煤储层内不同相态物质在地层演化过程中积聚有不同类型能量。为明确煤层气开发过程中，不同相态物质状态随能量变化而发生改变及其对煤层气开发影响，利用单位体积弹性变形势能公式和等效弹簧模型计算煤岩基块弹性势能及裂缝开度最大缩减量；利用朗格缪尔等温吸附公式和理想气体等温膨胀做功公式推算等温条件下吸附煤层气膨胀能；利用纳维-斯托克斯方程定性分析煤层水压强能、重力势能和动能间转化关系；利用氦气、甲烷和去离子水渗透率测试平行试验研究影响煤岩导流能力主要因素。综合分析煤层气开发全过程中，各相态物质间能量转化及各物质状态改变；并于郑庄区内选定地质条件相似但能量特征不同4个相邻煤层气井组，结合各自产出特征和局部煤储层能量特征，探讨煤储层能量对煤层气开发影响。结果表明：在系统能量平衡被打破之后，煤岩通过膨胀对外做功释放弹性势能，引发裂隙开度缩减；吸附煤层气是煤层气产出动力源，通过解吸、扩张释放膨胀能，同时持续侵占煤层水流动空间；裂缝开度缩减会阻碍煤层水压强能与吸附煤层气膨胀能间联系，使后者不再随前者变化而改变。研究认为：煤层水压强能越大，煤储层产水潜力越强；吸附煤层气膨胀能越大，越利于煤层气产出；煤岩基块弹性势能和裂缝开度最大缩减量越小，越利于煤层气开发；煤岩基质变形对煤储层内流体产出影响不明显，而流体运移方式以及传质效率的改变对煤储层内流体产出影响明显。煤储层局部小范围内所承载能量存在差异，此种差异对煤层气井产出影响显著。煤储层能量是决定煤层气开发效果关键要素。

During the process of formation evolution, different types of energy are accumulated in different phase substances of coal reservoir. To clarify the changes in the state of different phases of substances with energy changes and its impact on the development of coalbed methane. Firstly, the elastic deformation potential energy density formula and the equivalent spring model were used to calculate the elastic potential energy of the coal matrix and the maximum reduction of the crack opening. Then, the Langmuir isothermal equation and ideal gas isothermal expansion work formula were used to calculate the expansion energy of absorbed coal bed methane under isothermal condition. Later, the Navier Stokes equation was used to analyze coal bed water pressure energy, gravitational potential energy and kinetic energy. Finally, to analyze the main factors affecting coal permeability, the permeability test with helium, methane and deionized water was carried out. The energy conversion and matter state changes of every phase substances in the whole process of coal bed methane development were comprehensively analyzed. Four adjacent CBM well groups with similar geological conditions but different energy characteristics in Zhengzhuang block were selected, combining the respective output characteristics and the energy characteristics of local coal reservoir, the impact of coal reservoir energy on coal bed methane development was discussed in details. The results show that after the energy balance of the system is broken, the coal rock releases elastic potential energy through expansion, which causes the crack opening to decrease. Adsorbed coal bed methane is power source of coal bed methane production, which releases expansion energy through desorption and expansion, while continuing to invade the flow space of coal bed water. The reduction of crack opening will hinder the connection between coal bed water pressure energy and the expansion energy of adsorbed coal bed methane, so that the latter will no longer change with the change of the former. The studies indicate that the greater the coal bed water pressure energy of the coal bed, the stronger the water production potential of the coal reservoir. The greater the expansion energy of adsorbed coal bed methane, the more beneficial the coal bed methane production. The smaller the elastic potential energy and the maximum reduction of the crack opening of the coal matrix, the more conducive to the development of coal bed methane. The influence of coal matrix deformation on fluid productive is not obvious, but the mode of fluid migration and mass transfer efficiency is. There are differences in the energy carried by coal reservoir in a small area, and these differences have a significant impact on the production of CBM wells. Coal reservoir energy is the key to the evaluation of coal bed methane development.

1 研究目标区概况

2 煤储层中不同相态物质能量

   2.1 煤岩基块弹性势能

   2.2 煤层水机械能

   2.3 煤层气膨胀能

3 开发过程中煤储层能量变化

4 煤储层能量对产出特征影响分析

   4.1 局部储层条件与井组产出特征

   4.2 煤基质“变形效应”对产出影响分析

   4.3 煤储层能量对产出特征影响

5 结论与认识