钢悬链线立管清管过程触底段位移变化规律试验研究

钢悬链线立管（steel catenary riser， 简称SCR）是一种优质的深水开发设备，近几年广泛用于深海环境下油气资源的开采。在浮式平台的周期性升沉运动和海浪海流的载荷作用下，立管的触底区会产生较为严重的疲劳破坏问题。为保证深海立管的高效与安全运行，清管作业是一项必要的维护手段。目前对于清管载荷作用下钢悬链线立管的位移变化规律研究比较匮乏。基于ABAQUS有限元软件和缩比试验准则，设计并开展有关清管载荷作用下钢悬链线立管的位移变化规律的缩比模型试验研究，从清管载荷的大小和作用位置等角度分别研究立管的X向与Y向的位移变化特征。研究结果表明，清管器在立管的触底段中运行并逐渐靠近触底点的过程中，清管器所在立管处的X向与Y向的位移会产生逐渐减小的趋势；当改变清管载荷的大小时，对于立管的同一位置来说，清管载荷的变化会导致立管的X向位移产生较Y向位移更加显著的变化；在清管器通过立管某一位置的前后过程中，X向位移变化呈现先增大后减小的趋势，而Y向位移仅在清管器通过该处时会有明显的减小。

Experimental study on displacement variation of steel catenary riser at touchdown zone under pigging conditions

Steel catenary riser (SCR) is a high-quality development facility, which has been widely used in the exploitation of oil and gas resources in deep-water environment in recent years. Under the loads of sea current and wave as well as the periodical heave motion of the floating platform, this reciprocating motion often generates a large bending stress at TDZ (touchdown zone), leading to a high-risk fatigue damage. In order to maintain the normal transportation of deep-water risers with efficiency and security, the pigging job is an important and necessary method. At present, there is a lack of research on the displacement variation of steel catenary risers under the pigging conditions. Based on ABAQUS finite element software and scaling criterion, a scaling experimental model on the displacement variation of steel catenary riser under pigging conditions was designed. Experimental study was conducted to investigate the effect of pigging position and pigging load on the displacement characteristics of the riser in X and Y directions. The results show that the displacement of the X and Y directions of the riser where the pig is located will gradually decrease during the pig running in touch down zone of the riser and gradually approach the bottom point, and for the same position of the riser, the X-direction displacement of the riser will undergo a more significant change than the Y-direction displacement with the variation of the pigging load. Besides, the displacement in X-direction first increases and then decreases in the period of the pig passing through a position of the riser while the displacement in Y-direction will be significantly reduced only at the position where the pig is located.