Enrichment patterns and exploration countermeasures of deep coalbed methane in the Linxing-Shenfu block on the eastern margin of the Ordos Basin
XU Changgui;JI Hongquan;WANG Cunwu;ZHU Xueshen
鄂尔多斯盆东缘以大宁−吉县区块为代表的高煤阶深部煤层气富集成藏规律已取得一定认识,但位于东缘北段的临兴−神府区块中煤阶深部煤层气勘探刚刚起步,富集成藏规律认识还不够准确清晰,需要总结其富集成藏规律有效指导深部煤层气开放。
以临兴−神府区块太原组8+9号煤为研究对象,依据煤的烃源岩−储集层双重属性,开展了源储、生烃、赋存和富集控制因素及其耦合关系研究。
结果表明:(1)研究区具有东西分带性,分为东部断阶带和西部平缓带,主体埋深超过1 500 m。太原组8+9号煤层厚度大,微孔和宏孔发育,热演化程度中等、含气量整体较高,深部煤层气成藏条件优越,具备较大的资源勘探潜力。(2)研究区泥坪与分流间湾沉积微相煤层厚度大、镜质组含量高、煤层结构简单,随着热演化程度的增高,煤层含气量变大、气体中甲烷含量的占比显著增加,8+9号煤层温−压条件耦合控制的临界吸附带在1 750 m左右,泥岩良好的封盖性、稳定的构造环境和封闭的水动力条件是煤层气富集的重要保障。(3)针对研究区地质条件的差异性,平缓带的煤层气富集区应加快勘探节奏,围绕探明储量区扩大勘探,同时加强该区深部煤层可压性研究,推动规模建产;断阶带的煤层气富集区应开展试采评价,加强离石走滑断裂带的压扭、张扭过渡区研究,以期获得储量发现。研究成果系统总结了临兴−神府区块中煤阶深部煤层气富集成藏规律,指导了富集区的优选,对推动该区效益勘探与规模开发具有积极意义。
Some insights have been gained into the enrichment and accumulation patterns of deep coalbed methane (CBM) in high-rank coal seams on the eastern margin of the Ordos Basin, represented by the Daning-Jixian block. However, the exploration of deep CBM in medium-rank coal seams in the Linxing-Shenfu block, located in the northern segment of the basin's eastern margin remains in its initial stage, leading to an inaccurate and unclear understanding of the enrichment and accumulation patterns. This necessitates summarizing these patterns to effectively guide deep CBM production.
Focusing on the Nos.8 and 9 coal seams of the Taiyuan Formation in the Linxing-Shenfu block, this study investigated the factors controlling source rock - reservoir configuration, along with hydrocarbon generation, occurrence, and accumulation, and the coupling relationships between these factors based on the dual attributes of coals as both source rocks and reservoirs.
Key findings are as follows: (1) The study area exhibits an east-west zoning, consisting of the eastern fault terrace zone and the western gentle zone, with the main body manifesting burial depths exceeding
deep coalbed methane;enrichment pattern;exploration strategy;Linxing-Shenfu block
主办单位:煤炭科学研究总院有限公司 中国煤炭学会学术期刊工作委员会