Multi-well evaluation is a technology for predicting a reservoir and the plane distribution laws of its oil/gas bearing property based on single-well fine interpretation, comparison and analysis, but the conventional logging data cannot be used to distinguish carbonate karst reservoirs, so it is quite important to determine how to clarify the plane distribution laws of karst development degree by using the multi-well evaluation results. In this paper, the karst development characteristics were analyzed reflected by the imaging logging calibrated based on core samples from 15 wells in the Gaoshiti–Moxi area of the Sichuan Basin. Then, the standard imaging chart for each karst development zone in the Middle Permian Maokou Formation was established, and the response characteristics of the conventional logging in each zone were analyzed by using cross-plot and histogram. Finally, on this basis, a new method for identifying karst development zones by using the electrical imaging logging to calibrate the conventional logging was developed. And the following research results were obtained. First, the karst zone of Maokou Formation in the Gaoshiti–Moxi area is divided into weathering crust residue, vertical seepage karst zone, horizontal underflow karst zone and weakly karstified basement from the top to the bottom. Second, in the imaging logging image, the weathering crust residue is displayed in a banded mode of "dark-bright-dark", the vertical seepage karst zone is in a combined mode of vertical line and dark phyre, the horizontal underflow karst zone is in a combined mode of horizontal line-layer and phyre, and the weakly karstified basement is in a mode of bright block, occasionally with linear or phyric characteristics. Third, the effective reservoirs are mainly developed in the vertical seepage zone and the top of horizontal underflow zone. Fourth, the development of Maokou Formation karst is mainly controlled by fracture development, which is in close relation with faults. In conclusion, this newly developed technology is generally applicable to the multi-well evaluation of carbonate karst reservoirs, and its interpretation results provide the key technical support for the deployment of Middle Permian wildcat wells in the Sichuan Basin.
冯庆付,江青春,任梦怡,汪泽成,刘英明,田瀚,黄士鹏. 碳酸盐岩岩溶储层多井评价方法及地质应用[J]. 天然气工业, 2019, 39(9): 39-47.
Feng Qingfu, Jiang Qingchun, Ren Mengyi, Wang Zecheng, Liu Yingming, Tian Han & Huang Shipeng. A multi-well evaluation method for carbonate karst reservoirs and its geological application. NATURAL GAS INDUSTRY, 2019, 39(9): 39-47.