COLLECTING AND REMOVING CONDENSATE FROM
A GAS EXTRACTION SYSTEM
Technical Field
[0001] The present disclosure relates generally to devices for use in a drilling
environment and, more particularly (although not necessarily exclusively), to devices
and methods for collecting and removing condensate from a pressurized or nonpressurized
gas extraction system, and are particularly useful in conjunction with
drilling operations.
Background
[0002] Drilling operations often include a gas extraction system. Gas-in-air
measurements may provide qualitative and quantitative hydrocarbon gas data. This
measurement typically uses a gas trap. Drilling mud gasses are separated by
agitating the drilling fluid, mixing it with make-up air, and sending the resulting gas to
gas analyzers operated in the onsite Surface Data Logging (SDL) unit. Gas-in-mud
systems generally include a series of pumps, a separator, a coriolis meter, a heater,
and a degasser.
[0003] One type of gas extraction system allows a measurement to be taken
close to the time of the gas extraction. This system generates a gaseous sample
stream from an active drilling fluid system. The gaseous sample stream is delivered
to an array of analytical devices and/or collection systems for processing.
Brief Description of the Drawings
[0004] FIG. 1 is a schematic illustration of skid housing that supports various
components of a gas extraction system.
[0005] FIG. 2 is a schematic diagram illustrating flow of gas and condensates
in a gas extraction system according to aspects of the disclosure.
[0006] FIG. 3 is a flow chart illustrating the flow of gas and condensates in a
gas extraction system according to one example.
[0007] FIG. 4 is a side perspective view of a peristaltic pump that may be used
in accordance with this disclosure.
Detailed Description
[0008] The general goal of a gas extraction system for use in a drilling
environment is to extract gas from drilling fluids and to conduct various analytical
procedures on the extracted gas. The disclosed system may be placed near the
return drilling fluid path (flow line) so that a fluid sample may be taken without delay
between collection and analysis. The shorter the time lapse between sample
collection to sample analysis, the more accurately a hydrocarbon zone, or other zone
of interest can be identified. As time increases, more gases may be liberated from
the drilling fluid. Accordingly, the disclosed gas extraction system may be
associated with any type of drilling operation, but may provide additional benefits in
gas extraction systems that are positioned near the drilling fluid path. The gas
extraction system will generally liberate (e.g., separate and extract) dissolved or
entrained gases from active drilling fluids in a controlled manner for the purpose of
analytical evaluation.
[0009] Various aspects and features of the system disclosed may be used
with any appropriate gas extraction system. The gas extraction system may use
heat (among other methods) to extract or liberate entrained "species of interest" in
the form of gases that are dissolved in the drilling fluid. During this process, vast
amounts of water vapor and other gas species generated by this process are
subsequently cooled to the point of condensation. They may be collected in a
condensate separator or a "drop-out vessel," the contents of which are disposed of in
a continuous manner and prevented from traveling downstream to the analytical
devices. The process of removing unwanted particulates, vapors, and liquids from a
sample stream is referred to herein as "conditioning the sample" or "conditioning."
[001 0] During conditioning, the lighter species of gases targeted for analysis
are separated from the heavier species. The heavier species of gases and water
vapor that are collected are pumped out of the gas extraction system as a liquid.
[001 1] These illustrative aspects and examples are given to introduce the
reader to the general subject matter discussed here and are not intended to limit the
scope of the disclosed concepts. The following sections describe various additional
features and examples with reference to the drawings in which like numerals indicate
like elements, and directional descriptions are used to describe the illustrative
aspects but, like the illustrative aspects, should not be used to limit the present
disclosure.
[001 2] FIG. 1 shows one example of a gas extraction system 10 that may use
certain aspects and features described herein. The process flow of fluid and
condensate through a specific portion of this system 10 is outlined in FIG. 2 . One
goal of the system 10 may be to extract a portion of the gas from the drilling fluid and
to condition the extracted gas so that it can be analyzed. The system may also route
the condensates from the extracted gas appropriately.
[001 3] A portion of drilling fluid may be pulled into the system 10 through a
suction tube assembly. The suction tube assembly may be hard mounted into the
return drilling fluid path in a flow line. One or more filters may be associated with the
suction tube assembly to prevent large solids from entering the flow. Once the
drilling fluid has passed through the suction tube assembly, it travels through a hose.
