Best Practice to Ensure Integrity of Ageing Critical Pipeline Gas/NGL Distribution Facilities
Authors: Albraiki Ahmed , Al Ahmad Alya , Al Awadhi Ibrahim , Kant Nath Nahum , Mohamed Ismail Mohamed Sulaiman 
Published: November 2019

Abstract
ADNOC Gas Processing (AGP) plays a strategic role in ADNOC and the UAE hydrocarbon value chain by contributing significantly for the development of the Emirates. AGP operates and manages an integrated Pipeline Network of approximately 3200km length of Pipelines with the mission of uninterrupted supply to its Customers without any impact on the upstream plants. Various fluids are transported via pipelines such as Sales gas, Crude oil, NGL, Condensate, Water, Nitrogen and associated gases wherein majority of network contains Sales Gas. Pipeline Network is scattered over Ruwais, Habshan, Buhasa, Asab, Shuwaihat, Jebel Danna, Al Maqta, Taweelah, Jebel Ali, Al Ain, Ghantoot, Al Dhabbaya, Al Romaitha, Saadiyat Island, Yas Island, Mussafah and in some other areas within the Emirate of Abu Dhabi.
The Sales gas pipeline network connects gas plant facilities to consumers/ADNOC Plants through pipeline Distribution Facilities (Manifolds). The NGL pipeline network connects NGL plant facilities with manifolds to onward supply of NGL to AGP plant for fractionation into various products such as ethane, butane, propane and naptha etc.
These manifolds are old and highly critical, hence their safety and reliability are paramount to ensure shareholders commitment to various consumers in UAE and abroad. Failure of these manifolds will have a major impact on upstream & downstream production chain. Shut down of these manifolds are not possible as there is no bypass arrangement or back up manifold for business continuity. Failure of any of the manifold will have major impact on AGP Business and reputation.
Some of theses manifolds were constructed in late 70’s and have completed their design life. In line with current business scenario and fit for purpose approach being adopted by ADNOC, it is prudent to understand methods to assess the condition of existing ageing assets and apply techniques to enhance the reliability and integrity of the same. Ageing equipment is challenging and a systematic approach is necessary to decide on the life of ageing assets. AGP is one of the largest gas processing companies in the world, and it is considered as the major energy and feedstock supplier for the majority of the power, hydro carbon, and petrochemical industries based in the UAE.
In view of the above, AGP has carried out an Integrity/Adequacy assessment study to check fitness for service of the manifolds with due consideration to business continuity, the impact on upstream/downstream production, Company reputation, asset integrity, process safety and HSE aspects etc.
This paper presents the challenges faced and best practices adopted for ensuring/enhancing Process Safety (Prevention of Loss of Containment), improve integrity/reliability of the manifolds, minimize impact on normal operation and maintenance and reduce the risk of business interruption.
AGP best practices are based on the requirements of Pipeline Codes, International Standards, industry practices, ADNOC Gas Processing Specifications/Standards, and good engineering practices etc.
The Best Practices followed in this study have ensured the safety, efficiently and reliablty of operation of these manifolds. Confidence level in assuring integrity of againg facilities is boosted. Similar approach will benefit the oil and gas industries for ensuring safety and integrity of old ageing facilities.