OfiTE 151-00 User manual

Garrett Gas Train
Part No. 151-00
Instruction Manual
Updated 2/18/2020
Ver. 5
OFI Testing Equipment, Inc.
11302 Steeplecrest Dr. · Houston, Texas · 77065 · U.S.A.
Tele: 832.320.7300 · Fax: [phone] · www.ote.com
©Copyright OFITE 2013

OFITE, 11302 Steeplecrest Dr., Houston, TX 77065 USA / Tel: [phone] / Fax: [phone] / www.ote.com 1
Introduction.....................................................................................2
Specications .................................................................................2
Components ...................................................................................3
Safety...............................................................................................5
Setup................................................................................................6
Sulde Testing ................................................................................8
Procedure ...................................................................................9
Calculation ................................................................................ 11
Carbonates Testing ......................................................................12
Procedure ................................................................................13
Calculation ................................................................................16
Oil-Based Fluids ...........................................................................17
Procedure .................................................................................18
Calculation ................................................................................20
Maintenance..................................................................................21
Diagram .........................................................................................22
Warranty and Return Policy ........................................................23
Table of
Contents

OFITE, 11302 Steeplecrest Dr., Houston, TX 77065 USA / Tel: [phone] / Fax: [phone] / www.ote.com 2
The Garrett Gas Train is the most widely used portable instrument for deter-
mining the presence and quantity of soluble suldes and carbonate concen-
trations in drilling uid. Soluble suldes include H2S as well as sulde (S-2)
and bisulde (HS-) ions. Total soluble carbonates include CO2as well as
carbonate (CO3
-2) and bicarbonate (HCO3 -) ions.
Mud ltrate is acidied inside the gas train, converting all suldes to H2S or
all carbonates to CO2, depending upon the test. The gas train separates the
gas from the liquid and an inert carrier gas transports the gasses through
the separate chambers. In chamber three, the gas stream is passed through
a Dräger tube, which responds to H2S or CO2 by darkening along its length.
The stain length is proportional to the amounts of suldes or carbonates in
the ltrate. For qualitative H2S analysis, lead acetate paper disks may be
inserted to determine the presence or absence of suldes.
The OFITE Garrett Gas Train consists of a transparent train, pressure regula-
tor assembly, CO2and N2O cartridges (sold separately), Dräger tubes for H2S
and carbonate detection, a owmeter, and a convenient carrying case. For
determining active suldes in oil-based uids, OFITE offers a separate kit that
analyzes whole mud samples.
Body Dimensions:
Chamber 1: Depth 3.54" (90 mm) × Diameter 1.52" (39 mm)
Chambers 2 & 3: Depth 3.54" (90 mm) × Diameter 1.18" (30 mm)
Passages between chambers: Diameter 0.08" (2.0 mm)
Dispersion tube:
Stem: Diameter 0.315" (8.0 mm) × Length 5.9" (150 mm)
Frit Diameter: 1.18" (30 mm)
Carrier gas should be inactive with H2S or sulde salts, citric acid, demulsier
and isopropanol for the sulde analysis. CO2 bulbs are preferred, but nitrogen
gas or helium will work. Nitrous oxide bulbs are to be used only for the car-
bonate analysis. Avoid using compressed air or oxidative gases.
Flowmeter: Floating ball type is preferred, capable of measuring between 200
and 400 cm3/min. carrier gas.
Syringes and injection tubes must be glass or a plastic type that is inert to
suldes and oil muds.
Introduction
Specications

