Multi-String EM Corrosion Monitoring via Segmented Inversion
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Solution Overview
Problem
Managing corrosion detection in multi-string metal pipe networks for oil and gas exploration is challenging due to the complexity of interpreting electromagnetic (EM) logging tool data, especially when multiple casing strings are employed together.
Innovation Solution
An electromagnetic (EM) logging tool is designed to distinguish between different casing strings by using different sensor arrays, frequency channels, or time channels to collect and process EM log data, enabling the derivation of attributes like thickness, conductivity, and permeability, and employing multi-stage inversion methods to accurately determine corrosion levels and trigger corrective actions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple casing strings are monitored using conventional EM logging tools, then corrosion detection capability is provided, but data interpretation complexity increases significantly
Solution Approach 1:
The patent divides the monitoring task into separate stages, first monitoring outer casing strings and then inner casing strings independently. This segmentation allows complex multi-string data to be processed through systematic stages, reducing overall interpretation complexity while maintaining comprehensive corrosion detection capability across all casing strings.
Solution Approach 2:
The patent performs preliminary monitoring of outer casing strings before proceeding to inner casing strings. By completing the outer string monitoring first and using those results as a foundation, the system prepares the data structure and interpretation framework in advance, making subsequent inner string monitoring more manageable and less complex.
2Reliability
If conventional EM logging tools are used for multi-string corrosion monitoring, then corrosion detection is possible, but measurement precision deteriorates due to data ambiguity
Solution Approach 1:
By segmenting the monitoring process into outer string first, then inner string phases, the patent eliminates measurement ambiguity that would arise from attempting to monitor all strings simultaneously. Each phase has clearly defined measurement targets and interpretation criteria, ensuring precise corrosion measurements for each casing string without confusion from overlapping signals.
Solution Approach 2:
The preliminary monitoring of outer casing strings establishes a clear baseline and data structure before inner string monitoring begins. This preliminary action removes ambiguity from the measurement process by first characterizing the outer string properties, thereby enabling precise and unambiguous measurement of inner string corrosion in subsequent phases.
3Reliability
If multi-string corrosion monitoring is implemented, then comprehensive protection is achieved, but operational complexity increases
Solution Approach 1:
The patent segments the operational process into distinct phases: first monitoring outer casing strings, then monitoring inner casing strings. This segmentation transforms a complex single operation into multiple simpler, sequential operations, each with clear procedures and criteria, thereby reducing overall operational complexity while maintaining comprehensive corrosion protection.
Solution Approach 2:
By performing outer string monitoring as a preliminary action before inner string monitoring, the system establishes operational protocols and data processing frameworks in advance. This preliminary operational phase simplifies subsequent inner string monitoring operations by providing a ready-to-use framework, thereby reducing operational complexity while achieving comprehensive protection.
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
The EM logging tool effectively monitors corrosion in multi-string scenarios, providing accurate attribute calculations and enabling timely corrective measures, such as repairing or replacing casing segments, thereby mitigating corrosion and ensuring the integrity of the pipe network.
Implementation Method 1
an EM logging tool may collect EM log data, where the EM log data can be interpreted to correlate a level of flux leakage or EM induction with corrosion
Implementation Method 2
The fast forward model is used to ensure optimum tool design and allows development of an inverse model which realizes quantitative evaluation of the corrosion within multiple tubulars from field data
Data Source
Figure 1A~1B
Figure 2A~3
Figure 4A
AI summary
A multi-string corrosion monitoring method includes using a first set of electromagnetic (EM) log data to calculate attributes of a first casing string while attributes of a second casing string are assigned a fixed value. The method also includes using a second set of EM log data to calculate attributes of a second casing string while attributes of the first casing string are assigned a fixed value.