A novel approach of evaluating favorable areas for shale gas exploration based on regional geological survey and remote sensing data

Abstract

The periphery of the Huangling Massif is one of the principal prospecting regions of the Lower Cambrian shale gas resources in South China. The geological setting and ground surface conditions are complicated within this area, and the petroleum geological data is limited due to the low degree of exploration. A novel approach based on the regional geological survey and remote sensing data was proposed. The favorable areas for gas exploration targeting the Lower Cambrian Niutitang Shale within the periphery of the Huangling Massif were evaluated by using this approach. Seven key indicators, including the depositional facies and current burial state of the shale strata, density of the exposed faults, dip angle of exposed strata, elevation and slope of the current ground surface, and land utilization, were selected. An evaluation criterion of these indicators was established to facilitate the classification of the study area into four ratings: favorable, low-risk, high-risk, and unfavorable. The overall evaluation of the seven indicators suggested a favorable area of 386.02 km2, a low-risk area of 1784.81 km2, and a high-risk area of 1689.97 km2, accounting for 0.91%, 4.21%, and 3.99% of the whole area, respectively. These results achieved a high level of compliance with the actual exploration discoveries and eliminated over 90% of the total area unsuitable for exploration and production. It is demonstrated that this novel approach can be effectively adopted in the comprehensive evaluation of the favorable area for shale gas exploration with a low degree of prospecting.