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鄂尔多斯盆地西部余探1井在奥陶系克里摩里组缝洞体储层中获3.46×10~4 m~3/d天然气流,通过烃源岩地球化学特征和天然气碳同位素对比分析,发现属于原生油型气,对重新认识盆地西部海相碳酸盐岩勘探领域具有极其重要的地质意义。通过对该区奥陶系古地理演化、海相烃源岩特征、储层类型及成藏模式等进行综合研究,研究表明:1盆地西部发育上、下古生界2套有效的烃源岩,下古生界海相烃源岩具备较好的生烃能力;2研究区内发育岩溶缝洞型、白云岩型、礁滩型等3种类型的储集体,储集性能较好,其中岩溶缝洞型储层和白云岩型储层分布范围广、规模较大;3盆地西部奥陶系发育上生下储和自生自储2套有效成藏组合,在西缘冲断带和天环坳陷西翼,以奥陶系内幕气藏为主,即自生自储的成藏组合,天环坳陷东翼以上生下储成藏组合为主,岩溶缝洞体气藏和白云岩气藏是下一步有利的勘探目标。
In Well I of the western Ordos Basin, a natural gas flow of 3.46 × 10 ~ 4 m -3 / d was obtained in the Cretaceous reservoir of the Ordovician Cretaceous. Based on the geochemical characteristics of hydrocarbon source rocks and the carbon isotope comparison of natural gas, it was found that Belonging to the primary oil-gas, it is of extremely important geological significance to re-understand the marine carbonate exploration in the western part of the basin. Through the comprehensive study on Ordovician palaeogeographic evolution, marine source rock characteristics, reservoir types and reservoir forming patterns in the area, the study shows that there are two sets of effective source rocks in Upper and Lower Paleozoic in the western part of the basin , Lower Paleozoic marine source rocks have good hydrocarbon generation ability; (2) There are three types of reservoirs, such as karst cave type, dolomite type and reef-shoal type, which have good reservoir performance The karst fractured-cave reservoirs and dolomite reservoirs are widely distributed and large in scale. 3 Ordovician in the west of the basin developed two effective reservoir assemblages of upper and lower subsurface reservoirs, The western wing of the Central Depression is dominated by the Ordovician intrusive gas reservoirs, that is, self-generated and self-reservoiring assemblages. The upper limbs of the Tianhuan Depression are mainly composed of the Upper Cambrian and Lower Cretaceous gas reservoirs and dolostones Gas reservoir is the next favorable exploration target.