煤层气鱼骨状分支水平井轨道优化设计方法研究

鱼骨状水平井能够有效增大煤层气储层裸露面积,提高单井煤层气的产量。将各个分支拆分成相对独立的待钻轨道与主井眼轨道分别进行设计计算,拆分后的井眼轨道可以转化为二维轨道来进行设计。结合鱼骨状分支水平井的特点,建立了分支水平井井眼轨道最优化设计模型,并对分支井眼与主井眼的关系进行了分析研究。结果表明,随着井深、造斜率的增加,分支井眼与主井眼的直线夹角增加,且分支井眼偏离主井眼的距离是逐渐增大的;在直线夹角一定的情况下,造斜率与井深呈反比关系,即造斜率越高,所需要的分支井井段越短;造斜率越低,所需要的分支井井段越长。

Study on Optimization Design of Coalbed Methane Herringbone Multi-branch Horizontal Well

Herringbone horizontal well can increase bare area and output of coalbed methane reservoir.The design calculation is separately made in single awaiting drilling trajectory and main well bore trajectory,the separated well bore trajectory can be transformed into 2D trajectory for design.The optimization design model of multi-branch horizontal well bore trajectory was established according to the characteristics of herringbone multi-branch horizontal well and analysis was made on the relationship between multi-branch well bore and main well bore.The result shows that the distance and the angle between branch well and main well are in direct proportion with depth and dogleg;under the condition of fixed angle between branch well and main well,dogleg is in inverse proportion with depth.