Simulation and Analyze of a Failed Coiled Tubing Job in a Sour Gas Well With Effect of O2 on Corrosion Behavior
Volume Title: 1
Authors
1Coiled Tubing Service Supervisor,International Petro Offshore Niam Kish
2Department of Petroleum Engineering, Amir Kabir University Of Technology, Tehran, Iran
3Islamic Azad University, Ghoochan Branch
Abstract
Despite purity problems of membrane nitrogen generator units, the application of these technologies is extensively increasing for coiled tubing. In cases, where prolonged and continues unloading of heavy weight fluids within the well is needed, the use of these units are reasonable. Since the initiation of corrosion reactions chain is presence of O2 , then high amount of O2 causes severe weight reduction while H+ and Cl- ions from formation water and sour gas intensively increase corrosion reaction. Such reactions dramatically decrease the sweet life of coiled tubing and highly increase the risk of fatigue and remaining in well. Hydrodynamic corrosion analysis in a transient multi phase flow simulator can predict corrosion during an unloading operation in presence of O2 impurities in oilfields with H2S gas in this survey. With help of weight reduction test for a field samples of corroded coiled tubing and simulation scenario, results of failed operation in a sour volatile oil well with 8000 ppm H2S content is modeled. Technical methods suggested for decreasing coiled tubing corrosion for safer operation criteria based on simulation with different O2 impurities contents in well condition. Finally weight loss, flow regime, and impurity content are discussed together. Rate of corrosion in milli gram per year with investigating hydrodynamic corrosion and flow regime implemented valuable point of view for a real case prediction. By controlling weight loss and impurities, safer operation can be conducted with reducing risk concepts.
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