Royal Dutch Shell PLC’s 79%-owned Appomattox platform in the Gulf of Mexico about 80 miles south of New Orleans has become the first high-temperature (HT) project to gain approval from the US Bureau of Safety and Environmental Enforcement (BSEE) and begin crude oil production, the US Department of the Interior agency reported July 30 (OGJ Online, May 23, 2019).
It said that permitting for the project helped define and clarify the safety requirements in BSEE’s recently published high-pressure (HP), HT-related guidance documents.
Nexen Petroleum Offshore USA Inc. holds the other 21% of the project, which aims to tap Appomattox and Vicksburg fields in the gulf.
BSEE Director Scott A. Angelle said, “The collaboration between the offshore energy industry and BSEE spurred the innovation necessary to safely pursue resources in HP/HT operating conditions.”
Angelle noted that federal regulations define HP as greater than 15,000 psi and HT as greater than 350° F. Projects can fall within both or either HP or HT categories.
Shortly after taking the helm at BSEE, Angelle devoted his attention and staff resources to the development of guidance that made it clear to all offshore industry personnel how to conduct safe operations in HP/HT conditions. Notices to lessees (NTL) are the guidance documents BSEE uses to ensure safe operations in environments such as that surrounding the Appomattox project.
First producing HP/HT project
BSEE noted that while the first HP/HT project in the gulf was proposed in late 2009, Appomattox will be the first to begin production. In early June, National Oilwell Varco announced the sale of two 20,000-psi blowout preventer stacks expected to be deployed in the gulf in 2021, making Angelle’s Appomattox decision timely, it said.
“Having clear guidance available to all offshore operators drives safety and makes sense to ensure safe and environmentally sustainable operations,” Angelle said. “In the past we had companies individually submitting data on HP/HT operations, without the benefit of a comprehensive or systematic framework for organizing and sharing that information.”
Angelle said, “What we are implementing is a new approach that puts together industry experts to define the processes, procedures, and standards that make up best practices, and makes that knowledge available to everyone.”
BSEE already has approved 140 permits and plans covering different aspects of the Appomattox project, the agency said. Because the semisubmersible platform is a major deepwater production facility, BSEE’s approval process for the structure alone occurred in three phases. It required a review by a certified verification agent, who followed the design, fabrication, and installation of the structure, then recommended to BSEE’s Office of Structural and Technical Support to accept the work, the agency said.
It said that the approvals included the Conceptual Deepwater Operational Plan and subsequently the implemented Deepwater Operations Plan, which together consisted of hundreds of documents. BSEE's approvals also included 14 applications for permits to drill and 61 applications for permits to modify over three lease areas. Shell also submitted pipeline segments for approval, BSEE said.
Specific reviews, approvals
The agency approved 46 lease-term pipeline segments, 14 right-of-way pipeline segments, a pipeline modification, and five different pipeline risers. For each riser, BSEE said it again reviewed an agent nomination, the design, interim fabrication, final fabrication, interim installation, and final installation reports before approval.
Beginning in 2017, the agency conducted several production safety system reviews and two preproduction inspections prior to approving Shell’s production on the Appomattox platform. “In each permit review and inspection, high temperature conditions were factored into the approvals,” said BSEE Gulf of Mexico Region Director Lars Herbst. “The lessons we learned were incorporated into the newly published HP/HT-related guidance documents.”
Additional development activities related to the Appomattox project are subject to BSEE’s recently released guidance documents regarding HP/HT operations on the US Outer Continental Shelf, the agency said. The NTLs will enable other operators to also develop oil and gas resources using new high pressure and high temperature technologies in a safe and environmentally sustainable manner, it pointed out. They include:
• NTL 2019-G02, which provides guidance related to the process for requesting approval for well design, completion, and intervention operations for wells in an HP/HT environment.
• NTL 2019–G03, which provides guidance related to the process for requesting approval to install and use well completion equipment, well control equipment, well intervention equipment, trees, and production equipment designed for HP/HT environments. This NTL also provides guidance regarding information submissions related to material selection, design verification analysis, and design validation and functional testing process and procedures. It supersedes NTL No. 2007-G07.
• NTL 2019–G04, which provides guidance regarding the information that BSEE needs to analyze an operator’s request for approval to consider external hydrostatic pressure in the design and calculation of internal pressure containment capability of subsea equipment.
Shell said the Appomattox platform, which lies in 7,400 ft of water, is expected at peak to produce 175,000 boe/d. The platform’s hull, weighing 40,000 tonnes, is the largest floating production system that the European multinational oil company has ever built.
Constructed in Geoje, South Korea, it made its way to Ingleside, Tex., in 2017 where the host platform and subsea infrastructure were added. The finished platform left Ingleside in May for its final location in the gulf, where production started later that month, BSEE said.
Contact Nick Snow at [email protected].
