10 / 2021-05-27 20:10:53

Analysis of paleokarst development characteristic controlled by ordovician paleogeomorphology and slip fault in Tabei area

ancient landform,palaeokarst,ancient river system,slip fault,fracture-cave

Ordovician carbonate fracture-cave reservoirs in Tabei area are complex and variety. By analyzing the characterization of karst fracture-cave reservoirs which are interpreted from seismic data, the F_I7 fault zone is selected as the study area. The karst development period and the fault active period in this area are from the middle and late Caledonian period to the early Hercynian period. The fault is the main channel of karst fluid. The paleokarst segmented feature is obvious and closely related to the ancient landform in this area. Combining the results of fault interpretation based on different periods of slip fault movement, activity segmentation of slip fault, characteristic of faults in different horizons with geomorphology of the Ordovician Yingshan Formation, the paleokarst development characteristic of this fault zone can be divided into buried hill karst area, interlayer karst area, platform edge overlay area, platform edge steep slope area, nearshore gentle slope area, far shore gentle slope area. Based on the analysis of the data of seismic, logging, core and production, typical wells in different karst areas are selected. Fracture-caves for typical wells are Interpreted by seismic amplitude attributes and inversion attribute. Combine the ground river, karst depression, karst lake, monadnock with the underground river, interlayer karst cave, fault karst cave, the characteristic of paleokarst development is summarized and the karst development models in different karst areas are established.