Melanie Reid, Emma Perfect and Fiona Mackay, LUX Assure Ltd. Deep water chemical injection – How do you know your corrosion inhibitor can cope? Melanie Reid, Emma Perfect and Fiona Mackay, LUX Assure Ltd.

Presentation Plan Corrosion Inhibitors The Deepwater Challenge Slide 2 Corrosion Inhibitors The Deepwater Challenge Deepwater Chemicals Performance in the Field Presentation Plan Deepwater Chemical Injection – How do you know your Corrosion Inhibitor can cope?

ppm levels of complex mixtures Slide 3 Corrosion Inhibitors “A corrosion inhibitor is a chemical compound that, when added to a liquid or gas, decreases the corrosion rate of a material, typically a metal” Film-forming, thin barrier layer between steel surface and corroding fluid Chemisorption ppm levels of complex mixtures Deepwater Chemical Injection – How do you know your Corrosion Inhibitor can cope?

Surfactants Solvents Synergist Slide 4 Deepwater Chemical Injection – How do you know your Corrosion Inhibitor can cope?

Environmentally Acceptable Corrosion Inhibitors Non-Emulsifying Compatible Stable Cost Effective Environmentally Acceptable Safe to handle Low Dose Non-foaming Pump-able High Performance Deepwater Chemical Injection – How do you know your Corrosion Inhibitor can cope?

The Deepwater Challenge Longer chemical residence time Slide 6 The Deepwater Challenge Longer chemical residence time Inaccessible umbilicals Blockages – may leave wells untreatable Low temperature, high pressure High downhole temperature Deepwater Chemical Injection – How do you know your Corrosion Inhibitor can cope?

The Deepwater Challenge Slide 7 The Deepwater Challenge BASICS JIP Qualification Standard and Recommended Practice API STANDARD TR 17TR6 Guidelines for best practice Each chemical supplier developed own deepwater ‘brand’ Deepwater Chemical Injection – How do you know your Corrosion Inhibitor can cope?

All of the requirements of a regular production chemical plus: Slide 8 Deepwater Chemical Requirements NAS 8 or better High temperature stable Hydrate ‘proof’ Chemically compatible with wide range of materials Low viscosity Multi-Functional All of the requirements of a regular production chemical plus: Deepwater Chemical Injection – How do you know your Corrosion Inhibitor can cope?

Deepwater Chemical Testing Slide 9 Deepwater Chemical Testing Deepwater Chemical Injection – How do you know your Corrosion Inhibitor can cope?

Deepwater Chemical Handling Dedicated tanks for blending Filtering Slide 10 Deepwater Chemical Handling Dedicated tanks for blending Filtering Dedicated pumps, hoses, and containers Chain of custody Tank locks Ready to pump at site Deepwater Chemical Injection – How do you know your Corrosion Inhibitor can cope?

What about Performance? Slide 11 What about Performance? Deepwater Chemical Injection – How do you know your Corrosion Inhibitor can cope?

Estimation of corrosion rates using computer modelling Slide 12 Estimation of corrosion rates using computer modelling Performance testing in simulated field conditions Permanent intrusive coupons, electrical resistance (ER), non-intrusive acoustic monitors for general corrosion and erosion Retrieval issues; safety, costs, sensitivity, accessibility Corrosion inhibitors are water soluble, therefore the safest option may be water sampling topside Deepwater Performance Testing Deepwater Chemical Injection – How do you know your Corrosion Inhibitor can cope?

Residual analysis: quat, amide, imidazoline etc. Slide 13 Residual analysis: quat, amide, imidazoline etc. Corrosion inhibitors are complex Measure one component ≠ corrosion inhibitor as a whole However, corrosion inhibitors are surfactants…….. Deepwater Performance Testing Deepwater Chemical Injection – How do you know your Corrosion Inhibitor can cope?

Head Tail Surfactant Charged Water Soluble Oil Insoluble No Charge Slide 14 Surfactant Charged Water Soluble Oil Insoluble Head No Charge Water Insoluble Oil Soluble Tail Deepwater Chemical Injection – How do you know your Corrosion Inhibitor can cope?

Hydrophilic Head Hydrophobic Tail Slide 15 Water: Hydrophilic Head Hydrophobic Tail Solubility is satisfied at interfaces: Hydrophilic Head Hydrophobic Tail Oil: Metal surface charge attracts surfactant head Surfactant Solubility Deepwater Chemical Injection – How do you know your Corrosion Inhibitor can cope?

Corrosion Inhibition and the CMC Increase concentration = increased inhibition? True at low concentrations Not true above CMC Optimum inhibition at ‘sweet spot’ CMC Corrosion Inhibition and the CMC Pipe Cross-Section

How do we determine CMC? Surface tension measurement Slide 17 Surface tension measurement Increase surfactant concentration No further reduction = CMC found Further addition of surfactant forms micelles Questionable benefit for corrosion protection How do we determine CMC? Deepwater Chemical Injection – How do you know your Corrosion Inhibitor can cope?

Fluorescence, Optical Flow Analysis and Data Algorithms Fluorescent marker used as reporter probe Polarity sensitive marker localises in micelle core Optical flow analyser Data analysis and interpretation Deepwater Chemical Injection – How do you know your Corrosion Inhibitor can cope?

Fluorescence, Optical Flow Analysis and Data Algorithms LASER LIGHT SCATTER FLUORESCENCE SAMPLE + MARKER 2D 3D 4D, 5D, 6D…. Deepwater Chemical Injection – How do you know your Corrosion Inhibitor can cope?

CMC Measurement for Deepwater Functional dose rate of corrosion inhibitor Independent of other chemicals Safe Use over field life: changing water cuts Independent of corrosion inhibitor chemistry; ideal for chemical changeover Currently requires a specialist Not an inline method Deepwater Chemical Injection – How do you know your Corrosion Inhibitor can cope?

Corrosion Inhibitors are complex Conclusions Corrosion Inhibitors are complex Deepwater chemicals have extra requirements, whilst still maintain performance Traditional corrosion rate field tests are difficult to retrieve Colourimetric methods do not provide information about whole corrosion inhibitor Using CMC as the functional dose assures correct dose is applied = increased asset integrity Deepwater Chemical Injection – How do you know your Corrosion Inhibitor can cope?

Thank you for listening. Slide 22 Thank you for listening. Questions?