Composite Evaluation of Coalbed Methane Fields Based on Structure and Stress Characteristics-Case Study of B Field in Bowen Basin

The Permian Triassic Bowen basin is located in New South Wales and Queensland along the eastern coast of Australia. The basin is a back arc foreland basin. The complexity of structural evolution leads to the complexity of structure and in-situ stress distribution in Bowen basin. It also leads to the multiple effects of complex structure, fault distribution and stress distribution on the enrichment and production performance of coalbed gas fields. Taking a coalbed gas field in Bowen basin as an example, this paper analyzes the geological characteristics of the gas field area, and studies the geological zoning of the research gas field mainly based on the structural and stress characteristics of the gas field area. Due to the influence of faults and local stress, the gas content, permeability and cleat development characteristics of coalbed gas wells in each geological zoning have different characteristics, Therefore, the production characteristics of CBM wells in different geological zones also show different characteristics. The study shows that the enrichment and high yield of the coalbed gas field is mainly controlled by coal seam structure, fault and local stress. The fine dissection of local geological characteristics of coalbed gas fields is helpful to the designation of later coalbed gas field development strategy and the deployment of development well location. At the same time, it can also provide a favorable reference for the enrichment and high-yield law of coalbed blocks around the gas field.