基底断裂"隐性活动"对鄂尔多斯盆地上古生界天然气成藏的作用

Control of basement fault minor-activity on gas pool formation of Upper Paleozoic, Ordos Basin

鄂尔多斯盆地北东向基底断裂中、新生代"隐性"活动对上古生界天然气富集高产和成藏有明显控制作用。采用渗透率异常频率分析方法,预测了盆地中东部地区上古生界裂缝的分布,并建立了裂缝发育与基底断裂之间的成因关系,指出基底断裂后期活动不仅对盆地上古生界致密储集层的裂缝发育有控制作用,而且对天然气成藏有促进作用。应该重视盆地北东向基底断裂发育区次生天然气藏的勘探。

Large amount of fractures developed in tight reservoir rock in Upper Paleozoic in Ordos Basin. Based on the frequency analysis of abnormal value of permeability from a lot of data, the distribution of fractures in the central-east part of this basin is forecast which trend to NE, located mainly in area of NE basement faults. The heterogeneity of basement in Ordos Basin has led to the activity with minor scale of basement faults in the dominant NE orientation in particular since Mesozoic, which had given strong influence not only on the fracture forming, but also the gas pool forming. The secondary gas pool is believed to be discovered in the future exploration in the NE basement fault area.