Origin of Dolomitic Reservoir Rock in the Permian Fengcheng Formation in Wu-Xia Area of the Junggar Basin
详细信息
- 责任者：Zhu Shifa (State Key Laboratory of Petroleum Resource and Prospecting ; Beijing 102249 ; China) ; Zhu Xiaomin
- 刊名：Geological Journal of China Universities
- 出版年：2013
- 卷期：19(1)
- 页码：p.38-45
- issnNo：ISSN1006-7493
- isbnNo：CN32-1440/P
摘要
The dolomitic rocks of the Permian Fengcheng Formation are formed under special geologic conditions,and are important hydrocarbon reservoir rocks in Wu-Xia area in the Junggar Basin.Data of petrologic characteristics,SEM EDS and stable isotope composition indicate that dolomitizing host rocks are volcaniclassic rocks.Dolomitizing fluids probably came from brine from nearshore and shallow-water lake deposits in the Fengcheng Formation,which formed under arid climatic conditions,and from residual Mg-rich seawater from underlying Jiamuhe Formation and Carboniferous strata.Tuff has a significant content of plagioclase,in which anorthite and labradorite hydrolysis by CO 2 can be couple with calcite precipitation.Later,Mg-rich brine percolate and replace calcite of the first stage to precipitate dolostones.The dolomitizing fluid has been driven by the thermal convection flow generated by volcanic eruption.At the same time,the overthrust of the Wu-Xia growth fault have speeded up the flow of deep Mg-rich water upwards,and induced the water to quickly penetrate and horizontally migrate in the strata.Fracture and fault play important role in controlling the formation of dolostone and the distribution of favorable reservoir.