The Zia Subsea Project
Authors: Beer Paul , Myint Phillip 
Published: October 2008

The successful development of the Zia Field in deepwater Gulf of Mexico utilized a classic application of a five-step project management process, modified and accelerated in project schedule to bring a deepwater subsea field on-stream in a cost-effective manner. The reduced cycle time resulted in improved project economics for independent operator Devon Energy Corporation (formerly Ocean Energy, Inc.). A clear, up-front understanding of the risks involved and the effective management of those risks for the safe, on-time delivery of a subsea tieback system facilitated the accelerated schedule.

The project, executed with a small company team, achieved first oil within 12 months of project sanction, 7 percent under the approved budget. This paper discusses the project drivers, project management philosophies, concept selection, contracting strategy, execution challenges, best practices and lessons learned on Zia.

Introduction

The Zia Field, located in Mississippi Canyon Block 496 in 1,800 feet [549 m] of water, was Devon Energy Corporation's first operated deepwater development. As such, Devon did not have in place existing formal project management processes. The planning and execution of the project was achieved by a project management team, consisting of hand picked consultants, brought together to support a small company team.

Recognizing the challenges, the project team fully analyzed the risks involved, identifying the critical-path equipment necessary to successfully execute subsea development of a deepwater field. Key equipment was solesourced, which contributed to the reliability of the system while facilitating the accelerated schedule. The team's efforts paid off with the project completed ahead of schedule and below appropriated budgets. To date, the Zia field has met operability and financial expectations.

The Zia project achieved first oil in June 2003, just 18 months from commencing the development concept selection process and 12 months from project sanction. The Zia team attributed this success to a compressed process where criticalpath subsea hardware including subsea tree and control system drove the schedule. Ancillary systems and components such as umbilical, pipeline design and topsides modification then proceeded in parallel.

Figure 1 - Zia Field Overall Arrangement (Available in full paper)

Devon has developed the Zia Field using conventional subsea technology via a 16-mile [26 km] tieback to an existing Marathon Oil Company operated platform located in South Pass Block 89 in 422 feet [129 m] of water. Operator Devon holds a 65 percent working interest while partner Spinnaker Exploration Company maintains 35 percent working interest.

The field was developed with a single well tied back via dual flowlines to the host platform. The initial field development consists of the following major components:10 ksi [69 MPa] subsea tree and control systemIntelligent well completion with dual zone remote actuated sliding sleevesElectro-hydraulic multiplex umbilical with super duplex stainless steel tubesUmbilical termination assembly5-inch [141 mm] un-insulated service flowline rated for 7,000 psi [48 MPa] shut in tubing pressure