页岩热模拟过程中液态烃含量变化及对物性的影响  

Variation in liquid hydrocarbon content during thermal simulation and its influence on physical property of shale

作　　者：邓模[1] 段新国[2] 翟常博[1] 龙胜祥[3,4] 杨振恒[1] 郑伦举[1] 李章畅 曹涛涛 Deng Mo;Duan Xinguo;Zhai Changbo;Long Shengxiang;Yang Zhenheng;Zheng Lunju;Li Zhangchang;Cao Taotao(Wuxi Research Institute of Petroleum Geology,Petroleum Exploration and Production Research Institute,SINOPEC,Wuxi,Jiangsu 214126,China;State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation,Chengdu University of Technology,Chengdu,Sichuan 610059,China;Key Laboratory of Shale Oil and Gas Exploration&Production,SINOPEC,Beijing 100083,China;Petroleum Exploration and Production Research Institute,SINOPEC,Beijing 100083,China;Hunan Provincial Key Laboratory of Shale Gas Resource Exploitation,Hunan University of Science and Technology,Xiangtan,Hunan 411201,China)

机构地区：[1]中国石化石油勘探开发研究院无锡石油地质研究所,江苏无锡214126 [2]成都理工大学油气藏地质及开发工程国家重点实验室,四川成都610059 [3]中国石化页岩油气勘探开发重点实验室,北京100083 [4]中国石化石油勘探开发研究院,北京100083 [5]湖南科技大学页岩气资源利用与开发湖南省重点实验室,湖南湘潭411201

出　　处：《石油与天然气地质》2020年第6期1310-1320,共11页Oil & Gas Geology

基　　金：国家科技重大专项(2016ZX05061);国家自然科学基金项目(41802163);湖南省自然科学基金项目(2018JJ 3152)。

摘　　要：页岩热模拟演化过程中,液态烃含量及赋存状态的变化是深入研究页岩孔隙演化和储层表征的重要内容。对川西北广元上寺剖面低成熟大隆组页岩进行半封闭体系热模拟实验,并对原岩及热模拟样品进行氩离子抛光扫描电镜观察、热模拟样品及其萃取液态烃后的样品开展低温氮气吸附实验。结果表明,低成熟大隆组页岩中有机孔不发育,随着热模拟温度的增加,有机孔开始发育、数量增多、孔径变大,比表面积和微孔体积显著增加且与热模拟温度具有较好的线性正相关性,但中、大孔体积随热模拟温度增加并未表现出明显的变化规律;TOC减少量与比表面积和孔隙体积之间具有较好的正相关性,说明有机质转化为油气过程中微孔数量显著增加。扫描电镜揭示液态烃主要赋存在页岩的晶间孔及已生成的有机孔内;随着热模拟温度增加,液态烃呈现先显著增加后急剧降低的现象,在热模拟温度为325℃和340℃时,液态烃具有最高含量,在热模拟温度450℃以后,液态烃的含量可忽略不计。萃取液态烃后,样品的氮气吸附能力普遍增强;热模拟样品的孔隙呈单峰型分布,孔峰分布在14.36~23.56 nm,而萃取样品的孔峰向更小的孔隙移动,分布在12.05~22 nm。萃取后样品的比表面积、微孔和中孔体积比热模拟样品显著增加,且比表面积和微孔体积与热模拟温度之间的相关性变好,反映了液态烃主要赋存在泥页岩的微孔及部分中孔内。In the process of thermal simulation,the changes of liquid hydrocarbon content and occurrence mode are important to the in-depth study of pore evolution and shale reservoir characterization.A thermal simulation experiment of semi-closed system was conducted on the low mature Dalong Formation shale from Shangsi section,Guangyuan area,Northwestern Sichuan Basin.The original shales and thermally simulated samples were subjected to argon ion milling-scanning electron microscopy(SEM)observation.The simulated samples and their extracted samples to low temperature nitrogen adsorption experiment.The results show that organic pores are not well developed in the original Dalong Formation shale.With the increase of temperature in thermal simulation,organic pores begin to develop with increasing number and pore size.In addition,the specific surface area and pore volume also increase accordingly,and they are in a good linear positive correlation with the temperature in thermal simulation.However,there is no significant change in the mesopore and macropore volumes with the temperature increase.On the other hand,a positive correlation is suggested between TOC consumption and specific surface area,pore volume,indicating a significant increase of the number of micro-pores during the transformation from organic matter to hydrocarbon.The SEM observation revealed that liquid hydrocarbon mainly exists within shale inter-crystalline pores and organic pores,and its content is started with a quick leap but is followed by a sharp drop with temperature increase,reaching a peak at a thermal simulation temperature of 325℃to 340℃,but almost drop to zero at a temperature of 450℃or higher.After liquid hydrocarbon extracting,nitrogen adsorption capacity of the samples is generally enhanced.The samples’pore size distribution is single peaked with a peak within a pore size range of 14.36-23.56 nm,while for the liquid hydrocarbon extracted samples their peak pore size distribution moves to smaller pores of 12.06-22 nm.The specific surface

关 键 词：液态烃 萃取 孔隙演化 物性特征 热模拟实验 页岩 大隆组 四川盆地 

分 类 号：TE122.1[石油与天然气工程—油气勘探]