摘要
为弄清黔北地区下志留统龙马溪组海相富有机质页岩储层特征,文中利用有机地球化学、低温氮气吸附、甲烷等温吸附和场发射扫描电镜等资料,分析讨论了龙马溪组页岩的矿物学、有机地球化学、页岩储集空间和吸附能力等特征。结果表明:研究区龙马溪组页岩有机质类型以I型为主,有机质成熟度适中,总有机碳质量分数在0.39%~9.24%,平均为2.65%;热演化程度高,镜质组反射率平均为2.03%;页岩矿物组分以石英为主,碳酸盐矿物和黏土矿物质量分数分别为21.5%,21.4%;页岩储层整体脆性较高,利于后期压裂改造;主要发育有机质孔、粒间孔、晶间孔、溶蚀孔及微裂缝等5种孔隙类型,受热演化程度和成岩作用等影响,孔径、形状和发育规模上存在差异,狭缝状中孔提供了大部分的比表面积和孔隙体积,是页岩气的主要储集空间;龙马溪组页岩的吸附气量为1.596~2.127 cm3/g,有机质、热演化程度和脆性矿物质量分数对甲烷吸附能力均有一定贡献。
In order to study the characteristics of marine organic-rich shale reservoirs of the Lower Silurian Longmaxi Formation in the northern Guizhou area,the data of organic geochemistry,low temperature nitrogen adsorption,methane isothermal adsorption,and field emission scanning electron microscopy were used to study the mineralogy,organic geochemistry,reservoir space and adsorption capacity of the Longmaxi Formation shale.The results are as follows.The organic matter type of Longmaxi Formation shale in the study area is mainly type I kerogen;the organic matter maturity is moderate,and the total organic carbon content is 0.39%-9.24%,with an average of 2.65%;the thermal evolution degree is high,and the average of Ro is 2.03%.The mineral components of shale are mainly quartz,with carbonate mineral content and clay mineral content of 21.5%and 21.4%respectively.The shale reservoir has a high degree of brittleness,which is conducive to later fracturing reconstruction.There are mainly five pore types such as organic-matter pores,intergranular pores,intercrystalline pores,dissolved pores and micro-fractures,which are differences in pore size,shape and development scale influenced by thermal evolution and diagenesis.The slit-shaped mesopores,which provide most of the specific surface area and pore volume,are the main storage space for shale gas.The adsorption capacity of Longmaxi Formation shale ranges from 1.596 to 2.127 cm^3/g.The organic matter,thermal evolution degree and brittle mineral content have a certain contribution to methane adsorption capacity.
作者
谷阳
徐晟
徐佳佳
张百忍
姚树青
赵相宽
GU Yang;XU Sheng;XU Jiajia;ZHANG Bairen;YAO Shuqing;ZHAO Xiangkuan(Geoscience Documentation Center,CGS,Beijing 100083,China;National Geological Library of China,Beijing 100083,China)
出处
《断块油气田》
CAS
CSCD
北大核心
2021年第1期33-39,共7页
Fault-Block Oil & Gas Field
关键词
储集空间
甲烷吸附
龙马溪组页岩
黔北地区
reservoir space
methane adsorption
Longmaxi Formation shale
northern Guizhou
