Application of RS and GIS technology in shale gas geological survey and well site selection: a case study of Chengkou, Chongqing

To rapidly, accurately, and comprehensively acquire the basic geological characteristics and the optimal well site locations with favorable surface conditions, and increase the efficiency and cost-effectiveness of shale gas exploration, the geological interpretation and well site selection are carried out by RS and GIS technology in a case study of Chengkou, Chongqing. Using ZY-3 and ETM+ remote sensing data as data sources, the interpretation marks of 33 stratigraphic units and fault structures are established, and 50 stratigraphic boundaries and 143 fault structures are supplemented and corrected based on the 1∶50 000 geological map. The characteristics of the strata and fault structures in the study area are further obtained by remote sensing analysis. To acquire the optimal well site locations, the interpreted faults and strata are also used for well site selection on the basis of previous research. The suitability evaluation factors and grading indicators are optimized. Factors such as slopes, faults, roads, water systems, geological hazards, ecological protection red lines, residential land, and alluvial deposits are selected as suitability factors, and the “one-ballot-veto” method and GIS overlay analysis are adopted to obtain the suitable areas for well sites selection. Additionally, factors such as stratum and land use types are considered to determine optimal well site locations. For the first time, LocaSpaceViewer software is adopted to facilitate 3D visualization of the ground surface and indoor browsing of the well site landscape, which assisted technicians in conducting post-processing work and supporting managerial decision-making. Field investigations validate that the remote sensing geological interpretation outcomes and the selected well sites are consistent with the actual situation. The outcomes reveal that in shale gas exploration, the basic geological characteristics and well sites effectively obtained by RS and GIS technology could serve as valuable references for shale gas geological investigation, resource evaluation, exploration and development, and subsequent construction activities.