受限海域海底管道搬管技术

Subsea pipeline shifting technology in restricted sea area

在海底施工条件受限情况下,进行实际海底管道铺设施工时,一般会先偏离原来设计路由一定角度进行管道铺设,偏铺完毕后再倒船回来将海底管道搬回设计路由。以渤海某油田海底管道铺设施工过程中的搬管作业为例,首先,介绍了作业所需的船舶、舷吊、滑轮等设备,以及作业人员、作业船舶对海况条件的要求;其次,在给出搬管计算所需的基础参数的基础上,给出搬管具体方案,并对方案中的关键步骤进行详细的力学计算和校核;再次,详细论述了施工准备工作、作业船就位、搬管前潜水调查、安装起吊索具、安装浮袋、搬管、移动及下放、移除搬管辅助设备等施工过程;最后,结合工程实例的实际施工效果指出,搬管作业不可能将海底管道完全复原到设计路由,但能保证整体路由的精度。

In practice, when a subsea pipeline is laid under limited subsea construction conditions, it will generally deviate from the original design route at a certain angle, and once completed, the vessels will come back to move the subsea pipeline back to the design route. This study takes the pipeline shifting operation in the subsea pipeline laying construction of an oilfield in the Bohai Sea as an example. First, we introduce the vessels, davits, pulleys, and other equipment needed for the operation, as well as the requirements of operators and vessels for sea conditions. Secondly, given the basic parameters required for the calculation of pipeline shifting, we present the concrete scheme of pipeline shifting and conduct meticulous mechanical calculations and check for the key steps in the scheme.Thirdly, construction processes are elaborately described, including the construction preparation, main vessel in place, diving surveys before pipeline shifting, installation of lifting rigging, installation of airbags, pipeline shifting, pipeline moving and lowering, and removal of auxiliary equipment. Finally, considering the actual construction effect of engineering examples, it is pointed out that pipeline shifting operation cannot completely restore the subsea pipeline to the designed route, but it can ensure the accuracy of the overall route.