石油与天然气地质 ›› 2016, Vol. 37 ›› Issue (3): 399-407.doi: 10.11743/ogg20160313

• 油气地质 • 上一篇    下一篇

四川盆地页岩气富集控制因素及类型

朱彤1, 王烽1, 俞凌杰1, 孙润轩2   

  1. 1. 中国石化 石油勘探开发研究院, 北京 100083;
    2. 中国石油大学(北京) 地球科学学院, 北京 102249
  • 收稿日期:2015-09-15 修回日期:2015-12-10 出版日期:2016-06-08 发布日期:2016-06-22
  • 作者简介:朱彤(1968—),女,高级工程师,非常规油气勘探开发规划和页岩气。E-mail:zhutong.syky@sinopec.com。
  • 基金资助:
    中国石油化工股份有限公司科技开发部项目(P13085)。

Controlling factors and types of shale gas enrichment in the Sichuan Basin

Zhu Tong1, Wang Feng1, Yu Lingjie1, Sun Runxuan2   

  1. 1. Petroleum Exploration & Production Research Institute, SINOPEC, Beijing 100083, China;
    2. College of Geoscience, China University of Petroleum(Beijing), Beijing 102249, China
  • Received:2015-09-15 Revised:2015-12-10 Online:2016-06-08 Published:2016-06-22

摘要: 四川盆地页岩气具有多领域、多层系、多类型的特点。有利的沉积相、成熟度和保存条件是四川盆地页岩气富集的关键因素。海相深水陆棚优质页岩具有源、储、可压一体页岩气的富集条件,为最有利的沉积相类型。湖相碳酸盐湖坡风暴滩沉积的页岩与灰岩互层组合,具有源、储、可压近配页岩气富集条件,有利于微裂缝的发育,具有较好储渗性。适中的成熟度(2%~3%)生气高峰阶段,饱和气有机孔隙最发育,页岩的储集性最好。在埋藏条件下,页岩气的赋存总体上随着埋深增加,吸附气缓慢下降,而游离气则较快增加,超压区有利于游离气保存。在此研究基础上,将四川盆地页岩气划分为3个层系5种类型。其中,下志留统盆内缘超压和盆内超高压深水陆棚厚层页岩气型最有利于页岩气富集。依据各层系有利的沉积相带,适中演化程度(镜质体反射率1.3%~3.5%),压力系数大于1.2,埋深小于4 500 m分布区,预测出不同层系的页岩气有利区。

关键词: 成熟度, 保存条件, 沉积相, 勘探有利区, 页岩气, 四川盆地

Abstract: Shale gas in the Sichuan Basin features in multi-domain,multi-layer and multi-types.The main controlling factors for shale gas accumulation are favorable sedimentary facies,thermal maturity and preservation condition.High quality marine shale of deep shelf facies is high in hydrocarbon source quality,reservoir quality and fracturability,thus is the most favorable sedimentary facies.Sequences of carbonate lake slope storm beach facies consist of interbedded shale and limestone.The close combination of shale with high hydrocarbon source quality and limestone with high reservoir quality and high fracturability provides favorable conditions for shale gas accumulation.Shale with moderate thermal maturity(2%-3%) for peak gas generation has the most developed gas-saturated organic pores,thus the best storage capacity.Shale gas content generally increases with increasing buried depth under burial conditions.The adsorbed gas content decreases slowly,while the free gas content increase rapidly.Overpressure zone is favorable to free gas preservation.On this basis,gas shales in the Sichuan Basin can be divided into three layer series and five types.The thick shale of deep shelf facies with ultrahigh pressure within the Late Silurian basin and that with overpressure at the inner edge of the basin are the most favorable for shale gas enrichment.Favorable areas of shale gas in different layer series were predicted according to the criteria of favorable sedimentary facies zones,moderate thermal maturity (Ro=1.3%-3.5%),pressure coefficient over 1.2 and buried depth less than 4 500 m.

Key words: maturity, preservation condition, sedimentary facies, favorable area for exploration, shale gas, Sichuan Basin

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