Steel catenary risers (SCR) have been used to connect the export lines to the Morpeth TLP platform. To date, this is the shallowest water depth employment of SCR. The majority of the risers, in particular, the touchdown and sag-bend have been installed by employing the "S" lay technique, another first for SCR installation. Significant design effort was invested to understand the issues involved and resolving them, in a method to demonstrate the safety and reliability of such an application. Design effort consisted of an improved analysis model, non-linear modeling of the seabed and flex-joint, fatigue testing of full scale pre-strained riser joins, development of a VIV strake sizing procedure, and the extensive use of fracture mechanics and Engineering Critical Assessment.

British-Borneo Exploration Inc.'s Morpeth export system introduces two industry firsts -- the use of a diverless piggableb tie-in sled installed in a stacked orientation through a stinger and the installation of the first dynamic steel catenary riser (SCR) employing Slay techniques. Careful design and installation planning resulted in successful on-bottom positioning of the sleds within 5° of vertical without any rectification. The pipeline and SCR Slay work was performed from a conventional, moored barge in water depths ranging from 360 to 1650 feet along the 19.5-mile route. Introduction The Morpeth field is located in Ewing Banks Block 965. The field layout is illustrated in Figure 1. Oil and gas from the field are produced from three subsea wells in 1750 feet of water via flexible catenary risers to the Atlantia-designed SeaStar® mini-TLP located in EW 921 in 1650 feet of water. Product is then exported through a 12" and 8" gas steel catenary riser and pipeline system to a conventional platform in GI 115 in 360 feet of water. The subsea facilities are operated remotely from the TLP. The installation of the export system was performed with J. Ray McDermott's combination lay/crane barge DB28 in two phases to maintain the 21-month fast-track schedule. The bulk of the pipeline was laid in the first phase in the Slay configuration, terminating at the piggable tie-in sled location. The sled, the remaining 2 miles of each pipeline, and the SCRs were laid in the second phase in the S-lay and the J-lay configurations, completing the export system installation. Figure 1 Morpeth Field Layout (Available in full paper)