煤层气单井产量差异性强，实际开发效果与预期差距较大。分析微构造对煤储层地质条件和对煤层气开发生产的影响，剖析不同微构造部位压裂改造效果、压降漏斗形态、煤粉产出、气水动态对地质－工程因素的响应，讨论“动态气藏”形成及微构造控藏机理，明确了微构造的控产特征。研究表明：微构造、煤层气地质条件与开发动态特征的耦合作用，造就了不同微构造部位产气效果的明显差异。在长期开发过程中，不断解吸的煤层气顺着优势降压方向运移汇聚至微构造高部位形成“动态气藏”。与常规天然气圈闭控藏机理不同，“动态气藏”是开发生产过程中气水分异和运移聚集形成的新生气藏，这一机理得到生产实践验证。正是受控于这一机理，即使浅埋藏泄压区或背斜轴部煤层含气量不高，但若处于微构造高部位也可能获得高产。因此，相比其它地质因素，微构造对开发过程的影响更为重要。煤储层流场（气场和水场）在不同解吸阶段的变化规律与微构造形态有关：在浅埋藏和正向微构造条件下，煤储层将优先解吸产气；在正向构造背景的负向微构造、独立负向构造、地下水径流区、断层及陷落柱附近，沟通上下含水层井的产水量较大；在正向构造背景的负向微构造部位，煤层气井可为周边井做贡献且后期高产，形成高产水高产气型井；在独立向斜部位，煤层气井可为周边井做贡献，形成高产水低产气型井；其他4种地质条件下的井为“无效排水”的高产水低产气型井。据此，划分出六类煤层气井，其中五类井与微构造密切相关。在正向微构造与斜坡，以高稳产和缓慢递减A型井为主；产量突停B型井起源于煤粉卡泵，主要分布在构造陡变部位；在负向构造部位，以持续高产水低产气D型井为主；在采空区、断层附近，以间断产气E型井为主。上述成果改变了背斜轴部原位贫气等传统认识，有助于提高煤层气甜点评价和井位布置准确性，为预测未开发区相似地质条件煤层气井产能及开发规律提供了新的思路和依据。

There are strong differences in production among different wells of coalbed methane (CBM),and the actual development outcome is far from one expected. The authors analyze the impact of micro structures on the  CBM’s geological conditions,development and production,investigate the fracturing effects of different microstructures,pressure drop funnel shape,the output of pulverized coal and the response of gas water dynamics to geological and engineering factors,discuss the formation of “dynamic gas reservoir” and the reservoir controlling mechanism of microstructure,and define its production controlling characteristics. The research shows that the coupling effect of microstructure,the CBM geological conditions and development dynamics leads to some obvious differences in the CBM production at different microstructure locations. In the long term development process,the continuously desorbed CBM migrates along the dominant depressurization direction and converges to the high part of microstructure to form a “dynamic gas reservoir”. Being different from the conventional trapping and controlling mechanism of natural gas,the “dynamic gas reservoir” is a new type of gas reservoir formed by gas water difference,migration and accumulation in the process of development and production. The mechanism has been verified by the production practice. Controlled by this mechanism,even if the CBM content in shallow buried pressure relief area or anticline axis is not high,a high production level may be obtained if the wells are located at the high part of microstructure. Therefore,compared with other geological factors,the influence of microstructure is more important on the CBM development process. The variation of flow field (gas and water fields) in coal reservoir is related to microstructure at different desorption stages. The water production, in which negative microstructure with positive structural background, independent negative structure, groundwater runoff area, near fault and collapse column, open surrounding rock or wells connected with high aquifer by fracturing, is large. In the negative microstructural part of the positive tectonic background,the CBM wells contribute to the surrounding wells and get high gas production in a late stage,forming high production water and gas wells. In the independent syncline,the wells can also contribute to the surrounding wells to form high water and low gas production wells. The other four types of wells with different geological conditions are “ineffective drainage” wells with high water and low gas production. On the basis of above principles,the CBM wells are divided into six categories,of which the five types of wells are closely related to microstructures. In the positive microstructure and slope,there are mainly Type A wells with high stable yield and slow decline. Type B wells with sudden production stop result from the pump stuck by pulverized coal powder,and are mainly distributed in the positions with steep structural changes. Type D wells with continuous high water and low gas production are mainly located in the negative structural position. Type E wells with mainly intermittent gas production are located near the goaf and fault. The above results change the traditional understanding of in situ lean gas in anticline axis,help to improve the accuracy of the CBM sweet spot evaluation and well location layout,and provide a new idea and basis for predicting the productivity and development rules of similar geological conditions in undeveloped areas.

1 煤层微构造控藏控产原理

   1.1 微构造对煤储层地质条件和开发动态的控制与影响

   1.2 微构造对解吸后气、水动态变化规律的影响

   1.3 微构造与煤层气“动态气藏”

2 微构造控产模式案例分析

   2.1 不同微构造部位煤储层流场动态变化规律

   2.2 不同微构造部位煤层气井平均单井曲线特征

   2.3 负向构造煤层气井产气产水效果分区规律

3 基于微构造控产模式的增产工程措施

   3.1 甜点区评价、井位部署和开发方案调整

   3.2 老井产量递减原因分析与综合治理指导

   3.3 生产井管理与设备选型

   3.4 微构造控藏机理的可推广性

4 结论