深水钢悬链线立管浮动边界下清管行为及机理研究

Pipeline pigging is the important way to get rid of dirties such as wax deposition and hydrate in the pipeline for enhancing transportation efficiency. In order to guarantee the security of the pipeline during pigging, in case any accidents like the pig got stuck or crashed with pipe elbows, safety assessment should be conducted under the relative pigging theories which depends on the specific conditions, providing some references for the field operation. Till now, pigging theories for land pipeline are almost sophisticated. However, the related theories for deep water pipeline are still in the blank stage. Steel catenary riser for deep water development have become the main option, while characteristics like the complex route and its free hanging top make the pigging operation become tough, and the related theories are urgently needed for the steel catenary riser pigging operation. As a result, in this project, the pigging mechanism of steel catenary riser is investigated, to reveal the pigging behavior in steel catenary riser with complex curve. Dynamic model of pig in riser with the free hanging top has been built, and the contact mechanism between the pig and the riser is analyzed and the impact of the pig motion on the stress of steel catenary riser is evaluated as well. According to the experimental research, the theoretical model will be revised and improved in order to establish the corresponding theory for the pigging of deep water steel catenary riser, and providing theory foundation for the safety pigging of deep water pipeline.

清管器清管是清除管道积蜡、水合物等污垢，实现管道介质高效输送的重要手段。为保证管道的安全，防止清管器在管道中卡堵或者因为冲击载荷过大破坏管道弯头等事故，清管前均需结合具体工况，利用相应的清管理论进行分析计算以指导现场作业。目前，陆地管道清管的理论研究已日趋成熟，但深水海底管道清管相关理论的研究尚处于起步阶段。作为深水开发首选的立管形式，深水钢悬链线立管因其曲线复杂、顶部自由悬挂等特点而使得清管作业异常复杂，急需相关理论指导清管作业。因此，本项目旨在研究深水钢悬链线立管浮动边界下清管行为及机理，揭示复杂曲线型钢悬链线立管中的清管器清管行为，建立边界浮动下的深水钢悬链线立管清管动力学模型，分析浮动边界下清管时清管器与立管接触耦合机理，探明清管器动力学特性对立管受载特性的影响，并通过室内模拟实验来检验及修正理论模型，建立有关深水钢悬链线立管清管的相应理论体系，为深水海底管道安全清管提供理论依据。

管道是目前油气资源输送最为经济、有效的运输方式。为了保证管道输送质量，在管道建成之初或管道长期运营之后，都需要利用清管器清除管道内部杂质、积蜡和积液等污垢，或者完成管道缺陷如腐蚀、凹陷等的检测，以实现管道的完整性管理。为避免清管事故的发生，并准确的预测清管器在管道中的运行参数，清管前需利用相应的清管理论进行分析计算以指导现场作业。目前，陆地管道清管的理论研究已日趋成熟，但深水海底管道清管相关理论的研究尚处于起步阶段。作为深水开发首选的立管形式，深水钢悬链线立管因其大落差、顶部自由悬挂等特点而使得清管作业异常复杂，急需相关理论指导清管作业。经过三年的研究：（1）提出了截断设计混合实验的方法，完成了深水钢悬链线立管清管模拟实验装置的研制。解决了建立相似性物理模型过程中无法保证的参数相似性比例问题和实际材料选择问题，可在较小的空间得到比较理想的立管模型，并用于室内深水立管的模拟实验。（2）开展了复杂曲线型钢悬链线立管清管器摩擦力、里程检测和通径检测等清管行为的系统研究，有效提高了清管器在钢悬链线立管中的运动参数的预测和检测精度。（3）进行了清管器在深水钢悬链线立管中运行参数的模拟与实验检测，为评估清管器在钢悬链线立管中运动的规律的研究提供了更为可靠的参考。（4）基于研制的小尺寸室内模拟实验台，完成了深水钢悬链线立管清管作业时的立管受载力学特性研究，揭示了清管器载荷对立管不同位置的影响规律，为立管的安全清管提供理论指导，也为通过清管器性能参数或者清管工艺参数的主动调节提供依据，以期降低清管风险，提高清管效率。