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Components #142-58 O-ring for HTHP Coupling
#143-00 Regulator
#143-02-10 CO2 Puncture Head Assembly
#143-02-13 O-ring for Puncture Pin Holder Assembly, CO2Cartridge
#143-02-14 O-ring for Puncture Pin Holder Assembly
#143-03 Barrel for CO2Cartridge
#145-601 Hydrogen Sulde Test Papers, Package of 100
#151-01 Dispersion Tube
#151-02 Dräger Tube, Hydrogen Sulde 100/1, Range: 100 - 2,000 PPM
(Low Range)
#151-03 Dräger Tube, Hydrogen Sulde 0.2%/A, Range: 0.2 - 7% by Vol-
ume (High Range)
#151-04 Dräger Tube, Carbon Dioxide 0.01%/A, Range: 0.01 - 0.3% by
Volume
#151-06 Gas Bag
#151-07 Stopcock
#151-08 API Flow Meter Tube
#151-09 Dräger Hand Pump
#151-10 O-ring for Dräger Pump
#151-11 O-ring for Flow Meter Tube
#151-12 O-ring for 2nd and 3rd Chambers
#151-13 O-ring for 1st Chamber
#151-14 Rubber Hose, ¼" OD ×   " ID, 1' Length
#151-14-1 Nylon Tube, 3" Length
#151-16 Rubber Septum, Qty: 2
#151-17 Octyl Alcohol (Defoamer), 2 oz.
#151-53 Carrying Case
#153-34 Glass Pipet, 1 mL ×    mL
#153-40 Glass Pipet, 10 mL ×   mL
#153-63 10 cc Disposable Syringe with Needle
#230-15 *Sulfuric Acid, 5 N, 2 oz., (UN #2796)
Optional:
#153-53-9 Magnetic Stirrer, 1,500 RPM, 115 Barnant (for oil-mud analysis)
#151-20 Kit for Determining Active Suldes in Oil-Based Fluids:
#151-17 Octyl Alcohol Defoamer, 2 oz.
#151-20-1 *Citric Acid, 2M, Demulsier, IPA Solution, UN #1219, 16 oz
#151-20-2 Sample Injection Needle
#153-29 Glass-Tip Syringe, 2 CC
#153-29-1 Glass-Tip Syringe, 5 CC
#153-29-2 Glass-Tip Syringe, 10 CC
#153-66 Disposable Syringe, 20CC

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#151-00-SP Spare Parts Kit QTY
#142-58 O-ring for HTHP Coupling, 4
#143-00-1 Diaphragm for Airco Regulator 1
#143-02-13 O-ring for Puncture Pin Holder Assembly, CO2Car-
tridge
4
#143-02-14 O-ring for Puncture Pin Holder Assembly 4
#143-05 EZ-Puncture CO2 Bulbs, 8-Gram, UN #1013, Package
of 10
10
#143-07 Regulator Repair Kit 1
#143-08 EZ-Puncture N2O Bulbs, 8-Gram, UN #1070 5
#145-601 Hydrogen Sulde Test Papers, Package of 100 2
#151-01 Dispersion Tube 1
#151-02 Dräger Tube, Hydrogen Sulde 100/1, Range: 100 -
2,000 PPM
2
#151-03 Dräger Tube, Hydrogen Sulde 0.2%/A, Range: 0.2 -
7% by Volume
2
#151-04 Dräger Tube, Carbon Dioxide 0.01%/A, Range: 0.01 -
0.3% by Volume
2
#151-06 Gas Bag 5
#151-07 Stopcock 1
#151-10 O-ring for Dräger Pump 2
#151-12 O-ring for 2nd and 3rd Chambers 6
#151-13 O-ring for 1st Chamber 3
#151-14 Rubber Hose, ¼" OD ×   " ID, 1' Length 4
#151-15 Nylon Fitting for Filter Flow Tube 2
#151-16 Rubber Septum 12
#151-17 Octyl Alcohol (Defoamer), 2 oz. 2
#153-34 Glass Pipet, 1 mL ×    mL 4
#153-40 Glass Pipet, 10 mL ×   mL 2
#153-63 10 cc Disposable Syringe with Needle 12
#230-13 *Sulfuric Acid, 5N, UN #2796, 8 oz 2

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Safety The Garrett Gas Train is designed to test drilling uids for soluble suldes,
including hydrogen sulde (H2S). Hydrogen sulde is highly toxic and am-
mable. It smells like rotten eggs, but quickly deadens the sense of smell. You
may not be aware of the danger until it is too late.
When performing sulde testing with the Garrett Gas Train, use extreme
caution to avoid breathing any hydrogen sulde. Use appropriate personal
protection equipment at all times.
Nitrous oxide cartridges should not be used as pressure sources when run-
ning a standard H2S test. Under elevated pressures, nitrous oxide can pos-
sibly detonate in the presence of grease, ,oil or carbonaceous materials.
Nitrous oxide cartridges are to be used only for the Garrett Gas Train carbon-
ate analysis.
Carbon dioxide and nitrous oxide cartridges are pressurized to approximately
900 psi at 1 atmosphere (sea level). Therefore they should not be placed in
airplanes without proper packaging due to the possibility of the cabin depres-
surization. Nor should they be exposed to direct sunlight for prolonged peri-
ods of time.
Hydrogen sulde is extremely corrosive, so it is important to check all elas-
tomers (o-rings, rubber hoses, etc.) prior to running a test. Special attention
should be given to the elastomers that seal each of the three chambers as
these may easily be pinched or cut during assembly. Over time the elasto-
mers may become hard and brittle, which will require replacement.
The Garrett Gas Train test requires only a very small amount of pressuriza-
tion to move the gas between the three chambers. When turning the T-screw
on the regulator to initiate pressurization, turn it very slowly as it is easy to
overpressurize, resulting in hoses or the rubber septum explosively separat-
ing from their connections.
When inserting the Dräger Tube into the hole next to chamber three, be very
careful to push downward and vertically, as it will be a tight t due to the o-
ring seal. If inserting at an angle it is possible to break the glass Dräger Tube
resulting in injury to the hand or arm.
Dräger Tubes have a shelf life so pay attention to the date stamped on the
box. Expired Dräger Tubes can give incorrect results.