In one example, the drilling fluid may be delivered to a gas extraction skid 72 shown
in FIG. 1. The skid 72 is a structure that can house the various components of the
gas extraction system 10. It should be understood, however, that the gas extraction
system 10 may be positioned in any appropriate location. The drilling fluid may be
received by a delivery pump 74. The delivery pump 74 pulls the drilling fluid from the
suction tube assembly and pushes it through the process until it reaches the
degasser 12 . Prior to reaching the degasser 12, the fluid may pass through various
other pumps (such as a de-aerator pump) and solids removal systems (such as a
de-aerator, dampener, separator (DDS), heaters, and/or meters). These systems
are not described or shown in any more detail in this application, and are merely
referenced to provide background for how the drilling fluid arrives at the degasser 12
in the system 10 . It should be understood that any appropriate pumping system and
filtering and routing system may be used in connection with this disclosure.
[0014] Once the treated fluid 14 reaches the degasser 12, it is ready for
further separation. As shown more specifically in FIG. 2, a degasser 12 may receive
a stream of heated fluid 14. It can also receive an input of nitrogen 76 and/or an
input of de-aerated fluid 78. The degasser 12 may allow any light hydrocarbon gas
that may have been liberated by the earlier systems to be captured and conditioned.
The degasser 12 may provide a sealed vessel for liberating and separating dissolved
gases from the drilling fluids. The degasser 12 may generally agitate the fluids
delivered thereto, volatize the fluid for outgassing, and/or reduce surface tension to
liberate dissolved gasses. Any type of degasser 12 may be used in connection with
this disclosure.
[001 5] For example, a vacuum type degasser uses a vacuum action to pull
gas out of the liquid. When the liquid 14 enters the degasser 12 tank, it can flow and
be distributed to a layer of internal baffle plates designed for the liquid to flow in a
thin film. The film may be exposed to a vacuum that forces the gas to escape and
break out of the mud/liquid mixture. Alternatively, the degasser may be an
atmospheric degasser. An atmospheric degasser processes the liquid by
acceleration through a pump impeller that functions like a beater. Baffles may be
provided to maximize surface area. The liquid may be mixed, enabling the gas to
escape and vent to the atmosphere.
[001 6] The remaining fluid 80 from which the gas has escaped may be
delivered to a liquid trap assembly 32 (described in more detail below). The
released gases 16 may be transported to a vortex cooler 18. At this point in the
process, the released gases 16 may generally be moisture-laden and high in
temperature. Heat may also be added prior to the degassing process in order to
encourage escape of the gas. Accordingly, the vortex cooler 18 may be provided to
remove heat from the sample gas prior to analysis.
[001 7] The cooled sample gas 20 then leaves the vortex cooler 18 and may
be delivered to a condensate separator 22. The gas that leaves the vortex cooler 18
can be referred to as cooled sample gas 20 laden with condensate. The condensate
separator 22 may cause the sample gas to "drop out" any condensates 28. The gas
resulting from this final process may be referred to a cooled/dry sample gas 24 that
is ready for analyzing. This gas 24 may be delivered to any appropriate testing or
analyzing location. The resulting gas and condensate mixture 28 may then be
routed appropriately.
[001 8] Using a gas extraction system according to some examples can avoid
unused gas with condensates returning back to the degasser. For example, gas
analyzers generally require about 1000cc/min of sample gas. Certain gas extraction
systems, however, can be capable of producing about +/- 5 liters/min (5000 cc/min)
of sample gas. This results in extra gas that may be routed back into the system.
Instead of routing this gas/condensate material to the degasser for another flow
through the system due to a high-speed gas extraction loop, the examples described
allow delivery of the condensate 84 (and any accompanying unused gasses) to a
liquid trap assembly 32, as shown in FIG. 2 . In one example, this is because the
pump described allows the flow loop to be slowed. This can help reduce the
possibility of continuously recycling these gases and liquids in a decaying
concentration (through their re-delivery to the degasser). It is generally efficient to
have primarily "new" sample gas being delivered to the analyzers instead of
potentially recycling "old" or stale sample gas. It is also generally efficient to slow the
loop so that heat is not continuously being recycled as well.
