渤海湾盆地潍北凹陷致密气成藏过程分析  

Reservoir-forming analysis of tight gas in Weibei Sag,Bohai Bay Basin

作　　者：孙耀庭[1] 

机构地区：[1]中国石化胜利油田分公司地质科学研究院,山东东营257061

出　　处：《石油实验地质》2014年第3期325-331,共7页Petroleum Geology & Experiment

基　　金：国家重点基础研究发展计划项目(2008CB209102);中国石化重点攻关项目"潍北凹陷油气勘探潜力及勘探方向"(P11067)共同资助

摘　　要：潍北凹陷北部洼陷带具有形成致密气藏的良好地质条件，在孔二段形成自生自储自盖组合，埋深大于3500 m均为致密气藏发育区。通过分析孔隙尺度下的天然气运移模式、模拟实验确定含气饱和度影响因素，建立了渗透率与最终含气饱和度相关关系，相关系数为0．904，实验结果表明充注时间较早，气藏形成期存在异常高压。流体包裹体均一温度表明深层致密气藏经历了2期充注，第一期发生在沙河街组沉积早期（52～50．5 Ma），第二期发生在沙河街构造运动之前（43．5～36 Ma），以第二期充注为主。沙河街构造运动造成盆地泻压，致密气藏被破坏。新近系的沉积使储层进一步致密化，有利于孔店组致密气的保存。因此，潍北凹陷深层孔店组致密气为残留气藏，仍有一定的勘探前景。There were good geological conditions for tight gas reservoirs in the northern subsag of the Weibei Sag, forming the combination of self-generation, self-storage and self-cover in the 2nd member of the Kongdian Formation . Tight gas reservoirs generated in the area deeper than 3 500 m. The natural gas migration patterns under different porosity conditions were analyzed, and the influencing factors for gas saturation were studied with exper-iments. The relationship between permeability and final gas saturation was defined, and the coefficient was 0.904. Experimental results showed that gas charged early and abnormal high pressure existed during gas accumulation stage. The homogenization temperature of fluid inclusions showed that tight gas reservoirs experienced 2 charging periods. The 1st period was the early Shahejie period （52-50.5 Ma） and the 2nd one was before the Shahejie structural movement （43.5-36Ma）, among which the 2nd period played a more important role. The Shahejie structural movement caused pressure reducing and tight gas reservoirs were destroyed. The deposition of Neogene made reservoirs further compact, which was favorable for tight gas reservoir preservation in the Kongdian Forma-tion. The tight gas reservoirs of the Kongdian Formation in the Weibei Sag were residual gas reservoirs, and still had good exploration prospects.

关 键 词：含气饱和度 致密气 渗透率 孔二段 潍北凹陷 渤海湾盆地 

分 类 号：TE122.3[石油与天然气工程—油气勘探]