塔里木盆地塔河油田岩溶峡谷区海西早期洞穴系统发育模式*
Development model of Hercynian cave system in karst canyon area of Tahe Oilfield, Tarim Basin

塔河油田岩溶峡谷区发育大型岩溶洞穴型储集层,勘探效果较好。基于三维地震资料、钻井资料,并结合地震属性提取技术,对地下岩溶洞穴系统、古地貌、古水文系统进行精细刻画,探讨洞穴形成机理,进而总结洞穴发育模式。研究结果表明: (1)峡谷上游段地表水垂向侵蚀作用强烈,峡谷失去了排水功能演变为干谷,下游段水动力条件减弱。(2)峡谷区岩溶洞穴类型划分为暗河洞穴、峡谷—断裂双控型洞穴。暗河洞穴主要发育在峡谷上游段,与峡谷呈“映射”关系。峡谷—断裂双控洞穴发育于峡谷两侧,垂向上具有多层性特征。(3)综上探讨峡谷区岩溶洞穴形成机理,认为较充足的水源补给条件以及水流强烈的垂向侵蚀溶蚀作用控制了暗河洞穴发育,多期次排泄基面下降以及断裂系统共同控制峡谷—断裂双控洞穴的发育。结合现代恩施地区洞穴系统特征,提出了峡谷地区洞穴发育模式,为下一步洞穴储集层预测和勘探实践提供理论借鉴。
Giant karst cave reservoir develop in the karst canyon area of Tahe Oilfield,with good explotation result. Through high resolution 3D seismic data,data of drilling and the seismic attributes extracting the karst cave system,palaeo-gemorphology and palaeo-drainage system were rebuilt. The karst development mechanism was discussed and the model of the karst cave were summarized as following: (1)Surface water has strong vertical erosion in upper reaches of the canyon,the canyon lost the drainage function and evolution into dry valley,hydrodynamic conditions in lower reaches of canyon is weaken. (2)Cave types divided into underground water caves,canyon-fault caves,underground water caves development in the upstream of canyon, underground caves and canyon are mapping relationship,canyon-fault caves development on both sides of the canyon,with multilayer characteristics in vertical. (3)With a comprehensive analysis of the karst cave genesis mechanism in the canyon area,we thought that the underground water cave development in an adequate water supply condition and strong vertical erosion of water,canyon-fault caves development in a multiple-stage drop of base level and fault systems. Combined with the characteristics of modern Enshi cave systems. evolutionary model of the karst cave in canyon are proposed,which provides a theoretical reference for further cave reservoir prediction and exploration practice