The Daning-Jixian block, located in the eastern margin of the Ordos Basin, is abundant in deep coalbed methane (CBM) resources and serves as a pilot test block for deep CBM development in China. Currently, the exploration and development of a deep CBM are in the early stages. The production characteristics and development laws across different production stages are not fully elucidated, leading to uncertainties in discharge and production control measures as well as the optimization of the production system. This study addresses these challenges by analyzing actual production data from deep CBM wells. It establishes a classification standard for deep CBM wells and a production stage model diagram. Based on this, it compares and analyzes the production characteristics of deep CBM wells with middle and shallow CBM wells as well as the variations among different types of deep CBM wells. The findings reveal the following key points: (1) gas wells are categorized as low-, medium- and high-production wells based on average daily gas production of 1500 and 3000 m³/d, respectively; (2) deep CBM production is delineated into four stages: gas production rise, gas production decline, stable gas production, and gas production depletion; (3) in contrast to middle and shallow CBM wells, deep CBM wells predominantly produce free gas in the early stage, characterized by rapid and high gas production; and (4) the production capacity of deep CBM wells is mainly influenced by reservoir stress characteristics, the effectiveness of fracturing, and the continuity of production. This study provides a valuable reference for the formulation of deep CBM drainage and production systems and development strategies.

中文翻译：

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深层煤层气动态开采特征——以大宁—蓟县区块为例

大宁—蓟县区块位于鄂尔多斯盆地东缘，深层煤层气资源丰富，是我国深层煤层气开发先导试验区。目前，深层煤层气勘探开发正处于早期阶段。不同生产阶段的生产特征和发展规律尚未完全阐明，导致排放和生产控制措施以及生产系统的优化存在不确定性。本研究通过分析深层煤层气井的实际生产数据来解决这些挑战。建立了煤层气深井分类标准和生产阶段模型图。在此基础上，对比分析了深层煤层气井与中浅层煤层气井的生产特征以及不同类型深层煤层气井之间的差异。研究结果揭示了以下要点：（1）气井按平均日产气量1500 m ³ /d分为低产井、中产井和高产井。 （2）深层煤层气产量划分为产气量上升、产气量下降、产气稳定、产气枯竭四个阶段； （3）与中浅层煤层气井相比，深层煤层气井早期以游离气为主，具有产气快、产气量高的特点； (4)煤层气深井产能主要受储层应力特征、压裂效果和生产连续性的影响。该研究为深层煤层气抽采系统及开发策略的制定提供了有价值的参考。