岩溶盆地中微隆起带的存在及意义――以鄂尔多斯盆地奥陶纪岩溶古地貌为例

岩溶地貌可以划分为岩溶高地、岩溶坡地和岩溶盆地3种主要类型,岩溶盆地被认为是主要的混水区,其孔洞充填严重,储集性能较差,但随着勘探的深入,在岩溶盆地的局部地区也相继找到了储集性能较好的储层,这些储层的发育部位正好处于岩溶盆地中的微隆起带。根据鄂尔多斯盆地石炭系本溪组厚度图和基底断裂与岩浆岩体分布关系图的分析,指出这种微隆起形成的原因主要是由于基底断裂长期活动的结果;微隆起虽混水但不聚水,受渗流和潜流作用的共同影响,风化壳的发育仍具有一定的深度,由于早期孔洞发育,为后期储层的进一步改造创造了条件。认为岩溶盆地中的微隆起带仍具有较大的勘探潜力。

EXISTENCE AND SIGNIFICANCE OF MICROUMBONES IN KARST BASIN: SAMPLE FROM ORDOVICIAN KARSTIC PALEOGEOMORPHY IN ORDOS BASIN

Karstie geomorphies are consisted of karstic upland, slope and depression. Karst basins are considered mixed water area, in which pore spaces are sorely filled and reservoir properties are unsavoury. With ingoing exploration, good reservoir beds which are located in microumbones are found in some of karst depressions. Combined with thickness map of benxi formation of Carboniferous and distributed relation map of basement rift and magmatite, chronic activity of basement Carboniferous to the formation of microumbones. Under action of percolation and underflow, mieroumbones are composite water but not gathering water and weathered crust developes at sure depth. Early pore space growth provide conditions for reservoir beds reconversion, so microumbones in karst depression have good potention to exploration.