Microseismic Location Accuracy via Cramer-Rao Bound Framework

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Solution Overview

Problem

Current methods for microseismic event location estimation lack a comprehensive framework to accurately quantify accuracy, particularly in incorporating parameters like range, angle, sensor-source geometry, and noise environment, leading to uncertainties in resource management decisions.

Innovation Solution

A method and apparatus that utilize the Cramer-Rao Bound (CRB) to provide a framework for analytically studying microseismic source location estimation accuracy, incorporating geometric intuitions and quantitative relationships to understand and improve location estimate precision.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional microseismic location estimation methods are used, then location estimates can be obtained, but accuracy quantification is insufficient due to lack of comprehensive framework

Engineering Contradiction:
Improvelocation estimate accuracyVSAvoidmethod complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by deriving the Cramer-Rao Bound (CRB) expressions before actual microseismic event location estimation. The CRB framework is established in advance to provide theoretical accuracy limits, allowing practitioners to assess whether their location estimates are reliable before making resource management decisions. This preliminary theoretical framework enables proactive accuracy assessment rather than reactive correction.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent introduces the Cramer-Rao Bound as an intermediary theoretical construct that mediates between the raw location estimation process and the final accuracy assessment. The CRB serves as a mathematical bridge that connects the estimation methodology to quantifiable accuracy metrics, allowing indirect measurement of location precision through variance bounds without requiring direct comparison to true event locations.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If comprehensive parameters (range, angle, geometry, noise) are incorporated to improve accuracy, then location estimate reliability increases, but computational complexity increases

Engineering Contradiction:
Improvelocation estimate reliabilityVSAvoidcomputational framework complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies parameter changes by transforming the accuracy assessment problem from evaluating multiple complex geometric and noise parameters separately to computing a single unified Cramer-Rao Bound variance expression. The CRB framework consolidates range, angle, sensor-source geometry, and noise environment parameters into one comprehensive computational formula, maintaining reliability while reducing computational burden compared to separate parameter analysis.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent introduces a universal CRB framework that serves multiple functions simultaneously: it quantifies location accuracy, assesses the impact of geometric configurations, evaluates noise influence, and provides theoretical performance limits. This multi-functional approach eliminates the need for separate analytical frameworks for each parameter, reducing overall system complexity while comprehensively addressing all accuracy-affecting factors.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Measurement precision

If Cramer-Rao Bound framework is applied to quantify accuracy, then lower bounds on location estimate variance can be derived, but the method requires sophisticated statistical knowledge

Engineering Contradiction:
Improveaccuracy quantificationVSAvoidmethod implementation difficulty
Core Design Contradiction:
Measurement precisionVSDifficulty of detecting and measuring

Solution Approach 1:

The patent replaces complex mechanical or geometric intuition-based accuracy assessment methods with a statistical field approach using the Cramer-Rao Bound. Instead of relying on physical analogies or simplified geometric models, the CRB framework uses statistical theory to provide rigorous accuracy quantification. This substitution enables precise accuracy measurement but requires corresponding expertise in statistical estimation theory for proper implementation and interpretation.

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

Data Source

PatentUS9945970B1Method and apparatus for modeling microseismic event location estimate accuracy
Publication Date: 2018.04.17 SEISMIC INNOVATIONS
  • US9945970B1 patent drawing
  • US9945970B1 patent drawing
  • US9945970B1 patent drawing

AI summary

The present invention relates generally to microseismic event analysis, and more particularly to a method and apparatus for modeling microseismic event location estimate accuracy. According to certain aspects, the present invention provides a framework for analytically studying microseismic source location estimation accuracy and further provides new geometric intuitions and quantitative relationships that aid in the understanding of this problem. These intuitions and expressions can be shown to be in agreement with current observations in the state of the art.