venerdì 4 ottobre 2013

Drilling Gilsonite

Drilling Gilsonite – Fluid Loss Control (FLC)


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.

GILSONITE


1.      What is Gilsonite
GILSONITE is a pure hydrocarbon, with a melting point between 160°C and 220°C. The mineral is natural bitumen and geologically petroleum based solid and therefore extremely compatible with petroleum bitumen.



When blended, a very intimate molecule of GILSONITE and bitumen is formed, one that takes on some hardness and durability of GILSONITE while still retaining the flexibility of the bitumen.
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 Gilsonite or Uintaite. 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.

2.      What makes GiLSONITE different from other natural Asphalts

1
high purity and consistent properties
2
high nitrogen content
3
high molecular weight
4
high asphaltene content
5
high solubility in organic solvents

GILSONITE doesn’t contribute to low temperature cracking. This is contrary to logic and experience with other bitumen modifiers that also impart hardness, The semi-polymeric nature of GILSONITE and its unique chemical composition are responsible for this unusual behavior.
The high asphaltene content and high molecular weight function mainly as a solution thickener or flow controller, These two factors are the main reason for the improvement in the pavement stability characteristics.
The high nitrogen content of GILSONITE gives the modified bitumen better adhesion to aggregate which improves stripping characteristics, as well as oxidation resistance.
The minimal sulphur content also means that GILSONITE is a low odor product
GILSONITE only needs 1/3 of other natural asphalts to give even better performance. Due to its pureness, only a replacement of 5 — 15 % of the actual bitumen content shows significant improvement in stiffness and re­sistance to deformation as well as ductility and viscosity.

3.      Where to use GILSONITE
GILSONITE is a very economic and cost effective way to modify road construction bitumen for high performance roads.
Sophisticated test methods such as Indirect Tension Stress Test, Cryonic Tensile Stress Test and the Splitting and Erectile Tension Test have proved that GILSONITE modified bitumen offers superior properties in:
  • ·         fatigue behavior
  • ·         stiffness modulus
  • ·         cold temperature performance

Special computer software for the dimensioning of traffic surfaces of asphalt was used to calculate and compare the utilization period of Gilsonite and Polymer modified binder courses; result was that the calculated life time of binder courses on US federal motorways increased from 18 to 29 years.
GILSONITE modified bitumen will increase the susceptibility to deformation from static or slow moving loads at
Toll Plazas, Airport Taxiways, Exit Ramps, Container Terminals, Sharp Curves, Port Facilities, Intersections, Truck Terminals, Bus Stops and Lanes, Bridge Decks, Roundabouts, Park Decks.
GILSONITE modified bitumen will help against moderate rutting caused by high speed, heavy volume traffic at Truck Lanes, Racing Circuits, Highways, Airport Runways
A GILSONITE modification makes the most sense when used in high performance binder courses, but can also be used in a wide variety of asphalt surface courses such as Stone Mastic Asphalt, Asphalt Concrete, Gussasphalt, Hot Rolled Asphalt.
Gilsonite can significantly improve the high temperature properties of asphalt binders.
Gilsonite increases the Ring & Ball Softening Point, the Absolute Viscosity and reduces the Penetration values of both neat and modified asphalt binders.
Consequently, it also increases the high temperature stiffness and reduces the phase angle of the base asphalt
GILSONITE has been used widely in addition to up to 50 % with recycled asphalt.

