海上气田立管段塞流缓解方法数值模拟研究

Numerical simulation research for mitigation method of riser slug on offshore gas fields

立管段塞流是一种严重影响海洋油气安全输送与处理的混输管道常见流型。针对海管气液混输工况下立管段塞流缓解措施展开研究,采用多相流动态数值模拟方法,建立了某深海气田混输管道动态多相流模型,模拟复现了现场严重段塞流现象,并通过参数控制方法计算分析了输量、登平台压力、海管内径等控制条件对段塞流的缓解效果的影响。研究结果表明,输量及内径的调整可有效缓解段塞流,并随着调整范围扩大形成比较明显的立管底部压力拐点区域,其中输量临界区域约47×10^(4)m^(3)/d,内径临界区域101.6~152.4 mm,当接近并跨越该区域时,立管段塞流程度得到有效缓解甚至消除;登平台压力的调整,在该混输工况下无明显立管段塞流减缓效果,为现场生产缓解立管段塞流提供可行的研究思路与操作参考。

Riser slug is a common flow regime for multiphase flow transportation in pipelines that severely affects the safety of storage,transportation and processing of offshore oil and gas.Aiming at the mitigation measures of riser slug under the condition of gas-liquid mixed transportation in subsea pipeline,the dynamic multiphase flow model of mixed transportation pipeline in a deep-sea gas field is established by using the multiphase flow dynamic numerical simulation method,which simulates and reproduces the phenomenon of serious slug flow in the field,and calculates and analyzes influence of control conditions such as flowrate,platform arrival pressure and inner diameter of subsea pipe on the mitigation effect of slug flow.The results show that the adjustment of flowrate and inner diameter can effectively alleviate the slug flow,and form an obvious pressure inflection point area at the bottom of the riser with the expansion of the adjustment value,the turndown area of flowrate is about 47×10^(4)m^(3)/d,the turndown area of inner diameter is 101.6~152.4 mm.When approaching and crossing this area,riser slug can be effectively alleviated or even eliminated.The adjustment of platform arrival pressure can′t be effectively alleviated riser slug flow in this multiphase transportation condition,which provides a feasible research idea and operation reference for on-site production to alleviate riser slug flow.