Canyon Express Flowline System: Design and Installation
Authors: de Reals Thierry Boscals , Nogueira Andre C. , Ferroni Luigi Boscals 
Published: October 2008

This paper describes the design and installation of the twin 12- inch flowlines for the Canyon Express project. In addition to the world record-breaking water depth of 7,280 ft (2,220 m) in Mississippi Canyon block 348, several challenges were met and overcome by the design and installation team. Some of these challenges were: the fast track nature of the project; ten in-line sleds and two end-of-line sleds to be installed within tight tolerance areas on the seafloor; in the King's Peak field three sleds to be in the flowline catenary simultaneously with two of these 3,200 feet apart landing in a curve in 6,400-foot water depth; in the Aconcagua field two sleds to be in the catenary 3,700 feet apart in 7,100-foot water depth.

The Canyon Express project management team was lead by TotalFinaElf and included engineers in lead positions from the operating partners (BP and Marathon Oil). INTEC Engineering provided support from conceptual to detailed design in all aspects of the project, except drilling. Saipem was the flowline sled detail designer, fabricator, and installation contractor. The vessel used for the deepwater portion of the work was the SaiBOS Field Development Ship (FDS). Shallow water flowline installation work was performed with EMC's Castoro 10.

This paper describes several aspects of the Canyon Express project which includes a number of issues pertinent to deepwater flowline work: field development concept leading to selection of the daisy chain concept, flowline mechanical design, installation scope of work and bid strategy, the King's Peak multiple sled installation challenge, multi-phase flow meter and jumper design, installation procedures, and execution of the offshore work.

Saipem completed installation of the Canyon Express flowlines in the summer of 2002. The success of this endeavor is due in large part to the collaborative and team philosophy adopted by TotalFinaElf, as well as careful planning and attention to detail of the subsea components and equipment involved.

Introduction

One of the unique features of the Canyon Express development is that it commingles in a single delivery system the production of three different fields: BP's King's Peak (currently with three producing wells), TotalFinaElf's Aconcagua (four producing wells), and Marathon's Camden Hills (two producing wells). Production from each field is dry gas with nominal amounts of condensate. Expected production rates are in the range of 100 to 250 MMSCFD per flowline. As can be seen in Figure 1, the fields are connected by two (an east and a west) 12-inch flowlines (each approximately 55 mile long) in a daisy chain layout forming a piggable loop. Joining of the two flowlines at the deep end is made with the aid of a 12-inch jumper. The flowlines connect the MP261 JP Canyon Station platform (located in Main Pass 261 in 299 feet water depth) to the King's Peak field 39 miles away at a 6,400 ft water depth, then to the Aconcagua field 11 miles away at 7,100 feet water depth, and finally to the Camden Hills field 5 miles away at 7,280 feet water depth. The flowlines are routed such that they are laid at 60 feet nominal distance to each well.