Internal corrosion caused ADNOC to suffer losses in the oil flow lines of a huge onshore oil field. The desire to eliminate this problem and the need to determine specifications and an accurate future streamline integrity management plan led to field trials using grooved and flangeless high-density polyethylene (HDPE) lining technology in carbon steel pipes. This article introduces a five-year successful field test plan, and proves that the application of HDPE lining in carbon steel pipes can reduce internal corrosion in petroleum pipelines by isolating metal pipes from corrosive fluids, which is a cost-effective Methods. This technology is cost-effective in managing internal corrosion in oil flow lines.
The streamline is designed to have a service life of more than 20 years in ADNOC. This is very important for business continuity and reducing operating costs. However, maintaining these pipelines made of carbon steel becomes challenging because they are susceptible to corrosive fluids, internal corrosion by bacteria, and stagnant conditions caused by low flow rates. The risk of integrity failure increases with age and reservoir fluid properties.
ADNOC operates the streamline at a pressure of 30 to 50 bar, a temperature as high as 69°C and a water content of more than 70%. In a huge onshore oil field, due to internal corrosion, the oil streamline in the oil streamline suffers Many losses. Records show that there are more than 91 natural flow lines (302 kilometers) and more than 45 gas lift oil flow lines (100 kilometers) with high internal corrosion in the selected assets alone. Operating conditions that require internal corrosion mitigation include low pH (4.8-5.2), presence of CO2 (>3%) and H2S (>3%), oil-to-air ratio greater than 481 scf/bbl, streamline temperature over 55°C, streamline The pressure is higher than 525 psi. High water content (>46%), low flow rate (less than 1 m/sec), stagnant fluid and the presence of sulfate-reducing bacteria also affect mitigation strategies. Streamline leak statistics show that many of these pipelines have problems, and as many as 14 leaks have occurred in 5 years. This caused serious problems because it led to leaks and interruptions that adversely affected production.
The loss of tightness and the need to determine specifications and accurate future pipeline integrity management plans resulted in Schedule 80 API 5L Gr. B 6 inches at 3.0 km. flowline to solve this problem. The field test was first applied to the 3.527 km carbon steel pipeline of the selected asset, and then reinforced tests were carried out on the 4.0 km pipeline.
The oil giants of the Arabian Peninsula Gulf Cooperation Council (GCC) installed HDPE liners as early as 2012 for crude oil flow lines and water applications. A GCC oil giant operating jointly with Shell has used HDPE linings in water and oil applications for more than 20 years, making the technology sufficiently mature that it can be applied to solve the internal corrosion complications of oil pipelines.
The ADNOC project was launched in the second quarter of 2011 and installed in the second quarter of 2012. The monitoring started in April 2012 and was completed in the third quarter of 2017. The test spool is then sent to the Borouge Innovation Center (BIC) for evaluation and analysis. The success and failure criteria set for the HDPE liner pilot are zero leakage after liner installation, low gas permeability through the HDPE liner, and no liner collapse.
The paper SPE-192862 describes the strategies that contributed to the success of field trials. The focus is on planning, laying pipelines and evaluating the performance of HDPE linings in order to obtain the knowledge needed to implement HDPE pipeline positioning integrity management strategies for the entire oil pipeline. This technology is used in oil flow lines and transmission lines. In addition to existing oil pipelines, non-metallic HDPE linings can also be used in new oil pipelines. It focuses on the best practice methods to eliminate the damage caused by internal corrosion and lead to the failure of the integrity of the oil pipeline.
The complete paper describes the implementation standards of HDPE gaskets; the selection, preparation and installation sequence of liner materials; air leakage and hydraulic pressure tests; annular gas discharge and monitoring; circuit commissioning; and detailed test results after the test. The streamline life cycle cost analysis table illustrates the estimated cost advantage of carbon steel with HDPE lining compared to other corrosion mitigation methods, including chemical injection plus pigging, non-metallic pipes, and bare carbon steel. It also explained the decision to conduct a second enhanced field trial after the initial trial. In the first test, flange connections were used to connect the various parts of the streamline. As we all know, flanges are prone to failure due to external stress. Manual exhaust at the flange location not only requires regular monitoring, which increases operating costs, but also causes permeable gas to be emitted into the atmosphere. In the second test, the flange was replaced with a welded flangeless coupler with an automatic reinjection system and a grooved lining. There is an exhaust port at the end of the remote degassing station, which will terminate in a closed drainage system.
Five-year tests have confirmed that the application of HDPE lining in carbon steel pipes can reduce the internal corrosion of the petroleum pipeline by isolating the metal pipe from the corrosive fluid.
Added value through the following ways: providing uninterrupted streamline services, eliminating internal pigging of pipelines to remove sediment and bacteria, eliminating the need to use anti-scaling chemicals and biocides to save costs and reduce workload
The purpose of the test is to reduce the internal corrosion of the oil flow pipeline and prevent the loss of the primary containment.
Slotted HDPE linings with welded flangeless joints are used in combination with the re-injection system as an improvement based on the lessons learned from the initial deployment of ordinary HDPE linings with clamps on flange ends.
According to the success and failure criteria set for pilots, there have been no reports of leaks in the pipeline since installation. Further testing and analysis by BIC showed that the weight of the used lining has been reduced by 3-5%, and it will not cause chemical degradation after 5 years of use. Some scratches were found, but did not extend into the cracks. Therefore, it is recommended to consider the difference in density loss in future designs. The implementation of internal corrosion barriers should be the main focus, among which HDPE lining options (including the identified improvements, such as the replacement of flanges with connectors and the continuation of the lining and the application of check valves in the lining to overcome the lining Gas permeability) liner) is a reliable solution.
This technology eliminates the threat of internal corrosion and significantly saves the operating costs of chemical treatment procedures because chemical treatment is not required.
The on-site verification of this technology has a positive impact on operators' streamline integrity management, and provides more options for active streamline internal corrosion management, thereby reducing overall costs and improving HSE performance. It is recommended to use a flangeless grooved HDPE liner as an innovative method to manage internal corrosion of oil production pipelines in oil fields.
HDPE lining technology is recommended for existing oil and gas fields where there are frequent pipeline leaks and water injection pipeline interruptions.
This application will reduce the number of streamline failures caused by internal leakage, extend streamline life and increase productivity.
New full oilfield development can use this technology for internal corrosion management of the streamline and save the cost of monitoring programs.
This article was written by JPT technical editor Judy Feder, and contains the key points of the paper SPE 192862, "The innovative field test results of the application of the flangeless HDPE lining in the super giant oil field for internal corrosion management of the oil flow line", the author is Abby Kalio Amabipi, SPE, Marwan ADNOC's Hamad Salem, Siva Prasada Grandhe and Tijender Kumar Gupta; Mohamed Ali Awadh, Borouge PTE; Nicholas Herbig, Jeff Schell and Ted Compton of the United Special Technical Services Department in Abu from November 12 to 15 Preparation for the 2018 Abu Dhabi International Petroleum Exhibition and Conference in Dhabi. The paper has not yet been peer reviewed.
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Journal of Petroleum Technology is the flagship magazine of the Society of Petroleum Engineers, providing authoritative briefings and topics about the advancement of exploration and production technology, oil and gas industry issues, and news about SPE and its members.
ISSN: 1944-978X (online) ISSN: 0149-2136 (print)