为了探索复杂地质条件下非均质性煤层CO2-ECBM实施的可行性,以新景矿区15号煤层分叉合并区为例,首先利用测井约束波阻抗反演以及时深转换技术对煤层的空间分布特征进行精细刻画,随后结合本征相干与智能蚂蚁技术实现断裂的综合预测,并对CO2-ECBM地质有利区评价参数(厚度、构造、封盖条件等)进行阐述。研究结果表明,从煤岩厚度角度出发,煤储层厚度越大,CO2封存效果越好。15号煤层分叉区厚度较小且存在夹矸,煤泥系统的存在导致储层,不利于煤层气的采收与CO2封存。15号煤层合并区煤岩厚度相较于分叉区大,地质构造相对简单,煤层气含量较高。从围岩封盖条件出发,15号煤层合并区顶底发育厚层泥岩与灰岩,透气性差,有利于气体大面积、长期有效保存,属于典型的封闭性构造环境。对地质构造来讲,缓倾斜煤层有助于减缓CO2逸散速度,并使CO2更均匀地扩散到整个煤层中,且断裂不发育地区储集效果最佳,逆断层发育地区的储集效果优于正断层发育地区,因此优选15号煤层合并区倾角小于10°、断裂不发育或逆断层发育区块作为CO2-ECBM潜在实施有利区。研究有助于推动该技术在类似复杂煤层中的应用,为CO2在复杂煤层中的封存和注采提供依据。

In order to explore the feasibility of implementing CO2 -ECBM in heterogeneous coal seams under com-plex geological conditions, taking the No. 15 coal seam bifurcation merging area in Xinjing Mining area as anexample,the spatial distribution characteristics of coal seams were finely characterized by logging constrained wave im-pedance inversion and time-depth conversion technology,and then integrated fracture prediction was realized by com-bining eigencoherence and intelligent ant technology. The evaluation parameters (thickness,structure,capping condi-tions,etc.) of CO2-ECBM geological favorable area are also described. The results show that the higher the thicknessof coal reservoir,the better the effect of CO2 storage. The thickness of No. 15 coal seam bifurcation area is small and there is dirt inclusion, and the existence of coal-mudstone system leads to the reduction of reservoir, whichis not conducive to the recovery of coalbed gas and CO2 storage. The coal rock thickness in the coalescing area of No.15 is larger than that in the bifurcation area,the geological structure is relatively simple,and the content of coal-bed methane is higher. Starting from the sealing conditions of the surrounding rock, the top and bottom of theNo.15 coalseam area develop thick mudstone and limestone,which is poor in permeability,conducive to the large-scaleand long-term effective storage of gas,and belongs to a typical closed tectonic environment. In terms of geologicalstructure,the gently inclined coal seam helps to slow down the CO2 escape rate and make CO2 spread more even-ly throughout the coal seam,and the reservoir effect is the best in areas with undeveloped faults,and the reservoireffect in areas with developed reverse faults is better than that in areas with developed normal faults. Therefore,thezone with inclination less than 10°,undeveloped fault or reverse fault development in the No.15 coalseam area is se-lected as the potential favorable area for CO2-ECBM implementation. The study is helpful to promote the applicationof this technology in similar complex coal seams,and provide a basis for the storage and injection and production ofCO2 in complex coal seams.