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Setup 1. Be sure the gas train is clean and dry. Moisture in the train can cause the
owmeter to oat erratically and may affect the accuracy of the Dräger
tube reading.
2. Place the gas train on a level surface. Remove the top.
3. Add 20 mL of deionized water and 5 drops of octyl defoamer to chamber
1.
4. Place the owmeter tube into the designated hole between chambers 2
and 3. Make sure the word “Top” or “T” on the tube is pointing upward and
that the o-ring seals around the tube.
5. Place the dispersion tube into chamber 1. Place an o-ring into the hole
in the lid above chamber 1. Screw the nylon tube holder into the lid just
enough to hold the o-ring in place. Carefully place the lid onto the body,
making sure the dispersion tube goes into the hole above chamber 1.
When the lid is in place, tighten the nylon tube holder. Leave about ¼"
empty space below the bottom of the dispersion tube. Make sure the o-
ring seals around the tube.
6. Evenly hand-tighten all screws to seal the o-rings.
CO2 Barrel (143-03) Sample Entry Point
Rubber Hose (#151-14)
Flowmeter
Dräger Tube Hole
Regulator T-screw
Dispersion Tube
(#151-01)
Chamber 1 Chamber 2 Chamber 3
Nylon Tube Holder
(#151-15)
Thumb Screw
(#151-05)

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7. Unscrew (counter-clockwise) the regulator T-screw completely. Remove
the cartridge holder and place a new cartridge inside. Tighten the car-
tridge holder until the cartridge inside is punctured.
For sulde analysis, use CO2 gas. For carbonate analysis, use N2O gas.
8. Connect the regulator to the dispersion tube with one of the provided rubber
hoses. Connect the other rubber hose to the nylon tting on chamber 3.
9. Gently ow gas through the system for 30 seconds by tightening the regu-
lator T-screw. This will purge any remaining air from the system. Check
for leaks, then shut off the ow of gas.
Dispersion Tube
(#151-01)

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Sulde
Testing
The concentration of soluble suldes, including hydrogen sulde (H2S),
sulde (S-2), and (HS-) ions may be determined with the Garrett Gas Train.
Mud ltrate is acidied in the gas train, which converts all of the suldes to
H2S. The H2S is then evolved by bubbling an inert carrier gas, usually carbon
dioxide (CO2), through the sample. The gas train separates the gas from the
liquid. The gas stream is then passed through a Dräger tube which responds
to H2S by darkening along its length. The length of the darkened strip is
proportional to the total suldes in the mud ltrate. The low range Dräger tube
turns from white to brownish-black and the high range tube turns from pale
blue to jet black. No common drilling uid contaminant will cause these color
changes. Lead acetate paper disks may be used qualitatively to determine
the presence or absence of suldes. If the presence of sulde is indicated by
a darkening of the lead acetate paper, a Dräger tube may then be used for
quantitative analysis.

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Sulde
Testing
Procedure
1. Using the table below, determine the sample volume and type of Dräger
tube required for your test.
Sulde Range
(mg/L)
Sample Volume
(mL)
Dräger Tube
Identication
Tube Factor (Used
in Equation)
1.2 to 24 10.0 H2S 100/a .12
2.4 to 48 5.0 H2S 100/a .12
4.8 to 96 2.5 H2S 100/a .12
60 to 1,020 10.0 H2S 0.2%/A 1500
120 to 2,040 5.0 H2S 0.2%/A 1500
240 to 4,080 2.5 H2S 0.2%/A 1500
2. Break the tip from each end of the Dräger tube and place it in the desig-
nated hole next to chamber 3. Make sure the arrow on the tube is pointing
downward and that the o-ring seals around the tube.
3. Connect the rubber hose from chamber 3 to the Dräger tube.
4. With a lter press, collect a sufcient volume of solids free ltrate for
analysis. If a low concentration of soluble suldes is to be detected, a
large volume of ltrate will be required. Use the table above as a guide.
During the sampling, ltration, and preparation process, the sample
should not be exposed to air for an extended period of time. Suldes
can be lost rapidly due to air oxidation.
5. Fill the syringe with the measured amount of solid-free ltrate. Place a
rubber septum over the sample entry point above chamber 1. Force the
needle through the septum and inject the ltrate into chamber 1.
6. Slowly inject 10 mL of 5N sulfuric acid solution into chamber 1 through the
rubber septum using the syringe and needle.
7. Immediately start the CO2 gas ow. Adjust the rate such that the ball in
the owmeter stays between the two lines. One CO2 bulb should provide
about 15 to 20 minutes of ow at this rate.

