Moho Bilondo: Subsea Production System Experience
Authors: Carre Damien , O&apos;Sullivan John 
Published: July 2009

The Contract of the Subsea Production System Package was signed between TOTAL E&P Congo (TEPC) and FMC Technologies in July 2005. The FMC scope of work comprised the EPC for 2 manifolds (6 and 4 slots), 14 vertical Xmas-tree systems, the overall subsea control system located on the topsides (SCU, SPCU, HPU) and subsea as well as the work-over equipment required for the installation of trees. A second Contract was dedicated to the work to be performed in Congo on a base built by TOTAL E&P Congo and provided to FMC.

One of the main challenges was for FMC to engineer and fabricate Xmas-trees with a 6 hour thermal autonomy before hydrate formation, with low production temperatures

In order to avoid late surprises, an extensive test program was performed in Norway, prior shipment of the equipment to Congo. One manifold, one injection tree and one production tree were subjected to System Integration Tests(SIT), Shallow Water Tests(SWT), Xtree and Manifold Cool-Down Tests (CDT), Stack-Up Tests (SUT).

Despite the fact that Moho Bilondo was the first deep water offshore development in Congo, the installation of manifolds and the first trees and jumpers went very smoothly. Part of this success was the result of a detailed interfaces management. Finally, the constant presence of Company personnel in Congo enabled the project to maintain Quality and HSE including for the local subcontractors who had never worked in the past with such equipment and materials.

Introduction: Presentation and specificities of the Moho-Bilondo Subsea Production System

Presentation of the SPS package

The SPS package of Moho-Bilondo covers the permanently installed subsea equipment, plus the related tools for their installation and for intervention, and the set-up of a SPS base in Congo for the preparation of equipment before installation, maintenance of the tools and fabrication of the production well jumpers. After a competitive tender, two contracts were signed with FMC Technologies in the summer 2005; an EPC contract for the engineering, manufacturing, testing and transport of the SPS equipment and an IAC contract for all local work in Congo.

The Moho Bilondo subsea production system consists of production wells arranged in a close clusters around two manifolds, one at the Bilondo field, and one at the Mobim field. Each manifold is connected to the Floating Production Unit (FPU) via two thermally insulated flowlines, a gas lift umbilical and a control umbilical. The manifolds have a dual header configuration with a pig loop, allowing round trip pigging from the FPU. Water injection wells are positioned close to each cluster. See figure 1

As a parallel activity, the construction of a SPS base within TOTAL Base Industrielle in Pointe Noire was launched to host FMC customer support personnel as soon as the first equipment was delivered.

Moho Bilondo had a tight planning with the first manifold delivery planned at contract signature plus 14 months and keeping in line with the planning was a continuous struggle. The first pieces of equipment (the manifold foundations) were delivered on time, early in 2007, and were installed successfully. In general the delivery schedule has been respected, causing no disturbance to the installation planning, except for the Mobim manifold whose delivery date had to be postponed by a couple of month due to a technical incident which occurred during the fabrication.

Concerning the IAC contract, even though the installation campaign went generally fine, some stand-by time on the rig and UFL installation vessels could have been avoided.