Acoustic Sand-Pack Characterization via Tube Waves
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Solution Overview
Problem
Current sand-control methods for oil and gas wells, such as resin injection, slotted liners, and gravel packing, face challenges in effectively preventing sand production while maintaining long-term productivity and minimizing formation damage, particularly in unconsolidated reservoirs with high permeability.
Innovation Solution
The method involves inducing pressure changes in the wellbore to generate tube waves, which allow for the characterization and prediction of sand-pack or gravel-pack parameters, including fluid conductivity and pack quality, using pressure and time derivative measurements, enabling more accurate assessment and optimization of sand-control treatments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If gravel packing is used to prevent sand production, then sand control effectiveness is improved, but formation damage and reduced productivity may occur
Solution Approach 1:
The patent uses acoustic wave parameters (frequency, velocity, attenuation) to characterize the gravel pack properties. By measuring and analyzing these physical parameters, the system can evaluate pack quality and optimize placement to maintain productivity while ensuring effective sand control.
Solution Approach 2:
The patent replaces traditional mechanical evaluation methods (downhole measurements, production tests) with acoustic wave-based characterization. This non-invasive approach allows assessment of gravel pack properties without physical intervention that could cause formation damage.
2Measurement precision
If downhole measurements are used to evaluate sand-pack quality, then measurement precision is improved, but cost and operational complexity increase
Solution Approach 1:
The patent introduces acoustic waves as an intermediary medium to transmit information about gravel pack properties from the downhole environment to surface measurement equipment. This allows accurate characterization without complex downhole instrumentation or direct contact with the evaluation zone.
Solution Approach 2:
The patent substitutes complex mechanical downhole measurement systems with acoustic wave-based detection. The acoustic method provides sufficient measurement precision while eliminating the need for complex downhole tools, wireline operations, and associated operational complexities.
3Reliability
If traditional sand control methods are used, then sand production is prevented, but formation damage and long-term productivity loss occur
Solution Approach 1:
The patent performs preliminary acoustic characterization of the gravel pack immediately after placement to assess quality and identify potential issues before they affect long-term productivity. This early evaluation allows corrective actions to be taken while the well is still in the completion phase, preventing future productivity loss.
Solution Approach 2:
The patent establishes a feedback loop where acoustic measurements provide real-time information about gravel pack properties, which is used to optimize placement parameters and ensure the pack meets performance criteria. This continuous monitoring and adjustment process ensures both effective sand control and maintained productivity over the long term.
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 a non-invasive and cost-effective means to evaluate and predict the effectiveness of sand-control measures, reducing the need for costly downhole measurements and improving the reliability of sand-pack characterization, thereby enhancing well productivity and longevity.
Implementation Method 1
inducing a pressure change in a wellbore drilled through the subsurface formation so as to induce tube waves in the wellbore
Data Source
AI summary
A method for characterizing a sand-pack or gravel-pack in a subsurface formation includes inducing a pressure change to induce tube waves in fluid in a well drilled through the subsurface formation. At a location proximate to a wellhead at least one of pressure and a time derivative of pressure in the well is measured for a selected length of time. At least one of a physical parameter and a change in the physical parameter with respect to time, of the sand-pack or gravel-pack, is determined using the measured pressure and/or the time derivative of pressure.