OFITE, 11302 Steeplecrest Dr., Houston, TX 77065 USA / Tel: 832-320-7300 / Fax: 713-880-9886 / www.ofite.com
2
The Garrett Gas Train is the most widely used portable instrument for deter-
mining the presence and quantity of soluble sulfides and carbonate concen
-
trations in drilling fluid. Soluble sulfides include H
2
S as well as sulfide (S
-2
)
and bisulfide (HS
-
) ions. Total soluble carbonates include CO
2
as well as
carbonate (CO
3
-2
) and bicarbonate (HCO
3
-
) ions.
Mud filtrate is acidified inside the gas train, converting all sulfides to H
2
S or
all carbonates to CO
2
, 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 H
2
S or CO
2
by darkening along its length.
The stain length is proportional to the amounts of sulfides or carbonates in
the filtrate. For qualitative H
2
S analysis, lead acetate paper disks may be
inserted to determine the presence or absence of sulfides.
The OFITE Garrett Gas Train consists of a transparent train, pressure regula
-
tor assembly, CO
2
and N
2
O cartridges (sold separately), Dräger tubes for H
2
S
and carbonate detection, a flowmeter, and a convenient carrying case. For
determining active sulfides in oil-based fluids, 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 H
2
S or sulfide salts, citric acid, demulsifier
and isopropanol for the sulfide analysis. CO
2
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 cm
3
/min. carrier gas.
Syringes and injection tubes must be glass or a plastic type that is inert to
sulfides and oil muds.
Introduction
Specifications
