Thermovaporization Decontamination for Rock Samples
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Solution Overview
Problem
Rock samples obtained during petroleum exploration are often contaminated with organic matter from drilling fluids, which can lead to systematic errors in hydrocarbon potential analysis, as existing methods like pyrolysis are not effective in removing these contaminants without causing kerogen maturation or cracking.
Innovation Solution
A method involving the use of solvent decontamination followed by thermovaporization at controlled temperatures and durations to remove organic contaminants from rock samples, ensuring that the thermovaporization process does not exceed the cracking temperature of the organic matter, thereby maintaining the integrity of the kerogen for accurate analysis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If pyrolysis is used to analyze rock samples, then hydrocarbon generating potential can be estimated, but organic contaminants from drilling fluids cannot be removed without causing kerogen maturation or cracking
Solution Approach 1:
The patent applies preliminary action by performing thermovaporization decontamination before pyrolysis analysis. The rock samples undergo thermovaporization at controlled temperatures (e.g., 150-300°C) for a predetermined time to remove organic contaminants from drilling fluids before the actual pyrolysis analysis is conducted, ensuring that the kerogen is not yet subjected to high temperatures that would cause maturation or cracking.
Solution Approach 2:
The patent applies parameter changes by carefully controlling the temperature and time parameters of the thermovaporization process. The temperature is maintained below the cracking temperature of kerogen (typically <300°C) while the duration is optimized to achieve effective contaminant removal. This parameter optimization allows contaminant elimination without triggering kerogen decomposition or maturation reactions.
2Measurement precision
If thermovaporization temperature is increased to remove contaminants, then decontamination effectiveness improves, but kerogen cracking occurs
Solution Approach 1:
The patent applies parameter changes by establishing and maintaining the thermovaporization temperature within a specific range (150-300°C) that is sufficient to vaporize and remove organic contaminants from drilling fluids but remains below the activation temperature for kerogen cracking. The time parameter is also optimized to achieve complete decontamination within this safe temperature window, preventing any thermal degradation of the kerogen structure.
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 effectively reduces contamination levels in rock samples, allowing for accurate determination of hydrocarbon generating potential by maintaining the kerogen's maturity and preventing cracking, thus ensuring reliable geochemical analysis results.
Implementation Method 1
The second sample portion is decontaminated by thermovaporization for an initial duration of time at an initial thermovaporization temperature below that of a cracking temperature of an organic matter carried within the rock sample
Implementation Method 2
The thermovaporization includes heating up the second sample portion while passing an inert carrier gas over the second sample portion to at least partially decontaminate the second sample portion
Data Source
AI summary
A rock sample includes multiple rock samples that are each obtained from the borehole. The rock samples have been exposed to contamination during a drilling operation to drill the borehole. The rock sample is split into a first sample portion and a second sample portion. The first sample portion is decontaminated with a solvent. The second sample portion is decontaminated by thermovaporization for an initial duration of time at an initial thermovaporization temperature below that of a cracking temperature of an organic matter carried within the rock sample. A difference between a first pyrolysis Tmax value of the first sample portion decontaminated by the solvent and a second pyrolysis Tmax value of the second sample portion decontaminated by the thermovaporization is determined to satisfy a decontamination level threshold. The remainder of rock samples are decontaminated by the thermovaporization in response to determining that the difference satisfies the decontamination level threshold.