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8. Watch for changes in the appearance of the Dräger tube. Before the
front starts to smear, note and record the maximum darkened length in
units marked on the tube. Continue owing for a total of 15 minutes, even
though the front may attain a diffuse and feathery coloration. In the high
range tube, an orange color caused by SO2may appear ahead of the
black front if sultes are present in the sample. The orange SO2region
should be ignored when recording the darkened length. For more ac-
curate results, the darkened length should ll more than half of the tubes
total length. Therefore, the ltrate sample volume must be carefully se-
lected.
9. A lead acetate paper disk tted under the o-ring in chamber 3 may be
substituted for the Dräger tube in the gas train. The lead acetate paper
will show qualitatively the presence or absence of suldes in the sample.
A dark discoloration of the paper is a positive indication of suldes. After a
positive indication, the Dräger tube should be used on a separate sample
for quantitative analysis.

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Sulde
Testing
Calculation
Using the measured sample volume, the Dräger tube's maximum darkened
length and the Dräger tube factor from the table, calculate the suldes in the
sample.
Sulde (mg/L) = (Darkened tube length) × (Tube Factor)
Sample Volume (mL)

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Carbonates
Testing
The concentration of soluble carbonates in a drilling uid ltrate can be de-
termined using the Garrett Gas Train. Total soluble carbonates include CO2
as well as the carbonate (CO3
-2) and bicarbonate (HCO3 -) ions. Mud ltrate
is acidied in the gas train, converting all carbonates to CO2, which is then
evolved by bubbling nitrous oxide gas through the sample. The gas train sep-
arates the gas from the liquid which is collected in a 1-liter gas bag to allow
the CO2 to mix uniformly, and is subsequently drawn through a Dräger tube at
a xed ow rate. The Dräger tube will respond to CO2 by progressively stain-
ing purple along its length. A reaction between CO2and a hydrazine chemical
causes a crystal violet indicator to turn purple. The stain length is proportional
to the total carbonate concentration in the ltrate.

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Carbonate
Testing
Procedure
1. Check the gas bag for leaks. To do this, collapse the bag and then con-
nect the bag and stopcock to the hand pump, using a discarded Dräger
tube as the connection. Fully depress and release the hand pump. When
the bag is completely empty and free of leaks, the pump will remain de-
pressed for several minutes. If a leak is detected, check the pump and all
connections. To check the pump alone, insert a sealed Dräger tube into
the pump opening and depress the bellows. It will remain depressed if the
pump does not leak.
2. With the bag now fully collapsed, close the stopcock and connect the rub-
ber tubing from chamber 3 to the closed stopcock.
Sample Entry Point
Gas Bag (#151-06) Stopcock (#151-07)
3. Using the table below, determine the sample volume and type of Dräger
tube required for your test.
Sulde Range
(mg/L)
Sample Volume
(mL)
Dräger Tube
Identication
Tube Factor (Used
in Equation)
25 to 750 10.0 CO2100/a 2.5
50 to 1,500 5.0 CO2100/a 2.5
100 to 3,000 2.5 CO2100/a 2.5
250 to 7,500 10.0 CO2100/a 2.5
4. Fill the syringe with the measured amount of solid-free ltrate. Place a
rubber septum over the sample entry point above chamber 1. Force the
needle through the septum and inject the ltrate into chamber 1.