[001 9] Accordingly, certain aspects and features of this disclosure relate to
using a peristaltic pump 30 in a gas extraction system. For example, a peristaltic
pump 30 provides variable and/or slow flow through the flow loop, so that the
condensate/unused gas mixture 28 can be re-routed to a more desirable location.
The use of a peristaltic pump 30 provides an improved process flow change over
high speed loops.
[0020] As shown in FIG. 2, a peristaltic pump 30 can be used to deliver a
condensate/unused gas mixture 84 directly to a liquid trap assembly 32. The
peristaltic action of the pump 30 may be more controllable and/or slower than
typically-used diaphragm pumps. A peristaltic pump 30 may allow the gas extraction
system 10 enough time to collect sufficient gas for testing, such that the condensates
84 can be removed during their initial flow through the system 10 . In the example
shown, condensates 28 leaving the condensate separator 22 may be delivered to a
peristaltic pump 30, which delivers a condensate stream 84 to the liquid trap
assembly 32. In use, the liquid trap assembly 32 maintains a level of fluid that
remains in the trap 32 to act as a seal during operation.
[0021] Thus, the liquid trap 32 originally served as the main receptacle for
fluids 80 flowing out of the degasser 12 during the initial degassing step of the
process. By providing a slower, more controlled peristaltic pump 30 in the system
10, the liquid trap 32 can also now serve as a receptacle for condensates/gasses 84
at the end of the flow loop. The removed fluids 80 and the condensates 84 can exit
the liquid trap assembly 32 via an exit outlet 82 to rejoin the drilling fluid on the rig.
The removed materials may be directed via a return pump.
[0022] With the pump improvements described by this disclosure, the liquid
trap assembly 32 may now also serve as a direct receptacle for the condensates 84
removed from the condensate separator 22. This may be preferable to delivering the
condensates back to the degasser 12. This can help prevent depletion of all of the
sample from the system. The condensate mixture can then be subsequently
removed from the flow loop and remixed with the drilling fluids. This can eliminate
the possibility of recycling any sample gas components and can improve gas
extraction processes.
[0023] A schematic of this fluid flow is illustrated in FIG. 3 . FIG. 3 shows a
fluid flow through a gas extraction system. In block 100, fluid may be delivered to a
degasser. In one example, fluid may be delivered to the degasser from other filtering
systems on the skid. This delivery may be via tubing, piping or any other appropriate
fluid conduit. The fluid may have large solids removed and be ready for
extraction/liberation of gas from the fluid. The degasser agitates the flow in order to
release/extract gasses.
[0024] In block 110, the released gasses may be delivered from the degasser
to a vortex cooler. In one example, the released gasses may be in the form of a
hot/wet sample gas. This delivery may be via tubing, piping, or any other
appropriate fluid conduit. The vortex cooler 18 may act to cool the gas sample that it
receives.
[0025] In block 120, the cooled gas sample may be delivered from the vortex
cooler to a condensate separator. This delivery may be via tubing, piping, or any
other appropriate fluid conduit. In one example, the gasses received by the
condensate separator may be in the form of a cooled sample gas that may be laden
with condensates. The condensate separator separates the condensates from the
gas sample for analysis.
[0026] In block 130, the conditioned gas sample from the condensate
separator may be delivered to an analyzer or analyzer system. For example, the
gaseous sample stream may be delivered to an array of analytical devices and/or
collection systems for processing. The sample gas may be transported via a hose or
tube to an array of analyzers where the chemical signature of the gases can be
defined and recorded. The processed data gathered from the analyzers can be tied
back to the time/depth of the drilling event and used to construct a well log.
[0027] In block 140, the condensates that have been separated from the
sample gas are delivered from the condensate separator to a peristaltic pump. This
delivery may be via tubing, piping, or any other appropriate fluid conduit. The
peristaltic pump may be used to move the condensate from the condensate
separator to a liquid trap assembly. The peristaltic pump may have one or more of
the features described herein. For example, the pump may have specialized tubing
that is suitable for withstanding chemical aspects of drilling fluid. For example, the
pump may have a specialized air motor that allows it to function in a hazardous
environment. Other options are also possible.
