摘要
利用鄂尔多斯盆地临兴地区下石盒子组铸体薄片、扫描电镜、阴极发光、包裹体分析,地球化学等资料,通过统计与计算等方法,对研究区下石盒子组不同粒级砂岩的岩石学特征,成岩演化序列以及埋藏过程中孔隙的定量演化进行研究。结果表明:1岩石学组成中,粗砂岩刚性颗粒含量高,塑性颗粒则多集中在细砂岩中;粗砂岩中硅质胶结、碳酸盐胶结含量较高,中、细砂岩以高岭石胶结为主。2成岩演化阶段中,粗砂岩经历的成岩作用较为完全,而细砂岩在早成岩B期就已经基本致密化,中砂岩则为二者的过渡型。3二叠世—中晚三叠世为准同生—早成岩B阶段,成岩作用以压实为主,其对细砂岩孔隙度影响最大;晚三叠世—中侏罗世为中成岩A阶段,成岩作用以溶蚀和胶结为主,粗砂岩溶蚀作用较强,孔隙度较高,细砂岩基本不发育溶蚀和胶结作用;中侏罗世之后,成岩阶段达到了中成岩B,以亚铁碳酸盐胶结为主,粗砂岩受到胶结作用较强,降低了一定孔隙度,但物性依然较好,粗、中、细砂岩最终孔隙度分别为11.07%、6.08%及2.60%。综上所述,粗砂岩由于压实作用较弱,溶蚀作用较强,可以形成良好的储集空间,中砂岩主要受控于压实和胶结作用的双重影响,形成次一级的储集空间,而细砂岩以压实破坏为主,物性相对最差。
Based on analysis on casting thin sections, SEM, cathodeluminescence, inclusion, and geochemical data, and combining with the method ol statistics and calculation, we have discussed the petrologic feature, diagenetic se-quence, and quantitative evolution ol porosity from the different grain-sized sandstone ol the Lower Shihezi Formation in the study area. This research shows that the coarse sandstone has the characteristic with high rigidity particle and the plastic debris is enriched in line-grained sandstone, silicic cementation and carbonate cementation are enriched in coarse sandstone, medium and line sandstone has the high content ol kaolinite. On the diagenetic evolution process, the experience ol diagenesis is more completely in coarse sandstone, but the line sandstone had already become densi- lication in period B ol early diagenetic stage. The medium sandstone is the transition between the two types. The period ol Permian to middle Triassic is penecontemporaneous to period B ol early diagenetic stage, the dominant diagenesis is compaction, which has the greatest influence on the porosity ol line sandstone. In the late Triassic to Jurassic is the period A ol middle diagenetic stage, the dominant diagenesis are corrosion and cementation. The coarse sandstone dis-solution is strong, so has a higher porosity. Fine sandstone is not developed in dissolution and cementation by and large. The period B ol middle diagenetic stage is developed alter middle Jurassic, the dominant diagenesis is lerrous carbonate cementation. Coarse sandstone has strong cementation to reduce the porosity, but the property is still good. The linal porosity is 11.07% , 6.08% and 2.60%. In conclusion, coarse sandstone has better properties because lower compaction and higher corrosion, medium sandstone is secondary lormation because compaction and cementation, line sandstone is the worst lormation because ol higher compaction.
出处
《沉积学报》
CAS
CSCD
北大核心
2017年第1期163-172,共10页
Acta Sedimentologica Sinica
基金
低渗透油气田勘探开发国家工程实验室开放课题(2016GSKJ05-01)
国家自然科学基金(41502142)
中国科学院油气资源研究重点实验室开放基金(KFJJ2013-02)
中国科学院西部行动计划(KZCX2-XB3-12)
甘肃省重点实验室专项(1309RTSA041)~~
关键词
鄂尔多斯
下石盒子组
不同粒级砂岩
成岩演化
孔隙定量
Ordos
Upper Paleozoic
different grain-sized sandstone
diagenetic evolution
quantitative research of porosity
