The Middle East faces a substantial challenge to keep hundreds of aging offshore oil and gas structures operating safely and legally beyond their original design life, according to DNV GL Oil & Gas.
Anupam Ghosal, regional manager for Middle East and India, said: “There are at least 700 to 800 fixed platforms and bridges in the region. More than 70% are older than 25 years; some exceed 40 years. United Arab Emirates (UAE) alone has about 450.”
Constraining opex is vital to economic and safe operations, he continued, adding that Middle East operators are at different stages of implementing controlled approaches to asset integrity management (AIM) and structural integrity management (SIM) systems.
DNV GL is engaged in the process with various companies in the region.
Abu Dhabi Marine Operating Co. (ADMA-OPCO) is one of the NOCs addressing life extension opportunities; some of its earliest offshore facilities are more than 50 years old.
“We have an extensive fleet of structures undergoing continuous brownfield project developments to ensure sustainable oil production over the extended field-life,” said Dr. Tarek Omar, civil/structural engineering team leader at ADMA-OPCO. “Of these assets, 70% have already reached design life…”
ADMA-OPCO has developed a comprehensive structural management system (SMS) framework based on a quantitative approach, under which all changes are monitored and managed through an in-house developed management of change system for structures that meets all the company’s requirements.
“This SMS works with different database systems,” said Ebrahim Saleh AL-Shehhi, project manager for the integrated database management system, which covers asset integrity for structures, pipelines, and critical safety equipment.
“DNV GL’s Synergi Structure software is used for storing all structural characteristics data, inspection findings and reports, and risk ranking information. The Synergi dashboard presents results interactively showing main highlights across all assets.”
Ghosal said: “Technological advances provide opportunities to produce more hydrocarbons economically from existing structures. Low oil prices create the need to extract best value from current facilities.
“Other drivers include improved data on reservoirs, heightened regulation, updated design standards and knowledge, advances in risk management, and enhanced focus on safe operations.”
ADMA-OPCO plans to further increase the effectiveness of its SIM by mandating use of the management of change system company-wide; continuously updating structural assessment methods; and continuous interaction and joint innovation with industry partners.
Ghosal said: “Operators here face challenges encountered elsewhere in the world, but also ones that are specific to, or more pronounced, in this region, such as sour gas. DNV GL has had a presence here for more than 30 years and understands local needs.”
DNV GL’s software, database, quantitative and qualitative approaches, and other expertise in capturing, analysing, and managing information for SIM assists clients with scoping, designing, and implementing life extension strategies. The company’s “missing data methodology” addresses the absence of historic documentation, a common challenge for operators in the region. Another is aging effects in grouted piles.
In response to a DNV GL survey, some operators also expressed a desire to see regional acceptance criteria formulated for a SIM of existing fixed structures, but with flexibility to respond to local circumstances.
For offshore Abu Dhabi, they wanted to know how lateral pile capacity might be enhanced in carbonaceous rocks; more about the seismic vulnerability of platforms; and, how a range of site-specific responses might be put together.
Others saw a need for engineering studies to verify requirements for replacement of degraded items such as riser- and conductor-protectors.
Region-specific guidance on the below elements is useful when developing life extension strategies for aging offshore structures, according to DNV-GL:
- Wave spectra suitable for benign sea conditions in the Arabian Gulf to predict fatigue reliability and to assess the remaining fatigue life of structures
- Corrosion mitigation strategies for structures and critical appurtenances to optimize the operating expenditure of aging offshore structures
- New technology to acquire missing data on actual pile penetration depth and aging grout strength to assure drilled and grouted foundation integrity.