Cement Sheath Seismic Integrity Evaluation for Underground Gas Storage
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Solution Overview
Problem
Existing methods fail to effectively evaluate and predict potential damage to cement sheaths in underground gas storage facilities during earthquakes, which can lead to gas leakage and safety hazards due to mechanical instability at casing-cement and cement-rock interfaces.
Innovation Solution
A method involving data collection, deconvolution of earthquake waves, and computational modeling to simulate seismic events, assessing the integrity of cement sheaths and interfaces, and optimizing design parameters based on the results.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If computational modeling and seismic wave deconvolution are used to evaluate cement sheath damage, then prediction accuracy of cement sheath integrity is improved, but computational complexity and data processing requirements increase
Solution Approach 1:
The method applies preliminary action by performing deconvolution analysis on ground surface earthquake waves before the actual seismic event to predict subsurface waves. This allows the system to pre-process and prepare seismic data, enabling more accurate prediction of cement sheath damage without increasing the complexity of the physical evaluation system during the actual event.
Solution Approach 2:
The patent replaces direct mechanical evaluation of cement sheath integrity with computational modeling and signal processing methods. Instead of physically accessing and testing the cement sheath, the system uses deconvolution analysis and finite element modeling to predict damage, substituting complex mechanical measurement with computational analysis.
2Reliability
If comprehensive mechanical property data is collected for accurate modeling, then evaluation reliability is improved, but data collection time and resource requirements increase
Solution Approach 1:
The computational model serves multiple functions simultaneously: it evaluates cement sheath integrity, analyzes casing-cement-rock interface damage, and predicts subsurface seismic wave propagation. This multi-functionality allows comprehensive evaluation using a single integrated model, reducing the need for separate data collection processes for each evaluation aspect.
Solution Approach 2:
The patent introduces computational modeling as an intermediary that synthesizes available mechanical property data with seismic wave information. Rather than requiring direct measurement of all properties, the model acts as a mediator that fills gaps using established relationships and predictions, reducing the burden of complete data collection.
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
Enables prediction of cement sheath integrity and stability during seismic events, allowing for optimized design and operation of underground gas storage facilities to prevent gas leakage and enhance safety.
Implementation Method 1
performing a deconvolution analysis on the ground surface EQ wave to produce a subsurface EQ wave
Implementation Method 2
simulating a first dynamic seismic event based on the first gas pressure value and the subsurface EQ wave
Implementation Method 3
continuously evaluating a first effect of the first dynamic seismic event on a first integrity of the casing-cement-rock well system
Data Source
AI summary
A method for evaluating potential damage to a cement sheath in an underground gas storage facility during an earthquake. A ground surface earthquake (EQ) wave is obtained on which a deconvolution analysis is performed, producing a subsurface EQ wave. Static and dynamic mechanical properties of a casing-cement-rock well system are obtained, and a computational model of the underground gas storage facility is generated. A gas pressure value is applied to the model, and, after boundary conditions are applied, a static equilibrium state is simulated. The subsurface EQ wave and boundary conditions are applied to the model, and, based on the gas pressure value, a dynamic seismic event is simulated. Based on the effect of the seismic simulation on the integrity of the underground gas storage facility, at least one parameter related to the operation of the underground gas storage facility may be adjusted.