石油与天然气地质 ›› 2022, Vol. 43 ›› Issue (3): 621-632.doi: 10.11743/ogg20220311

• 油气地质 • 上一篇    下一篇

四川盆地上二叠统龙潭组烃源岩生、排烃特征及资源潜力

张心罡1(), 庞宏1(), 庞雄奇1,2, 陈君青3, 吴松1, 马奎友1, 张思玉1,2   

  1. 1.中国石油大学(北京) 地球科学学院,北京 102249
    2.中国石油大学(北京) 油气资源与探测国家重点实验室,北京 102249
    3.中国石油大学(北京) 理学院,北京 102249
  • 收稿日期:2021-07-05 修回日期:2022-03-10 出版日期:2022-05-06 发布日期:2022-05-06
  • 通讯作者: 庞宏 E-mail:zxg45466@163.com;panghong19820107@126.com
  • 作者简介:张心罡(1997—),男,硕士研究生,油气藏形成机理与分布规律。E?mail: zxg45466@163.com
  • 基金资助:
    海相深层油气富集机理与关键工程技术基础研究项目(U19B6003)

Hydrocarbon generation and expulsion characteristics and resource potential of source rocks in the Longtan Formation of Upper Permian, Sichuan Basin

Xingang Zhang1(), Hong Pang1(), Xiongqi Pang1,2, Junqing Cheng3, Song Wu1, Kuiyou Ma1, Siyu Zhang1,2   

  1. 1.College of Geosciences,China University of Petroleum (Beijing),Beijing 10224,China
    2.State Key Laboratory of Petroleum Resources and Prospecting,China University of Petroleum (Beijing),Beijing 102249,China
    3.College of Science,China University of Petroleum (Beijing),Beijing 102249,China
  • Received:2021-07-05 Revised:2022-03-10 Online:2022-05-06 Published:2022-05-06
  • Contact: Hong Pang E-mail:zxg45466@163.com;panghong19820107@126.com

摘要:

上二叠统龙潭组是四川盆地多个大中型气田的烃源岩,热演化程度较高,无法通过热模拟实验或化学动力学方法对其进行有效的生、排烃特征和油气资源潜力研究,制约了油气勘探开发。基于国内主要含油气盆地的大量岩石热解、总有机碳(TOC)含量分析及成熟度资料,采用生烃潜力法,建立了龙潭组高、过成熟烃源岩的生、排烃演化模型,分析了生、排烃特征,评价了资源潜力,预测了常规和非常规(页岩)油气有利区。结果表明:龙潭组烃源岩生烃潜力巨大。Ⅱ型和Ⅲ型有机质均在镜质体反射率(Ro)为0.5 %时达到生烃门限,分别在Ro为0.8 %和0.9 %时达到排烃门限;原始生烃潜力指数分别为570 mg/g和200 mg/g;龙潭组现今生烃量达7 460 × 108 t,排烃量达3 840 × 108 t,残留烃量达3 620 × 108 t,其中页岩气资源量为24.6 × 1012 m3,可采资源量为3.7 × 1012 m3;川北应以常规气勘探为主,川中及川东北油气勘探可以常规气与页岩气并举,川东和川南应以页岩气勘探为主。

关键词: 生烃潜力法, 生、排烃量, 页岩气资源量, 有利区预测, 烃源岩, 页岩气, 龙潭组, 上二叠统, 四川盆地

Abstract:

The Upper Permian Longtan Formation provides most source rocks for many large- and medium-sized gas fields in the Sichuan Basin. Due to their advanced thermal evolution, the source rocks are beyond ordinary thermal simulation experiments or chemical kinetics methods that are commonly resorted to while defining the hydrocarbon generation and expulsion characteristics of less thermally evolved source rocks. This hinders the exploration and development of oil and gas generated from the formation. To deal with the problem, this study proposes a model suitable for analyzing the characteristics of hydrocarbon generation and expulsion, evaluating hydrocarbon potential and predicting most promising hydrocarbon accumulation for these source rocks by using the hydrocarbon potential method based on pyrolysis, TOC content analysis and maturity data of source rocks from major petroliferous basins in China. The model shows that the formation has great hydrocarbon generation potential. TypesⅡand Ⅲ organic matter in the formation initiate hydrocarbon generation process when the vitrinite reflectance (Ro) reaches 0.5 %, and start to expel hydrocarbon when Ro reaches 0.8 % and 0.9 %, respectively. The original hydrocarbon generation potential indexes for the two types are 570 mg/g and 200 mg/g respectively. The formation has up to the present the capacity of generating 746 billion tons of hydrocarbon, of which 384 billion tons of hydrocarbon are expelled and 362 billion tons of hydrocarbon are left behind. Shale gas resource volume is 24.6 TCM in the formation, of which 3.7 TCM of gas is recoverable. This predication indicates that exploration shall be focused on finding conventional gas in the north part of the basin, on both conventional and unconventional gases in central and northeast parts of the basin, and on shale gas in the east and south parts of the basin.

Key words: hydrocarbon potential method, hydrocarbon generation/expulsion amount, shale gas resource volume, play fairway prediction, source rock, shale gas, Longtan Formation, Upper Permian, Sichuan Basin

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