Drilling Acoustical Signal Analysis for Mechanical Boundary Mapping

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Solution Overview

Problem

Current drilling techniques for unconventional reservoirs face challenges in accurately characterizing rock properties and identifying mechanical boundaries, leading to inefficient hydraulic stimulation and reduced hydrocarbon production due to the high cost and limited effectiveness of existing tools.

Innovation Solution

A method involving sensors on a bottom hole assembly to measure acoustical signals from a drill bit interacting with the rock formation, processing these signals to determine mechanical rock properties, and aligning them with the axis of material symmetry to identify elastic coefficients and mechanical discontinuities, such as fractures, while drilling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional logging tools are used to characterize rock properties, then measurement precision is improved, but device complexity and cost increase

Engineering Contradiction:

Improverock property characterizationVSAvoidlogging tools

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces complex mechanical logging tools with a simplified system using acoustical sensors and signal processing. Acoustical signals generated during drilling are processed to extract mechanical rock properties, substituting direct mechanical measurement with indirect acoustical measurement and computational analysis.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces acoustical signals as an intermediary between the drilling process and rock property measurement. The acoustical signals serve as a mediator that carries information about rock mechanical properties, allowing indirect measurement without direct contact with the rock formation.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Measurement precision

If existing drilling techniques are used, then ease of operation is maintained, but measurement precision and reliability of rock property identification deteriorate

Engineering Contradiction:

Improvemechanical boundary identificationVSAvoiddrilling process

Core Design Contradiction:

Measurement precisionVSEase of operation

Solution Approach 1:

The patent makes the drilling process itself serve multiple functions: not only does it create the wellbore, but it also generates acoustical signals that provide rock property measurements. The drilling operation becomes a dual-purpose process that simultaneously advances the well and characterizes the formation.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent implements feedback by continuously monitoring acoustical signals during drilling and using this information to identify mechanical boundaries and rock properties in real-time. This feedback loop allows operators to adjust drilling parameters based on formation characteristics without stopping the drilling process.

Inventive Principle:

Principle #23Feedback

3Productivity

If hydraulic stimulation is performed without accurate rock property data, then productivity is maintained, but loss of energy and reduced hydrocarbon production occur

Engineering Contradiction:

Improvehydrocarbon productionVSAvoidhydraulic stimulation efficiency

Core Design Contradiction:

ProductivityVSLoss of energy

Solution Approach 1:

The patent performs preliminary characterization of rock mechanical properties and identification of mechanical boundaries during the drilling process, before hydraulic stimulation is conducted. This advance knowledge allows optimization of stimulation parameters and targeting of the most productive zones, preventing energy waste on poor candidates.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The drilling process itself provides the characterization data needed for optimization of subsequent operations. The acoustical measurements taken during drilling serve the dual purpose of monitoring drilling progress and providing formation evaluation data for stimulation planning, eliminating the need for separate logging operations.

Inventive Principle:

Principle #25Self-service

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

This approach reduces logging costs, allows for widespread use, and improves well economics by targeting suitable rock properties for stimulation, enhancing initial production and avoiding non-conductive zones, thereby optimizing hydraulic fracturing.

Implementation Method 1

measuring acoustical signals generated by a drill bit of the drilling system interacting with a formation

Methodology Applied

Scientific EffectAcoustical signal generation: Acoustic Emission

Data Source

PatentUS10519769B2Apparatus and method using measurements taken while drilling to generate and map mechanical boundaries and mechanical rock properties along a borehole

Publication Date: 2019.12.31 EOG RESOURCES

AI summary

The present disclosure involves a novel way of using drilling vibrations generated by the deformation of a rock formation in response to forces acting on the rock formation, where the forces are related to a drill bit and/or drilling fluid system, to identify the nature and occurrence of fractures, fracture swarms and other mechanical discontinuities (boundaries) such as bedding planes and/or faults that offset or otherwise separate rock formations with different mechanical rock properties.