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5. Slowly inject 10 mL of 5N sulfuric acid solution into chamber 1 through the
rubber septum using the hypodermic syringe and needle.
Over-ll the syringe by at least 0.5 mL so an exact amount may be injected.
6. Loosen the nylon tube holder and lower the dispersion tube to about ¼"
from the bottom of the chamber.
7. Open the stopcock on the gas bag. Restart the ow of N2O by tighten-
ing the regulator T-screw. Allow the gas bag to ll slowly and steadily for
ten minutes. When the bag is rm to the touch, shut off the ow of gas by
unscrewing the regulator T-screw. Close the stopcock to seal off the bag.
8. Immediately break the tip off each end of the Dräger tube. Remove the
rubber hose from the chamber 3 connection and connect the end of the
hose to the upstream end of the Dräger tube. An arrow on the Dräger
tube indicates the gas ow direction. Connect the hand pump to the other
end of the Dräger tube. The arrow on the Dräger tube should point from
the bag toward the hand pump.
9. Open the stopcock on the gas bag. With steady hand pressure, fully de-
press the hand pump. Release the pump so that gas ows out of the bag
and through the Dräger tube. Operate the pump and count the strokes
required to empty the bag. If it takes more than ten strokes to empty the
bag there is probably a leak in the system and the test will be invalidated.
Gas Bag (#151-06)
Stopcock (#151-07)
Dräger Hand Pump (#151-09)
Dräger Tube (#151-04)

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10. If CO2 is present in the gas bag, the Dräger tube will turn purple. Record
the stain length in units marked on the Dräger tube and include any faint
blue tinge color that may develop as part of the total stain reading. For
more accurate results, the darkened length should ll more than half of
the total length of the tube. Therefore, the ltrate sample volume must be
carefully selected.

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Carbonate
Testing
Calculation
Calculation:
Using the measured sample volume, the Dräger tube stain length, and the
tube factor of 2.5 (from the table on page 13) calculate the total soluble
carbonates (CO2+ CO3
-2 + HCO3 –) in the ltrate sample using the follow-
ing equation:
Carbonate (mg/L) = 2.5 (Darkened Stain Length)
Sample Volume (mL)

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Oil-Based
Fluids
Whole oil mud (not ltrate) should be analyzed in order to capture all of the
“active suldes”. Oil muds consisting of liquid and solid phases contain the
“active suldes” and are typically the neutralization products of hydrogen sul-
de (H2S) and lime plus any unreacted H2S. By using a 2M citric acid which
is a weak acid, inert suldes (such as solid ZnS, CuS, or PbS) are not mea-
sured and only active suldes are analyzed.
Sample Injection Tube

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Oil-Based
Fluids
Procedure
1. Place the stirring bar from the magnetic stirrer into chamber 1.
2. Assemble the gas train apparatus for normal sulde testing (see pages
6 and 7 for instructions).
3. Place the gas train apparatus on top of the magnetic stirrer.
4. Using the table below, determine the sample volume and type of Dräger
tube required for your test.
5. Break the tip from each end of the Dräger tube and place it in the desig-
nated hole next to chamber 3. Make sure the arrow on the tube is pointing
downward and that the o-ring seals around the tube.
6. Insert the sample injection tube through the rubber septum on top of
chamber 1, being sure that it seals in the septum.
7. Add 20 mL of the 2M Citric acid, demulsier, and isopropanol mixture
(#151-20-1) into chamber no. 1.
8. Add 10 drops of octyl defoamer to chamber 1.
9. Operate the magnetic stirrer at a moderate speed. Carefully lower the
dispersion tube into the circulating liquid to a point just above the rotating
stirring bar.
10. With a syringe, slowly inject the correct sample volume of oil mud allowing
it to mix into the vortex from the stirring bar. Stir for at least 2 minutes.
Over-ll the syringe by at least 0.5 mL so an exact amount can be injected.
11. Immediately start the CO2 gas ow. Adjust the rate such that the ball in
the owmeter stays between the two lines. One CO2 bulb should provide
about 15 to 20 minutes of ow at this rate.
Sulde Range
(mg/L)
Sample Volume
(mL)
Dräger Tube
Identication
Tube Factor (Used
in Equation)
1.2 to 24 10.0 H2S 100/a .12
2.4 to 48 5.0 H2S 100/a .12
4.8 to 96 2.5 H2S 100/a .12
60 to 1,020 10.0 H2S 0.2%/A 1500
120 to 2,040 5.0 H2S 0.2%/A 1500
240 to 4,080 2.5 H2S 0.2%/A 1500

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12. Watch for changes in the appearance of the Dräger tube. Before the
front starts to smear, note and record the maximum darkened length in
units marked on the tube. Continue owing for a total of 15 minutes, even
though the front may attain a diffuse and feathery coloration. In the high
range tube, an orange color caused by SO2may appear ahead of the
black front if sultes are present in the sample. The orange SO2region
should be ignored when recording the darkened length. For more ac-
curate results, the darkened length should ll more than half of the tubes
total length. Therefore, the ltrate sample volume must be carefully se-
lected.