Performance study of erosion resistance on throttle valve of managed pressure drilling
Performance study of erosion resistance on throttle valve of managed pressure drilling
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DOI：
10.1016/j.petrol.2017.05.011
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发表时间：
2017-07
影响因子：
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通讯作者：
Gang Hu;Peng Zhang;Guorong Wang;Hao Zhu;Quanchang Li;Shiping Zhao;Qiao Kai;W. Tao
中科院分区：
文献类型：
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作者：
Gang Hu;Peng Zhang;Guorong Wang;Hao Zhu;Quanchang Li;Shiping Zhao;Qiao Kai;W. Tao
控压钻井节流阀是控压钻井技术的核心设备。由于节流阀在现场直接与钻井液接触，流动性强的钻井液会对节流阀内部流道造成冲蚀磨损，影响节流阀的工作性能和使用寿命。为此，基于节流阀的工作原理和几何结构，采用计算流体力学（CFD）技术建立三维流体数值模型，选择重整化群k-ε（RNG k-ε）模型作为控压装置节流阀内液固两相流的湍流模型。同时，壁面区域的流体流动采用壁面函数求解，使壁面附近的物理量与核心湍流区的物理量相联系。另外，离散相模型选用离散相模型（discrete phase model，简称DEM）模型，冲蚀模型选用Ahlert冲蚀模型。离散计算采用有限体积法，求解控制方程时，连续性方程、动量方程、能量方程和湍流动能方程采用SIMPLE算法。采用CFD方法研究了节流阀开度、钻井液流量、钻井液密度、固相颗粒质量流量等钻井参数对控压钻井节流阀磨损特性的影响。结果表明，固体颗粒对MPD节流阀阀壁的冲蚀主要发生在阀芯端部。同时，钻井液流量对固体颗粒冲蚀率的影响最大，其次是固体质量流量。与以上两者相比，固体颗粒冲蚀率受节流开度和钻井液密度变化引起的进出口节流压差的影响较小。此外，模拟结果与实验室节流阀磨损试验数据吻合较好。本研究可为相关节流阀的研究工作及操作人员提供减少节流阀磨损的建议。
The throttle valve designed for managed pressure drilling (MPD) is a core equipment of MPD technology. Due to the direct contact with drilling fluid at well site, the throttle valve's internal flow passage will be eroded and worn by the drilling fluid with high mobility, which would negatively affect the working performance and service life of the throttle valve. Therefore, based on the working principle and geometric structure of throttle valve, the computational fluid dynamics (CFD) technique is used to establish the three-dimensional fluid numerical model, and the renormalization group k-epsilon (RNG k-ε) model is selected for the turbulence model of liquid-solid two-phase flow in throttle valve of MPD. At the same time, the fluid flow in the wall region is solved by wall function which allows the physical quantity near the wall surface to connect with it in the core turbulence region. In addition, the discrete phase model (DPM) model is selected for the discrete phase model, and the Ahlert erosion model is selected for the erosion model. The finite volume method is used in discrete calculation, and the SIMPLE algorithm is applied in continuity equation, momentum equation, energy equation and turbulent kinetic energy equation when solving the control. The influences of drilling parameters (such as throttle valve opening, drilling fluid flow rate, drilling fluid density, mass flow rate of solid particle) on the erosion characteristics of throttle valve of managed pressure drilling are studied by CFD. The results show that the erosion of the solid particles on the wall of MPD throttle valve mainly occurs at the end of the valve spool. Meanwhile, the drilling fluid flow rate has the greatest impact on the erosion rate of solid particles, which is followed by the solid mass flow. Compared with the above two, the erosion rate of solid particles is less influenced by the throttle pressure difference between inlet and outlet which is caused by the change of throttle opening and drilling fluid density. In addition, the simulation result reaches a good agreement with the laboratory data of throttle valve erosion experiment. This study could give several advices for relevant throttle valve investigation work and operators who attempts to decrease the erosion in valves.