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以鄂尔多斯盆地延安地区下石盒子组储层为研究对象,在储层成岩作用、埋藏史与热史研究的基础上,应用动力学模型与作用模拟方法分析了该区孔隙度演化史。结果表明,中等地温场、长深埋期煤系地层内的石英砂岩类储层,成岩早期孔隙介质呈酸性而缺乏早期碳酸盐胶结物,压实损失孔隙度较大;溶蚀作用产生了一定的次生孔隙,但长深埋期、较高地温环境下溶蚀产物沉淀为更为稳定的次生石英和黏土矿物,加之含铁碳酸盐胶结物的胶结与交代,造成粒间孔隙大量封闭的同时,又充填了部分溶孔;压实损失孔隙度较大的情况下,石英次生加大的普遍发育及黏土矿物与含铁碳酸盐胶结物的充填,往往造成此类储层为低渗—超低渗储层。
Based on the study of reservoir diagenesis, burial history and thermal history, the evolution of porosity in the Lower Shihezi Formation in Yanan area, Ordos Basin, is studied by using dynamic model and function simulation method. The results show that the medium geothermal field, the quartz sandstone reservoir in the deep-burial coal measure strata, the early diagenetic pore media are acidic and lack early carbonate cement, and the compaction loss porosity is larger; the dissolution has certain effect However, the deposition of corrosion products in deeper and deeper, higher temperature environments is more stable secondary quartz and clay minerals. In addition, the cementation and replacement of iron-bearing carbonate cements results in a large number of intergranular pores being closed While filling some of the pores; compaction loss porosity greater circumstances, the general increase of quartz secondary growth and the filling of clay minerals and iron-bearing carbonate cement often result in such reservoirs as Low permeability - ultra low permeability reservoir.