High-Resolution Rock Property Estimation via CT and Well Data Integration

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Solution Overview

Problem

Conventional well data resolution is insufficient for evaluating thinly laminated geological formations, such as shale, which requires higher resolution to determine elastic properties and mechanical properties necessary for effective well completion and fracture treatment.

Innovation Solution

A method integrating well data with high-resolution computed tomography, using formulaic relationships between parameters like photoelectric effect index, effective atomic number, and bulk density to estimate elastic properties and other formation properties, by curve-fitting and applying these relationships to CT scan data.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional well data methods are used, then the evaluation process is simple and straightforward, but the resolution is insufficient for thinly laminated formations

Engineering Contradiction:
ImproveresolutionVSAvoidcomplexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent combines conventional well data with high-resolution CT scan data from rock samples to create a hybrid evaluation system. This merging allows the system to achieve high resolution for thinly laminated formations while maintaining the simplicity of conventional methods through automated integration algorithms that correlate well log data with CT-derived properties at matching depths.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent introduces rock core samples as an intermediary medium between conventional well data and the desired high-resolution formation properties. The CT scans of these samples serve as a bridge, providing detailed microstructural information that can be upscaled and integrated with well log data to derive formation properties at the well scale with enhanced resolution.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If high-resolution CT imaging is used, then detailed rock properties can be obtained, but elastic properties needed for mechanical property computation are not directly provided

Engineering Contradiction:
ImproveresolutionVSAvoidelastic properties
Core Design Contradiction:
Measurement precisionVSLoss of information

Solution Approach 1:

The patent replaces direct mechanical testing with a computational approach. Instead of performing physical mechanical tests on rock samples to obtain elastic properties, the system uses CT-derived rock properties (density, porosity, mineral composition) as input to petrophysical models and machine learning algorithms that predict elastic properties, thereby substituting mechanical measurement with computational prediction.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent transforms the problem from directly measuring elastic properties to deriving them through parameter transformation. The system measures easily obtainable parameters (density, porosity, mineralogy) via CT scanning and then applies mathematical relationships and empirical models to transform these parameters into elastic properties (Young's modulus, Poisson's ratio) needed for mechanical evaluation.

Inventive Principle:
Principle #35Parameter changes

3Measurement precision

If well data resolution is increased, then thinly laminated formations can be evaluated, but the cost and complexity of data acquisition increases

Engineering Contradiction:
ImproveresolutionVSAvoidease of data acquisition
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent applies partial action by obtaining CT scan data from selected rock core samples rather than continuously acquiring high-resolution data along the entire wellbore. This selective sampling approach achieves the necessary resolution for evaluation while minimizing the cost and complexity associated with comprehensive high-resolution data acquisition throughout the formation.

Inventive Principle:
Principle #16Partial or excessive action

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 high-resolution estimation of elastic properties and mechanical properties in thinly laminated formations, improving the accuracy of well planning and fracture treatment by bridging the resolution gap between conventional well data and CT imaging.

Implementation Method 1

performing an X-ray CT scan of a rock sample obtained from a depth interval in the formation for generating a digital image of the rock sample

Methodology Applied
Scientific EffectX-ray attenuation: X-Ray

Implementation Method 2

determining photoelectric effect index, effective atomic number, or bulk density in correspondence to the first parameter used in the curve-fitting

Methodology Applied
Scientific EffectPhotoelectric effect: Photoelectric Effect

Data Source

PatentUS9921334B2Combining multiple energy X-ray imaging and well data to obtain high-resolution rock, mechanical, and elastic property profiles
Publication Date: 2018.03.20 HALLIBURTON ENERGY SERVICES INC
  • US9921334B2 patent drawing
  • US9921334B2 patent drawing
  • US9921334B2 patent drawing

AI summary

A method is provided for evaluating a geological formation which integrates well data and high resolution computed tomography of rock samples thereof. Relationships are determined for a formation between a formation property, such as an elastic property, and at least one of photoelectric effect index (PEF), effective atomic number (Zeff), and bulk density (RHOB), using well data, and tomographic imaging is used to determine at least one of the latter mentioned properties (PEF, Zeff, RHOB) at higher resolution, which can be used in the relationship to determine a corresponding formation property. This affords an opportunity to develop formation property data for more challenging formations to evaluate, such as thinly laminated formations or others. Computerized systems, computer program products on non-transitory computer usable storage media, and programs for performing the methods are also provided.