Upstream oil production assets, including oil production pipeline network and gas oil water separation facilities, play a dominant role in sustaining production targets to meet customer requirements. Corrosion management of such assets encompasses various phases, such as design, construction, operation, and decommissioning. Proper engineering design and sound construction practices combined with effective monitoring are essential to manage and maintain the corrosion of these assets within acceptable limits. Some of the considerations taken into account during design include: safety, environment, pressure, temperature, material availability, delivery time, and cost. Operating these assets outside of the design boundaries could influence the corrosion process, significantly impacting integrity. Close monitoring of operating parameters, along with identifying the corrosion by employing appropriate inspection techniques, and implementing timely corrective measures, are of paramount importance to preserving the integrity of these critical assets, which otherwise could lead to safety and environmental issues. This paper highlights three case studies involving the importance of cathodic protection monitoring, and failure analysis of an oil pipeline, along with corrosion inhibitor optimization efforts carried out to ensure asset integrity.
For many decades, paint strippers have used hazardous solvents such as methylene chloride and N-Methyl-2-pyrrolidone (NMP) to effectively remove paints and coatings. But safety and environmental concerns have introduced an urgent need for environmentally-friendly alternatives. In March 2019, EPA banned the use methylene chloride in all paint removers for consumer use. However, its replacement, NMP, is now also deemed as a substance of very high concern (SVHC) and in jeopardy of being an option for paint stripping by regulatory forces.
The newly developed green paint stripper discussed here is free from methylene chloride and NMP. It achieves an environmentally-friendly profile by utilizing agricultural base stocks and recycled industrial solvents. It meets USDA criteria for biobased paint strippers and graffiti removers, and it complies to the VOC requirements of the California Reduced Emission Regulation for Consumer Products. This low odor and biodegradable paint stripper/graffiti remover effectively removes acrylic, alkyd, and urethane-based coatings, as well as marker ink comparably to petrochemical-based and NMP-containing products. In addition, the product contains corrosion inhibitors to prevent discoloration and flash rust on ferrous metals, aluminium, copper, and brass during and after paint removal.
The fire water system on an offshore facility is a critical system. In the event of a fire, this system must not only deliver water for active fire management, but the system must also survive the worst-case scenarios of blast, jet fire and or hydrocarbon fire and for a duration anticipated in that scenario. The fire water system must also survive the duration of time needed for the safe evacuation of personnel from the facility.
This paper addresses the complexities involved in the use of composite pipes for fire water applications. It focuses on how blast effects are managed and the survivability of GRE piping in highly intense and high heat flux fire cases. Results from tests simulations will be shared which were carried out to assure certifying body, operator and engineer that GRE piping is the right material of choice for this application under such circumstances.
The paper concludes with examples of several floating production and storage offloading facilities installed with GRE piping for the fire water application.
Thermal insulation is used in operating facilities to conserve heat and protect against freezing amongst others. A consequence of insulating the pipe is the necessity to manage the introduced threat of corrosion under insulation (CUI). For CUI to occur water and oxygen must enter and migrate through the insulation to reach the external surface of the pipe. The water transport characteristics are dependent on several factors such as type of insulation type of jacketing pipe operating temperature external weather water entry/leakage rate and cyclic service. In hot piping there are competing water transport characteristics as in water vapor moves outwards away from the pipe as water enters into insulation. Knowing the water transport and the parameters that influence the time of wetness at the metal surface helps in understanding conditions favoring CUI.The use of transient hygrothermal models for moisture control is well established in the building insulation design codes and standards. The building designs naturally shed the liquid water to minimize entry and facilitate breathing of vapor so that moisture doesn’t accumulate within building. Several building industry hygrothermal models have been developed and are available for commercial use. One such commercial model has been used to understand water transport in a CUI application. The case study involves evaluation of piping and pipeline installed with a closed cell polyurethane insulation. The hygrothermal model provided insights on the parameters influencing the time of wetness and the ease of water escaping the pipe-insulation-jacketing system. Additional results comparing different insulations are also presented.Key words: Corrosion under insulation water transport hygrothermal models building industry polyurethane insulation
Large standoff magnetometry (LSM), a novel screening technology, has shown strong industry relevance in several pipeline integrity investigations. LSM is used to detect changes in the magnetic field of a pipeline due to changes in the magnetic susceptibility of steel. These changes are known as inverse magnetostriction (a.k.a. the Villari effect) and occur when a ferromagnetic material (steel) is subjected to mechanical stress, such as the presence of stress on the wall of a pipeline. Geometric anomalies (ovalities, dents, wrinkles), hoop stress, ground and slope movement, bend strain, thermal expansion, cracks, and material defects are examples of potential sources of stress that LSM can detect from aboveground.
This paper summarizes the use of LSM as a complimentary tool in several pipeline integrity assessments conducted on oil and gas pipelines, in this case, to pinpoint a lost inline inspection pig and to identify dents, cracks, buckles, slope movement, casing ends, unknown valve locations and other pipeline integrity and direct assessment applications. Ongoing development programs and lessons learnt from practical, real-life projects and validations of the technology are presented to demonstrate the effectiveness of LSM for pipeline integrity investigations.
The corrosive fluids transportation inside carbon steel pipelines is critical due to internal corrosion. To avoid failures barrier corrosion protection techniques are applied by insulating the inner metal wall of the pipe. However when the tubes are welded together the inner coating is damaged by the heat generated during the welding process. As a result the ends of the tubes are uncoated and consequently subjected to corrosion. There are solutions to this problem but all have some kind of inconvenience either by the cost of implementation or the difficulty of application. This work aims to present the results of the tests of the application of an alternative technique: zinc thermally sprayed as sacrificial anode for internal protection of welded joints.
Although computational methods have been separately developed to predict corrosion and fatigue crack growth rates for metallic structures, challenges remain in implementing a methodology that considers the combined effects. In this work the output from a galvanic model is used to determine the spatial distribution of corrosion damage; providing a guide for the location of discrete corrosion damage features that can be analyzed using stress fields from structural models. In order to build confidence in this approach the galvanic models are validated by comparing predicted results to surface damage measurements from test specimens subject to ambient atmospheric exposure. There was good comparison between the predicted spatial distribution of corrosion damage and the measured surface damage profiles obtained from the galvanic test specimens. Following this exercise novel computational corrosion damage features were developed to represent simplified cracks shapes emanating from corrosion pits. Stress intensity factors (SIF) for these newly developed hybrid pit-crack features were determined and these solutions compared to cases where the pit is assumed to be an equivalent crack. The impact of the local, cavity induced stress field, on the SIF solutions is discussed. Building on these findings a fatigue crack growth simulation was performed using an initial flaw emanating from a hemispherical cavity (corrosion pit) located at the edge of hole in a plate. A reasonable comparison, of the predicted number of crack growth cycles, to available experimental test results was achieved.