Drilling
Gilsonite – Fluid Loss Control (FLC)
by Bitumexport; http://bitumexport.weebly.com
What Is Gilsonite: Gilsonite is mined in underground shafts and resembles
shiny, black substance similar in appearance as the mineral Obsidian It is
brittle and usually micronized into dark brown powder. It is mainly composed of
asphaltenes; thus, Gilsonite Is classified as a Natural Asphalt and also known
as uintaite or uintahite. Discovered in the 1860s, it was first marketed as a
lacquer, electrical insulator, and waterproofing compound. This unique mineral
is used in more than 160 products, primarily in dark-colored printing inks and
paints, oil well drilling muds and cements, asphalt modifiers, foundry sand
additives, and a wide variety of chemical products.
What are Asphaltenes: Asphaltenes are molecular substances that are found in
crude oil, along with resins, aromatic hydrocarbons, and alkanes (i.e.,
saturated hydrocarbons). The word "asphaltene" was coined by
Boussingault in 1837 when he noticed that the distillation residue of some
bitumen had asphalt like properties. Asphaltenes in the form of distillation
products from oil refineries are used as "tar-mats" on roads.
Asphaltenes consist primarily of carbon, hydrogen, nitrogen, oxygen, and
sulfur, as well as trace amounts of vanadium and nickel. The C:H ratio is
approximately 1:1.2, depending on the asphaltene source. Asphaltenes are
defined operationally as the n-heptane (C7H16)-insoluble, toluene (C6H5CH3)-
soluble component of a carbonaceous material such as crude oil, bitumen or
coal. Asphaltenes have been shown to have a distribution of molecular masses in
the range of 400 u to 1500 u with a maximum around 750 u.
Gilsonite use in Drilling sector: Gilsonite is used in drilling mud
fluids and oil well cementing. Gilsonite, in a range of softening points and
particle sizes, is a standard ingredient in oil-based drilling muds used in
shale and other difficult geological formations. The addition of
specially-treated Gilsonite to water-based drilling fluids helps minimize hole
washout by stabilizing troublesome shale, and seals off highly permeable sands
while reducing torque and drag. The addition of Gilsonite to oil well cements
reduces slurry weight without loss of compressive strength and acts as an
effective bridging and plugging agent to seal fractures in weak formations
while cementing The maintenance of circulation of the drilling fluid is
essential to successful drilling by the rotary method. The drilling fluid or
mud is supplied at the surface of the well in large earthen pits or metal tanks
and is pumped from these into the bore hole through the drill pipe and the
drill bit to the bottom of the hole. The mud returns to the surface between the
drill pipe and the bore hole wall, bringing with it the drill cuttings. The
circulation of the mud serves not only to carry the cuttings to the surface but
also to cool and lubricate the drill bit, thus making possible the further
effective penetration of the bit into deeper geological strata. In conventional
drilling operation a drilling mud based on bentonite or other materials such
cane fiber, ground walnut hulls, sawdust etc. is commonly used, but The solid
organic materials used are difficult to keep suspended in the drilling fluid,
being of a higher specific gravity than the fluid, while materials such as
expanded perlite, though easily to suspend, become compressed to a specific
gravity higher than that of the fluid under the bore hole. Furthermore, the
commonly used materials lack adhesive power and are insoluble, and they have
been known to become lodged in the wall of the bore hole so as to obstruct or
seal off a producing oil or gas zone, thus causing a costly or even a complete
loss of production. To prevent Lost Circulation is needed a material with
following specifications:
·
Incompressible
material
·
Specific
gravity lower than the fluid
·
Solubility
·
Adhesive
power
All the common varieties of Gilsonite
are substantially incompressible and have a specific gravity sufficiently near
to that of water that properly sized granules of the Gilsonite can be readily
suspended in aqueous liquid carrier. Thus, Gilsonite is used for this purpose
in powder. Particle size (mesh) is variable according to the characteristic of
the well bore. Softening point is very important as Gilsonite must soften at a
temperature above the temperature of well formation. The first patent, dated
1954, indicated the use of a Gilsonite with softening point from 150 to 180°C
and mesh from 4 to 100.Actually, with more technological devices, the most
commonly used is 200/200 (softening point/mesh) type; by the way, Groupeve can
supply Gilsonite in a range of 40/400 mesh and 140/230°C softening point.
Drilling
Gilsonite Data Sheet
1.
Product description
Gilsonite
is mined in underground shafts and resembles shiny, black substance similar in
appearance as the mineral Obsidian. It is brittle and usually micronized into
dark brown powder. It is mainly composed of asphaltenes; thus, Gilsonite Is
classified as a Natural Asphalt.
2.
Application and usage
Gilsonite is
used in drilling mud fluids and oil well cementing. Gilsonite, in a range of
softening points and particle sizes, is a standard ingredient in oil-based
drilling muds used in shale and other difficult geological formations. The
addition of specially-treated Gilsonite to water-based drilling fluids helps
minimize hole washout by stabilizing troublesome shale, and seals off highly
permeable sands while reducing torque and drag. Gilsonite is normally used in a
range of 40/400 mesh and 160/230°C softening point.
3.
Technical data
GRADE B
|
|||
No.
|
Test
|
Result
|
Method
|
1
|
Ash Content, wt%
|
9-14
|
ASTM-D174
|
2
|
Moisture Content, wt%
|
<1
|
ASTM-D173
|
3
|
Volatile Matter, wt%
|
63
|
ASTM-D175
|
4
|
Fixed Carbon, wt%
|
29
|
ASTM-D172
|
5
|
Solubility in CS2,wt%
|
89
|
ASTM-D4
|
6
|
Specific Gravity @ 25 Cº
|
1,11
|
ASTM-D3289
|
7
|
Color in mass
|
Black
|
-
|
8
|
Softening Point, Cº
|
220
|
ASTM-D36
|
9
|
Flash Point
|
>420
|
Cleveland O.C.
|
10
|
Penetration @ 25 Cº
|
0
|
ASTM-D5
|
11
|
Particle Size (mesh)
|
200
|
Tyler
|
GRADE A
|
|||
No.
|
Test
|
Result
|
Method
|
1
|
Ash Content, wt%
|
8-10,8
|
ASTM-D174
|
2
|
Moisture Content, wt%
|
<1
|
ASTM-D173
|
3
|
Volatile Matter, wt%
|
69
|
ASTM-D175
|
4
|
Fixed Carbon, wt%
|
25
|
ASTM-D172
|
5
|
Solubility in CS2,wt%
|
91
|
ASTM-D4
|
6
|
Specific Gravity @ 25 Cº
|
0.98
|
ASTM-D3289
|
7
|
Color in mass
|
Black
|
-
|
8
|
Softening Point, Cº
|
200-220
|
ASTM-D36
|
9
|
Flash Point
|
>400
|
Cleveland O. C.
|
10
|
Penetration @ 25 Cº
|
0
|
ASTM-D5
|
11
|
Particle Size (mesh)
|
>200
|
Tyler
|
4.
Packaging
In anonymous 25 kg or 21,5 kg craft paper
bags, palletized and shrink wrapped. Tolerance in weight: ±2%. Certificate
of fumigation is provided.
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