Downhole Mass Spectrometer Operating Above 10-2 Torr
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Solution Overview
Problem
Downhole analysis of wellbore fluids and gases is complicated by the small diameter of wellbores and stringent operating conditions, including vibrations, elevated temperatures, and high pressures, which constrain the design of measurement tools and limit their effectiveness.
Innovation Solution
The integration of a gas chromatograph and a mass spectrometer, including an ion trap or quadrupole mass analyzer, within a wellbore tool that can operate at pressures greater than 10−2 Torr, using robust components such as scroll pumps and rotary valves to withstand harsh conditions, allowing for onsite analysis of formation fluid compositions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a mass spectrometer is used for downhole analysis, then measurement precision is improved, but the device cannot operate under high pressure conditions (greater than 10^-2 Torr)
Solution Approach 1:
The patent modifies the operating parameters of the mass spectrometer to function at pressures greater than 10^-2 Torr, which is a significant departure from conventional vacuum operation. This involves adjusting the ionization source, mass analyzer, and detector parameters to maintain performance under elevated pressure conditions, thereby enabling downhole operation without sacrificing measurement precision
Solution Approach 2:
The patent replaces traditional mechanical vacuum pumping systems with alternative pressure management mechanisms that can operate in high-pressure downhole environments. This substitution allows the mass spectrometer to function without requiring a deep vacuum, making it suitable for wellbore conditions where vacuum maintenance is impractical
2Ease of operation
If the wellbore diameter is small (five inches or less), then the measurement tool can be deployed in the wellbore, but the geometry of the tool components is constrained
Solution Approach 1:
The patent employs a nested configuration where the mass spectrometer components are arranged concentrically and in series to minimize the radial footprint. The ionization source, mass analyzer, and detector are positioned in a compact, nested arrangement that fits within the constrained diameter of the wellbore while maintaining functional integrity
Solution Approach 2:
The patent transitions from a traditional horizontal or radial layout to a vertical or axial arrangement of components, utilizing the length dimension rather than the radial dimension. This dimensional reconfiguration allows the instrument to fit within small-diameter wellbores by extending along the axis of the wellbore rather than requiring radial space
3Reliability
If robust components (scroll pumps, rotary valves) are used to withstand harsh conditions, then reliability under vibration and temperature is improved, but the device complexity increases
Solution Approach 1:
The patent selects robust components such as scroll pumps and rotary valves that serve multiple functions: they provide the necessary pressure management and sample injection while simultaneously being designed to withstand vibrations, elevated temperatures, and high pressures. This multi-functionality reduces the need for additional protective components, thereby limiting the increase in overall device complexity
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
Enables accurate and sensitive analysis of wellbore fluid components, including hydrogen sulfide, mercaptans, and oxidants, improving worksite safety and informing decisions on wellbore casing and tool selection by providing detailed information on hydrocarbon maturity and reservoir properties.
Implementation Method 1
a gas chromatograph having a column configured to separate a fluid sample into at least partially separated components
Implementation Method 2
The mass spectrometer is configured to operate downhole at a pressure greater than 10−2 Torr and includes at least one of (a) an ion trap analyzer and (b) a quadrupole mass analyzer
Implementation Method 3
a mass spectrometer configured to receive the at least partially separated components from the gas chromatograph. The mass spectrometer is configured to operate downhole at a pressure greater than 10−2 Torr and includes at least one of (a) an ion trap analyzer and (b) a quadrupole mass analyzer
Data Source
AI summary
Wellbore tools in accordance with the present disclosure may include a gas chromatograph; and a mass spectrometer, wherein the mass spectrometer is configured to operate at a pressure greater than 10−2 Torr. Systems in accordance with the present disclosure may include a gas chromatograph; and a mass spectrometer, wherein the mass spectrometer is configured to operate at a pressure greater than 10−2 Torr. Methods in accordance with the present disclosure may include emplacing a wellbore tool in a wellbore, the wellbore tool containing a gas chromatograph and a mass spectrometer, wherein the mass spectrometer is configured to operate at a pressure greater than 10−2 Torr; drawing a sample of a fluid from the wellbore into the wellbore tool; and determining a molecular weight of one or more components of the fluid.