Fracture Density Map Generation from Seismic Data

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Solution Overview

Problem

Current methods are inadequate for reliably estimating subsurface fracture density using seismic data, as seismic attributes are influenced by multiple rock properties, making it challenging to uniquely relate a single attribute to fracture density, which is critical for reservoir development and hydraulic fracturing operations.

Innovation Solution

A multi-step workflow that combines multiple seismic attributes such as amplitude, frequency, coherency, and curvature using statistical methods like multivariate non-linear regression to generate a fracture density map, discounting other rock properties, and utilizing FMI well logs to validate predictions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a single seismic attribute is used to estimate fracture density, then the estimation process is simple, but the reliability is low because the attribute is influenced by multiple rock properties

Engineering Contradiction:

Improveestimation process complexityVSAvoidfracture density estimation reliability

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The patent combines multiple seismic attributes (amplitude, phase, frequency, coherency, curvature) into a composite indicator for fracture density estimation. This merging approach allows the system to discount the influence of individual rock properties that affect single attributes, thereby improving reliability while maintaining reasonable process complexity through automated multivariate analysis.

Inventive Principle:

Principle #5Merging (Combining)

2Reliability

If multiple seismic attributes are combined to estimate fracture density, then the reliability improves, but the device complexity increases

Engineering Contradiction:

Improvefracture density estimation reliabilityVSAvoidestimation process complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent transforms multiple seismic attributes (amplitude, phase, frequency, coherency, curvature) into a unified fracture density estimate by changing the parameter space from individual attributes to a composite multivariate indicator. This parameter transformation approach improves reliability by considering multiple rock property influences simultaneously while managing complexity through standardized processing workflows.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent introduces multivariate statistical analysis as an intermediary process that mediates between multiple seismic attributes and the final fracture density estimate. This intermediary layer discounts the confounding effects of individual rock properties by analyzing the combined information from multiple attributes, thereby improving reliability while keeping the overall process systematic and manageable.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Loss of time

If seismic data is used to estimate fracture density without drilling, then the loss of time is reduced, but the measurement precision is insufficient with single attribute methods

Engineering Contradiction:

Improvetime to obtain fracture density informationVSAvoidfracture density measurement precision

Core Design Contradiction:

Loss of timeVSMeasurement precision

Solution Approach 1:

The patent merges multiple seismic attributes to create a more precise fracture density estimate from seismic data alone, eliminating the need for drilling while improving measurement precision. The combination of amplitude, phase, frequency, coherency, and curvature attributes provides a robust estimate that discounts individual rock property influences, achieving both time efficiency and precision.

Inventive Principle:

Principle #5Merging (Combining)

4Loss of substance

If seismic attributes are analyzed to estimate fracture density, then the loss of substance is avoided, but the difficulty of detecting and measuring increases due to complex interactions

Engineering Contradiction:

Improvedrilling and sampling materialVSAvoiddifficulty of relating seismic attributes to fracture density

Core Design Contradiction:

Loss of substanceVSDifficulty of detecting and measuring

Solution Approach 1:

The patent uses multivariate statistical analysis as an intermediary that simplifies the complex relationships between seismic attributes and fracture density. By analyzing multiple attributes simultaneously, the method discounts the confounding effects of individual rock properties (mineralogy, porosity, permeability, fluid saturation) and provides a direct path from seismic data to fracture density estimation without physical drilling or sampling.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS10422902B2Methods of generation of fracture density maps from seismic data

Publication Date: 2019.09.24 BOARD OF REGENTS FOR OKLAHOMA STATE UNIVERSITY

AI summary

A method is herein presented to statistically combine multiple seismic attributes for generating a map of the spatial density of fractures. According to an embodiment a first step involves interpreting the formation of interest in 3D seismic volume first to create its time structure map. The second step is creating depth structure of the formation of interest from its time structure map. In this application geostatistical methods have been used for depth conversional, although other methods could be used instead. The third step is extraction of a number of attributes, such as phase, frequency and amplitudes, from the time structure map. The next step is to project the fracture density onto the top of the target formation. The final step is to combine these attributes using a statistical method known as Multi-variant non-linear regression to predict fracture density.