Devils Tower Export Lines: 160 Miles of 18" OD Reeled Rigid Pipe

Abstract

Abstract The Paper starts with a summary of the Devils Tower development in the GOM and gives the characteristics of the 18" Oil and 18" gas export lines from the shallow water platforms to the deep water terminations. It continues with the description of the sub-sea tie-ins branch in 14" diameter from the export lines to the SPAR in 5000' water depth including the Steel Catenary Risers at SPAR. Provisions for futures ties-ins of nearby fields will be covered. The application is any deep or ultra deep development up to 7,500' water depth of rigid or flexible flow-lines, steel catenary risers and umbilical. The paper will give the elements to assess the performance of the Deep Blue / Theodore spool-base spread. Weather sensitivity and offshore performance is analyzed and the advantages to S- lay laying method in terms of safety and quality and further developed. The high capability of the Deep Blue combined with the Theodore, Alabama onshore spool-base has offered an economic alternative to the conventional S-lay laying method for the Devils Tower development. It can be further applied to any mid-size rigid pipe flow-lines SCR installation in deep waters. It combines the advantages of the low cost steel pipe, of the large onshore line pre-fabrication and of the reduced offshore installation time. Devils Tower Development Overview Discovered in 2000, The Devils Tower field is located in Block MC-773 in the Mississippi Canyon, 140 miles southwest of New Orleans, in the Gulf of Mexico. The development by Williams Field Services Company consists of a SPAR platform in 5610 ft of water, and two export pipelines totaling approximately 165 miles of pipes. Technip Offshore has been contracted by Williams to design, supply and install the Mountaineer Oil Export Pipeline connecting the Devils Tower field to MP 313 platform and the Canyon Chief Gas export pipeline connecting the Devils Tower field to MP 261 platform. From the SPAR two 14" steel catenary risers run into two 14" sea-lines 6 miles long to tie-in point to the tow 18" export pipelines. From this point the two 18" main export pipelines run in parallel on the seabed, northerly towards block MC 114. At this point the Oil export continues north to the MP 313 platform, the Gas export line continues northeast to MP 261 platform. Both lines tin-in to shallow platforms via an 18" riser. The SPAR will be able to handle 60,000 barrels of oil per day. The Mountaineer pipeline will have a capacity of 150,000 bpd; the Canyon Chief pipeline will have capacity of 350 million cubic feet of gas per day. Figure 1. Devils Tower Deepwater Development Project(AVAILABLE IN FULL PAPER) Technip-Coflexip Scope on Devils Tower The Epic contract includes all necessary tasks to hand-over to Williams Field Services a complete pipeline system ready for production.