阜康白杨河矿区欠饱和浅层煤含气量测试方法对比研究

Comparative Study on Gas Content Measurement Methods for Undersaturated Shallow Coal in the Baiyanghe Mining Area, Fukang

摘要: 针对新疆阜康白杨河矿区欠饱和煤传统含气量测试方法误差大、制约煤层气资源精准评价的问题，本研究以FK矿区4口取芯井(FC-2, FC-3, FS-24, FK56)实测数据为基础，对GB/T 19559-2008与GB/T 19559-2021两版含气量测试标准进行了系统的对比与评价，探讨了含气量与煤质、埋深及储层参数的关联规律。结果表明：41煤层为矿区主力储气层，横向含气稳定性强，含气饱和度普遍高于70% (排除异常灰分干扰)；含气性呈现“优质埋深区间”特征，850~920 m埋深段因“压力适宜 + 煤质优质”成为含气峰值段，打破了“埋深越大含气量越高”的传统认知；工业分析指标与含气量显著相关，灰分、水分与含气饱和度呈负相关，挥发分存在38%~40.5%的适宜区间；以FK56井10个样品同台对比计算，2008版方法因采用常规取心、常温解吸及静态损失气估算，导致损失气量仅为2021版的25%~45%，总含气量平均误差达12.8% (95%置信区间约11.0%~14.6%，n = 10)，而2021版通过高速保压取心、恒温(±1˚C)解吸及动态损失气校正等技术，将误差控制在±5%以内，可更准确地判定经济层。本研究为阜康浅层煤层气资源评价与开发方案优化提供了技术支撑，也为新疆类似欠饱和煤区含气量测试标准的选用与评价提供了参考。

Abstract: There is a key problem in the Baiyanghe Mining Area, Fukang. Traditional methods measure gas content in undersaturated coal. These methods have large errors. The errors restrict accurate evaluation of coalbed methane (CBM) resources. The measured data come from four cored wells in the mining area (FC-2, FC-3, FS-24, FK56). The study systematically compares and evaluates two versions of gas content measurement standards (GB/T 19559-2008 and GB/T 19559-2021). The laws link gas content to coal quality, burial depth, and reservoir parameters. The results are as follows: 41# coal seam is the main gas-storing layer in the mining area. Its lateral gas-bearing stability is strong. Gas saturation is generally higher than 70%. This excludes interference from abnormal ash content; The gas-bearing property has a high-quality burial depth interval feature. The burial depth section of 850~920 m is the gas content peak. This is due to “suitable pressure + high-quality coal properties”. It breaks the traditional cognition. The old idea was “the greater the burial depth, the higher the gas content”; Proximate analysis indices are significantly correlated with gas content. Ash content and moisture content show negative correlation with gas saturation. Volatile matter has a suitable range. The range is 38%~40.5%.; Based on the same-sample comparison of 10 specimens from Well FK56, the lost gas volume estimated by the 2008 version is only 25%~45% of that by the 2021 version, and the average error of total gas content reaches 12.8% (95% CI approximately 11.0%~14.6%, n = 10). In contrast, the 2021 version uses new technologies. These technologies include high-speed pressure-retaining coring, constant-temperature (±1˚C) desorption, and dynamic lost gas correction. It controls the error within ±5%. This allows more accurate identification of economic coal seams. This study provides technical support for CBM resource evaluation in Fukang’s shallow coal seams. It also helps optimize development plans. Besides, it offers a reference for the selection and evaluation of gas content measurement standards in similar undersaturated coal areas in Xinjiang.