Recognition Technology and Applications of Multi-Genesis Superimposed Karst Reservoir in Tarim Basin-A Case Study on Weathering Curst in Ordovician Yingshan Formation of Tazhong Area

Wang, Hongbin; Zhang, Huquan

Large-scale karst-fractured-cave reservoirs were developed in the weathering curst of Ordovician Yingshan Formation in the northern slope of Tazhong area, which was formed by karstification of two stages: the first stage was karstification of weathering curst that was controlled by karst palaeogeomorphology in mid-Caledonian, and the second stage was burial dissolution that was controlled by fault-fracture network in early Hercynian. This set of reservoir was formed by multi-stages and characterized by multi-types, which result the complexity in the seismic identification for reservoirs. Taking the reservoir evolution as the main line, seismic-response mode of reservoirs and its geological connotation have been confirmed by forward modeling in this paper, based on the genetic types and genetic models of reservoirs. The distribution rules of multi-genesis superimposed karst reservoirs have been described by types and scales according to palaeogeomorphology recovery technology, the well-seismic inversion technology (constrained by multi-attributes) for pore-cave reservoir prediction in weathering crust, the intrinsic correlation calculation for large-scale fracture detection, pre-stack seismic of anisotropy for small-scale fractures detection and etc, where the drilling rate of deployed wells for fractured-cave resrvoirs by this method was up to 100% .

AAPG Search and Discovery Article #90163©2013AAPG 2013 Annual Convention and Exhibition, Pittsburgh, Pennsylvania, May 19-22, 2013