Inversion Workflow for Nuclear Density Image Interpretation

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Solution Overview

Problem

Interpreting density images in high-angle and horizontal wells is challenging due to inconsistencies and lack of robustness in existing inversion-based workflows, which affect the accuracy of formation evaluation and hydrocarbon reserve estimation.

Innovation Solution

A parallelized workflow for inversion-based interpretation of nuclear density images using interval processing and extended parameterization, allowing for non-parallel boundaries, variable dips, and lateral property changes, along with automatic extraction of model boundaries and graphical user interface adjustments for improved accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If separate HA and HZ workflows are used for inversion processing, then the tool can handle different well orientations, but the interpretation consistency deteriorates between high-angle and horizontal well sections

Engineering Contradiction:

Improveability to handle different well orientationsVSAvoidinterpretation consistency

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent implements a unified inversion workflow that can process both high-angle and horizontal well data using the same algorithmic framework. The system automatically adapts the inversion parameters and models based on the well orientation detected from the input data, eliminating the need for separate HA and HZ workflows while maintaining interpretation consistency across different well types.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

Instead of having the workflow adapt to different processing methods for HA and HZ wells, the patent inverts the approach by having a single workflow that automatically detects well orientation and adjusts its internal parameters accordingly. This reversal of the adaptation logic resolves the consistency issue while preserving versatility.

Inventive Principle:

Principle #13The other way round (Inversion)

2Adaptability or versatility

If short segments are processed in HZ workflow, then the tool can account for non-crossed boundaries, but the interpretation robustness deteriorates compared to HA interpretation

Engineering Contradiction:

Improveability to account for non-crossed boundariesVSAvoidinterpretation robustness

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent implements dynamic segment length selection where the processing segment length is automatically adjusted based on the well orientation and formation characteristics. For horizontal wells with non-crossed boundaries, longer segments are used to capture the full boundary geometry, while for high-angle wells, shorter segments are appropriate. This dynamic adaptation maintains both the ability to handle non-crossed boundaries and interpretation robustness.

Inventive Principle:

Principle #15Dynamics

3Ease of manufacture

If different inversion assumptions are used for HA and HZ wells, then each workflow can be optimized for its specific geometry, but the overall formation model consistency deteriorates

Engineering Contradiction:

Improveworkflow optimization for specific geometriesVSAvoidformation model consistency

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent employs a unified inversion framework where key parameters such as segment length, boundary detection thresholds, and inversion regularization are dynamically changed based on the detected well orientation and formation characteristics. This allows the workflow to be optimized for specific geometries (HA or HZ) while maintaining overall model consistency through parameter adaptation rather than fundamentally different processing assumptions.

Inventive Principle:

Principle #35Parameter changes

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

Enhances the consistency and accuracy of interpreted structure and density profiles, enabling more precise formation modeling and hydrocarbon reserve estimation in high-angle and horizontal wells.

Implementation Method 1

collecting data from the subterranean formation using a nuclear density tool, wherein the nuclear density tool is configured to collect data to form azimuthal images representative of a density and photoelectric factor of the formation

Methodology Applied

Scientific EffectGamma ray interaction: Absorption (EM radiation)

Data Source

PatentEP3052756B1Inversion-based workflow for consistent interpretation of nuclear density images in horizontal wells

Publication Date: 2021.05.26 SERVICES PETROLIERS SCHLUMBERGER SA

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AI summary

Systems and methods are disclosed for well logging using radiation detection and/or emission of gamma rays. A method according to the disclosure includes collecting data from the subterranean formation using a nuclear density tool, wherein the nuclear density tool is configured to collect data to form an azimuthal image. The method further includes characterizing a section of the subterranean formation comprising data and images acquired in a high angle wellbore section, a horizontal wellbore section, or a combination thereof. The method additionally includes performing a parallel inversion using apparent densities and volumetric photoelectric factor images to build a formation model, wherein the parallel inversion comprises a high angle workflow that models high angle wellbore sections and a horizontal workflow that models horizontal wellbore sections.