Abstract:
As one of the core areas for coalbed methane (CBM) development in China, the Panhe Block in the southern Qinshui Basin has entered a stage of continuous production decline after decades of large-scale exploration and development of main coalbed methane. Stabilizing production and developing replacement resources have become the primary challenges for the high-quality development of the regional CBM industry. Against this background, the replacement development value of multi-layer thin coal seams in the block has become increasingly prominent, serving as a key support for maintaining regional production stability. Previous geological exploration results show that the No. 5—No. 13 thin coal seams in the block are all anthracite reservoirs, characterized by “high gas content, low porosity, and ultra-low permeability”. Vertically, they present a spatial distribution feature of “many layers, thin single layer, and scattered distribution”, which leads to great difficulty in reservoir reconstruction and unbalanced interlayer production, bringing many technical bottlenecks to the efficient development of multi-thin coal seams.To address the above development challenges, this study closely combined the geological conditions and resource endowments of the Panhe Block, and systematically constructed an efficient development technology system suitable for the characteristics of complex thin coal seams. The core technical modules include five aspects: first, a thin coal seam development sweet spot identification method based on the analytic hierarchy process (AHP) and fuzzy comprehensive evaluation method to accurately screen favorable development layers; second, a drilling leakage prediction and discrimination technology integrated with actual drilling geological and engineering data to reduce drilling construction risks; third, establishing multi-type layer configuration optimization models and differential fracturing process charts to achieve precise matching between processes and reservoirs; fourth, developing a combined reconstruction technology centered on “general commingled layer + ball sealer temporary plugging + sand filling separate layer” fracturing to effectively improve reservoir seepage conditions; fifth, proposing an interlayer interference quantification and production allocation system optimization method based on production dynamic curves to improve production efficiency.Based on this technology system, the study area has successfully formed a three-dimensional development model of “main coal seam coordinated commingled production with multi-thin coal seams and replacement development supported by new technologies”, which has effectively released the production capacity of thin coal seams, realized stable production and efficiency improvement of regional CBM development, and provided important technical reference and practical support for the comprehensive development and utilization of similar thin coalbed methane resources in China.