Abstract: An apparatus and method for placement and deployment of grout bags which, when deployed by filling with grout, act as supports for subsea pipelines or structures. The apparatus includes a pallet to which a collapsed grout bag is attached for placement, an alignment member, and a manifold assembly for distributing grout to multiple bags or compartments. The alignment member is abutted against the subsea pipeline or structure to assure proper placement of the grout bag beneath the pipeline or structure. The pallet base structure permits level deployment of the pallet on sloping seabeds. The pallet base structure includes legs and brace members which are specially designed to suit the seabed conditions at the installation site. The length of the pallet legs depends upon the relative softness of the seabed, with longer legs providing frictional support as they embed themselves into the seabed. Short legs provide support for the pallet on relatively hard seabeds by resting on the seabed with minimal embedding.
Abstract: A recovery head for use in retrieving a submerged pipeline to the water surface. The recovery head includes a center of gravity arm attached to one end of the recovery head by a connecting pin. The center of gravity arm maintains the recovery head in a level orientation to allow divers or an ROV to more easily insert the head into the pipeline. After insertion into the pipeline, the center of gravity arm is removed from the recovery head. With the center of gravity arm removed, the recovery head does not obstruct or interfere with any steps involved in the actual retrieval and securing of the pipeline on the lay barge. The rear portion of the recovery head includes two T-posts which connect to oval links attached to the end of a retrieving cable. The links are such that, when placed over the T-posts and the retrieval cable is pulled to retrieve the pipeline to the surface, the links rotate.
Abstract: A method for severing and recovering a submerged pipeline is disclosed. The severing and recovering operation may be performed with divers or with a remotely operated vehicle. The deflated lift bag is lowered to the submerged pipeline. The deflated lift bag is positioned under the submerged pipeline and then inflated until a section of the pipeline has been raised off of the sea floor. A cutoff saw is next lowered to the raised section of the pipeline. The cutoff saw is clamped to the pipeline prior to severing the pipeline. The cutoff saw is then removed from the severed pipeline. A recovery head is lowered to the raised end of the severed pipeline. The recovery head is aligned and placed in the raised end of the severed pipeline. The recovery head is activated to establish a gripping relationship with the pipeline. A recovery cable is lowered and connected to the recovery head. The recovery cable is retrieved to recover the recovery head and the pipeline to the water surface.
October 30, 1990
Date of Patent:
September 3, 1991
Diverless Systems, Inc.
David A. Gray, Walter E. Gray, Jr., Charles R. Yemington