石油学报 ›› 2013, Vol. 34 ›› Issue (增刊一): 51-56.DOI: 10.7623/syxb2013S1005

• 地质勘探 • 上一篇    下一篇

烃源岩高—过成熟阶段排烃机理

王义凤1,2, 王东良2, 马成华2, 李剑2, 李志生2, 陈践发1, 王晓波2   

  1. 1. 中国石油大学油气资源与探测国家重点实验室 北京 102249;
    2. 中国石油勘探开发研究院廊坊分院 中国石油天然气集团公司天然气成藏与开发重点实验室 河北廊坊 065007
  • 收稿日期:2013-03-22 修回日期:2013-07-05 出版日期:2013-09-25 发布日期:2013-09-15
  • 通讯作者: 王义凤
  • 作者简介:王义凤,女,1980年1月生,2003年毕业于曲阜师范大学化学专业,2006年获中国石油大学(北京)地球化学专业硕士学位,现为中国石油勘探开发研究院廊坊分院工程师,主要从事油气成因与成藏研究。Email:yifengwang69@petrochina.com.cn
  • 基金资助:

    国家重大科技专项(2011ZX05007)资助

Mechanism of hydrocarbon expulsion from source rocks at high-over maturation stage

WANG Yifeng1,2, WANG Dongliang2, MA Chenghua2, LI Jian2, LI Zhisheng2, CHEN Jianfa1, WANG Xiaobo2   

  1. 1. State Key Laboratory of Petroleum Resources and Prospecting, China University of Petroleum, Beijing 102249, China;
    2. Langfang Branch, PetroChina Research Institute of Exploration and Development; CNPC Key Laboratory of Gas Reservoir Formation and Development, Langfang 065007, China
  • Received:2013-03-22 Revised:2013-07-05 Online:2013-09-25 Published:2013-09-15

摘要:

烃源岩排烃过程也就是油气的初次运移过程,常规油气只有排出烃源岩后才有可能对油气的运聚成藏作贡献。古老烃源岩演化程度高,怎样排烃的问题,一直以来没有一个普遍认同的观点。针对这个问题,选择高—过成熟泥岩和灰岩样品,通过环境扫描电镜、压汞、孔隙度、渗透率及CT扫描等实验技术,观察原始泥灰岩中微孔隙及微裂隙的发育情况;然后再将岩石样品在高压釜中加热并恒温恒压72 h,生排烃后与原始样品进行比对后发现,岩石在高成岩阶段温压共控下矿物发生了明显的重结晶作用,矿物颗粒变大,有大量烃类的生成,许多细小颗粒被生成的酸性物质溶蚀,从而产生了微孔隙。烃源岩孔隙度及渗透率明显改善,没有增加新裂缝。研究认为,高成岩阶段微孔隙是烃源岩的主要排烃通道之一。

关键词: 烃源岩, 高-过成熟阶段, 排烃机理, 微孔隙, 模拟实验

Abstract:

Hydrocarbon expulsion refers to the initial migration of oil and gas in source rocks. It is only after oil and gas being expelled from source rocks that the hydrocarbons can contribute to oil and gas mitigation and accumulation. The mechanism of hydrocarbons expelled from source rocks of high maturity has long been a controversial issue. In this study, the development of microstructures(micropore and microfracture)in original marlstone is examined with high- and post-maturity mudstone and limestone samples by means of environmental scanning electron microscopy, mercury porosimeter, porosity and permeability determination, and computed tomography scanning. Then, the source rocks are heated in an autoclave at constant temperature and pressure for 72 h of hydrocarbon generation and expulsion. In the thermal simulation experiment, the source rocks undergo a significant mineral recrystallization at the late diagenetic stage under the joint control of temperature and pressure. The mineral particles grow in size while substantial amounts of hydrocarbons are generated. A large number of fine particles are corroded by acid products, leading to the formation of micropores. The porosity and permeability of source rocks are significantly improved with no formation of new fractures. The results demonstrate that micropore is one of the primary channels for hydrocarbon expulsion from source rocks at late diagenetic stage.

Key words: source rocks, high-over maturation stage, hydrocarbon expulsion mechanisms, micropore, simulation experiment

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