BRUTUS: The Rigid Spoolpiece Installation System

Abstract The Brutus System has been designed and built to fulfil an industry need for the deep-water installation of rigid lines and spoolpieces. This has been driven by the operators' need to reduce capex coupled with the development of high pressure/high temperature wells, which are not compatible with flexible tie-ins. In the design of Brutus, Sonsub have drawn on experience from the Diverless Flowline Connection System (DFCS), the Flanged Pipeline Re-Connection System (FPRCS) and the Diverless Sealine Repair System (DSRS). The DFCS is used to pull-in and connect umbilicals and flexibles up to 18, diameter and "deflect to connect" rigid steel pipe. The FPRCS is an "industry first", as it is the first time an ROV has connected a bolted flange. Additionally, Sonsub's DSRS demonstrated that large heavy packages can be maneuvered by the ROV. As a basic requirement, the Brutus system is lightweight and ROV friendly. It is able to connect a rigid spool to a rigid pipe or sea structure and, while independent of any particular connection system, it minimizes any modification to the subsea hardware. The main design parameters are: 3000 meters water depth operation, up to 24" diameter pipe management and the capacity to connect flanges as well as clamp and/or collect connectors. The system should be able to be deployed from any ROV DP construction vessel utilizing any work class ROV. The System consists of an Axial Force Tool (AFT) which, as its name suggests, provides the pull-in force, a Reaction Tool (RT), pipe supports (lightweight H-Frames) and the connector system. The paper will explain the components of the system along with an update of its current status. Background Sonsub International has extensive experience in pipelines tie-ins using remote technology. This started in the early 90s' when a 4" line and three 20" lines were connected using the deflect-to-connect method (Ref. /1/) and continued in 1994 with the successful development of the DFCS - Diverless Flowline Connection System (Ref. /2/). The above systems were both based on the use of remote operated connectors such as the collet connector (deflect-toconnect) and the clamp connector. Following a problem in West Shetland in 1997, Sonsub International developed a system which was based on a tool capable of connecting compact flanges and succesfully used it to connect an 8" and a 10" flange in water depth in excess of 500 meters/1,600 feet (Ref. /3/). Subsequently, the successful experience in connecting flanges at such water depths, along with the positive track record of the DFCS, led to the development of a completely new concept. This concept combined the philosophy of a flying buoyant tool with the requirement for large forces and the use of flanges as a standard connection system. This concept/system has since been designed, built and tested, and it is named BRUTUS. The Predecessors The following sections give a brief description of the tie-in/connection systems developed by Sonsub International, which can be considered the predecessors of BRUTUS: DFCS and FPRCS (Flowlines and Pipelines Rigid Connection System). The following is only a general description and the author encourages the audience to refer to previous OTC papers (see reference section for further details).