AUTHOR=Zou Bing , Qu Haizhou , Zhao Rongrong , Zhang Lianjin , Zhang Yu , Ma Zike , Zhang Xingyu , Huang Qinyang , Mo Qianwen , An Hongyi , Pei Yu 

TITLE=Diagenesis of the first member of Canglangpu Formation of the Cambrian Series 2 in northern part of the central Sichuan Basin and its influence on porosity

JOURNAL=Frontiers in Earth Science

VOLUME=Volume 10 - 2022

YEAR=2023

URL=https://www.frontiersin.org/journals/earth-science/articles/10.3389/feart.2022.1059838

DOI=10.3389/feart.2022.1059838

ISSN=2296-6463

ABSTRACT=In this paper, taking the first Member of the Canglangpu Formation of the Cambrian Terreneuvian in the northern central Sichuan Basin as an example, the diagenesis and its influence on reservoir quality are systemically studied based on the observations and identifications of cores, casts and cathodoluminescence thin sections. The results show that the rock types of the first Member of the Canglangpu Formation are complex, and the sand-bearing oolitic dolomite, sandy oolitic dolomite, sparry oolitic dolomite and fine-grained detrital sandstone are mainly developed. At the same time, the Cang 1 Member has experienced five types of diagenetic environments, including seawater, atmospheric freshwater, evaporative seawater, shallow burial, and medium-deep burial diagenetic environments. Moreover, the main diagenetic processes under different diagenetic environments include cementation, dissolution, compaction, pressure solution, dolomitization and tectonic rupture. According to the analysis, fabric-selective dissolution in atmospheric freshwater diagenetic environment, dolomitization in evaporative seawater environment, and non-fabric-selective dissolution, dolomitization and tectonic rupture in buried diagenetic environment are beneficial to the development of pores in the reservoir. However, cementation, compaction and pressure-solution in medium and deep burial environments, are unfavorable for the development of reservoir pores.