A DEMATEL–AHP-based suitability assessment framework for geothermal water extraction from low- to medium-temperature sedimentary-basin resources: a case study of Lindian County, China

Existing assessments of geothermal water extraction suitability in sedimentary basins are often limited by subjective indicator selection, insufficient consideration of inter-indicator relationships, and weak adaptability to low- to medium-temperature geothermal systems. Taking Lindian County, a representative geothermal field in the northern Songnen Plain, as a case study, this work develops a process-based assessment framework integrating spatial zoning, key-factor identification, indicator quantification, and weighted evaluation. The study area was divided into 16 sub-regions using dominant-factor zoning and GIS-based overlay analysis. Five core driving indicators were then identified from 20 candidate indicators using DEMATEL, and their weights were determined using AHP after passing the consistency test. A four-level scoring scheme was established, and the linear weighted-sum method was used to generate quantitative suitability scores and spatial zoning maps. The results indicate that Lindian County has generally favorable conditions for geothermal water extraction, although clear spatial heterogeneity exists among the sub-regions. Overall, 87.5% of the sub-regions were classified as having good or relatively good suitability. WAI and WDI were identified as the optimal zones, whereas KAII and BEII showed relatively poor suitability. The spatial pattern supports the interpretation that geological structure controls both reservoir development and geothermal fluid occurrence, with hydrochemical properties and reservoir water-richness acting as secondary controlling factors. The proposed framework improves the transparency of indicator selection and provides a practical basis for zoning-based geothermal water extraction planning in similar sedimentary basins. The DEMATEL method is used to reveal the causal and interaction relationships among evaluation indicators, accurately identify the core driving factors, and eliminate the subjectivity in indicator selection. Construct a full - process evaluation framework to achieve a breakthrough from qualitative description to quantitative evaluation, and from single - factor analysis to multi - factor coupling, which is suitable for the core characteristics of sedimentary - basin - type medium - low - temperature geothermal resources. Taking Lindian County as a case to implement the model, differentiate development areas, and provide a replicable technical paradigm and practical reference for the development of similar geothermal resources.