Taggant-Based Rock Cuttings Depth Detection During Drilling

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Solution Overview

Problem

Inaccurate determination of rock cutting depth during drilling operations, particularly in deviated and horizontal wells, leads to uncertainties of several centimeters or meters, affecting the efficacy of mud logging and well placement.

Innovation Solution

A method and system utilizing taggants, such as polymeric nanoparticles with encoded identification codes, are injected into drilling fluid to impregnate rock cuttings, detected at the surface, and analyzed to generate injection profiles, adjusting pump parameters for precise depth determination.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional methods are used for rock cutting depth determination, then the system is simple, but the measurement precision is poor with uncertainties of several centimeters or meters

Engineering Contradiction:
Improvedepth determination precisionVSAvoidsystem complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent introduces taggants as intermediary markers that are injected into the drilling fluid and attach to rock cuttings. These taggants serve as mediators between the drilling process and the detection system, enabling precise depth determination through optical or other detectable signals without requiring complex direct measurement equipment at the drill bit

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces complex mechanical depth measurement systems with an optical/detection-based system using taggants. Instead of using mechanical sensors or complex positioning systems downhole, the invention uses detectable taggant markers that can be identified at the surface, substituting mechanical complexity with optical or electromagnetic detection

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

2Measurement precision

If taggant injection is used to improve depth determination, then the measurement precision improves, but the device complexity increases due to pump control requirements

Engineering Contradiction:
Improvedepth determination precisionVSAvoidpump control complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent implements a feedback control system where the detection of taggant signals provides information about cutting depth and taggant distribution. This feedback is used to automatically adjust pump injection parameters, creating a closed-loop system that improves precision while managing complexity through automated control rather than manual operation

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system uses the natural circulation of drilling fluid to transport taggants and cuttings through the wellbore, eliminating the need for complex pumping systems downhole. The existing mud circulation system serves the dual purpose of cooling the bit and transporting both taggants and rock cuttings, reducing additional device complexity

Inventive Principle:
Principle #25Self-service

3Measurement precision

If multiple batches of taggant are injected to improve depth resolution, then the measurement precision improves, but the loss of time increases due to multiple injection cycles

Engineering Contradiction:
Improvedepth resolutionVSAvoidinjection cycle time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent employs periodic injection of taggant batches at regular intervals during drilling operations. This periodic action creates distinct temporal signatures for different depth zones, enabling high-resolution depth determination through time-based separation of taggant signals without requiring continuous or frequent injections that would waste time

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The system performs preliminary injection of taggant batches before reaching critical depth zones or formation boundaries. By proactively tagging cuttings in advance, the system ensures that depth information is captured before the drilling condition changes, eliminating the need for repeated injection cycles to achieve the same depth resolution

Inventive Principle:
Principle #10Preliminary 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

Accurately determines the depth of rock cuttings with an uncertainty of 0.3 meters, improving petrophysical analysis and well placement by enhancing the quality of mud logging.

Implementation Method 1

the first batch of taggant are transported downhole by the drilling fluid to impregnate a first batch of rock cuttings

Methodology Applied
Scientific EffectFluid transport: Advection

Implementation Method 2

detecting, using a taggant detector at a surface location, a first time-dependent signal from the first batch of taggant

Methodology Applied
Scientific EffectTaggant detection: Absorption Spectroscopy

Implementation Method 3

the first batch of taggant are transported up-hole by the drilling fluid subsequent to impregnating the first batch of rock cuttings

Methodology Applied
Scientific EffectFluid transport: Advection

Data Source

PatentEP4229275B1Method for intelligent automatic rock fragments depth determination while drilling
Publication Date: 2025.12.03 SAUDI ARABIAN OIL CO
  • EP4229275B1 patent drawingFigure 1
  • EP4229275B1 patent drawingFigure 2
  • EP4229275B1 patent drawingFigure 3

AI summary

A method for depth determination of drilled rock cuttings is disclosed. The taggant is injected and transported downhole along the mud stream (204, 205) and attaches to the rock cuttings. Taggant impregnated cuttings are detected at the surface (108) based on molecular weight, emission wavelengths or radio frequency characteristics for encoding the taggant. The identification code identifies the depth of the drill bit when the particular batch of the taggant is released into the mud. The detection data, in addition to mud properties, flow rates, drill volume and penetration rates, formation characteristics, and well specifications are transferred to and analyzed by a taggant analysis and control engine (202). The taggant analysis and control engine (202) controls an IoT controller (203) that adapts the parameters of the taggant injection pump (206) to achieve an intelligent controlled release to optimize the depth characterization process.