[0028] In block 150, the peristaltic pump may deliver the condensate through
the peristaltic pump tubing to a liquid trap assembly 150. This delivery may be via
tubing, piping, a direct connection between the components, or any other appropriate
fluid conduit.
[0029] Certain systems of this disclosure provide improved flow. For example,
use of a peristaltic pump 30 can improve the gas extraction process and the
readings from the sample gas obtained. It may ensure that "new" gasses are
delivered to the analyzers. Removing the high-speed gas loop may allow the
product 28 of the condensate separator 22 to be pumped through the peristaltic
pump 30, and the condensate stream 84 can then be routed to the liquid trap
assembly 32 and subsequently removed from the process, as shown by arrow 34.
[0030] For example, the use of a peristaltic pump 30 can also help eliminate
the high speed loop. This can appreciably restore the cooling effect of the vortex
cooler 18. The peristaltic action of slowly pumping the condensate from the
separator 22 can slow the high speed loop. For example, the pump may move fluid
at a rate of about 10-50 cc/min. Slowing the movement of the system flow can allow
removal of the heated condensates 84, such that the heat may not be transferred
back to the vortex cooler 18. It can also increase the efficiency of the system 10 by
minimizing the moisture that may otherwise travel to downstream analyzers.
[0031] Historically, degassing drilling fluids has been atmospherically
balanced (open to the atmosphere) and not conducted in a pressurized system. In
the last few years, drilling companies have been exploring gas extraction in a
pressurized/sealed environment (not open to the atmosphere). This renders use of a
self-sealing pump, such as the disclosed peristaltic pump, more workable in a
pressurized environment. The peristaltic pump 30 described may be self-sealing in
both directions. The peristaltic pump 30 described may be sealed at its inlet due to
pressure of one roller, cam, lobe, or other protrusion of the rotor on the tubing near
the inlet and may be sealed at its outlet due to pressure from a second roller, cam,
lobe, or other protrusion of the rotor on the tubing near the outlet. This renders the
pump self-sealing in both directions.
[0032] Mechanical and electrical components that are used in potentially
explosive atmospheres may be ATEX rated (a directive describing what equipment is
allowed in an environment with an explosive atmosphere and is an acronym for
Appareils destines a etre utilises en Atmospheres Explosives). Because they may be
used in connection with a potentially explosive atmosphere, the components should
be tested and certified. Traditional electric motors of peristaltic pumps have not
been so tested and most ATEX certified electrical drive motors are expensive and
weigh more than desirable. Accordingly, a customized drive mechanism 36 for the
peristaltic pump 30 may be provided.
[0033] The peristaltic pump 30 is not electrically driven, but uses an air motor
38 which takes the place of the electrical device. In one example, the electric pump
may be replaced with an air motor 38 on a peristaltic pump head 42 in the
condensate circuit. One example of an air motor that has been tested and ATEX
certified is manufactured and sold by Gast Manufacturing, Inc. It has been found
that various embodiments according to the present disclosure provide combinations
of the following improvements.
[0034] For example, an improved data quality may be generated from a
hydrocarbon gas extraction and measurement system. Process control may be
improved by using the improved peristaltic pump 30, which can generally be
controllable with regard to volume/rate. For example, there may be an increased
mean time between failures (MTBF) once the peristaltic pump 30 is installed in the
system 10 . For example, there may be quicker and easier maintenance and/or
replacement of the pump. One reason for this is because the peristaltic pump 30
may be a less complex device than the current pump.
[0035] Referring now to FIG. 4, the peristaltic pump 30 may also have a
gearbox 40 between the pump head 42 and the air motor 38 to increase torque, to
change the pump head speed (as compared to the air motor speed), or both. The
gearbox 40 may be secured to the pump head housing 56 via an adapter plate 58.
The gearbox 40 may increase torque, change pump head speed, or both. A sensor
housing 60 may also be provided, which may include a proximity switch sensor that
counts RPM of the peristaltic rotor.
