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煤层气井水源层判识,对于单井排采动态诊断、优选作业井层和制定科学的压裂方案均具有重要意义。针对寿阳勘探区煤层气井高产水问题,开展了区域水动力场和能量场、煤系砂岩和灰岩含水性、目标煤层围岩岩性连井对比、井筒与煤层围岩含水层连通关系以及典型煤层气井水源层剖析等方面的研究。研究表明,区域水动力场和煤层渗透率是煤层气井平均产水水平的决定因素,而煤层气井产水量的井间差异主要受控于单井波及范围内局部地质工程因素(断裂、压裂缝类型和高度及岩性组合),水力压裂缝是除断裂外煤层与围岩含水层沟通的一种方式。通过综合分析,本文取得的结论是,煤系砂岩是寿阳勘探区煤层气井的主要水源层,太原组灰岩对排采的影响有限。建议在煤层气开发井层优选和压裂方案设计时,重点考虑目标煤层与砂岩含水层的垂向组合关系。
The identification of water source layer in coalbed methane wells is of great significance to the dynamic diagnosis of single-well drilling, the optimization of working well and the development of scientific fracturing schemes. In view of the high production of coalbed methane wells in the exploration area of Shouyang, regional hydrodynamic and energy fields, water-bearing properties of coal-bearing sandstones and limestones, correlation of lithologic wellbores in surrounding rock of target coal seams, connectivity between wellbore and coalbed surrounding rock aquifers, Typical coalbed methane water source analysis and other aspects of research. The results show that the regional hydrodynamic field and coal seam permeability are the determinants of the average water production level of coalbed methane wells. The differences between the wells in CBM wells are mainly controlled by the local geologic factors (fracture and fracture type And the combination of height and lithology), hydraulic fracturing is a way to communicate with surrounding rock aquifer except fracturing. Through comprehensive analysis, the conclusion obtained in this paper is that coal-bearing sandstone is the main water source of coalbed methane wells in Shouyang prospecting area. The limestone in Taiyuan Formation has a limited impact on the drainage. It is suggested that the vertical combination of the target coal seam and sandstone aquifer should be considered in the design of well optimization and fracturing scheme of CBM development.