Many GASCO pipelines cross major highways in Abu Dhabi through concrete culverts (lengths varying from 50 to 125m). Some culverts are in severely deteriorated condition and required immediate replacement. Collapse of culvert(s) may lead to failure of the pipeline resulting in Loss of Containment, environmental degradation and potential risks to personnel/neighbourhoods. This paper presents a techno-economical solution as an alternate to the repair/replacement option for safeguarding the integrity of the pipelines. GASCO identified four severely deteriorated concrete culverts which are protecting 6nos vital oil/gas pipelines, for major repair/replacement. Performing the repair/replacement of these culverts pose challenges due to access restraints, traffic obstructions/diversions, massive civil works, risk of working in the live gas pipeline vicinity etc., with huge overall estimated cost and more than two years execution time. GASCO studied/explored different options including the repair/replacement of existing culverts and ended up with selecting the option of flooding the culverts with a self-compacting mixture of sand and water using specialized pumps which can satisfy/meet the technical, commercial aspects and extend the remnant life. Detailed study was carried out to verify the various technical aspects and evaluate the methodology, with data collection of existing pipe sizes, pipeline wall thicknesses from pipe condition inspection reports, vehicle loads, vibration measurements due to vehicle movements at pipe depths and desktop evaluation of data. The existing pipelines wall thicknesses were checked for Barlow stress (Hoop stress), Circumferential Stress, Longitudinal Stress, Radial Stress and Fatigue check for Girth & Longitudinal Welds considering the overburden loads of earth/sand fill, vehicle cyclic load and internal pressure/temperature and found adequate. Methods of construction and different materials for filling were explored. In some culverts, there was not adequate headroom for people/ equipment access. The method of pumping sand (using special pumps) and compaction of each sand layer by water flooding was found to be the most suitable option in terms of technology, local equipment availability/easy mobilization, locally available filling material, reduced risk of working in the vicinity of live gas pipes, etc. The solution was successfully implemented for the four culverts (each 60m long) across the busy Abu Dhabi – Al Ain highway at Mussafah, in Sep-2015, within 2 months duration and resulted in a huge cost saving of AED 38millions. The followed approach is a long term solution that can be executed by the in-house resources of maintenance team with some support from local contractors (for pumping facilities, etc.) and it also eliminates the future maintenance cost. This solution is first of its kind that was implemented among ADNOC group companies and can be shared with/ adopted by other companies having similar facilities to benefit from the cost optimization & other advantages.

Pipeline Design and Construction in populated areas to ensure Safety and Integrity of Pipeline System as well as Public Safety in the pipeline vicinity is a major challenge. GASCO 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, hydrocarbon, and petrochemical industries based in the UAE. GASCO operates pipelines network having total length of approximately 3,500km, and supplies Sales (fuel) gas to the various consumers such as ADWEA, EMAL, ICAD, UAN Refinery etc. in UAE. GASCO Sales Gas Pipelines pass through populated/industrial/city areas such as Mussafah, Maqta, Yas-Island, Khalifa City, Al Raha and Shahama, etc. This paper presents the challenges and best practices adopted for Pipeline Design and Construction in GASCO Projects to ensure safety of the people in the vicinity, enhance process safety, improve integrity/reliability of the pipelines, minimize impact on normal operation and maintenance and reduce the risk of business interruption. Major challenges faced in populated area are the finalization of pipeline route in city area, proper and adequate design to protect the pipeline and subsequently ensuring public safety, minimum impact to the environment, consideration of future developments, construction activities in congested area/ crossings, protection of existing utilities/facilities and third party activities in the vicinity of pipeline. In GASCO Projects, during pipeline design in populated areas, it is ensured that minimum spacing requirement between pipeline and populated/residential area is as per GASCO Standard Practice, International Standards and QRA recommendations. Selection of Pipeline Location Class/Design Factor, maximum distance requirement between Sectionalizing Valves are complied with Pipeline Codes. Increasing Pipeline cover, Corridor Fencing, Markers and installing slabs for the pipeline protection from third party activities are other measures are taken into an account. The pipeline integrity is enhanced by considering remote operated block valves and pipeline leak detection system, increasing the frequency of Patrolling. Also conducting Pipeline Constructability review to identify the hazards during construction activities is very important. As a proactive approach, future developments in the vicinity of the pipeline is also considered. GASCO best practices are based on the requirements of Pipeline Codes, International Standards, industry practices, and GASCO Specifications/Standards and experiences from previous pipeline projects. The Best Practices followed in GASCO projects have ensured the safety of the public and GASCO pipelines for their safe, efficient and reliable operation. Confidence level in assuring integrity of pipelines is boosted. Similar approach will benefit the oil and gas industries for protecting pipelines and ensuring public safety in populated areas.

