摘要
为研究鄂尔多斯盆地东南部下古生界碳酸盐岩天然气成藏特征,指导下一步天然气勘探开发,采用地质与地球化学相结合的方法,通过岩溶古地貌恢复、烃源岩有机碳对比、储层成岩作用研究,对下古生界天然气成藏地质条件进行了探讨.结果表明：研究区处于古岩溶斜坡地带,其西部为古岩溶高地,东部为古岩溶盆地,古岩溶斜坡呈北西-南东向展布,古沟槽呈树枝状沿东西向展布;气藏的形成受不整合面沟槽地貌的控制,在斜坡与侵蚀沟槽及斜坡与高地的边缘地带含气性能好.上古生界煤系烃源岩是下古生界主要的供烃层位,其生烃强度是下古生界的4～5倍.在裂缝的沟通作用下,天然气由古沟槽侵蚀区和铝土岩缺失部位进入下古生界风化壳岩溶储层,表生岩溶作用和溶蚀作用形成的孔、洞、缝为油气充注提供了储集条件.
In order to research the characteristics of natural gas in Paleozoic carbonate rocks in the southeastern Ordos Basin and guide natural gas exploration and development, we have a discussion on the Lower Paleozoic gas reservoir geological conditions by combining geology and geochemistry, paleo- geomorphic ,hydrocarbon source rock, organic carbon comparative, and the diagenesis of reservoir. The results showed that the studied area is in Palaeokarst slope zone. The west is in the Palaeokarst high- land, the east is in palaeokarst basin, Palaeokarst slopes in NW-SE spread between highland and basin, palaeogroove is dendritic and spread in EW; Gas reservoir formation is controled by unconformity of groove topography, the edges of slope and erosion groove and the slope and highlands are with gas area. Upper Paleozoic source rocks are the main hydrocarbon layers, their hydrocarbon intensity is 4 -5 times than those of Lower Paleozoic. Paleozoic sandstone-cracks lose eondutor is gas downward migration of the channel, down from Shanxi group in each period, gas have the ability migration from top to bottom of Ma- jiagou group in different degrees, gas enter the weathering crust karst reservoir from palaeogroove erosion area and bauxite missing parts. Supergene karstification and pore, hole, slot formed by the dissolutionprovides storage conditon for the oil and gas charging.
出处
《西安科技大学学报》
CAS
2014年第6期713-718,共6页
Journal of Xi’an University of Science and Technology
基金
中国地质调查局地质调查计划项目"鄂尔多斯盆地多种能源综合调查评价"(12120114009201)
关键词
古地貌
烃源岩
成藏条件
下古生界
鄂尔多斯盆地东南部
paleogeomorphic
hydrocarbon source rock
reservoir forming conditions
Lower Paleozoic
southeastern ordos basin
