石油学报 ›› 2020, Vol. 41 ›› Issue (2): 216-225.DOI: 10.7623/syxb202002007

• 油田开发 • 上一篇    下一篇

川南地区龙马溪组页岩混合润湿性评价新方法

郭建春, 陶亮, 陈迟, 李鸣, 赵志红   

  1. 西南石油大学油气藏地质及开发工程国家重点实验室 四川成都 610500
  • 收稿日期:2019-03-29 修回日期:2019-12-15 出版日期:2020-02-25 发布日期:2020-03-09
  • 通讯作者: 陶亮,男,1986年10月生,2010年获东北石油大学学士学位,2014年获俄罗斯国立石油与天然气大学硕士学位,现为西南石油大学石油与天然气工程学院博士研究生,主要从事油气藏增产理论与技术研究工作。Email:taoliangyouxiang@163.com
  • 作者简介:郭建春,男,1970年9月生,1992年获西南石油学院学士学位,1998年获西南石油学院博士学位,现为西南石油大学石油与天然气工程学院教授、博士生导师,主要从事油气开采与储层改造理论与技术、非常规天然气开发等方面的教学与研究工作。Email:guojianchun@vip.163.com
  • 基金资助:

    国家自然科学基金项目(No.51525404,No.51874250)和国家科技重大专项(2016ZX05023-001,2016ZX05048-004)资助。

A new method for evaluating the mixed wettability of shale in Longmaxi Formation in the southern Sichuan

Guo Jianchun, Tao Liang, Chen Chi, Li Ming, Zhao Zhihong   

  1. State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Southwest Petroleum University, Sichuan Chengdu 610500, China
  • Received:2019-03-29 Revised:2019-12-15 Online:2020-02-25 Published:2020-03-09

摘要:

由于页岩矿物组分众多且关系复杂,造成页岩润湿性评价十分困难,因此明确影响页岩润湿性的关键因素对高效开发页岩气尤为重要。以四川盆地川南地区龙马溪组页岩为研究对象,利用多种实验手段,对页岩混合润湿性进行定性分析与定量表征,并建立混合润湿性模型,计算有机质接触角,定量评价有机质亲水能力,同时将层次分析法与灰色关联分析法相结合,建立多层次评价体系,明确影响页岩润湿性关键因素,形成了页岩润湿性评价新方法。研究结果表明:龙马溪组页岩表面呈复杂的非均匀混合润湿性特征,既亲油又亲水,且页岩表面更趋于油湿;页岩亲水性能力与黏土含量正相关,但黏土含量高于一定值时,亲水能力受到抑制;地层温度条件下页岩亲水能力更强,随着页岩与液体浸泡时间的增加,页岩亲水能力逐渐增强;存在最佳液体盐浓度,使得页岩表面接触角最小,在实验条件下KCl溶液测试范围为4%~6%;有机质平均接触角为73.8°,其润湿性为弱亲水,表明水相能够进入有机孔,但亲水能力弱于无机孔;黏土含量对页岩润湿性影响最大,其次为有机碳含量、液体盐浓度和温度。

关键词: 四川盆地, 龙马溪组, 页岩, 混合润湿性, 有机碳含量, 关键因素

Abstract:

It is very difficult to evaluate shale wettability due to the large number and complex relationship of mineral components, and it is particularly important to identify the key factors affecting shale wettability for the efficient development of shale gas. Taking Longmaxi Formation shale in the southern Sichuan Basin as the research object, using a variety of experimental methods, this paper conducts qualitative analysis and quantitative characterization of the mixed wettability of shale, and establishes a model of mixed wettability to calculate the contact angle of organic matter and quantitatively evaluate the hydrophilic property of organic matter. Moreover, through the combination of analytic hierarchy process and grey correlation analysis, this paper establishes a multi-level evaluation system, clearly identifies the key factors impacting shale wettability, and forms a new evaluation method for shale wettability. The results show that in Longmaxi Formation the surface shale is characterized by mixed complex heterogeneous wettability being lipophilic, hydrophilic and oil-wet; the hydrophilic property of shale is positively correlated with the clay content. However, when the clay content is higher than a certain value, the hydrophilic property is inhibited; under formation temperature, the hydrophilic property of shale is stronger. With the increasing soak time of shale in liquid, the hydrophilic property of shale is gradually enhanced; there is an optimal liquid salt concentration making the surface contact angle of shale the smallest. The test range of KCl is from 4% to 6% under the current experimental condition; the average contact angle of organic matter is 73.8°, and its wettability is weakly hydrophilic, indicating that the water can enter into organic pores, but showing the weaker hydrophilic property as compared with inorganic pores; clay content has the greatest effect on shale wettability, followed by total organic carbon content, liquid salt concentration and temperature.

Key words: Sichuan Basin, Longmaxi Formation, shale, mixed wettability, total organic carbon content, key factors

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