Unoriented Core Orientation via CT Scan Reference Mark

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Solution Overview

Problem

Conventional un-oriented cores extracted from rock formations lack the ability to determine the geographical orientation of features or geobodies such as channels, hindering the assessment of oil or gas reservoir potential.

Innovation Solution

A method and system utilizing CT scan images to select an inclined plane, realign voxels to create a horizontal plane, determine correcting angles, and map the orientation of features to compass coordinates, enabling the determination of the orientation of reservoir features from unoriented cores.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional un-oriented cores are used for analysis, then core extraction and CT scanning can be performed, but the geographical orientation of features or geobodies cannot be determined

Engineering Contradiction:
Improveorientation measurementVSAvoidcompass direction information
Core Design Contradiction:
Measurement precisionVSLoss of information

Solution Approach 1:

A reference mark is attached to the core before CT scanning to preserve orientation information. This preliminary action ensures that when the core is scanned and analyzed, the geographical orientation can be determined by referencing the known position and orientation of the reference mark in the CT images.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

A reference mark serves as an intermediary between the core and the CT scanning system. The reference mark with known orientation properties allows the system to translate the unoriented core data into geographically referenced information without requiring modification to the core itself or the CT scanner.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If CT scanning is used to analyze core composition, then sediment layers can be distinguished, but the compass direction orientation of channels or features remains unknown

Engineering Contradiction:
Improvefeature orientationVSAvoidorientation determination system
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

A reference mark is introduced as an intermediary element that bridges the gap between the core sample and the orientation determination system. The reference mark contains known orientation information that can be detected by the existing CT scanner, allowing orientation determination without adding complex new imaging equipment.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The system changes the parameter being measured by the CT scanner from purely compositional data to include spatial orientation data. By incorporating a reference mark with known orientation parameters, the existing CT scanning system can extract both compositional and orientational information from the same dataset.

Inventive Principle:
Principle #35Parameter changes

3Loss of information

If conventional core analysis methods are used, then presence or absence of channels can be identified, but the geographical orientation relative to compass directions cannot be determined

Engineering Contradiction:
Improvegeographical orientation informationVSAvoidanalysis method complexity
Core Design Contradiction:
Loss of informationVSEase of manufacture

Solution Approach 1:

The reference mark is attached to the core in advance, before the analysis process begins. This preliminary action ensures that orientation information is preserved throughout the entire analysis workflow, from CT scanning to image processing to final interpretation, without requiring complex real-time orientation tracking.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The reference mark creates a copy or representation of the core's orientation state that can be independently analyzed. The known orientation of the reference mark serves as a template against which the orientation of geological features can be compared and determined.

Inventive Principle:
Principle #26Copying

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 accurate orientation of reservoir features, enhancing reservoir modeling and subsequent drilling operations by correctly positioning geo-features in real coordinates, thereby improving the assessment of rock formation potential.

Implementation Method 1

a computed tomography (CT) scanner to determine the various layers of sediments present in the core. However, although various layers of sediments can be distinguished using a CT scanner

Methodology Applied
Scientific EffectX-ray: X-Ray

Implementation Method 2

The term "oriented" is used herein to define the geographical orientation or compass direction

Methodology Applied
Scientific EffectTomography: Tomography

Data Source

PatentEP2994747B1System and method for determining an orientation of reservoir geobodies from unoriented conventional cores
Publication Date: 2017.07.19 CHEVRON USA INC
  • EP2994747B1 patent drawingFigure 1A~1C
  • EP2994747B1 patent drawingFigure 2A~3E
  • EP2994747B1 patent drawingFigure 4A~4B

AI summary

A system and method for determining an orientation of a reservoir feature from an unoriented core. The method includes selecting an arbitrary inclined plane in a longitudinal or transverse cross sectional CT scan image of the unoriented core; flattening the inclined plane by realigning all voxels within a volume of the unoriented core so as to obtain a horizontal plane in a realigned core; selecting a transverse cross sectional CT scan image of the realigned core where a desired feature is present; determining a correcting angle to be added to an angle of a flat-bed contact plane of the realigned core relative to a reference mark in the realigned core to obtain a correct inclination angle relative to compass map coordinates; determining a first angle between a direction perpendicular to the feature relative to the reference mark; and determining a second angle by adding the correcting angle to the first angle.