鄂尔多斯盆地东缘深部煤层气生产特征及开发对策——以大宁—吉县区块为例

Development strategy and production characteristics of deep coalbed methane in the east Ordos Basin: Taking Daning-Jixian block for example

我国埋深在1 000~2 000 m的深部煤层气地质资源量为22.5×1012m3,占总资源量的61.2%,如何提高深部煤层气单井产量,形成针对性的开发对策是研究和攻关的热点。通过统计分析大宁—吉县区块地质参数和试采井生产数据,表明深部煤储层具有渗透率低、微孔发育、可采系数低的特点,丛式井具有长期低产、上产缓慢和排采期长的生产特征,L型水平井具有上产期短,产气量高的生产特征。以此为基础建立了深部煤层气产能评价指标体系,影响深部煤层气产气效果的因素主要包括地质条件、工程技术及质量与管理三大类。因此,提高深部煤层气单井产量要做好以可采性为重点的高产区评价及预测,开展压裂施工参数优化和井型井网井距互相匹配的地质工程一体化设计,加强工程质量管理,降低储层伤害、实现长期持续排采。

Deep coalbed methane resources（ coal seam depth in 1 000-2 000 m） is 22.5×1012 m^3 in China,accounting for 61.2% of the total resources.How to improve the single well production and form relative development strategy is a research focus in China. Through statistical analysis of geological parameters and production data of trial production wells in Daning-Jixian block,it shows that the deep coal reservoir has the characteristics of low permeability,micropore development and low recovery coefficient.The cluster wells have the characteristics of long term low production,slow and long production period,and the L type horizontal well has the characteristics of short production period and high gas production.On the basis of above,the index system for evaluating the productivity of deep coal bed methane is established.The factors that affect the effect production of deep coalbed methane include three major categories： geological conditions,engineering technology and quality and management. Therefore,in order to improve the single well production of deep coalbed methane,the evaluation and prediction of high yield area with the focus on recoverability needs to be well done,and geological and engineering integration design of the fracturing parameters optimization andthe well spacing well spacing requires to be carried out.The engineering quality management needs to be reinforced in order to reduce the damage of the reservoir and realize the long continuous production.