土工基础

›› 2016, Vol. 30 ›› Issue (2): 214-218.

• 工程实录 • 上一篇    下一篇

用前缘排替功度量盖层对非润湿流体的封闭能力

吕广忠1，白 冰2，郭迎春1，李志鹏1,胡启芳2   

  1. （1.中石化胜利油田公司，山东东营 257061;
    2.中国科学院武汉岩土力学研究所，岩土力学与工程国家重点实验室，武汉 430071）
  • 收稿日期:2015-03-26 出版日期:2016-04-20 发布日期:2016-04-27
  • 通讯作者: 白 冰(1980-)，男，副研究员,研究方向为岩土力学理论、实验及应用。
  • 作者简介:吕广忠(1974-)，男，博士，教授级高工，研究方向为油气田开发工程。
  • 基金资助:

    国家科技支撑项目(2012BAC24B02)；中石化胜利油田外协项目（Y531131G01）

Measurement of the Cap Rock Sealing Capability to a Non-wetting Fluid with Front Displacement Work

LV Guangzhong1, BAI Bing2, GUO Yingchun1, LI Zhipeng1, HU Qifang2   

  1. (1.Shengli Oilfield Company, SINOPEC, Dongying, 257061；
    2.State Key Laboratory of Geomechanics and Geotechnical Engineering, Institute of Rock and Soil Mechanics, 
    Chinese Academy of Sciences, Wuhan 430071)
  • Received:2015-03-26 Online:2016-04-20 Published:2016-04-27

摘要： 盖层对非润湿流体封闭能力的度量指标是盖层定量评价研究的重要内容。在前人研究基础上，提出了度量盖层封闭能力的前缘排替功指标，它能够同时反映物性封闭和超压封闭机理，也能反映厚度的封闭作用。该指标是在准静态排替条件下，驱替前缘力所做的功，恰好反映了盖层准静态驱替的难易程度。该指标表明，排替压力和厚度同时决定了盖层封闭能力。即使盖层厚度很薄，只要具备足够高的排替压力也能阻止流体泄露。利用新指标评价了东营凹陷沙三段中下亚段盖层的密封性。结果显示利津洼陷封闭能力最强，具有较强的封气能力。牛庄洼陷最小，向东营凹陷南部斜坡区, 差值逐渐减小, 盖层封闭性能较差,不利于深层天然气的储存, 这与综合评价方法的评价结果一致。新指标简单但反映了盖层封闭性的主要机理，建议在实践中推广应用。

关键词: 盖层, 密封性, 封闭能力, 前缘排替功, 东营凹陷

Abstract: The measurement of the cap rock sealing capability to the nonwetting fluids is one of the key tasks in the quantitative assessment of the cap rock. The existing measures cannot represent the sealing mechanism of cap rock thickness. A new method in terms of the Front Displacement Work (FDW) is developed to overcome this disadvantage. This measurement is the work that the fluid front pressure performs at the front displacement during the quasistatic displacement process, and therefore has a clear physical meaning. This measurement covers the two primary sealing mechanisms, i.e. the capillary sealing mechanism and the overpressure sealing mechanism. More importantly, it can reflect the sealing role of the cap rock thickness. Then, this measurement is compared with a newly presented methodology in the literature and applied to evaluate the cap rock sealing capability of Shasan segment of Dongying Depression. The results show that the Lijin depressing has the highest sealing capability and Niuzhuang depression has a lower sealing capability. The sealing capability is relatively low in the south slope area. The new measurement predicts the similar trend of sealing capability. This new measurement is very simple and it can simultaneously reflect the primary sealing mechanism.

Key words: Cap Rock, Sealing, Sealing Capability, Front Displacement Work, Dongying Depression