| 摘要 |
A method and apparatus for direct tie-in of pipelines is presented. The apparatus comprises a tensioning member 2, which is attached to the pipeline 1 at at least two places, one of which one can be at a location of direct tie-in. The attachment can be made using clamps during the pipe laying on the lay vessel. The apparatus further comprises a buoyancy element 3 attached to the tensioning member 2. This can be attached on the lay vessel, during preparation for tow out, or underwater, and can be made via a connecting member. When submerged, the pipeline 1 is deflected as a result of a buoyancy force tensioning the tensioning member 2, and on releasing the buoyancy element 2, direct tie-in of the pipeline is performed. To restrict the amount of deflection, a displacement control member 5b can be used. The buoyancy element 3 can be located on the sea bed prior to attaching to the tensioning member 2, it being anchored by a weight, such as a clump weight. A remotely operated vehicle (ROV) can be used to make the attachment between the buoyancy element 3 and the tensioning member 2 when underwater. |
