基于OLGA的海底管道水合物生成规律模拟

OLGA based simulation on the formation laws of hydrates in pipelines

为了研究海底油气混输管道内水合物的形成过程及管道堵塞问题,结合凝析气生成水合物的相平衡曲线和CSMHyK v2.0水合物动力学模型,使用OLGA软件对海底立管和水平输送管道内水合物生成情况进行数值模拟。结果表明:在某海底管道工艺参数下,无论是立管还是水平输送管内都有大量水合物生成,其水合物浆黏度分别增加了10倍、18倍。在立管中从海底到海平面管段水合物生成速率由大到小,最后趋于0;在水平输送管道中,水合物生成速率保持不变。管道出口压力降低,水合物生成区域减小,且水合物浆的黏度大幅下降。当立管和水平输送管道出口压力分别控制在3 MPa、2 MPa时,可以避免水合物生成,保障管道安全运营。

To investigate the formation process and blockage of hydrates in deepwater oil-gas multiphase pipelines,the formation process of hydrates in subsea risers and subsea horizontal transportation pipelines was numerically simulated by OLGA,based on the phase equilibrium curve of hydrate formation from condensate gas and the hydrate kinetic model(CSMHyK v2.0).It is shown that under the process parameters of one certain subsea pipeline,a large amount of hydrates are formed in both risers and horizontal transportation pipelines,and the viscosity of hydrate slurry increases 10 times in risers and 18 times in horizontal transportation pipelines.The formation rate of hydrate in risers decreases from the sea floor to the sea level and finally approaches to zero,while that in horizontal transportation pipelines remains unchanged.The area of hydrate formation and the viscosity of hydrate slurry decrease with the decline of pipeline outlet pressure.When the outlet pressure of risers and horizontal transportation pipelines are controlled at 3 MPa and 2 MPa,respectively,the formation of hydrates can be avoided and the smooth flow of pipelines can be ensured.