煤田地质与勘探2025，Vol.53Issue(5)：81-92,12.DOI:10.12363/issn.1001-1986.24.12.0795
临兴-神府区块深部煤储层地温场特征及控制模式
Characteristics and control modes of geothermal fields in deep coal reservoirs in the Linxing-Shenfu block
摘要
Abstract
[Objective]Geothermal fields serve as a crucial geological condition controlling the phases and seepage of deep coalbed methane(CBM).Investigating geothermal fields facilitates the assessment and efficient development of deep CBM resources.[Methods]This study explored the Nos.8 and 9 coal seams in the Linxing-Shenfu block using data from drilling,well logging,well tests,and experiments.Specifically,this study summarized the regional distribu-tion patterns of geothermal fields in deep coal reservoirs in the block,analyzed the impacts of the geothermal fields on the gas-bearing and physical properties of the reservoirs,and revealed the controlling factors and mechanisms of the geo-thermal fields.Furthermore,it proposed differential control modes of regional geothermal fields in the block.[Results and Conclusions]The results indicate that coal seams in the study area have a present-day average temperature of about 52℃and geothermal gradients ranging from 1.72℃/hm to 2.64℃/hm(average:2.21℃/hm),suggesting slightly low to normal geothermal gradients.The geothermal fields in the study area are negatively correlated with the adsorption ca-pacity and mechanical properties of coal seams but are weakly positively correlated with their permeability.Specifically,higher geothermal gradients and reservoir temperatures correspond to lower critical depths of gas content in coal seams,a higher amount of adsorbed gas converted to free gas,and improved reservoir permeability.In contrast,higher geo-thermal gradients are associated with lower peak strength,smaller modulus of elasticity,and enhanced plasticity of coals.The geothermal fields in the study area are influenced by multiple factors,including burial depth,structures,groundwa-ter,and the thermal conductivity of rocks.The small differences in the lateral thermal conductivity of strata result in the lateral heat transfer,followed by heat accumulation in uplift zones.As a result,high-temperature geothermal fields are formed.In contrast,faults destroy strata or connect groundwater,leading to thermal diffusion.Consequently,lower-tem-perature geothermal fields are formed.Four temperature control modes of geothermal fields in the study area are identi-fied:(1)The universal mode with temperature controlled by horizontal strata,characterized by normal geothermal gradi-ents but reservoir temperatures varying with the burial depth.(2)The mode with temperature primarily governed by lat-eral heat transfer,occurring in Zijinshan basement uplift.(3)The mode with temperature primarily influenced by faults,observed in the northern Linxing and western Shenfu blocks.(4)The composite mode with temperature dominated by both faults and groundwater,occurring in the eastern Shenfu block.This study reveals the distribution patterns of geo-thermal fields in the study area and their impacts on the physical properties of deep coal reservoirs.Under similar geolo-gical conditions,structurally higher parts with high-temperature geothermal fields are more enriched in free gas.There-fore,it is recommended that these parts serve as significant zones for resource assessment to promote the high produc-tion of deep CBM.关键词
深部煤储层/地温场/含气性/力学性质/控温模式Key words
deep coal reservoir/geotemperature field/gas-bearing property/mechanical property/geotemperature con-trol mode分类
地质学引用本文复制引用
徐立富,白玉湖,徐兵祥,胡维强,陈建奇,李勇..临兴-神府区块深部煤储层地温场特征及控制模式[J].煤田地质与勘探,2025,53(5):81-92,12.基金项目
国家自然科学基金项目(42072194) （42072194）
