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The Effect of Nitrite on Pitting and Stress Corrosion Cracking of Corrosion Resistant Alloys (CRA) Under Oil Field Conditions

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The Effect of Nitrite on Pitting and Stress Corrosion Cracking of Corrosion Resistant Alloys (CRA) Under Oil Field Conditions The University of Manchester Research The Effect of Nitrite on Pitting and Stress Corrosion Cracking of Corrosion Resistant Alloys (CRA) under Oil Field Conditions Link to publication record in Manchester Research Explorer Citation for published version (APA): Okeremi, A. O. (2011). The Effect of Nitrite on Pitting and Stress Corrosion Cracking of Corrosion Resistant Alloys (CRA) under Oil Field Conditions. University of Manchester. Citing this paper Please note that where the full-text provided on Manchester Research Explorer is the Author Accepted Manuscript or Proof version this may differ from the final Published version. If citing, it is advised that you check and use the publisher's definitive version. General rights Copyright and moral rights for the publications made accessible in the Research Explorer are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights. Takedown policy If you believe that this document breaches copyright please refer to the University of Manchester’s Takedown Procedures [http://man.ac.uk/04Y6Bo] or contact [email protected] providing relevant details, so we can investigate your claim. Download date:10. Oct. 2021 The Effect of Nitrite on Pitting and Stress Corrosion Cracking of Corrosion Resistant Alloys (CRA) under Oil Field Conditions. A thesis submitted to the University of Manchester for the degree of PhD in the Faculty of Engineering and Physical Sciences. 2011 Akinyemi O. Okeremi School of Materials LIST OF CONTENT LIST OF CONTENT .................................................................................................. 2 LIST OF TABLES ...................................................................................................... 4 LIST OF FIGURES ................................................................................................... 5 ABSTRACT ............................................................................................................. 10 DECLARATION ...................................................................................................... 11 CERTIFICATION .................................................................................................... 12 COPYRIGHT STATEMENT .................................................................................... 13 DEDICATION .......................................................................................................... 14 ACKNOWLEDGEMENT ......................................................................................... 15 PREFACE ............................................................................................................... 20 LIST OF ABBREVATIONS ..................................................................................... 22 1 INTRODUCTION ........................................................................................ 24 2 LITERATURE REVIEW .............................................................................. 34 2.1 Reservoir Souring due to Water Injection ............................................ 34 2.2 Nitrate Injection to control Reservoir Souring ...................................... 34 2.2.1 Mechanisms of Nitrate Inhibition of Reservoir Souring ................... 36 2.2.2 Field Application of Nitrate Injection to Control Reservoir Souring .. 42 2.2.3 Effect of Nitrate/Nitrite on Corrosion Rate ....................................... 46 2.3 Passivity of Metals............................................................................... 77 2.4 Passivity Breakdown ........................................................................... 85 2.5 Repassivation .................................................................................... 105 2.6 Electrochemical Testing .................................................................... 107 2.6.1 Thermodynamics .......................................................................... 107 2.6.2 Kinetics ......................................................................................... 108 2.7 Deterministic Modelling of Passivity Breakdown ............................... 117 2.8 Pitting Resistance.............................................................................. 126 2.9 Stress Corrosion Cracking ................................................................ 128 2.10 Stress Corrosion Cracking Mechanisms ........................................... 131 2.10.1 Slip Dissolution mechanism .......................................................... 133 2.10.2 Film Induced Cleavage Mechanism .............................................. 136 2.10.3 Hydrogen Embrittlement Mechanism ............................................ 138 2 2.11 Effect of Stress Intensity Factor on the rate of SCC .......................... 141 2.12 Managing Stress corrosion cracking ................................................. 146 3 EXPERIMENTAL PROCEDURE .............................................................. 149 3.1 EL400 Working Electrodes for Electrochemical Tests ....................... 149 3.2 Preparation of Test Solution .............................................................. 150 3.3 Electrochemical Cell Setup ............................................................... 151 3.4 Electrochemical Test Methods .......................................................... 154 3.4.1 Open Circuit Potential ................................................................... 154 3.4.2 Cyclic Potentiodynamic Polarisation (CPP) Test .......................... 154 3.5 Potentiostatic Polarisation Test ......................................................... 156 3.5.1 Determination of Critical Nitrite Concentration .............................. 156 3.6 C-ring Test ........................................................................................ 156 3.7 Slow Strain Rate Test ........................................................................ 166 4 RESULTS AND DISCUSSION ................................................................. 171 4.1 Open Circuit Potential Measurements ............................................... 171 4.2 Cyclic Potentiodynamic Polarisation (CPP) Test ............................... 176 4.2.1 Effect of nitrite on the cathodic curve ............................................ 225 4.3 Potentiostatic Polarisation Test ......................................................... 229 4.3.1 Determination of Critical Nitrite Concentration .............................. 231 4.4 C-ring test for Stress Corrosion Cracking .......................................... 235 4.5 Slow Strain Rate Test ........................................................................ 247 5 CONCLUSIONS ....................................................................................... 271 6 RECOMMENDATIONS ............................................................................ 275 7 REFERENCE ........................................................................................... 276 3 LIST OF TABLES Table 1: RBI Critical Matrix .......................................................................... 147 Table 2: Chemical composition of synthetic seawater ................................. 151 Table 3: Initial settings for the Gamry potentiostat for anodic CPP test ....... 155 Table 4: Initial settings for the Gamry potentiostat for cathodic CPP test .... 155 Table 5: C-Ring Test Matrix ......................................................................... 157 Table 6: Slow Strain Rate Test Matrix for 13Cr-L80 .................................... 167 Table 7: Slow Strain Rate Test Matrix for 25Cr-F255 .................................. 168 Table 8: Summary of CPP Testing Results ................................................. 221 Table 9: Summary of C-Ring Tests ............................................................. 246 Table 10: Slow Strain Rate Test Results for 13Cr-L80 Material. ................. 250 Table 11: Slow Strain Rate Test Results for 25Cr-F255 Material. ............... 251 4 LIST OF FIGURES Figure 1: Cartoon illustrating a conducive environment for reservoir souring1 ............ 25 Figure 2: Typical Water Injector wells Downhole Components5 ................................. 27 Figure 3: Road Map for the Research Work ............................................................... 30 Figure 4: Anodic polarisation curves for iron in 0.15M Na3PO4/NaOH solutions of different pH values showing the dissolution current, IFe (solid curves) and the total current, I (dashed curves) after 1h in the steady state99 ................ 79 Figure 5: Schematic of processes that lead to the formation of bilayer passive films on metal surface96 ....................................................................................... 81 Figure 6: Schematic Pourbaix diagram for iron illustrating the resolution of the Faraday paradox in the corrosion of iron in nitric acid96 .............................. 82 Figure 7: Potential energy diagram for the movement of cation through an oxide film assuming that cation injection from the metal is rate-limiting99 ............. 86 Figure 8: Schematic diagram of place exchange mechanism for the growth of oxide films on metal surface99 .............................................................................. 88 Figure 9: Processes assumed to occur during the anodic growth of passive films according to PDM.99 ...................................................................................
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