煤层气成藏效应量化表征及类型判识

Quantitative models of coalbed methane accumulation effect and type recognition

定量表征煤层气成藏效应对于有利区识别及开发方式选择具有指导意义.基于煤层气成藏控制因素分析,构建了表征煤层气成藏效应含气性、储层能量及流动能力三大关键要素定量模型.以服务于煤层气产能建设为目标,构建了耦合三大关键要素综合效应模型及四维煤层气成藏效应类型判别模式.按成藏耦合效应指数ξ>50×103,5×103~50×103,ξ<5×103将成藏效应划分为有利、中等、不利3个层次.在每一层次中,以煤层气富集指数100和200、煤层输导能力指数0.5和1.0以及煤层有效流体能量构成指数9和12为界,进一步划分出27种类型.以鄂尔多斯东部煤层为例,分析结果显示:研究区共有Ⅰ类有利区3种类型,Ⅱ类中等有利区18种类型.其中,Ⅰ类区主要分布在地鄂5井—榆24井北;Ⅱ类区包括大宁-吉县、榆17井区及台7井—榆47井一带.

Quantification of coalbed methane （CBM） accumulation effects is significant for fa- vorable area recognition and development mode selection. Based on controlling factor analysis for combed methane accumulation, this study constructed the quantitative models to character- ize resource, reservoir energy and flowing capacity. Comprehensive indexes, including these three key factors, were established to evaluate CBM production potential, and 4 dimension di- vision of CBM accumulation types was built in this study. CBM accumulation effect was divided into favorable, medium and unfavorable types based on the comprehensive CBM accumulation index^50 X 10~ , 5--50 X 103 and ~5 ）〈 103 , respectively. Further, 27 secondary types was ob- tained by thresholds of 100 and 200 of CBM enrichment index, thresholds of 0.5 and 1.0 of flowing capacity index, and thresholds of 9 and 12 of effective reservoir energy index. Taking the east Ordos basin as an example, the results show that it has three secondary types of favor- able area, and 18 secondary types of medium area. The favorable area distributes at Er5 well-Yu 24 well block, and the medium area distribute at Daning--Ji County, Yu17 well block, and TaiT--Yu47 well Block.