限制空间安装膨胀弯的推荐方法

Recommended method for expansion bend installation in restricted space

膨胀弯是连接海底管道平管和平台立管的重要桥梁,可以通过局部变形释放平管由于热膨胀等因素产生的应力,保障海底管道能够正常运行。以实际工程项目为例,介绍两种在限制空间安装膨胀弯的方法:一种是通过增加配重将膨胀弯的重心调整到平台结构物外侧,浮吊船直接将膨胀弯与配重吊装下水进行法兰对接;另一种是在水下布置导向,在不影响平台结构物的前提下先将膨胀弯放置泥面,通过浮袋将膨胀弯上浮至悬浮状态,由潜水员通过导向绳将膨胀弯调整至安装位置完成法兰对接。最后对两种方法进行了对比,膨胀弯重心与平台结构物重叠较多并且能通过强度校核计算时,优先选用调整重心法;膨胀弯重心与平台结构物重叠较少时,优先选用导向调节法。两种施工方法均得到成功应用,可为类似工程提供借鉴。

Expansion bend is an important bridge connecting submarine pipeline horizontal section and platform riser.It can release axial stress of submarine pipeline through local deformation caused by the factors such as thermal expansion to ensure the normal operation of the submarine pipeline.Taking an actual engineering project as an example,this article introduces two methods of installing the expansion bend in restricted space.One method is to adjust the center of gravity of the expansion bend to the outside of the platform structure by adding counterweight,the expansion bend and counterweight are lifted by a floating crane and then sunk into water to make flange connection;another method is to arrange underwater guides,the expansion bend is already placed on seabed without affecting the platform structure,then the expansion bend is floated up to the suspended state by using floating bags,the divers adjust the expansion bend to the installation position with the guiding ropes to make flange connection.Finally,the two methods are compared.When the center of gravity of the expansion bend overlaps with the platform structure more and can pass the strength check calculation,the center of gravity adjustment method is preferred;the center of gravity of the expansion bend overlaps the platform structure less,the guide adjustment method is preferred.These two construction methods have been successfully applied,which can provide reference for similar projects.