深部煤层气勘探开发进展与研究

Progress and study on exploration and production for deep coalbed methane

我国煤层气资源主要分布于深部。鄂尔多斯、准噶尔等盆地部分煤层气井勘探成功表明深部煤层气资源在含气量、含气饱和度、储层压力及临界解吸压力等关键参数方面较浅部有利,开展深部煤层气研究及勘探是重要前瞻性课题。鄂尔多斯盆地东南缘延川南煤层气田的勘探,尤其是万宝山构造带延3井组的成功开发是我国深部煤层气开发获得突破的1个典型实例。一般来说,影响深部煤层气开发的因素较复杂,是一个系统工程,通常可以将这些因素划分为资源地质条件和开采技术条件两大类。延川南煤层气田开发的经验表明,影响深部煤层气井产能的主要因素是受地质条件控制的压裂技术与排采技术,提高深部煤层气单井产量的途径是做好富集高渗区选区评价和预测,加强以压裂为核心技术的工程工艺攻关研究及做好排采管理。

According to the results of China ＇s new round of CBM resource evaluation in 2006,coalbed methane（ CBM） resources were mainly concentrated in the deep seams（ coal seam depth in 1 000-2 000 m）,but studies related to deep CBM theory were limited,and exploration operations were rare.In this paper,based on the main distribution of coalbed methane resources in the deep coal seams in China,the current deep coal seam mining and CBM exploration wells in Erdos basin and Junggar basin indicate that the exploration and development of deep CBM shows some potential,although the appraisal wells of commercial value occur only in a few pilot areas.By comparing different coal seam depth studies in Yanchuannan block in Erdos basin,it could be concluded that the key parameters such as the gas content,gas saturation,reservoir pressure and critical desorption pressure of deep coal seams were commonly higher than in shallow coal seams.In general,it was a complex system engineering to evaluate the factors of deep CBM production,which generally include resource geology and development technology. Geological conditions of deep CBM were more complicated than those of shallow CBM,which resulted in that the development technology applied in these area was difficult.According to the experience of exploration and production in Yanchuannan pilot CBM project,it was fracturing technique adapted for deep geological condition and draining technology that responsible for favorable well production.Based on this study,it is proposed that the improved well production way of deep CBM is to do the evalua-tion and prediction of sweet point,to study the fracturing technology and to manage drainage working system.