沁水盆地樊庄区块煤层气高产富集规律及开发实践

为弄清沁水盆地樊庄区块煤层气的高产富集规律，根据近5年来在该区的勘探开发实践，从烃源条件、储层条件和保存条件3个方面系统分析了煤层气的成藏条件与富集规律。结果表明：该区煤层气成藏条件决定了其富集特点，即整体含气性较好，局部贫瘠，呈现“富集成片、贫瘠成带、富中有贫”的含气量分布特点；由东向西，煤层气逐渐由贫瘠变为富集，这主要是受封盖条件和构造断裂活动控制的结果。根据产气压力与理论临界解吸压力拟合关系对煤层含气量进行了预测，预测结果与实测数据基本一致，证明前者是一种可靠、实用的新方法。针对煤层气富集程度和压裂效果的差异，引入了煤层气开发单元的概念来指导生产，后期生产的效果表明，煤层气井产量的高低与开发单元的划分吻合良好。

Laws of coalbed methane enrichment and high productivity in the Fanzhuang Block of the Qinshui Basin and development practices

To make it clear the laws of coalbed methane enrichment and high productivity in the Fanzhuang Block of the Qinshui Basin, we learn from the development practices in this area over the past 5 years, on this basis, we make a systematic analysis of coalbed methane gas pooling conditions and patterns in the three aspects of source rocks, reservoir beds and preservation conditions. In conclusion, the CBM gas pooling conditions resulted in the CBM gas enrichment in this study area, which is characterized by good gas-bearing properties on the whole but poor at some parts, i.e., gas content is rich in fields, poor in zones, and some poor zones in rich fields. From east to west in this study area, the CBM gas gradually becomes richer and richer mainly due to the restriction by sealing conditions and structural fault activities. According to the simulation effect of gas deliverability on the theoretical critical desorption pressure, the CBM gas content is forecasted, the result of which agrees well with the actual data. Thus, this forecasting method is proved to be reliable and practical. In view of the differences in CBM gas enrichment degrees and fracturing effects, the concept of CBM gas development unit is introduced; from the latter period of CBM gas production, it is shown that the CBM gas well deliverability matches well with the division of development units.