Polymeric Taggants for Depth-Tagged Drill Cuttings Logging
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Solution Overview
Problem
Current surface logging methods face challenges in accurately determining the depth of origin for drill cuttings due to shifting or scrambling during transport and storage, and struggle with interference from contaminants in the drilling process, which affects the quality of formation evaluation and wellbore positioning.
Innovation Solution
The use of polymeric taggants with distinct ceiling temperatures, added in a sequence to the drilling fluid, which attach or penetrate into drill cuttings, allowing for precise depth correlation through pyrolysis-gas chromatography-mass spectrometry analysis, even in the presence of contaminants, enabling near-real-time depth information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional surface logging methods are used to examine drill cuttings, then formation evaluation information can be obtained, but the depth of origin for drill cuttings cannot be accurately determined due to shifting or scrambling during transport and storage
Solution Approach 1:
Polymeric taggants are added to the drilling fluid in advance during the drilling process, before the drill cuttings are transported and stored. This preliminary tagging ensures that each cutting carries depth information from its origin point, preventing loss of depth information during subsequent handling operations.
Solution Approach 2:
Polymeric taggants serve as an intermediary carrier that transfers depth information from the drilling fluid to the drill cuttings. These taggants attach to or penetrate into the cuttings, acting as a mediator that preserves and conveys depth origin information through the entire workflow from drilling to analysis.
2Measurement precision
If polymeric taggants are added to drilling fluid to enable depth tagging, then depth correlation precision is improved, but the system complexity increases due to sequence management and analysis requirements
Solution Approach 1:
The depth tagging system divides the continuous drilling process into discrete segments by adding polymeric taggants in specific sequences corresponding to different depth intervals. Each taggant concentration pattern represents a segmented portion of the well depth, making complex depth information manageable and analyzable through concentrated measurement points.
Solution Approach 2:
The system uses changes in polymeric taggant concentrations as measurable parameters to indicate different depth zones. By monitoring concentration variations of specific polymers in the drill cuttings, the system translates complex depth correlation into simple quantitative parameter measurements that can be analyzed using pyrolysis-gas chromatography-mass spectrometry.
3Object-affected harmful factors
If polymeric taggants with ceiling temperatures between 400-800°C are used, then interference from drilling fluid contaminants is reduced, but the requirement for high-temperature pyrolysis analysis increases system demands
Solution Approach 1:
The polymeric taggants are specifically selected to undergo phase transition (depolymerization) at well-defined ceiling temperatures between 400-800°C. This controlled phase transition allows the taggants to decompose into characteristic monomers that can be detected by gas chromatography-mass spectrometry, creating a clear thermal signature that distinguishes them from drilling fluid contaminants with different thermal stability.
Solution Approach 2:
The taggant system introduces localized thermal properties to specific depth zones by using polymers with distinct ceiling temperatures. Each polymer type has a unique thermal decomposition characteristic that corresponds to a specific depth interval, allowing differentiation of cuttings from different depths based on their local thermal response during pyrolysis analysis.
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 provides accurate and cost-effective depth tagging of drill cuttings, reducing uncertainty and interference from drilling fluids, allowing for improved formation evaluation and wellbore positioning by correlating taggant concentrations with specific depths, even in challenging drilling conditions.
Implementation Method 1
Portions of the polymeric taggants attach to the drill cuttings during generation of the drill cuttings
Implementation Method 2
measuring concentrations of individual polymeric taggants attached to the drill cuttings in the sample comprises using pyrolysis-gas chromatography-mass spectrometry
Implementation Method 3
Ceiling temperature, Tc, indicates the temperature greater than which depolymerization (or unzipping of the polymer chain) of a specific polymer will occur and the polymer will revert to its monomer
Data Source
AI summary
Systems and methods of surface logging a well use a plurality of polymeric taggants distinguishable from each other. The systems and methods can include adding each of the plurality of polymeric taggants in a repeating sequence to a circulating drilling fluid while drilling the well and taking a sample drill cuttings carried by the circulating drilling fluid. The systems and methods can also include measuring concentrations of individual polymeric taggants attached to the drill cuttings in the sample and identifying a depth associated with the sample based on the measured concentrations of individual polymeric taggants and on the sequence.