水平井旋转射流冲砂洗井水力参数设计方法

Hydraulic Parameters of Sand-Flushing with Rotating Jets in Horizontal Wells

水平井旋转射流冲砂洗井,是通过旋转射流清洗工具在井筒内产生射流冲击作用和环空旋流效应来洗井,不仅能有效解决油田冲砂作业中存在的砂卡问题,还能在一定程度上解除井筒近井地带的污染,降低表皮系数。但是,目前国内冲砂洗井的各种水力参数往往是根据直井冲砂经验确定的,喷嘴也没有经过专门设计,没有形成完善的工艺,给现场应用带来了很大困难。从水平井旋转射流冲砂洗井机理入手,建立了水力参数优化设计方法:首先计算出水平井不同井段所需要的最小工作排量,再根据最小工作排量求出循环压耗、喷嘴压降和射流冲击力等参数;以最大射流冲击力为目标函数,以最小排量为起点,设一个排量基数,在最小排量基础上逐渐增加排量基数,在满足泵压和泵功率的条件下,选择最大射流冲击力下的排量为最优排量。水力参数设计方法在长庆油田元东平6井等3口井进行了现场应用。应用结果表明,设计的排量既能满足各个井段的冲砂洗井要求,又获得了最大的射流冲击力,节省了冲砂洗井作业时间,降低了作业成本,经济效益明显。

Horizontal well sand-flushing with rotating jet technique uses cleaning tools to generate jet impact and strong annular helical flow to clean wellbore.The technique can effectively solve sanding in and remove near wellbore formation damage to increase horizontal well production.However,horizontal well sand-flushing hydraulic parameters are generally determined from vertical wells and nozzles are not specially designed.Those caused a lot of difficulties in field application.This paper studies the mechanism of sanding in removal from rotating jets and hydraulic parameters optimization.First the minimum displacement for different sections in horizontal well is calculated,then other parameters including the flow circulation pressure drop,nozzle pressure drop and jet impact are determined according to the minimum displacement.To achieve the maximum jet impact,starting from the minimum displacement then gradually increasing the displacement under pump pressure and pump power requirement,the maximum displacement was selected.Those designed hydraulic parameters were used in well Yuandongping 6 and other 2 wells in Changqing oilfield.Application results show that the designed displacement can meet the requirement of sand-flushing,and good jet results were obtained.The operation time and cost was reduced and economic results were obtained.