Wellbore Optical Speckle Interferometry for Rock Displacement Sensing

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Conventional wellbore characterization techniques using LiDAR and calipers are limited by operational range and require high reflectance, making them ineffective for precise rock property identification during high-power laser operations.

Innovation Solution

A downhole tool system with a laser head and sensing assembly that emits and receives laser and light beams to generate speckle interferograms, determining angular and axial displacements of the wellbore using optical interference, and integrates optical receivers and controllers for real-time rock property analysis.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional LiDAR is used for wellbore displacement detection, then measurement capability is provided, but operational range is limited to above ten centimeters and high reflectance is required

Engineering Contradiction:

Improvedisplacement measurement accuracyVSAvoidapplicability in wellbore characterization

Core Design Contradiction:

Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The patent changes the operational parameters of the detection system by using a different wavelength regime (infrared at 1500-1600 nanometers) and a different measurement principle (speckle interferometry based on optical interference) to overcome the limitations of conventional LiDAR. This allows operation at much shorter distances with lower reflectance requirements, making it suitable for wellbore characterization.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent replaces the conventional LiDAR measurement system with an optical interference-based speckle interferometry system. This substitution enables the system to function effectively in the constrained wellbore environment where conventional LiDAR fails due to distance and reflectance limitations.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Power

If high-power laser operations are conducted on rock formations, then rock characterization is enabled, but real-time identification of rock properties during operations is difficult

Engineering Contradiction:

Improvelaser power for rock interactionVSAvoidreal-time rock property information

Core Design Contradiction:

PowerVSLoss of information

Solution Approach 1:

The patent implements a feedback mechanism where the speckle interferometry system continuously measures wellbore displacement and rock formation changes in real-time during high-power laser operations. This feedback provides immediate information about rock properties and operational effects, enabling real-time identification and characterization.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent introduces an optical intermediary system (the speckle interferometry measurement system) that mediates between the high-power laser operations and the information acquisition need. This intermediary enables real-time monitoring of rock property changes without interfering with the primary laser processing function.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 precise, real-time characterization of rock properties and wellbore displacements with improved accuracy and applicability, facilitating geo-steering and sweet spot classification in complex laser interactions with subsurface matter.

Implementation Method 1

receive a reflected laser beam from the reservoir rock formation and a reflected light beam from the reservoir rock formation

Methodology Applied

Scientific EffectReflection: Reflection

Implementation Method 2

interfere the reflected laser beam with the reflected light beam

Methodology Applied

Scientific EffectInterference: Interference

Implementation Method 3

generate at least one speckle interferogram based on the interference between the reflected laser beam and the reflected light beam

Methodology Applied

Scientific EffectSpeckle interferometry:

Implementation Method 4

emit the laser beam toward the reservoir rock formation to induce a thermal change on the reservoir rock formation

Methodology Applied

Scientific EffectThermal change: Heating

Implementation Method 5

change a stress state of the reservoir rock formation

Methodology Applied

Scientific EffectStress state change:

Implementation Method 6

the emitted light beam has a wavelength at a long IR spectrum... the wavelength is at 1500-1600 nanometers... tuned to transmit through a wellbore fluid

Methodology Applied

Scientific EffectInfrared radiation transmission: Infrared Radiation

Data Source

PatentUS12487075B2Characterizing rock properties with optical energy sources in a wellbore

Publication Date: 2025.12.02 SAUDI ARABIAN OIL CO

AI summary

A downhole tool system includes a bottom hole assembly that includes a connector; a laser head; a light source; a sensing assembly; and a controller. The connector is configured to couple to a downhole conveyance run into a wellbore to a reservoir rock formation. The laser head is configured to emit a laser beam toward the reservoir rock formation at a fixed frequency. The light source emitter is configured to emit a light beam toward the reservoir rock formation. The sensing assembly includes at least one optical receiver configured to (1) receive a reflected laser beam and a reflected light beam, and (2) interfere the reflected laser beam with the reflected light beam. The controller is configured to perform operations including generating a speckle interferogram based on the interference; and determining an angular displacement and an axial displacement of the wellbore based on the speckle interferogram.