径向钻井倾斜井底高压水射流流场分析

为了对径向钻井倾斜井底高压水射流的流场进行研究,建立了三维单喷嘴水射流井底模型,采用Fluent软件对模型的流场结构进行了数值模拟分析。分析结果表明,径向钻井高压水射流喷嘴外部流场中存在"负压效应"和"水垫现象",负压的存在有利于射流从喷嘴内部流出,水垫会对喷头的推进产生阻碍作用;当径向钻井临时井底倾斜角度为0°时,射流到达井底后沿井底壁面中心向外对称流动,但随着井底墙壁倾斜角度的增大,由于倾斜井底的引流作用,大部分流体会沿着井底倾斜的方向流动,并且沿倾斜方向的流速较大;径向钻井中,如果井底是倾斜的,则沿着井底倾斜方向的压力比井底另一侧高。

Analysis of High Pressure Water Jet Flow Field at Inclined Bottomhole in Radial Drilling

To analyze the flow field of high pressure water jet at inclined bottomhole in radial drilling,the three-dimensional bottomhole model of single-nozzle water jet was established.The Fluent software was adopted to conduct a numerical simulation analysis of the flow field structure of the model.The analysis shows that there exist "negative pressure effect" and "water cushion phenomenon" in the external flow field of radial drilling high pressure water jet nozzle.The existence of negative pressure is favorable to the jet flowing out of the nozzle.The water cushion will be a barrier to the advancement of the nozzle.When the temporary bottomhole angle of inclination in radial drilling is 0°,the jet reaches the well bottom and then follows a symmetrical outward flow along the bottomhole wall center.But with the increase of bottom wall tilt most of the fluid will flow in the direction of bottom tilt due to the diversion effect of inclined bottom.And the flowrate in the incline direction is remarkable.The pressure in the direction of bottom tilt is higher than that on the other side in radial drilling if the bottomhole is inclined.