鄂西渝东地区下寒武统石龙洞组成岩作用特征

Diagenesis Features of Lower Cambrian Shilongdong Fm in the Western Hubei and Eastern Chongqing Region

应用鄂西渝东地区利1井(或剖面)下寒武统石龙洞组301件碳酸盐岩薄片的观察资料,结合储层流体包裹体以及埋藏史、热史资料,对其成岩作用类型、成岩演化序列、储层孔隙演化进行了研究。结果显示:该区石龙洞组的主要成岩作用类型包括胶结、压实—压溶、白云石化、破裂、溶蚀等作用;浅埋藏阶段白云石化以及中—深埋藏阶段溶蚀是储层形成的关键性成岩作用;研究区石龙洞组沉积时期潟湖边缘浅滩、浅缓坡浅滩发育区域(龙山茨岩塘一带及其以西)将是储层发育有利区。

Applying the observation data of 301 carbonate rock thin slices in Well Li 1( or profiles) from Lower Cambrian Shilongdong Fm in the Western Hubei and Eastern Chongqing region,combining data of reservoir fluid inclusion,burial history and thermal history,its diagenesis types,diagenetic evolution series and reservoir porosity evolution were studied. The study results show that the major diagenesis types in Shilongdong Fm in this region include cementation,compaction- pressolution,dolomitization,cracking,dissolution etc.; Dolomitization during shallow burial stage and dissolution during middle- deep burial stage are the key diagenesis for forming reservoir beds; Shallow shoals at lagoon edges and shallow ramps( in Ciyantang town of Longshan county and its western region) formed during the deposit period of the Shilongdong Fm are the favorable areas for developing reservoir beds.