沁南盆地煤层气U型水平井部署优化研究

针对煤层气生产中提高单井产能的需要,提出采用U型水平井进行开发的技术思路,并依据构造简单、煤层厚度大、含气量高、煤体结构完整、水文地质条件简单等标准对U型水平井的部署区域进行了区块优选。对影响该区域U型水平井部署的水平段距离、水平段长度和水平段位置进行了优化研究。结果表明:U型井水平段间距过小,会造成控制地质储量偏小,影响稳产期长短和后期的产气潜力;井距过大,虽然控制储量会相对变大,但是很难形成井间干扰,难以达到面积降压的目的,累产气量也并未增加;从15 a的累产气量来看,最优井距为300 m;最优间距的大小受煤储层割理渗透率的影响明显,随着渗透率增大,最优间距增大;水平段位于煤层中部时日产气量和累产气量较高,推荐水平段位于煤层中部。

Optimization of U-shaped CBM horizontal wells in Qinnan Basin

To improve the coalbed gas single well productivity, present idea of using U-shaped CBM well technology in CBM reservoir, and optimize the target area based on simple structure,large coal thickness and gas content, complete coal structure, and simple hydro-geological conditions.Meanwhile optimization includes horizontal well space, length, and location in coalbed. The results show that small well space effects on stable production stage and late-stage production potential because of small reserves,While large well space causes the in- terference between wells is so difficult that large scale of pressure drop does not happen and high production is not available.The optimal well space is 300 m based on 15 years .cumulative production.The optimal value becomes larger as cleat permeability gets larger.The productive rate and cumulative production are the highest when the horizontal well locates in the middle of coalbed reservoir.