Depth-Dependent Lateral Tectonic Strain Estimation

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Solution Overview

Problem

Conventional methods for estimating depth-dependent lateral tectonic strain in earth formations assume constant tectonic strain values, leading to inaccurate stress profile estimations due to varying lateral tectonic strain with depth, which affects the accuracy of stress characterization and operation planning in hydrocarbon production and drilling operations.

Innovation Solution

A method involving a linear-to-linear transformation that maps shear wave velocity parameters to corresponding lateral tectonic strain values, allowing for the estimation of minimum and maximum lateral tectonic strain in different directions, enabling the generation of a depth-dependent lateral tectonic strain profile for more accurate stress estimation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If conventional methods assume constant tectonic strain values, then the estimation process is simplified, but the accuracy of stress profile estimations deteriorates

Engineering Contradiction:
Improveestimation process complexityVSAvoidstress profile estimation accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent applies the dynamics principle by transitioning from static constant tectonic strain values to dynamic depth-dependent tectonic strain values. The method estimates tectonic strain as a function of depth, allowing the strain parameters to vary dynamically throughout the formation rather than remaining fixed, thereby improving stress profile accuracy while maintaining computational feasibility through systematic estimation procedures.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent implements parameter changes by modifying the tectonic strain parameters from constant values to depth-dependent variable values. This involves changing the mathematical representation of tectonic strain from a single constant parameter to multiple parameters that vary with depth, enabling more accurate stress estimations that reflect the actual geological conditions at different depths.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If depth-dependent lateral tectonic strain is accounted for, then stress characterization accuracy is improved, but the computational complexity increases

Engineering Contradiction:
Improvestress characterization accuracyVSAvoidcomputational complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies segmentation by dividing the formation into multiple depth intervals and estimating tectonic strain separately for each interval. This segmentation approach allows the complex depth-dependent strain estimation to be broken down into manageable segments, improving stress characterization accuracy at each depth level while keeping the computational process systematic and organized.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent uses partial action by estimating tectonic strain at selected depth intervals rather than continuously at every possible depth point. This partial sampling approach provides sufficient accuracy for stress characterization while avoiding the excessive computational complexity that would result from continuous depth-dependent estimation, achieving an optimal balance between accuracy and computational efficiency.

Inventive Principle:
Principle #16Partial or excessive action

Data Source

PatentUS10823868B2Estimating depth-dependent lateral tectonic strain profiles
Publication Date: 2020.11.03 BAKER HUGHES CO
  • US10823868B2 patent drawing
  • US10823868B2 patent drawing
  • US10823868B2 patent drawing

AI summary

Methods and apparatus for acoustic velocity well logging. Methods may include estimating a property of an earth formation, including estimating a depth-dependent lateral tectonic strain profile for the earth formation by generating a linear-to-linear transformation constrained to map a first value of a shear wave velocity parameter of the formation to an estimated minimum value of lateral tectonic strain in at least one direction corresponding to at least one principal horizontal stress of the formation, and map a second value of the shear wave velocity parameter of the formation to an estimated maximum value of lateral tectonic strain in the at least one direction, wherein the strain values may be estimated using closure pressure. The first value of the shear wave velocity parameter may be a minimum value of shear wave slowness and the second value of the shear wave velocity parameter is a maximum value of shear wave slowness.