Andrew

Discovery and Early Evaluations

The Andrew field was first discovered in 1974 in Block 16/28, at a water depth of 381 feet (116 meters). Despite its discovery, the field remained marginal due to technical and economic challenges, including a thin oil leg overlaying lower Cretaceous gas and water. From 1983 to 1986, BP evaluated several development options, but none were deemed economically viable at the time.

Project Development and Alliance Approach

In the early 1990s, BP adopted an alliance approach to develop the Andrew field. This involved forming the Andrew Alliance, which included BP, Trafalgar House (now part of AMEC), Brown & Root, Santa Fe, Baker Hughes Inteq, Schlumberger, and ASCo. The alliance was crucial in reducing costs and improving project efficiency.

The alliance members shared cost risks and profits, fostering a non-adversarial relationship that encouraged innovative thinking and cooperation. This approach was pivotal in making the project economically viable, especially after the oil price dropped to $12/bbl in 1994, necessitating further cost reductions.

Technological and Operational Innovations

Several technological and operational innovations were key to the project's success:

• Horizontal Drilling: The use of horizontal drilling significantly aided in the development of the field. Initially, 18 conventional wells were planned, but this was reduced to 10 horizontal producers, which helped in easing the cost estimates.
• Integrated Deck and Jacket: The main installation consists of a fixed platform with a 10,300-ton integrated deck and a 7,500-ton steel jacket. The deck was installed by Saipem's crane vessel S7000, setting a world record for a vessel in DP mode.
• Onshore Completion: Unlike traditional practices where large decks are only 97% complete when they leave the yard, the Andrew project aimed for 100% onshore completion. This was achieved, saving £20 million from the original £27 million budget for offshore hook-up.
• 3D CAD Design: Brown & Root developed a simplified 3D CAD facilities design system known as Triton, which saved 40,000 staff hours in deck and topsides fabrication and another 10,000 hours through direct issuance of electronic drawings to plate-cutting machines.

Cost Savings and Efficiency

The collaborative approach and technological innovations led to substantial cost savings:

• Budget and Schedule: The project was completed £80 million under budget and six months ahead of schedule.
• Staff Hours and Redesign: Trafalgar House saved 40,000 staff hours in deck and topsides fabrication and another 10,000 hours through the use of electronic 3D CAD drawings. Early input into the process avoided unnecessary redesign, further reducing costs.
• Modular Design: The rig was designed to be fit-for-purpose, weighing 1,800 metric tons, significantly less than typical UK platform rigs. This modular design allowed for potential reuse and reduced costs.

Production and Infrastructure

The Andrew field is part of a two-field project that includes the Cyrus field, located 10 km to the north. Here are some key production and infrastructure details:

• Combined Output: The combined output from the Andrew and Cyrus fields is expected to peak at 70,000 barrels per day (b/d).
• Production Life: The expected production life of the fields is 17 years.
• Infrastructure: Processed oil feeds into the Brae-Forties system through a new 16 km, 10-inch diameter pipeline. Treated gas is transmitted to the CATS transmission system through a new 44 km, 8-inch diameter line.

Operational Phase and Future

The success of the Andrew Alliance has extended into the operational phase, with BP forming a separate alliance for development drilling and well management. This includes contractors such as Santa Fe, Baker Hughes Inteq, Schlumberger, and ASCo for logistics support. The focus on lifecycle costs and continuous improvement is expected to drive further efficiencies and cost savings in the operational phase.

The Andrew project serves as a model for the development of marginal fields worldwide, demonstrating the benefits of alliances, innovative technologies, and collaborative project management.