石油与天然气地质 ›› 2019, Vol. 40 ›› Issue (6): 1247-1258.doi: 10.11743/ogg20190609

• 油气地质 • 上一篇    下一篇

涪陵地区五峰组-龙马溪组页岩吸附-游离气定量评价及相互转化

庞小婷1, 陈国辉1, 许晨曦1, 佟茂胜1, 倪彬午1, 包汉勇2   

  1. 1. 中国石油大学(华东) 地球科学与技术学院, 山东 青岛 266580;
    2. 中国石化 江汉油田分公司 勘探开发研究院, 湖北 武汉 430223
  • 收稿日期:2018-12-28 修回日期:2019-08-02 出版日期:2019-12-28 发布日期:2019-10-15
  • 作者简介:庞小婷(1994-),女,硕士研究生,非常规油气地质学。E-mail:601567447@qq.com;陈国辉(1986-),男,博士,非常规油气地质学及分子模拟。E-mail:chenguohui@s.upc.edu.cn。
  • 基金资助:
    国家自然科学基金项目(41672130,41802157,41330313);博士后创新人才支持计划项目(BX201700289);中国博士后科学基金项目(2017M620296,2018M630811);山东省自然科学基金项目(ZR2018BD017)。

Quantitative evaluation of adsorbed and free gas and their mutual conversion in Wufeng-Longmaxi shale,Fuling area

Pang Xiaoting1, Chen Guohui1, Xu Chenxi1, Tong Maosheng1, Ni Binwu1, Bao Hanyong2   

  1. 1. School of Geosciences, China University of Petroleum(East China), Qingdao, Shandong 266580, China;
    2. Research Institute of Exploration and Development of Jianghan Oilfield Branch Company Ltd., SINOPEC, Wuhan, Hubei 430223, China
  • Received:2018-12-28 Revised:2019-08-02 Online:2019-12-28 Published:2019-10-15

摘要: 地层条件下页岩气主要以吸附和游离两种形式存在,确定页岩气的吸附-游离比例,对于评价页岩含气量及合理制定页岩气开发方案有着重要意义。对涪陵地区五峰组-龙马溪组页岩气而言,目前仍缺乏对其吸附-游离量的精细评价,对吸附-游离气的影响因素及转化规律尚未有清晰的认识。因此,在分析涪陵页岩吸附-游离气影响因素的基础上,建立根据页岩物质定量表达最大吸附量的模型,并选用微孔填充模型表征页岩绝对吸附量,评价实际吸附气和游离气含量,计算吸附-游离气比例。并研究了温压、TOC、含水饱和度、孔隙度等因素对吸附-游离气转化的影响,探讨不同条件下页岩吸附-游离气之间的相互转化。研究表明,涪陵地区五峰组-龙马溪组页岩由浅层到深层吸附气量逐渐增多,但随着深度进一步增加,页岩绝对吸附量不再变化;研究区页岩吸附气比例平均值约34%。在2 000~3 500 m深度范围内比较单一因素对吸附-游离气转化的影响,发现孔隙度、TOC对吸附比例影响显著,含水饱和度的影响次之,而压力系数改变对吸附气比例的影响最弱。

关键词: 吸附-游离气转化, 定量评价, 五峰组-龙马溪组, 页岩气, 涪陵地区

Abstract: Shale gas tends to exist in the forms of adsorbed and free gas in reservoirs.Accurate determination of the ratio of adsorbed-free gas is of great significance to evaluating shale gas content and making reasonable plan for shale gas exploitation.At present,there are hardly any fine evaluation of the adsorbed-free gas content,and the influential factors and mutual conversion pattern of adsorbed-free shale gas are rarely known in the Wufeng-Longmaxi Formations,Fuling area.Hence,based on the analyses of influential factors on adsorbed-free gas,we built a model to quantitatively calculate the maximum adsorption capacity according to the mass of shale,and chose a preferred micropore filling model to characterize the absolute adsorption capacity of shale,in an effort to measure the real adsorbed and free gas contents of shale and figure out the ratio of adsorbed-free gas.In addition,the effect of factors including temperature,TOC,water saturation and porosity,on the mutual conversion of adsorbed-free gas,is also under discussion.The results show that,the adsorbed gas content tends to increase from shallower to deeper layers of the Wufeng-Longmaxi Formations,but the absolute adsorbed gas content of the shale stays steady as the depth further increasing.The average ratio of the adsorbed-free gas is about 34% in the shale studied.In comparing the effects of individual factors on the mutual conversion at a depth of 2 000 m to 3 500 m,we found that the effect of porosity and TOC is the most significant,followed by the water saturation,and that of pressure coefficient variation is the least.

Key words: adsorbed-free gas mutual conversion, quantitative evaluation, Wufeng-Longmaxi Formations, shale gas, Fuling area

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