"Optimization" or "Fit for Future" is the new norm for any industry in this competitive global environment. To encounter the challenges and to embed 100% HSE, efficiency, performance and profitability in operation, maintenance and new constructions, there is an urgent necessity to review and update existing design and construction specifications related to Pipeline. Hence, this paper summarizes the latest specification optimization efforts in pipelines material engineering without compromising the safety and integrity of the assets. In ADNOC Gas Processing, specifications for various engineering disciplines namely, process, automation, control, electrical, static/ rotating equipment, piping/ pipeline, civil/ structural are followed in engineering, construction and maintenance activities. These were developed over years to steer the Company towards unparalleled reliability, operability and integrity. Now, the challenging market demands adaptability, agility and forward thinking with a need to "balance the performance with efficiency and profitability", without compromising HSE. Hence, a "Lean" approach towards the specifications is emphasized by focusing on cost-saving and value addition in terms of optimized schedules and enhanced efficiency. A set of pipelines DGSs were reviewed internally based on International standards/specifications, best engineering practices, lessons learnt from involvement with Operation and Projects and consultants optimized specifications. Through this paper, major changes in pipeline specifications are elaborated highlighting potential areas of optimization and realized cost savings. 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. ADNOC Gas Processing (AGP) operates and manages an integrated Pipeline Network of approximately 3500km length of Pipelines with the mission of uninterrupted supply to its Customers and 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. AGP is involved in executing many Major Pipeline Projects. This paper presents "Fit for Future" initiative that has changed the organizational culture and reflects effectively in all activities across the Company. As all the technical activities are based on DGSs, update plan and potential cost realization are the main drivers for enhancing the performance without compromising HSE. This approach of re-visiting the technical specifications in the light of "high efficiency with low cost" can be adopted across other OPCOs and move towards common specifications for ADNOC.

With focus on enhancing Integrity and efficiency, ADNOC Gas Processing identified an opportunity for optimization of existing FRP firewater system in Ruwais. A comprehensive study of complete firewater network and review of operating and control philosophy performed in order to optimize the system performance and mitigate pressure surge problems. This paper presents measures that ADNOC Gas Processing have adopted to achieve improved system efficiency and lower operating cost. A study was undertaken by GASCO to review issues with existing Fire Water network (FWN) at Ruwais to enhance overall performance of system in terms of design, operation and control. Initiative was to identify problems, evaluate root cause and think of optimization including some cost saving solutions. Study explored various operating configurations of existing 4-working+ 4-standby pumps with active involvement of operation personnel followed by hydraulic and surge analysis with different operating scenarios. Study revealed reduction in flow, head and pressure to mitigate fire water piping surge problems. Study also engaged pump vendors to establish feasibility of modifying the existing pumps. The study identified that each existing fire water pump is suitable to deliver 1400 m3/hr against required flow of 1000 m3/hr. Additional flow may create pressure spikes and surges in FWN. Hydraulic analysis found that pressure was above minimum requirement of 7bar (g) at the most remote point in network. Simulation indicated that fluid velocity was above 3.5 m/s at specific sections on the ring main. Increase in pipe sizes is required to arrest velocity within recommended limit in these areas. Option of lowering the operating pressure of main fire water pumps without the fire water network pressure falling below 7bar (g) at the most hydraulically remote point in the network was studied. Also the option of 3W+3S and 4W+4S [working (W) and standby(S)] pumping configuration was studied so as to establish that system can work with less number of pumps. Hydraulic study concluded that rated pressure should be reduced along with shut-off pressure. The maximum worst case fire water demand is 3200 m3/hr. The demand is found to be achieved with three Fire Water Pumps. During study pump vendors were engaged to arrive at the conclusion that 3W+3S configurations are hydraulically acceptable with pump / impeller modifications and de-staging options.

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.