Wellbore Cement Property Estimation via Mechanical Penetration
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Solution Overview
Problem
Existing methods for assessing wellbore cement integrity often rely on non-invasive techniques like acoustic wave analysis, which can be ambiguous and fail to confirm adequate zonal isolation, leading to potential hydrocarbon contamination and safety issues.
Innovation Solution
A method involving a testing assembly with a motor and bit that penetrates the cement, monitoring operational data to correlate with a reference database for estimating physical properties such as mechanical specific energy and unconfined compressive strength, and optionally refining results with acoustic testing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If non-invasive acoustic wave analysis is used to assess cement integrity, then the assessment process is less intrusive and equipment deployment is simpler, but the measurement precision and reliability of cement property assessment deteriorates due to ambiguous results
Solution Approach 1:
The patent replaces non-invasive acoustic wave analysis with a mechanical drilling system that directly contacts and penetrates the cement. The motor-driven bit mechanically engages the cement, and operational parameters (power, torque, rotational speed) are monitored to directly measure cement properties, substituting indirect acoustic sensing with direct mechanical interaction for improved measurement precision.
Solution Approach 2:
The patent introduces a motor-driven drilling system as an intermediary between the assessment equipment and the cement. This intermediary mechanically transmits force to the cement and converts cement resistance into measurable operational parameters, serving as a mediator that transforms indirect acoustic signals into direct mechanical measurements of cement strength and properties.
2Reliability
If acoustic transducers are deployed to interrogate the wellbore, then the assessment can be performed without direct cement contact, but the reliability of zonal isolation confirmation deteriorates due to inability to definitively detect fluid leakage
Solution Approach 1:
The patent extracts the assessment function from complex downhole acoustic equipment and relocates it to surface-based drilling machinery. By using the motor and bit as assessment tools during normal drilling operations, the system eliminates the need for specialized downhole acoustic transducers and signal processing equipment, reducing device complexity while maintaining reliability through direct mechanical measurement.
Solution Approach 2:
The patent makes the drilling system multi-functional by combining the motor-driven bit's primary drilling function with a secondary cement assessment function. The same motor and bit used for drilling also serve as the assessment tools, monitoring operational parameters to evaluate cement integrity. This universal application reduces equipment complexity by eliminating dedicated assessment hardware.
3Measurement precision
If core samples are obtained and analyzed to confirm cement properties, then the measurement precision of cement strength improves, but the loss of time and productivity deteriorates due to additional sampling and laboratory analysis steps
Solution Approach 1:
The patent enables the drilling system to self-assess cement properties during the drilling process itself. The motor's operational parameters automatically record cement strength information in real-time, eliminating the need for separate core sampling and laboratory analysis. The system serves its own assessment function, continuously monitoring and recording data without requiring external intervention or additional time-consuming steps.
Solution Approach 2:
The patent skips the traditional multi-step process of core sampling, transportation, and laboratory analysis by performing cement assessment directly in-situ during drilling. The mechanical drilling process rapidly penetrates the cement while simultaneously measuring properties, rushing through what would otherwise be separate sequential steps and significantly improving productivity.
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 provides accurate and confirmatory assessment of cement properties, ensuring effective zonal isolation and reducing the risk of hydrocarbon contamination, while utilizing existing equipment with minimal additional cost or modification.
Implementation Method 1
rotating the bit by energizing the motor
Implementation Method 2
the bit is bored into the cement
Implementation Method 3
monitoring an amount of power or energy required for the penetration
Data Source
AI summary
A method of estimating properties of wellbore cement by penetrating the cement, and monitoring the amount of energy or power required for penetrating the cement. Penetrators include a drill bit that bores into the cement, and probes or pins that are forced into the cement. The energy or power monitored can be current and/or voltage supplied to a motor that drives the drill bit or probe. Comparing the monitored energy or power with that required to penetrate a reference cement sample of known properties can yield information about the cement being sampled. When the wellbore is lined with multiple coaxially disposed strings of casing with cement between adjacent strings and on the outer surface of the outer string; the method further includes obtaining core samples from portions of each string, each layer of cement, and formation adjacent the wellbore.