Garrett Gas Train Test

 Garrett Gas Train Test

Measures the concentration of soluble sulfides and soluble carbonates
The Garrett Gas Train (GGT) measures the concentration of sulfides or carbonates in drilling fluids and drilling fluid filtrates. This measurement gives a quantitative indication of the rate and amount of intrusion of hydrogen sulfide or carbon dioxide from the formation in the drilling fluid.
The Garrett Gas Train kit contains all hardware and reagents required to conduct the procedure according to API Recommended Practice 13B-1, ANSI/API 13B-1/ISO 10414-1. Two types of Dräeger tubes are supplied to adequately span the range of hydrogen sulfide concentrations that may be found in water based drilling fluid filtrates and in oil based drilling fluids. CO2 Dräeger tubes and 1 liter gas bags are supplied for determination of carbonate concentration. Inert carrier gases, both  CO2 and NO2 are supplied for all tests. All items are securely packaged in a waterproof, high-impact plastic carrying case.
Hydrogen Sulfide Test Paper discs (supplied) can be used in the Garrett Gas Train to give a qualitative indication of the presence of sulfide. If the presence of sulfide is indicated by darkening of the paper disc, a Dräeger tube should be used for quantitative analysis.

Sulfides
Soluble sulfides include H2S and the sulfide (S2-) and bisulfide (HS-) ions. Drilling fluid filtrate is acidifiedin a Garrett Gas Train, converting all sulfides to H2S which is evolved by bubbling an inert carrier gas through the sample. The gas train separates the gas from the liquid. The gas stream is passed through a Dräeger tube which responds to H2S by darkening along its length. The darkened length is proportional to the total sulfide in the drilling fluid filtrate. The low-range Dräeger tube, H2S 100/a, (0-120 ppm) turns from white to brownish-black. The high-range Dräeger tube, H2S 0.2%/A, (60-4080 ppm) turns from pale blue to jet-black.

Carbonates
Total soluble carbonates include CO2 and the carbonate (CO32-) and bicarbonate (HCO3-) ions. Drilling fluid filtrate is acidified in a Garrett Gas Train, converting all carbonates to CO2, which is then evolved by bubbling an inert carrier gas through the sample. The gas train separates the gas from the liquid. The gas stream is collected in a 1 liter gas bag (to allow CO2 to mix uniformly) and subsequently drawn through a Dräeger tube at a fixed flow rate. The Dräeger tube responds to CO2 by progressively staining purple along its length. A reaction between CO2 and a hydrazine chemical causes a crystal violet indicator to turn purple. The stain length is proportional to the total carbonate concentration in the filtrate. 
1. Introduction
Garrett Gas Train Kit contains the essential equipment and reagents for measuring sulfides and carbonates by the Garrett Gas Train method. This procedure follows API Recommended Practices.
This kit includes the following:
Garrett Gas Train
Draeger Tubes (H2S & CO2)
CO2 Cartridges
Reagents
Pressure Regulator
Hydrogen sulfide (H2S) and carbon dioxide (CO2) are undesirable gases that can be detected and quantitatively measured using the Garrett Gas Train method.
The Garrett Gas Train has three chambers. Sample is added to the first chamber where it is mixed with acid. An inert carrier gas carries hydrogen sulfide or carbon dioxide that is released through the chambers.

Advantages
Reliable, quantitative results
Proven method that complies with API Recommended Practices
Wide measurement ranges for sulfide and carbonate
Portable kit packaged in durable plastic carrying case
2. Type Specification
3. Technical Specification