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鄂尔多斯盆地中部气田的储层为奥陶系马家沟组白云岩风化壳,马五_1层为其主力气层,该层可分为四个小层,沉积相为分布稳定的蒸发潮坪环境,经历了表生期和浅、深埋藏期岩溶作用,天然气主要聚集在岩溶孔洞缝中。就岩溶发育程度而言,潮上、潮间沉积单元高于潮下沉积单元;古地貌高部位和斜坡带高于相对低凹部位。该区68口产气井统计结果显示,在潮上、潮间带的各小层中获气的井占绝对多数,且产量也相对较高,尤其是马五_1~2、马五_1~3两小层,在潮上、潮间带钻遇天然气的井达到在这两小层中获气井总数的95%以上。另外,在古地貌高部位的气井产量明显高于古地貌低部位的气井。
The reservoirs in the central gas field of the Ordos Basin are dolomite weathering crusts of the Ordovician Majiagou Formation and Ma Wu-1 layer is the main gas layer. This layer can be divided into four sublayers, and the sedimentary facies is a stable evaporative tidal flat Environment, experienced epigenetic epoch and shallow, deep burial karstification, natural gas mainly in the karst hole. In terms of the degree of karst development, the tidal and intertidal sedimentary units are higher than the tidal flat sedimentary units; the paleo-topographic highs and slopes are higher than the relatively low-lying ones. The statistics of 68 gas wells in this area show that the gas wells in each sub-layer in the tide and intertidal zone account for the absolute majority and the yield is also relatively high, especially Ma Wu_1 -2 and Ma Wu_1 Three or three small layers of wells on the tide and intertidal zone met the natural gas well to achieve more than 95% of the total number of wells drilled in the two sub-layers. In addition, the productivity of gas wells in areas with high paleogeomorphology is obviously higher than that in the lower part of paleogeomorphology.