[0036] As shown in FIG. 2, the peristaltic pump 30 has an inlet 44 for receiving
condensate 28 from the condensate separator 22. The pump 30 also has an outlet
46 for delivering condensates 28 to the liquid trap assembly 32. The peristaltic pump
30 may be a positive displacement pump that has a flexible tube 48 fitted between
the inlet 44 and the outlet 46. Fluid and condensates 28 travel from the separator 22
to the pump inlet 44. The fluid/condensate mixture 28 travels through the flexible
tube 48 and exits at the pump outlet 46, for delivery to the fluid trap assembly 32.
[0037] A rotor 50 with two or more protrusions compresses ("occlusion") and
releases ("restitution") the flexible tube 48. The protrusions 52 may be rollers, cams,
lobes, or any other structure capable of occluding and releasing the tube 48. As the
rotor 50 turns, the part of the tube 48 under compression may be pinched closed (or
"occluded") by a protrusion 52. Fluid in the tube in front of the protrusion 52 is
"pushed" through the tube via rotation of the rotor 50 and pressure from the
protrusion 52. As the tube 48 opens to its natural state ("restitution") after the
protrusion 52 passes, the fluid flow may be pressed out the outlet 46. The tube
space behind the protrusion 52 is without fluid, but a new portion of fluid to be moved
is created by a new pinching of the protrusion 52 due to continued movement of the
rotor 50. By providing alternating sections of fluid to be moved and by trapping
portions of fluid to be moved between protrusions 52, the peristaltic pump 30 can
create a slowed and controlled flow of fluid. The pump 30 may run continuously, or it
may be indexed through partial revolutions to deliver smaller amounts of fluid.
[0038] Because the gas extraction system 10 may be intended for use in
extreme conditions of pressure and temperature, and in some instances, offshore,
the tubing 48 may be designed to withstand such conditions. The material may be
chemically compatible with drilling fluids and gasses and not degrade or otherwise
fail. The material may also experience aggressive pressure from the protrusions 52,
so it may be capable of withstanding continued peristaltic rotations and pressure
from the protrusions 52. The material may be able to withstand chemical aspects
due to contact with the drilling fluid, as well as the mechanical aspects due to
continued pressure and contact with the protrusions. Nonetheless, the material may
be compressible such that the rotor protrusions can depress portions of the tubing
and then allow it flex back to shape to move the fluid contained therein.
[0039] In one example, the material used for the pump tubing 48 may be an
expanded polytetrafluoroethylene (PTFE) reinforced tubing, such as that sold by
Gore® STA-PURE® pump tubing. It has been found that this material can withstand
the rigors of the gas extraction system described. In another example, the material
used may be a synthetic fluoropolymer or tetrafluoroethylene (such as Teflon or
Viton®), a fluoro elastomer, or any other material that can withstand the abovedescribed
conditions.
[0040] The material may be provided in any appropriate dimensions that suit
the particular size and capacity of the desired pump. In one particular example, the
tubing may be about ¼" in diameter and about 13" long.
[0041] The system 10 may also include one or more computers or other
controllers 54 that provide a control loop for the peristaltic pump 30. The controller
can set a specific RPM for the pump 30 in order to maintain speed control. The
controller 54 can create a speed control loop that can work with an RPM sensor on
the pump 30 in order to sense and make necessary changes.
[0042] The peristaltic pumping action of the peristaltic pump 30 can thus add
significant improvements to the control and management of condensate 28 removal.
The peristaltic pump 30 designed for this disclosure may be capable of slowed pump
rates. The peristaltic pump 30 designed for this disclosure may be capable of nonshearing
action. The peristaltic pump 30 designed for this disclosure may be
capable of the ability to pump gases, liquids, slurries, and high viscosity fluids. The
peristaltic pump 30 designed for this disclosure may be capable of self-sealing in
both forward and reverse directions, during pumping and/or when stopped. The
peristaltic pump 30 designed for this disclosure may be capable of dosing consistent
and/or measureable volume/rates. The peristaltic pump 30 designed for this
disclosure may have a limited number of moving parts, rendering it a less
complicated design, and providing ease of repair and maintenance. The peristaltic
pump 30 designed for this disclosure may be capable of maintaining the
condensates to be pumped distinct from any exposed pump components.
