Automated Lithology Determination from Wellbore Measurement Logs

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Solution Overview

Problem

Current methods for determining the lithology of a subterranean formation during wellbore drilling are manual, inconsistent, and time-consuming, relying on human interpretation of multiple measurements which can lead to operator bias and delayed decision-making.

Innovation Solution

A method and system that automatically receive and process measurement logs to segment the wellbore into regions based on trend changes and rock type appearance/disappearance, generating a lithology log with accurate location, length, and rock type information using algorithms like Change Point detection, enabling real-time, operator-independent lithology determination.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If manual interpretation of measurement logs is used, then operator flexibility and experience-based judgment are maintained, but consistency and time efficiency deteriorate

Engineering Contradiction:

Improvelithology interpretation accuracyVSAvoidtime for lithology determination

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The patent replaces the manual mechanical interpretation process with an automated computer-based system that processes measurement logs using algorithms. The system automatically segments wellbores into regions and zones, detects rock type appearances and disappearances, and generates lithology logs without human intervention, thereby eliminating time loss while maintaining or improving accuracy through consistent algorithmic application.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The system enables self-service by allowing the measurement logs to speak for themselves through automated analysis. The computer system independently processes the data, identifies trends, segments regions, and determines lithology without requiring operator intervention, making the process both faster and more consistent by eliminating human variability.

Inventive Principle:

Principle #25Self-service

2Adaptability or versatility

If manual lithology interpretation is performed, then complex geological judgment can be applied, but operator bias and inconsistency increase

Engineering Contradiction:

Improvegeological interpretation capabilityVSAvoidconsistency of lithology determination

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent applies segmentation by dividing the wellbore into distinct regions based on changes in measurement log trends, and further subdividing regions into zones based on rock type appearance and disappearance. This systematic segmentation ensures that each segment is analyzed independently with consistent criteria, eliminating operator bias while maintaining the ability to handle complex geological variations through localized analysis.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The system monitors multiple measurement parameters simultaneously (gamma ray, resistivity, density, etc.) and detects changes in these parameters to identify rock type transitions. By using multiple parameters and their changes rather than single-parameter interpretation, the system achieves both adaptability to complex geology and consistency through objective, repeatable parameter-based decision rules.

Inventive Principle:

Principle #35Parameter changes

3Loss of information

If detailed manual analysis of measurement logs is conducted, then comprehensive lithology information is obtained, but the process becomes tedious and lengthy

Engineering Contradiction:

Improvecompleteness of lithology dataVSAvoidspeed of lithology log generation

Core Design Contradiction:

Loss of informationVSProductivity

Solution Approach 1:

The patent replaces tedious manual analysis with automated computer processing that can simultaneously evaluate multiple measurement logs and generate comprehensive lithology information instantly. The system performs all necessary analyses—trend detection, region segmentation, zone identification, rock type determination—automatically, maintaining complete information while dramatically increasing productivity.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The system performs preliminary actions by automatically preprocessing the measurement logs, identifying trends, and segmenting regions before the user needs the final lithology interpretation. This preliminary automated processing prepares the data in advance, allowing comprehensive analysis to be completed rapidly without manual intervention at each step.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS11661843B2Method and system for determining a lithology of a subterranean formation

Publication Date: 2023.05.30 SCHLUMBERGER TECH CORP

AI summary

A method is provided for determining a lithology of a subterranean formation into which a wellbore has been drilled. The method includes receiving a set of measurement logs including one or more measurement logs, each representing a measured characteristic of the wellbore plotted according to depth. The method also includes segmenting the wellbore into regions based on identified change of trend in one or more of the measurement logs of the set, and sub-segmenting at least one region into zones based on detection of appearance or disappearance of a rock type in the cuttings percentage log, The method also includes determining, in each zone, a location, length and rock type of one or more layers based on a total percentage of each rock type in the zone in the cuttings percentage log and at least one of the additional measurement logs.