井下油管的流动诱导腐蚀数值模拟研究

NUMERICAL SIMULATION OF FLOW INDUCED CORROSION IN DOWNHOLE TUBES

张智 施太和 吴优

Zhang Zhi Shi Taihe Wu You

西南石油学院CNPC石油管力学和环境行为重点实验室, 四川成都 610500

Southwest Petroleum Institute

根据现代流体力学的基本理论建立了流体运动的连续性方程、动量、湍流动能、湍流耗散率的守恒方程以及化学组分的传质守恒方程。根据流动诱导腐蚀的特点,建立了流动诱导腐蚀的数学模型。采用SIMPLE算法求解流动数学模型,用壁函数法计算了管壁附近湍流边界层的流体力学参数,并用VisualBasic6.0编制了计算机程序,对油管腐蚀过程进行了数值模拟。模拟结果表明,在正常生产过程中,油气井油管的中上部腐蚀严重,建议油管防腐工作的重点放在降低中上部油管的腐蚀方面。应用文中方法及求解程序,设计合理的油管直径及组合,可防止或减轻由于腐蚀、冲蚀等对油管造成的严重后果,减少油气井的维护费用,从而取得良好的经济效益。

In this paper, based on the modern computational fluid dynamics theory, a comprehensive mathematics model for hydrodynamic flow fields induced corrosion include the following formula,conservation of mass, conservation of momentum, conservation of the kinetic energy of turbulence and the turbulent dissipation and conservation of turbulent mass transfer of species. Based on the characteristics of hydrodynamic flow induced corrosion, a mathematics model for hydrodynamic flow fields induced corrosion is obtained. The SIMPLE algorithm is used to calculate the hydrodynamic flow fields mathematical model and the wall function is used to calculate hydrodynamic flow parameters of turbulence boundary layer near pipe wall. A computer program is designed based on Visual Basic6.0. Direct numerical simulation is employed to study the corrosion rate in downhole tubes. The numerical simulation result suggests that the corrosion of middle and upper downhole tubes is worse during the oil/gas production period normally. Application of the method and solve programs presented in this paper will help us design reasonable tube diameter and can prevent or reduce the serious corrosion and flow fields induced corrosion of downhole tubes, and reduce the maintenance cost greatly, and obtain better economic benefit using the method and calculation program in this paper.

10.3969/j.issn.1000-7393.2004.06.019