冀中坳陷前第三系碳酸盐岩岩溶发育模式

冀中坳陷前第三系碳酸盐岩沉积演化经历了多期岩溶地质作用,根据古岩溶形成的时间、成因以及形态特征共识别出5种模式,即同生期层间岩溶、暴露期不整合岩溶、暴露期断裂岩溶、压释水岩溶和热液岩溶。前三者属于表生期岩溶,受构造运动及相对海平面变化控制,是岩溶储集层发育的基础;后两者属于埋藏期岩溶,与酸性流体和地下热液的溶蚀作用有关,该两期岩溶作用对前期古风化壳岩溶的残余孔洞进行了进一步改造,是储层建设的主导和直接因素。多期次岩溶作用的叠加控制了区内岩溶缝洞系统的发育与分布,对碳酸盐岩储集物性的改造有着重要的地质意义。 

Palaeo-karst development model of the Pre-Tertiary carbonate rock in Jizhong Depression

The formation of the Pre-Tertiary carbonate rocks in Jizhong Depression has gone through multi-phase karstifications. In light of the formation time, cause, and the morph character of the palaeo-karst, 5 models of Palaeo-karstification are recognized as syngenetic karst formed in the interlayer during the formation of the rocks, supergene karst formed in weathered crust during denudation, fracture karst formed in fractures or joints during denudation period, phreatic karst formed under the released water and thermal fluid condision. The former three kinds of karst are superficial karst and controlled by geo-structures and sea level fluctuation, they are the basis for the development of the reservoir stratum. The latter two, belonging to buried karst that relating to acidic fluid and under ground thermal fluid, have remolded the erosion holes in the former weathered crust and formed the major and direct factors for the development of the reservoir stratum. The development and distribution of the karst fissure and cave system is controlled by the multi-phase karstification, so the paleo-karstifications are of important geologic significance for the formation of the reservoir stratum.