循环注水治理煤粉技术在郑庄区块中的应用研究

Application Research of Circulating Water Injection Technology for Coal Powder Control in Zhengzhuang Block

  • 摘要: 针对沁水盆地郑庄区块煤层气井普遍存在煤粉堵塞、泵卡频发及设备磨损严重等问题,基于煤粉临界携带速度和“注采平衡”理论的动态联动机制,提出“便携式+固定式双模式注水系统”协同运行与“一泵三井分路联注”一体化集成技术,构建闭环循环注水煤粉治理系统。通过高压清水回注油套环空,提高井筒流速和扰动强度,实现煤粉持续悬浮携带,防止泵筒及管柱煤粉沉积。现场11口煤层气井应用表明:井口煤粉平均浓度由6.5 g/L降至2.1 g/L,泵卡月均次数下降70%,抽采电流波动幅度由±6.9 A降至±4.4 A,平均检泵周期由38 d延长至115 d,最长达211 d,稳产气量保持稳定甚至略有提升。系统集成了变频自适应注采控制及“一泵三井”分路联注,支持不停产携粉,显著提升设备稳定性和运行效率。

     

    Abstract: Addressing the prevalent issues of coal dust blockage, frequent pump sticking, and severe equipment wear in coalbed methane wells in the Zhengzhuang block of the Qinshui Basin, a "portable + fixed dual-mode water injection system" collaborative operation and "one pump, three wells shunt joint injection" integrated technology are proposed based on the dynamic linkage mechanism of coal dust critical carrying velocity and the "injection-production balance" theory, to construct a closed-loop circulating water injection coal dust control system. By re-injecting high-pressure clean water into the tubing-casing annulus, the wellbore flow velocity and disturbance intensity are increased, achieving continuous suspension and carrying of coal dust and preventing coal dust deposition in the pump barrel and tubing string. The application in 11 coalbed methane wells on site shows that the coal dust average concentration at the wellhead has decreased from 6.5 g/L to 2.1 g/L, the average monthly frequency of pump sticking has decreased by 70%, the fluctuation range of extraction current has decreased from ±6.9 A to ±4.4 A, the average pump inspection cycle has been extended from 38 days to 115 days, with a maximum of 211 days, and the stable gas production rate has remained stable or even slightly increased. The system integrates variable frequency adaptive injection-production control and "one pump, three wells" shunt joint injection, supporting continuous powder carrying without production suspension, significantly improving equipment stability and operational efficiency.

     

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