鄂尔多斯盆地东缘深部煤层气勘探开发的重大突破，正面回应了深部煤层气能否实现高效开发的疑虑，展示了深部煤层气勘探开发的巨大潜力。深部煤层气赋存态与浅部煤层气相比发生了根本性变化，多相态气体共存使深部煤层气兼具“常规”与“非常规”双重地质属性。深部煤层气藏形成与演化过程中，煤层气赋存相态不断发生变化，多态甲烷的相互转化存在于煤层气富集成藏、破坏调整的整个过程中，厘清深部煤层气成藏过程中气体赋存状态及动态转化规律是预测深部煤层含气量和圈定“高饱和-超饱和”甜点区的前提和关键。本文以鄂东缘大宁-吉县区块为解剖对象，综合利用盆地模拟技术与流体包裹体示踪技术，还原并分析了区块深部煤层气藏 “五史”演化过程，结合孔隙度、孔隙结构、含水饱和度等储层物性变化，探索了深部煤层气成藏演化过程中气体赋存相态及比例关系动态变化规律。研究结果表明：煤系地层在石炭-二叠纪稳定沉降，煤层处于常压状态；三叠纪早期煤系进入快速埋藏阶段，欠压实作用导致煤层超压，煤层温度在90-120℃， R_o达到0.5%，煤层进入初次生气阶段，但该阶段生气总量低，吸附能力弱，煤层孔隙度与含水饱和度高，气体主要以游离态存在，吸附气占比仅在5%左右；侏罗纪晚期地层经历了短暂抬升，之后再次快速沉降，早白垩世煤层达到最大埋深，地层温度可达220℃以上，热演化进程加速，R_o达到3%以上，煤层进入二次生气高峰，强烈的生烃作用引起煤层异常高压，压力系数达1.5，同时，该阶段煤层裂隙闭合，孔隙度降低，孔隙结构以微小孔为主，游离气储集空间减少，受高温影响，煤岩吸附能力仍较低，该阶段气体仍以游离态为主，但吸附气量占比增加；早白垩世晚期，在燕山运动和喜山运动作用下煤系地层持续抬升剥蚀，煤系生烃作用停滞，气体大量散失，含气量大幅降低，随着温、压持续下降，煤层吸附能力增加，游离气占比降低，最终不同赋存态气体达到新的平衡。吸附气主要赋存在微孔内表面，而游离气主要以高压压缩状态赋存于宏孔及微裂隙中。

Abstract: The major breakthrough in the exploration and development of deep coalbed methane (CBM) in the eastern margin of the Ordos Basin has positively responded to the doubts about whether deep CBM can be developed efficiently and demonstrated the great potential of exploration and development of deep CBM. Compared with shallow CBM, the occurrence state of deep CBM has undergone fundamental changes. The coexistence of multiphase gases makes deep CBM have both “conventional” and “unconventional” geological attributes. During the formation and evolution of deep CBM reservoirs, the phase state of CBM is constantly changing, and the interconversion of multiphase methane exists in the whole process of CBM enrichment and accumulation, destruction and adjustment. Occurrence state and its dynamic change law are the premise and key to predict the gas content in deep coal seams and delineate the “highly saturated-supersaturated” sweet spots. Taking the Daning-Jixian block in the eastern Ordos Basin as an anatomical object, this paper used basin simulation technology and fluid inclusion tracing technology to restore and analyze the evolution process of the “five histories” of deep CBM reservoirs in this block. Combined with changes in reservoir physical properties such as porosity, pore structure, and water saturation, the dynamic change law of gas occurrence phase state and proportional relationship in the process of deep CBM accumulation evolution was explored. The research results show that the coal-measure strata settled steadily in the Carboniferous-Permian, and the coal seams were in a state of normal pressure. In the early Triassic, coal-measures entered a rapid burial stage, and the undercompaction effect caused the overpressure of the coal seam, the temperature of the coal seam was between 90-120℃, and R_o reached 0.5%. The coal seam enters the initial gas generation stage, but the total amount of gas generation in this stage is low, the adsorption capacity is weak, and the porosity and water saturation of the coal seam are high, so the gas mainly exists in free state and the proportion of adsorbed gas is only about 5%. In the later Jurassic, the formation has gone through a short uplift, and then rapidly settled down again. The coal seams reached the maximum burial depth in the early Cretaceous, the temperature reached above 220°C, which caused the thermal evolution process to accelerate, and the R_o reached above 3%. The coal seam entered the secondary gas generation peak, and the strong hydrocarbon generation caused the coal seam to be abnormally high pressure, with a pressure coefficient of about 1.5.  At the same time, the fracture of coal seam was closed and the porosity was reduced, and the pore structure was dominated by micropores, so the storage space of free gas is reduced. Affected by high temperature, the adsorption capacity of coal was still low, and the gas is still mainly in the free state at this stage, while the proportion of adsorbed gas increased. In the late Early Cretaceous, under the action of Yanshan and Himalayan Movements, the coal-measure strata continued to be uplifted and denuded, the coal-measure hydrocarbon generation stagnated, a large amount of gas was lost, and the gas content was greatly reduced. As the temperature and pressure continued to decrease, the adsorption capacity of the coal increased, while the proportion of free gas decreased, and eventually the gas in different states reached a new balance. Adsorbed gas was mainly on the inner surface of micropores, and free gas occurred in macropores and micro-fractures in a high-pressure compressed state.