Hewett

Discovery and Development

• The Hewett gas field was discovered in 1966 by US-based Philips Petroleum through the wells 48/29-1 (Arpet) and 52/5-1 (Phillips).
• The field began production in 1968 from the Lower Bunter reservoir and later from the Upper Bunter reservoir in 1973.

Location and Geology

• The Hewett field is situated in the United Kingdom’s Southern North Sea, straddling blocks 48/28, 48/29, 48/30, 52/4a, and 52/5a, at a water depth of approximately 30 meters.
• The field consists of two main reservoirs: the Lower Triassic Upper Bunter and Lower Bunter Sandstones, along with a smaller Zechstein Carbonate reservoir.

Infrastructure and Platforms

• The field is developed through a cluster of assets, including a central complex and three satellite platforms: 48/29-A, 48/29-B, 48/29-C, 48/29-FTP, 48/29-Q, and 52/5-A.
• The platforms are connected by bridges, with the central complex comprising three bridge-linked platforms (48/29-A, 48/29-FTP, and 48/29-Q). The other platforms (48/29-B, 48/29-C, and 52/5-A) are not permanently attended installations (NPAIs).
• Each platform was designed to carry wellhead equipment for multiple gas wells, with the largest platforms supporting up to 11 wells.

Production History

• The field was initially operated by Philips Petroleum and later by various other companies, including Conoco-Philips and Tullow Oil, before ENI took ownership in 2008.
• The cumulative production from the Hewett field is approximately 3,490 billion standard cubic feet (Bscf) of gas, with an estimated original gas in place (OGIP) of 3.88 trillion cubic feet (Tcf).

Decommissioning

• The Hewett field ceased its main production activities at the end of 2020, with gas production continuing solely for fuel gas usage offshore until the end of 2021.
• Petrofac, as the Duty Holder and Pipeline Operator since 2003, is overseeing the decommissioning process. This involves the plugging and abandonment of wells, removal of platforms, and other infrastructure. The decommissioning is expected to be completed by 2025.
• The decommissioning process is highly regulated and involves meticulous planning, stakeholder engagement, and regulatory approvals. The goal is to remove every trace of the field’s infrastructure.

Future Potential

• Although the primary decommissioning plan is to remove all infrastructure, there have been discussions about potential future uses for the field, such as converting it into a gas storage facility or utilizing it for carbon capture and storage (CCS) projects.

Environmental and Regulatory Considerations

• The decommissioning process is subject to strict environmental and safety regulations. Petrofac and ENI are working closely with regulatory bodies, including the Offshore Petroleum Regulator for Environment and Decommissioning (OPRED) and the Health and Safety Executive (HSE), to ensure compliance with all regulatory requirements.

Historical Significance

• The Hewett field was one of the first in the North Sea to be developed and played a significant role in the UK's oil and gas industry. The field's development had a profound impact on the local community, particularly in Great Yarmouth, where many American oil workers were based during the 1960s and 1970s.

In summary, the Hewett gas field is a landmark project in the UK's offshore oil and gas industry, with a rich history and significant contributions to the country's energy production. Its decommissioning marks the end of an era but also highlights the industry's transition towards more sustainable practices and potential future uses for such infrastructure.