Corrosion Testing Apparatus with Anoxic Fluid Trains
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Solution Overview
Problem
Current laboratory corrosion testing methods fail to accurately simulate field conditions, particularly in oilfield environments, due to inadequate simulation of microbiological influences, acid-forming gas pressures, and shear conditions, leading to inaccurate determination of corrosion rates and mechanisms.
Innovation Solution
The development of a testing apparatus with one-pass fluid trains that maintain fluids under anoxic conditions, featuring a reservoir, pre-conditioning chamber, autoclave chamber with an impeller, and sampling receptacles, which simulate field conditions by controlling temperature, pressurizing with anoxic gases, and applying shear forces to metal test coupons.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If current laboratory corrosion testing methods are used, then testing can be performed with simple equipment and procedures, but the simulation of field conditions is inadequate leading to inaccurate corrosion rate determination
Solution Approach 1:
The testing apparatus is divided into multiple independent one-pass fluid trains, each capable of simulating specific field conditions. Each fluid train includes separate reservoirs, pre-conditioning chambers, autoclave chambers, and sampling receptacles that can be independently controlled and optimized for different testing parameters such as temperature, pressure, and microbial presence.
Solution Approach 2:
The apparatus performs preliminary conditioning of fluids in pre-conditioning chambers before exposing metal test coupons to corrosive environments. This includes pre-heating, pressurizing with acid-forming gases, and introducing microorganisms to achieve steady-state conditions that accurately represent field operational conditions before corrosion testing begins.
2Reliability
If laboratory tests use static conditions, then testing is simpler to conduct, but they fail to account for shear conditions present in field environments
Solution Approach 1:
The apparatus introduces dynamic shear conditions by circulating fluids through the autoclave chambers at controlled flow rates that simulate field conditions. The one-pass fluid trains create continuous flow patterns that exert shear forces on metal test coupons, dynamically replicating the mechanical stresses experienced by pipelines and equipment in operational environments rather than using static immersion methods.
3Measurement precision
If sampling frequency is increased to capture real-time corrosion data, then more accurate corrosion rates can be determined, but sample preservation and analysis become more difficult
Solution Approach 1:
The apparatus includes integrated sampling receptacles that automatically collect fluid samples directly from each autoclave chamber at predetermined intervals without requiring external intervention. The system self-manages the sampling process, maintaining anoxic conditions and sealing samples immediately upon collection to preserve their integrity for subsequent analysis of corrosion products and fluid composition changes.
Solution Approach 2:
The apparatus uses intermediate storage chambers and sealed transfer systems to move fluid samples from the corrosive environment to analysis equipment. These intermediary components maintain controlled atmospheres and prevent contamination during sample transfer, enabling frequent sampling without compromising sample quality or requiring complex preservation protocols.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach allows for a more accurate simulation of field conditions, enabling the differentiation between acid-induced and microorganism-induced corrosion, and providing a more reliable assessment of corrosion rates and mechanisms, thereby improving corrosion management efforts.
Implementation Method 1
agitated with an impeller... applying shear forces to metal test coupons
Implementation Method 2
pressurized with one or more anoxic gases
Data Source
AI summary
No reliable test presently exists for predicting the amount or type of corrosion a metal surface may experience during field use, particularly when the corrosion can be a result of both acid-induced corrosion and microorganism-induced corrosion mechanisms. Apparatuses affording more field-like testing conditions may comprise: a one-pass fluid train comprising a reservoir configured to maintain a fluid at a first temperature state under anoxic conditions; a pre-conditioning chamber in fluid communication with the reservoir and configured to receive a defined volume of the fluid; an autoclave chamber having an impeller in fluid communication with the pre-conditioning chamber that is configured to receive the defined volume of the fluid from the pre-conditioning chamber; and one or more sampling receptacles in fluid communication with the autoclave chamber that are configured to receive the defined volume of the fluid while maintaining anoxic conditions. The pre-conditioning chamber and the autoclave chamber are configured to maintain anoxic conditions at a second temperature state different than the first temperature state.