鄂尔多斯盆地西北部地区奥陶系岩溶缝洞型储层发育特征及有利目标区分析

摘要

Karst porous fractured reservoirs are found in Ordovician limestones of Qilian sea area in northwestern Ordos basin and have better gas-bearing ability, showing that karst porous fractured reservoirs are a new form for carbonatite's natural gas exploration. Through the analysis of geologic setting of paleokarst cavity's development, the characteristics of paleokarst porous fractured reservoir based on the well drilling, logging data and seismic response are analyzed and two types of reservoirs are classified. Based on the seismic identifying pattern of wells, it is concluded that the target areas of Kelimoli Formation karst porous fractures are planar distributed , forming better reservoir-forming assemblage with Ordovician source rocks, which are the important areas for the future's natural gas exploration.%在鄂尔多斯盆地西北部地区祁连海域奥陶系石灰岩发育段发现岩溶缝洞型储层,并且具有较好的含气性,表明岩溶缝洞型气藏是该盆地碳酸盐岩天然气勘探的新类型.通过对盆地西北部奥陶系古岩溶缝洞发育的基本地质条件进行分析,从钻井、录井、测井及地震响应特征方面阐述了古岩溶缝洞型储层的特征,划分出两种储层类型;根据天1、鄂19井岩溶储层的地震识别模式,预测克里摩里组岩溶缝洞体的有利目标区的平面分布,其与奥陶系烃源岩构成较好的成藏组合,是今后西北部地区天然气勘探的重要区带.