[0043] In some aspects, a gas extraction system may be provided for
removing condensate from the gas to be analyzed according to one or more of the
following examples.
[0044] Example 1: A gas extraction system for gas analysis that has a
degasser for separating gasses out of drilling fluid; a vortex cooler for removing heat
from separated gasses; a condensate separator for separating cooled gas laden with
condensates; a peristaltic pump for moving condensates to a liquid trap assembly;
and a liquid trap assembly for receiving condensates from the peristaltic pump.
[0045] Example 2 : The gas extraction system of Example 1 can feature the
peristaltic pump having an air motor.
[0046] Example 3 : The gas extraction system of Example 1 can feature the
peristaltic pump having tubing of a material suitable for withstanding drilling fluid
condensates and intermittent occlusion and restitution.
[0047] Example 4 : The gas extraction system of Example 1 can feature the
peristaltic pump including a rotor and at least two protrusions.
[0048] Example 5 : The gas extraction system of Example 1 can feature the
peristaltic pump including an inlet in fluid communication with the condensate
separator and an outlet in fluid communication with the liquid trap assembly.
[0049] Example 6: The gas extraction system of Example 1 can feature the
liquid trap assembly returning condensates to a drilling fluid flow.
[0050] Example 7 : The gas extraction system of Example 1 can feature the
peristaltic pump including an inlet, an outlet, tubing extending between the inlet and
the outlet, and a rotor having at least first and second protrusions, with the pump
being self-sealing due to pressure on the tubing from the first protrusion near the
inlet and pressure on the tubing from the second protrusion near the outlet.
[0051] Example 8: The gas extraction system of Example 1 can feature the
peristaltic pump including a pump rate of about 10-50 cc/min.
[0052] Example 9 : The gas extraction system of Example 1 can feature the
peristaltic pump including a gearbox between a pump head and an motor to increase
torque, change pump head speed, or both.
[0053] Example 10: A gas extraction system that includes a condensate
separator and a liquid trap, the gas extraction system further including a self-sealing
peristaltic condensate pump, comprising a peristaltic pump head and an air motor,
wherein the peristaltic condensate pump delivers condensate received from the
condensate separator to the liquid trap assembly.
[0054] Example 11: The gas extraction system of Example 10 can feature the
peristaltic pump having tubing of a material suitable for withstanding drilling fluid
condensates and intermittent occlusion and restitution.
[0055] Example 12: The gas extraction system of Example 10 can feature the
peristaltic pump including a rotor and at least two protrusions.
[0056] Example 13: The gas extraction system of Example 10 can feature the
peristaltic pump including an inlet in fluid communication with the condensate
separator and an outlet in fluid communication with the liquid trap assembly.
[0057] Example 14: The gas extraction system of Example 10 can feature the
peristaltic pump being self-sealing.
[0058] Example 15: The gas extraction system of Example 10 can feature the
peristaltic pump including a pump rate of about 10-50 cc/min.
[0059] Example 16: The gas extraction system of Example 10 can feature the
peristaltic pump further including a gearbox between a pump head and an motor to
increase torque, change pump head speed, or both.
[0060] Example 17: A method for extracting gas from a fluid using a gas
extraction system can include releasing gasses from the fluid by a degasser;
delivering released gasses from the degasser to a vortex cooler; cooling the
released gasses to provide a cooled sample gas laden with condensate; delivering
the cooled sample gas laden with condensate from the vortex cooler to a condensate
separator; separating sample gas from condensates; delivering sample gas from the
condensate separator to an analyzer; delivering condensate from the condensate
separator to a peristaltic pump; pumping the condensate to a liquid trap assembly.
[0061] Example 18 : The fluid flow of Example 17 can feature the peristaltic
pump including an air motor and tubing of a material suitable for withstanding drilling
fluid condensates and continued intermittent occlusion and restitution.
[0062] Example 19 : The fluid flow of Example 17 can feature the peristaltic
pump including an inlet in fluid communication with the condensate separator and an
outlet in fluid communication with the liquid trap assembly.
[0063] Example 20: The fluid flow of Example 17 can feature the liquid trap
assembly collecting condensates and returning the condensates to a drilling fluid
flow via a return pump.
