EM Log Data Coupling Effect Reduction
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Solution Overview
Problem
Corrosion of metal pipes in oil and gas exploration and production is a persistent issue, and existing EM logging tools face challenges in accurately monitoring corrosion in multi-string arrangements due to the complexity introduced by pipe couplings, leading to errors in thickness estimations.
Innovation Solution
Incorporating the properties of pipe couplings, such as position, dimensions, and electrical properties, into the EM log data inversion process to reduce errors and improve the accuracy of pipe attribute determination, including the use of 2D models and techniques like subtracting coupling responses from overall responses to isolate pipe defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If pipe couplings are used to connect pipe segments in multi-string arrangements, then the structural integrity and connectivity of the pipe system is improved, but the accuracy of EM log data interpretation deteriorates due to ghosting effects and data complexity
Solution Approach 1:
The EM log data processing is segmented into distinct components: pipe coupling responses are identified and separated from pipe wall thickness signals. The inversion process is divided into multiple stages, with coupling effects being modeled and removed independently before final thickness estimation, allowing accurate measurement despite the presence of couplings
Solution Approach 2:
A coupling response model acts as an intermediary element that mediates between the raw EM log data and the final thickness interpretation. By introducing this intermediate modeling step, the ghosting effects of couplings are accounted for and subtracted, enabling accurate thickness measurement beneath the coupling interference
2Productivity
If standard EM log data processing is applied to multi-pipe configurations with couplings, then the processing speed is maintained, but the reliability of corrosion detection deteriorates due to errors from coupling interference
Solution Approach 1:
Pipe coupling properties (position, dimensions, electrical properties) are determined in advance through preliminary analysis of the EM log data. This preliminary characterization of coupling effects allows the main inversion process to focus solely on thickness estimation without being distracted by coupling interference, maintaining processing efficiency while improving reliability
Solution Approach 2:
The inversion process incorporates feedback mechanisms where the modeled coupling responses are continuously compared with actual measured data. The discrepancy between modeled and measured coupling effects is used to refine the thickness estimation, ensuring accurate corrosion detection even in the presence of coupling interference
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 significantly improves the accuracy of pipe attribute determination, reducing errors caused by pipe couplings and enhancing the reliability of corrosion monitoring in multi-pipe configurations.
Implementation Method 1
One type of EM logging tool uses electromagnetic (EM) fields to estimate pipe thickness or other corrosion indicators
Implementation Method 2
an EM logging tool may collect EM log data, where the EM log data may be interpreted to correlate a level of flux leakage or EM induction with corrosion
Data Source
AI summary
Systems and methods for reducing effects of pipe couplings in electromagnetic log data. A method for corrosion detection comprises disposing an electromagnetic logging tool within a plurality of concentric pipes in a wellbore; obtaining electromagnetic log data along the concentric pipes; and identifying a location of at least one pipe coupling on at least one of the concentric pipes; and processing the electromagnetic log data to determine one or more attribute of the concentric pipes as a function of depth, wherein the processing uses the location of at least one pipe coupling to account for effect of the at least one pipe coupling on the electromagnetic log data.