Taggant-Based Drill Cuttings Depth Tracking in Deviated Wells
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Solution Overview
Problem
Conventional mud logging methods face inaccuracies in determining the depth of rock cuttings due to depth uncertainties, especially in deviated and horizontal wells, where cuttings' flows are delayed by gravitational debris accumulation and problematic hydraulics, leading to errors of several feet in depth determination.
Innovation Solution
The method involves using polymeric nanoparticles encoded with bar codes or radio frequency characteristics as taggants, injected into drilling fluids to impregnate rock cuttings, detected at the surface, and analyzed to generate an injection profile that adjusts the taggant release parameters, ensuring accurate depth determination through an IoT-controlled system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional mud logging methods are used to determine rock cutting depth, then the process is simple and equipment is basic, but depth determination accuracy deteriorates with errors of several feet due to gravitational debris accumulation and problematic hydraulics in deviated and horizontal wells
Solution Approach 1:
The patent introduces taggants (fluorescent particles, magnetic particles, or other detectable markers) as intermediaries to trace the journey of drill cuttings from the wellbore bottom to the surface. These taggants are injected at specific depths and attach to cuttings, allowing precise depth determination by detecting which taggant batch is present in the returned cuttings, thereby resolving the depth accuracy problem without requiring complex hydraulic or gravitational control systems
Solution Approach 2:
The patent creates a simplified model of depth tracking by using taggant batches as proxies for specific depth intervals. Instead of directly measuring the physical position of cuttings through complex systems, the invention uses detectable taggant signatures (fluorescence, magnetic properties) that copy and represent the depth information, enabling accurate depth determination through simple detection of these markers at the surface
2Measurement precision
If taggant injection is performed continuously without optimization, then coverage of all cuttings is improved, but signal overlap between consecutive batches increases reducing measurement precision
Solution Approach 1:
The patent employs periodic injection of taggant batches at optimized time intervals rather than continuous injection. By injecting taggant batches periodically with calculated time spacing that accounts for circulation time and well conditions, the system ensures that each batch's signal is fully detected and distinguished before the next batch arrives, preventing signal overlap while maintaining continuous depth monitoring capability
Solution Approach 2:
The system uses feedback from detected taggant signals to dynamically adjust subsequent injection timing and parameters. By monitoring the arrival and duration of each taggant batch's signal at the surface, the control system optimizes the timing of the next injection to prevent overlap, thereby maintaining high measurement precision while minimizing unnecessary waiting time between injections
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
This approach improves the accuracy of rock cutting depth determination to within 1 foot, even when cuttings are shifted or mixed, enhancing petrophysical analysis and reducing errors in geosteering and well placement.
Implementation Method 1
the first batch of taggant are transported downhole by the drilling fluid to impregnate a first batch of rock cuttings
Implementation Method 2
detecting, using a taggant detector at a surface location, a first time-dependent signal from the first batch of taggant upon surface arrival
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
Data Source
AI summary
A method for depth determination of drilled rock cuttings is disclosed. The taggant is injected and transported downhole along the mud stream and attaches to the rock cuttings. Taggant impregnated cuttings are detected at the surface 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. The taggant analysis and control engine controls an IoT controller that adapts the parameters of the taggant injection pump to achieve an intelligent controlled release to optimize the depth characterization process.