NDLI: General Recommendations From the Results of Reassessment of 21 Platforms in Bay of Campeche

Content Provider	The American Society of Mechanical Engineers (ASME) Digital Collection
Author	Chakrabarti, Partha Juan, De Dios De La O.
Copyright Year	2010
Abstract	Pemex Explorac´ion y Produccio´n (Pemex) owns and operates several fields for oil and gas exploration in the Bay of Campeche located in the south Gulf of Mexico. In order to meet the growing demand for oil and natural gas it was necessary to extend the service life for many existing platforms by at least another 15 to 30 years. To ensure a safe operation throughout this period, thorough and systematic reassessment studies needed to be conducted leading to the identification of any structural weakness. Finally, to control the fatigue behavior of the welded joints, risk based inspection planning (RBI) was adopted to ensure extended service life. In these reassessment studies the ultimate strength of the platforms is evaluated through nonlinear pushover analyses as a part of condition assessment. Spectral fatigue analyses are performed to identify the fatigue sensitive joints. This is followed by redundancy analyses, assuming that one individual member at a time becomes ineffective given a weld fatigue failure at the joint. For the inspections aimed to control the development of predictable degradation such as fatigue crack growth, the inspection efforts can be targeted such that the risks implied by the degradation are kept within acceptable limits. This is done through a risk based inspection planning strategy. The analytical aspects for this approach were discussed in previous papers on the subject by the authors. The current paper presents the overall results of 21 platforms taken up for a recent study and discusses the trends in view of broad parameters such as water depth, loading, structural arrangement. These structures include drilling, production, gathering and living quarter platforms. The platforms are located in various assets in water depths ranging from 40 to 90m, have different configurations with 3, 4 and 8 legged jackets, they also support different deck weights. In the present paper overall results of the study performed for 21 platforms are presented. The platforms have been classified in terms of platform type, number of legs, framing pattern, leg diameter etc. The results for strength of the platforms obtained from pushover analyses, and fatigue life are analyzed in light of the classification parameters. The differences in the platform characteristics such as stiffness, wave loading and natural period are discussed along with their implications to strength and fatigue life. Inspection requirements are also interpreted in the light of these global parameters. Finally, some general recommendations are made for design of jackets keeping in view the overall behavior and inspection requirements. It is believed that if the recommendations are followed in the initial design there would be benefits in the future for inspection, maintenance, and repair and possible life extension increasing their economic return.
Sponsorship	Ocean, Offshore and Arctic Engineering Division
Starting Page	43
Ending Page	51
Page Count	9
File Format	PDF
ISBN	9780791849095
DOI	10.1115/OMAE2010-20056
e-ISBN	9780791838730
Volume Number	29th International Conference on Ocean, Offshore and Arctic Engineering: Volume 1
Conference Proceedings	ASME 2010 29th International Conference on Ocean, Offshore and Arctic Engineering
Language	English
Publisher Date	2010-06-06
Publisher Place	Shanghai, China
Access Restriction	Subscribed
Subject Keyword	Drilling Water Fatigue life Service life (equipment) Inspection Fatigue Fatigue failure Maintenance Fatigue analysis Risk-based inspection Waves Tensile strength Design Structural frames Gulf of mexico Welded joints Framing (construction) Life extension Stiffness Fatigue cracks Natural gas Redundancy (engineering)
Content Type	Text
Resource Type	Article

Sl.	Authority	Responsibilities	Communication Details
1	Ministry of Education (GoI), Department of Higher Education	Sanctioning Authority	https://www.education.gov.in/ict-initiatives
2	Indian Institute of Technology Kharagpur	Host Institute of the Project: The host institute of the project is responsible for providing infrastructure support and hosting the project	https://www.iitkgp.ac.in
3	National Digital Library of India Office, Indian Institute of Technology Kharagpur	The administrative and infrastructural headquarters of the project	Dr. B. Sutradhar bsutra@ndl.gov.in
4	Project PI / Joint PI	Principal Investigator and Joint Principal Investigators of the project	Dr. B. Sutradhar bsutra@ndl.gov.in Prof. Saswat Chakrabarti will be added soon
5	Website/Portal (Helpdesk)	Queries regarding NDLI and its services	support@ndl.gov.in
6	Contents and Copyright Issues	Queries related to content curation and copyright issues	content@ndl.gov.in
7	National Digital Library of India Club (NDLI Club)	Queries related to NDLI Club formation, support, user awareness program, seminar/symposium, collaboration, social media, promotion, and outreach	clubsupport@ndl.gov.in
8	Digital Preservation Centre (DPC)	Assistance with digitizing and archiving copyright-free printed books	dpc@ndl.gov.in
9	IDR Setup or Support	Queries related to establishment and support of Institutional Digital Repository (IDR) and IDR workshops	idr@ndl.gov.in