[0064] The foregoing description, including illustrated aspects and examples,
has been presented only for the purpose of illustration and description and is not
intended to be exhaustive or to limiting to the precise forms disclosed. Numerous
modifications, adaptations, and uses thereof will be apparent to those skilled in the
art without departing from the scope of this disclosure.

Claims
What is claimed is:
1. A gas extraction system for gas analysis, comprising:
a degasser for separating gasses out of drilling fluid;
a vortex cooler for removing heat from separated gasses;
a condensate separator for separating cooled gas laden with condensates;
a peristaltic pump for moving condensates to a liquid trap assembly; and
a liquid trap assembly for receiving condensates from the peristaltic pump.
2 . The gas extraction system of claim 1, wherein the peristaltic pump comprises
an air motor.
3 . The gas extraction system of claim 1, wherein the peristaltic pump comprises
tubing of a material suitable for withstanding drilling fluid condensates and
intermittent occlusion and restitution
4 . The gas extraction system of claim 1, wherein the peristaltic pump comprises
a rotor and at least two protrusions.
5 . The gas extraction system of claim 1, wherein the peristaltic pump comprises
an inlet in fluid communication with the condensate separator and an outlet in fluid
communication with the liquid trap assembly.
6 . The gas extraction system of claim 1, wherein the liquid trap assembly returns
condensates to a drilling fluid flow.
7 . The gas extraction system of claim 1, wherein the peristaltic pump comprises
an inlet, an outlet, tubing extending between the inlet and the outlet, and a rotor
having at least first and second protrusions, and wherein the pump is self-sealing
due to pressure on the tubing from the first protrusion near the inlet and pressure on
the tubing from the second protrusion near the outlet.
8 . The gas extraction system of claim 1, wherein the peristaltic pump provides a
pump rate of about 10-50 cc/min.
9 . The gas extraction system of claim 1, wherein the peristaltic pump further
comprises a gearbox between a pump head and an motor to increase torque,
change pump head speed, or both.
10 . A gas extraction system that includes a condensate separator and a liquid
trap, comprising: a self-sealing peristaltic condensate pump, comprising a peristaltic
pump head and an air motor, wherein the peristaltic condensate pump delivers
condensate received from the condensate separator to the liquid trap assembly.
11. The gas extraction system of claim 10, wherein the peristaltic pump
comprises tubing of a material suitable for withstanding drilling fluid condensates and
intermittent occlusion and restitution.
12 . The gas extraction system of claim 10, wherein the peristaltic pump
comprises a rotor and at least two protrusions.
13 . The gas extraction system of claim 10, wherein the peristaltic pump
comprises an inlet in fluid communication with the condensate separator and an
outlet in fluid communication with the liquid trap assembly.
14. The gas extraction system of claim 10, wherein the peristaltic pump is selfsealing.
15 . The gas extraction system of claim 10, wherein the peristaltic pump provides
a pump rate of about 10-50 cc/min.
16 . The gas extraction system of claim 10, wherein the peristaltic pump further
comprises a gearbox between a pump head and an motor to increase torque,
change pump head speed, or both.
17 . A method for extracting gas from a fluid using a gas extraction system,
comprising:
releasing gasses from the fluid by a degasser;
delivering released gasses from the degasser to a vortex cooler;
cooling the released gasses to provide a cooled sample gas laden with
condensate;
delivering the cooled sample gas laden with condensate from the vortex
cooler to a condensate separator;
separating sample gas from condensates;
delivering sample gas from the condensate separator to an analyzer;
delivering condensate from the condensate separator to a peristaltic pump;
pumping the condensate to a liquid trap assembly.
18 . The fluid flow of claim 17, wherein the peristaltic pump comprises an air motor
and tubing of a material suitable for withstanding drilling fluid condensates and
continued intermittent occlusion and restitution.
19 . The fluid flow of claim 17, wherein the peristaltic pump comprises an inlet in
fluid communication with the condensate separator and an outlet in fluid
communication with the liquid trap assembly.
20. The fluid flow of claim 17, wherein the liquid trap assembly collects
condensates and returns the condensates to a drilling fluid flow via a return pump.