Carbonate fracture-cave volume quantitative calculation and its influencing factors analysis: case study of the main area in Tahe Oilfield

The main production type is the Ordovician carbonate Karst fracture-cave reservoir in Tahe Oilfield. Karst fracture-cave displays strong string reflection amplitude anomaly on seismic sections. On the basis of the analysis about the resolution of seismic data and the theoretical basis for quantitative calculation of Karst fracture-cave, we quantitatively calculated the effective fracture-cave volume by the characterization of the strong seismic anomaly body, apparent-volume estimation, as well as volume correction coefficient of estimated results correction by statistics of a large number of numerical simulation results, and obtain preliminary results for quantitative calculation of the volume for Karst fracture-cave in Tahe Oilfield. Furthermore, some main factors which impact the calculation precision are analyzed. The analysis indicates that the calculation accuracy of effective fracture-cave volume would be improved by large-scale high-precision seismic data acquisition, further development of application new prestack depth migration technologies suitable for accurate imaging of fracture-cave, and much systematical physical modeling in the nextstep.