滇东威信地区龙潭组煤系致密砂岩储层特征

Characteristics of coal-bearing tight sandstone reservoir in Longtan Formation of Weixin area, eastern Yunnan

杨甜甜 张晓丽 何金先 师帅 曹文杰 谢莹

中国矿业大学煤层气资源与成藏过程教育部重点实验室，江苏 徐州 221116 中国矿业大学资源与地球科学学院，江苏 徐州 221116 中国石油华北油田分公司勘探开发研究院，河北 任丘 062552

MOE Key Laboratory of Coalbed Methane Resources and Reservoir Formation Process, China University of Mining and Technology, Xuzhou 221116, China School of Resources and Geosciences, China University of Mining and Technology, Xuzhou 221116, China Research Institute of Exploration and Development, Huabei Oilfield Company, PetroChina, Renqiu 062552, China

扫描电镜（SEM）观测是研究岩石微观结构和形态的重要手段。文中以滇东威信地区龙潭组致密砂岩为研究对象，采用SEM和X射线能谱技术，对其显微形貌以及黏土矿物的形态特征进行了研究。结果表明：威信地区龙潭组致密砂岩孔隙包括原生孔隙和次生孔隙两大类，主要发育次生孔隙，以溶蚀孔和微裂隙为主。采用面孔率定量研究方法对不同类型岩石的面孔率和平均孔隙度进行比较，得出了与实验结果一致的结论。砂岩矿物主要由石英和长石组成，其次为绿泥石和高岭石等黏土矿物。龙潭组储层成岩作用包括压实作用、胶结作用和溶蚀作用。黏土矿物种类的组合特征表明，威信地区龙潭组致密砂岩处于中成岩阶段早期。

Scanning electron microscope (SEM) is an important tool to study the microstructure and morphology of rocks. In this paper, taking the tight sandstone of Longtan Formation in Weixin area, eastern Yunnan as example, its microscopic morphology and morphological characteristics of clay minerals by using SEM and X-ray energy spectroscopy techniques was studied. The results show that the pores of the tight sandstone in Longtan Formation of Weixin area include two categories: primary pores and secondary pores, and secondary pores are mainly developed with mainly dissolved pores and micro-fractures. The surface porosity and average porosity of different types of rocks were compared through the quantitative analysis of surface porosity, and conclusions consistent with the experimental results were drawn. The sandstone minerals are mainly composed of quartz and feldspar, followed by clay minerals such as chlorite and kaolinite. The reservoir diagenesis of the Longtan Formation is mainly compaction, cementation and dissolution. The combination characteristics of clay mineral species indicate that the tight sandstone in the Longtan Formation of the Weixin area is in the early intermediate diagenetic stage.

10.6056/dkyqt202204007