Deducing Cavern Strength Parameters via Seismic Amplitude Ratios

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Conventional techniques fail to provide a quantitative method for estimating the elastic properties of materials filling caverns in subsurface formations, such as carbonate rocks, relying solely on seismic amplitude analysis which is not precise.

Innovation Solution

A method that utilizes seismic information by determining the relationship between the seismic amplitude of caverns and surrounding formations, leveraging known property values and ratios to deduce strength parameters within the caverns through a process involving seismic data analysis and synthetic seismic modeling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional techniques relying solely on seismic amplitude analysis are used, then the method is simple and quick, but the measurement precision of elastic properties of fill material is insufficient

Engineering Contradiction:
Improveprecision of elastic properties estimationVSAvoidcomplexity of analysis method
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent introduces synthetic seismic data as an intermediary between the actual seismic data and the fill material properties. Synthetic seismic data generated from modeled caverns with known fill material properties serves as a bridge to interpret actual seismic amplitudes, enabling quantitative estimation of elastic properties through comparison and matching processes.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces direct mechanical measurement of fill material properties with a seismic wave-based indirect measurement system. By substituting physical sampling or direct measurement with seismic amplitude analysis and synthetic data modeling, the method enables non-invasive quantitative estimation of elastic properties without contacting the fill material directly.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If iterative refinement process is implemented to deduce property values, then the measurement precision improves, but the loss of time increases

Engineering Contradiction:
Improveprecision of property value determinationVSAvoidtime for iterative analysis
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent performs preliminary actions by pre-calculating and storing synthetic seismic data for various possible fill material properties and cavern configurations before actual analysis. This pre-computed synthetic seismic database enables rapid matching against actual seismic data, reducing the time required for iterative refinement while maintaining high measurement precision.

Inventive Principle:
Principle #10Preliminary action

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 accurate determination of properties like strength parameters within subsurface caverns by normalizing seismic amplitudes and iteratively refining proposed property values until a suitable correspondence with actual seismic data is achieved, improving the precision of material identification within caverns.

Implementation Method 1

Anomalous high amplitude diffractors are sometimes imaged in formations such as carbonate rocks. Such diffractors can include buried 'megaporosity', or small caverns, existing at depth

Methodology Applied
Scientific EffectSeismic wave diffraction: Diffraction

Data Source

PatentEP2926168B1System and method for deducing cavern properties
Publication Date: 2020.05.06 CHEVRON USA INC
  • EP2926168B1 patent drawingFigure 1
  • EP2926168B1 patent drawingFigure 2
  • EP2926168B1 patent drawingFigure 3

AI summary

Strength parameters of the contents of subsurface caverns are deduced through seismic information. Known properties of formations surrounding the caverns, and ratios of seismic amplitudes between the caverns and the surrounding formations are leveraged to deduce the strength parameters within the caverns.