Dual-String Pipe Cement Evaluation Without Tubing Removal
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Solution Overview
Problem
Conventional cement bond logging methods require unimpeded access to the outer casing, necessitating costly and time-consuming removal of production tubing or milling of the inner casing, which complicates plug and abandonment (P&A) operations and increases carbon footprint.
Innovation Solution
A method using dual-string pipes with an acoustic logging tool to assess cement integrity and isolation without removing production tubing, involving wavefield analysis and in-situ calibration to determine bond index and generate cement maps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional acoustic logging methods are used to assess cement integrity, then measurement precision is improved, but device complexity and operational time increase due to requiring removal of production tubing or milling of inner casing
Solution Approach 1:
The acoustic logging tool is deployed nested within the existing dual-string casing configuration, specifically running through the inner production tubing while assessing the cement sheath between the outer and inner casings. This nested approach allows cement evaluation without removing either tubing or casing, eliminating the need for complex removal and reinstallation operations while maintaining measurement capability through the nested tool configuration
Solution Approach 2:
The acoustic logging tool acts as an intermediary device that transmits acoustic signals through the production tubing and analyzes the returned signals to assess cement integrity. This intermediary approach enables indirect measurement of cement bond conditions without direct access to the cement sheath, resolving the contradiction by providing measurement capability through the tubing rather than requiring its removal
2Measurement precision
If production tubing is removed or inner casing is milled to access outer casing, then measurement precision is improved, but loss of time and loss of substance increase
Solution Approach 1:
The method utilizes the existing dual-string casing configuration and deployed production tubing as part of the measurement system from the outset, rather than removing them. The acoustic logging tool is introduced through the already-present tubing, performing cement assessment during the normal operational state. This preliminary arrangement eliminates time-consuming removal and reinstallation operations while maintaining measurement capability
Solution Approach 2:
The acoustic logging tool is nested within the production tubing, which itself is nested within the inner casing, creating a nested measurement configuration. This allows the tool to reach the cement sheath assessment zone through the existing nested structure without requiring disassembly, thereby preserving operational time while achieving measurement objectives
3Measurement precision
If rig mobilization and tubing cutting are performed, then measurement precision is improved, but object-generated harmful factors increase due to carbon footprint
Solution Approach 1:
The method replaces mechanical intervention (rig mobilization, tubing cutting, milling operations) with acoustic wave-based measurement. The acoustic logging tool uses sound wave propagation and reflection principles to assess cement integrity, substituting destructive mechanical access methods with non-intrusive acoustic sensing. This substitution eliminates the carbon footprint associated with rig mobilization and mechanical cutting while maintaining measurement precision through acoustic signal analysis
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
Significantly reduces operational time and costs while simplifying P&A operations and minimizing environmental impact by eliminating the need for rig mobilization and tubing cutting.
Implementation Method 1
conventional evaluation methods primarily rely on acoustic logging measurements
Data Source
AI summary
A method for cement evaluation through dual-string pipes comprising the steps of: i) acquiring waveforms data using a cement bond logging tool; ii) processing the acquired waveforms data to eliminate one or more potential DC offsets; iii) selecting a first receiver to further process the processed acquired waveforms data in a common-receiver domain; iv) performing in-situ calibration using the processed acquired waveforms data from the common-receiver domain to identify free-pipe and wall-bonded waveforms; v) calculating normalized amplitudes from monopole waveforms and azimuthal waveforms obtained from the free-pipe and wall-bonded waveforms to determine bond index and generate cement map; and vi) calculating statistical averages and variances using the calculated normalized amplitude to generate a final presentation.