1,2(), 杨春龙1,2(), 谢武仁1, 芮宇润3, 王晓波1,2, 张璐1,2, 谢增业1,2, 郭泽清1   

  1. 1.中国石油 勘探开发研究院,北京 100083
    2.中国石油天然气集团有限公司 天然气成藏与开发重点实验室,河北 廊坊 065007
    3.中国矿业大学(北京) 地球科学与测绘工程学院,北京 100083
  • 收稿日期:2022-06-06 修回日期:2022-11-15 出版日期:2023-01-14 发布日期:2023-01-13
  • 通讯作者: 杨春龙 E-mail:lijian69@petrochina.com.cn;yangchunlong69@petrochina.com.cn
  • 第一作者简介:李剑(1966—),男,博士、教授级高级工程师,天然气地球化学与油气成藏。E-mail:lijian69@petrochina.com.cn
  • 基金项目:
    中国科学院A类战略性先导科技专项(XDA14010403);中国石油天然气股份有限公司创新基金项目(2020D-5008-01);国家自然科学基金项目(41973068)

Differences of natural gas accumulation and play fairways in the marginal zone and interior of Sinian platform in Anyue gas field, Sichuan Basin

Jian LI1,2(), Chunlong YANG1,2(), Wuren XIE1, Yurun RUI3, Xiaobo WANG1,2, Lu ZHANG1,2, Zengye XIE1,2, Zeqing GUO1   

  1. 1.Research Institute of Petroleum Exploration & Development,PetroChina,Beijing 100083,China
    2.Key Laboratory of Gas Reservoir Formation and Development,CNPC,Langfang,Hebei 065007,China
    3.College of Geoscience and Surveying Engineering,China University of Mining & Technology (Beijing),Beijing 100083,China
  • Received:2022-06-06 Revised:2022-11-15 Online:2023-01-14 Published:2023-01-13
  • Contact: Chunlong YANG E-mail:lijian69@petrochina.com.cn;yangchunlong69@petrochina.com.cn

摘要:

四川盆地安岳气田是中国迄今为止发现的最大规模的海相碳酸盐岩气田,探明天然气地质储量1.03×1012 m3,其中震旦系灯影组占56.3 %。目前灯影组勘探开发主要围绕灯影组四段台缘带展开,且台缘带单井产能明显高于台内地区。基于台缘带和台内地区天然气地球化学特征及气藏对比关系,结合成藏条件分析,探讨其成藏差异性。研究表明:①灯影组台缘带较台内地区天然气甲烷氢同位素明显偏重,对应寒武系源岩古水体介质盐度高于震旦系,反映由台缘带到台内地区震旦系烃源岩贡献比例的增加;②台缘带与台内地区储层在岩石类型、储集空间等方面一致,但台缘带储层内部溶蚀孔洞发育程度强于台内地区,主要受控于丘滩发育程度和表生岩溶作用强度;③台缘带和台内地区成藏组合存在差异,台缘带紧邻裂陷内烃源岩,储层侧向对接烃源岩,存在旁生侧储、上生下储等多种成藏组合,而台内地区距裂陷内烃源岩较远,需要通过沟通油、源的断裂输导油气,成藏组合单一;④震旦系-寒武系烃源岩贡献比例的不同和优质储层发育位置及组合类型的差异,是导致台缘带和台内地区产能差异巨大的主要原因。川西北蓬莱—剑阁地区是未来深层灯影组台缘带的有利勘探领域,古隆起围斜部位台地内部构造-岩性气藏是灯影组台内地区主要有利勘探区。

关键词: 台内地区, 台缘带, 成藏差异, 碳酸盐岩, 寒武系, 震旦系, 安岳气田, 四川盆地

Abstract:

Anyue gas field in the Sichuan Basin is the largest marine carbonate gas field discovered so far in China, with discovered gas-in-place of 1.03×1012 m3, of which gas in Dengying Formation accounts for 56.3 %. In recent years, the exploration and development of Dengying Formation mainly focus on its 4th member (Deng 4 Member) in the marginal zone of platform, and the single well productivity of the platform marginal zone is markedly higher than that of the platform interior. In the study, we discuss the differential gas accumulation based on the geochemical characteristics of natural gas and the correlation between gas reservoirs in the platform marginal zone and the interior, combined with the analysis of accumulation conditions. The results show that the hydrogen isotope value in methane of natural gas in the platform margin zone is obviously larger compared with the platform interior, and the salinity of the paleowater medium of the Cambrian source rocks is correspondingly higher than that of the Sinian source rocks, which reflects the contribution increase of the Sinian source rocks from the platform marginal zone to interior. Second, the reservoirs in the two zones are consistent in multiple aspects like the rock type and reservoir space, but the dissolved pores or cavities of reservoirs in the platform marginal zone is better developed than that in the platform interior, which is mainly controlled by the development extent of mound-shoals and the intensity of epigenetic karstification. Third, there are differences in source-reservoir assemblages between the two zones. The platform marginal zone is adjacent to the source rocks in the rift with its reservoir laterally juxtaposed with the source rocks, resulting in various source-reservoir assemblages such as the side source rock-lateral reservoir assemblage as well as the upper source rock-lower reservoir assemblage. However, the platform interior is located far away from the source rocks in the rift, and faults rooted in source rocks are needed to transport the hydrocarbons, resulting in single-type source-reservoir assemblage. Fourth, the difference in the contribution between the Sinian and Cambrian source rocks and the differences in the development position and assemblage type of high-quality reservoirs are the main reasons for the huge differences in productivity between the two zones. Penglai-Jian’ge area in northwestern Sichuan Basin is a favorable play fairway for deep hydrocarbon exploration in the Dengying Formation of platform marginal zone in the future, while the surrounding slope areas of paleo-uplift are favorable for exploration of structural-lithologic gas reservoirs in the Dengying Formation of platform interior.

Key words: platform interior, platform marginal zone, accumulation difference, carbonate rock, Cambrian, Sinian, Anyue gas field, Sichuan Basin

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