TTR PRACTICAL

EXPERIENCE

TTR MANAGEMENT EXPERIENCE

• Focal point for DTU surface Xmas Tree, TTR and TTR tensioner system.

• Focal point for upper completion (surface Xmas tree to mudline).

• Prepares functional specifications for well, TTR, and facilities interface requirements to be incorporated in the Basis of Design.

• Facilitates and agree on interface points definition preparing matrix with issues ranked according to risk.

• Interprets and resolves potential design impacts with respect to DTU design on riser installation and well operability.

• Prepares P50 and P90 riser costs, including ancillary equipment.

• Reports to subsea manager and drilling and completion team on design activities, policies and management actions with respect to TTR & Xmas tree and facility issues.

• Acts as liaison between engineering & hardware contractors. Oversees dry tree hardware and TTR interface design.

TTR RELEVANT PROJECTS

Cameron GOM Placid Riser

• Member of the riser team for the hybrid top tension riser designed by Stress Engineering. Ran parallel analyses to make comparisons with Stress Engineering’s design.

Chevron GOM Genesis Spar

• Riser Lead for TTR Design. Supervised Stress Engineering on the analyses of the production and export risers. Interfaced with DrilQuip and ABB Vetco on the design and drawings approval of components and ancillary equipment.

Chevron Truss Spar for Deep Water GOM

• Develop TTR configuration based on air cans as a function of water depth for ultra-deepwater GOM. Supervised testing of scale model of DTU/TTR in Marintek facilities in Oslo, Norway.

Chevron West Africa Agbami DTU

• Riser Lead for TTR Design. Supervised 2H Offshore on TTR analyses, which were used to make comparison with bidders proposed design for three types of DTUs:• TLP

• Production Barge

• Spar

• Interfaced with vendors for the design of the subsea wellhead, bottom connectors, riser stress joint, flexible drapes and keel joint components

TTR ANALYTICAL EXPERIENCE

DTU/TTR

• Global analyses of DTU/TTR extreme response using either Orcaflex or Flexcom3D.

• TTR irregular or regular wave time domain fatigue analyses using either Orcaflex or Flexcom3d.

• TTR VIV analysis using either Shear7 or VivaArray.

• Flexible drapes fatigue and extreme storm analyses for design verification of the flexible pipe.

• Verification of surface tree motions and accelerations

• TTRs could be modeled with or without the DTU and its mooring system. Motions of the DTU are driven by RAOs.

• Supervision and approval of documentation such as: DTU Top Tension Risers Global Performance Specification and Basis of Design

TTR TESTING EXPERIENCE

• Supervised scale model test of DTU/TTR in Marintek facilities in Oslo, Norway. Objective: understand better the following technical challenges:

• Fatigue in the Wellbay

• Vortex Induced Vibration (VIV)

• Strake Performance

• Riser Interference and clashing

• Riser – guide/Gap Interaction (friction creates a slip-stick load on guide).

• Mid-water flowlines between DTU and FPSO.

• The issue was to find a Riser top tension that avoid clashing; or reduce cost of tensioning device by allowing risers to clash when the clashing energy is low.

TTR DESIGN EXPERIENCE

• TTR stack-up configuration from mudlineto surface tree including: stress joint, riser joints, keel joint, keel-transition joints, tensioning joint, and stem joint interface to surface tree.

• Verification of production and gas lift tubing to MAOP, collapse, and buckling. Recommends spacing of centralizers.

• Engineering interfaces with either hydraulic or ram tensioning systems; surface tree and flexible drapes design.

• Applicable TTR standards: API 1111, API RP 2A. ABS or DNV fatigue S-N curves. API 17B and 17J for flexible drapes.

• Verification of dry tree motions; recommends interface design values for flexible drapes and working platforms.

SCHEMATIC OF TTR USING HYDRAULIC TENSIONING SYSTEM