Reservoir-Forming Conditions of the Ordovician Weathering Crust in the Maigaiti Slope, Tarim Basin , NW China
详细信息
- 责任者：Wu Guanghui (School of Marine Science ; Sun Yat-Sen University ; Guangzhou 510275 ; China) ; Li Honghui
- 刊名：Petroleum Exploration and Development
- 出版年：2012
- 卷期：39(2)
- 关键词：碳酸盐岩油气藏 ; carbonate reservoir ; 风化壳 ; weathering crust ; 塔里木盆地 ; Tarim Basin
- 页码：p.144-153
- 图表：11 illus., 25 refs.
- 分类号：1003
- issnNo：ISSN1000-0747
- isbnNo：CN11-2360/TE
摘要
Based on the seismic and drilling data,the characteristics and reservoir controlling factors,as well as oil and gas distribution law and exploration direction,are analyzed in the Ordovician weathered crust in the Maigaiti slope and its periphery with paleo-uplift background in the Tarim Basin.Structure mapping and analysis reveal that the largest carbonate weathered crust is developed around the Maigaiti slope which forms a favorable reservoir-seal assemblage with the overlying Silurian/Carboniferous mudstone.The Ordovician carbonates experienced multi-stages of karstification and are dominated by small-size fracture-vug reservoirs which are controlled by the karst palaeo-geomorphology,tectonism and lithology.Drilled wells are located mainly in the northern karst depression which has weak karstification and heavy filling.Palaeo-geomorphology reconstruction and seismic reservoir prediction suggest that reservoirs be well-developed in the southern karst slope.The comprehensive analysis of structure revolution and hydrocarbon generation history demonstrates that the hydrocarbon migration and accumulation is controlled by the evolution and migration of the palaeo-uplift.There are two charging stages: large scale oil accumulation in the late Hercynian period and adjustment and re-accumulation of oil cracked gas in the late Himalayan period.The Manan and Maixi slopes in the eastern and western sides of the palaeo-uplift are the favorable areas for hydrocarbon accumulation and adjustment over a long period of time,have the conditions of forming large-scale carbonate fracture-vug type pools,and are important strategic relay exploration areas in the Tarim Basin.