TG-8, Drilling Fluid Materials
(Xanthan WG)
Charge – Develop addendum to current
xanthan gum specifications in API 13A/ISO
13500 that address anomalies observed in
the current test methods used to detect the
presence of starch and guar as diluents in
xanthan gum
SC13 – Drilling Completion and Fracturing Fluids
TG-8, Drilling Fluid Materials
(Xanthan WG)
Members – Mac Seheult, Kelco Oil Field Group
Tim Wilkin, MiSwaco
Don Kraus, Baker Hughes Drilling Fluids
Shannon Sobkowiak, Baroid Halliburton
Luis Del Valle, Cargill
Mike Azizi, WEGO/Fufeng
Don Lindblad, Jungbunzlauer
Carl Stouffer, Drilling Specialties
David Breeden, Newpark
SC13 – Drilling Completion and Fracturing Fluids
TG-8, Drilling Fluid Materials
(Xanthan WG)
Last Meeting – Teleconference on 12/9/10
> Presented an overview of charge and opened floor for discussion of current position
> Slides presented to re-visit impact of guar contamination and point at which presence of
guar as a diluent was readily detectable using test method in 13A
> Reviewed script for the starch contamination addendum as proposed by Tim Wilkin; all
members in attendance agreed to proposal as written
> It was concluded that a script similar in content to that of the starch addendum would be
drafted by the Task Group Chair and forwarded for approval
SC13 – Drilling Completion and Fracturing Fluids
TG-8, Drilling Fluid Materials
(Xanthan WG)
(Xanthan Addendum Wording – Starch Test Anomaly)
Referring to 19.2.6.2, 19.2.6.3, and 19.2.6.4, it has been determined by
consultation with xanthan gum manufacturers that different carbon sources
may be used in the manufacture of xanthan gum, including but not limited to
dextrose, glucose, fructose, unmodified dent corn starch, unmodified waxy
corn starch, unmodified tapioca starch, and unmodified potato starch. Other
starch sources are also used, but may be less common.
Some of the above referenced carbon sources may result in the color
changes listed in these clauses without the xanthan gum tested having been
intentionally adulterated with starch type carbon sources.
The manufacturing process for xanthan gum, if not carried to completion
may result in a product that contains residual unreacted starch or starch
derivatives that may result in a color change by this procedure.
SC13 – Drilling Completion and Fracturing Fluids
TG-8, Drilling Fluid Materials
(Xanthan WG)
(Xanthan Addendum Wording)
Conversely, some carbon sources for example maltodextrins may not result
in color changes when tested by the procedure listed in the clauses
referenced above.
The user and manufacturer should discuss the starting raw material source
for xanthan manufacture to determine if color changes in this test might be
influenced by the manufacturing process.
It may be useful for the user and manufacturer to test xanthan gum
production to determine the influence of carbon source and its
concentration in the finished product on color changes observed in this
series of clauses. An example of a test useful in determining the potential
influence of a carbon source on this test procedure would be development of
a concentration curve of carbon source versus color intensity generated by
the procedure in clause 19.2.5. A dark blue-black coloration would indicate a
xanthan intentionally adulterated with starch.
SC13 – Drilling Completion and Fracturing Fluids
TG-8, Drilling Fluid Materials
(Xanthan WG)
(Xanthan Addendum Wording)
Refer to Clause 19.1.1 for advice on intended product composition. The
material described in this Section is intended to be solely xanthan gum with
no adulterants added.
SC13 – Drilling Completion and Fracturing Fluids
TG-8, Drilling Fluid Materials
(Xanthan WG)
(Xanthan Addendum Wording)
Guar Detection Test Anomaly
Adulteration of Xanthan Gum with Guar Gum or Guar Derivatives
Referring to 19.3.7 and 19.3.8, it has been determined by consultation with xanthan gum manufacturers that
small increases in viscosity observed in the test described in these sections cannot be attributed to
adultration of xanthan gum with guar gum or guar derivatives CMG, CMHPG and HP G, etc.), but may be
an artifact of the testing regimen. Small increases in viscosity do not necessarily mean that the xanthan
gum in question has been adulterated.
It may be useful for the user and manufacturer to test xanthan gum production to determine the influence of
guar gum additions on xanthan gum viscosity. An example of a test useful in determining the potential
influence of adulteration on this test procedure would be development of data generated by the
procedure in clause 19.3.7 with increasing amounts of guar gum added to a xanthan gum solution. Large
increases in viscosity are indicative of adulteration.
•
Refer to Clause 19.1.1 for advice on intended product composition. The material described in this
Section is intended to be solely xanthan gum with no adulterants added.
SC13 – Drilling Completion and Fracturing Fluids