4.      How to use GILSONITE
GILSONITE is a free flowing granular material which will not cake or block during storage.
Because of the nature of this hydrocarbon, GILSONITE is completely soluble in bitumen, forming a very intimate molecule that will NOT separate. It can be used:
·         in bitumen pre-blend: a pre-blend of GILSONITE and bitumen in the proper percentage (5-15 %) can be produced in the bitumen tank with temperatures maintained around 170°C. During the GILSONITE solution, agitation and recirculation under heat should be maintained for 12 — 24 hours.
·         in pug mill: addition of GILSONITE to a pug mill can be accomplished by the introduction of pre-weighted plastic bags, or in bulk by using an automatic dosage system. The GILSONITE should be added onto the hot aggregate before the bitumen is added. The wet mix circle must be extended by 15 sec. to ensure proper blending.
·         in drum plants: GILSONITE may be added to a drum plant, either by the master batch method or with a dry mineral feeder at the correct rate of flow along with the bitumen.
Paving conditions should remain identical to non-modified bitumen, except that mix temperatures should be maintained at a minimum of 160°C to compensate for the addition of the GILSONITE. Lay down and compaction should be normal providing this slightly higher temperature is maintained.
GILSONITE is available in 25 kg meltable plastic bags, 30 kg craft paper bags and 1,000 kg big bags.

5.      Purpose of GILSONITE modification of Asphalt Pavement Mixtures

1
Improved resistance to deformation
2
Improved the economic performance of the road
3
Improved resistance to stripping
4
Improved resistance to fatigue
5
Improved durability
6
Compensation for poor mix design
7
Compensation for poor aggregates

6.      Gilsonite in Hot Mix Asphalt
According to FHWA (U.S. Federal Highway Administration) research data, up to 80% of pavement flexibility is lost during the first 5 years. When the aging process is halted and the pavement is preserved early on, maintenance is less invasive and much less expensive.
Furthermore, FHWA, FAA (Federal Aviation Administration), NAVFAC (Naval Facilities Engineering Command), MDOT (Michigan Department of Transportation), and AzDOT (Arizona Department Transportation), research shows agencies that used Gilsonite-based treatments reduced pavement replacement costs by up to 60% compared to using the worst first-practices.
While HMA (Hot Mix Asphalt) pavements perform poorly when they become hard (like cement), when Gilsonite is applied to the surface of asphalt pavement it maintains oils, resiliency, and flexibility by filling micro-voids and keeping asphalt binders soft and pliable. The use of Gilsonite lowers viscosity by over 30%, increases ductility by 30%, and increases Marshall Stability by almost 40% (strength of binder) after just 5 years. Contrary to many engineers’ belief, Gilsonite does NOT harden pavement. However, it DOES toughen the surface to better withstand traffic and the aging process. The stability of Gilsonite-fortified pavements makes them more resistant to problems, such as rutting and shoving, and increases the pavement’s load carrying ability. In some cases these high-performance mixes will halt, and reverse the effects of aging and degradation from water penetration, oxidation, and UV radiation. In addition, other benefits include increased resistance to water stripping, oxidation and the aging process.

7.      Notes on Ashes and Volatiles
GILSONITE is an Organic matter; a hydrocarbon consisting of Carbon and volatile gases like Methane. With very special characteristics defining it as Bituminous matter. These characteristics are very similar to those, which are synthetically produced in the refineries.
This chemistry, which defines this bitumen without its volatile gases, is nothing but something similar to a Coal. Then “the higher the volatile matter Ratio to Carbone the closer it is to synthetic Bitumen”.
In the laboratory the test procedure is defined to quantify these matters. We slowly apply heat to GILSONITE to initially reach to its softening points 170-220 degrees C . The heat is applied further at a constant rate in order to reach the temperature of 350 degrees C at which the volatile gases are fully evaporated. At this stage we reach a point referred to as FIXED CARBON.
The Temperature is still increased beyond 350 degrees C at a constant rate until all Fixed Carbone is disintegrated fully at temperatures above 800 degrees C. The specimen is kept at this temperature for a while and then cooled off. The remaining balance is then analyzed and measured.
The balance is collectively referred to “ASH” which, are basically Ferrous Silicate: FeSi2, Calcium Carbonate: CaCo3 , SO2, MgO, Al2O3 and SIO2

8.      Notes on Asphaltene content
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-heptanes (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.
Unique natural hydrocarbon is high in asphaltenes and nitrogen. It makes it fully compatible with bitumen. It be melted into hot bitumen, added during the hot-mix manufacturing process, or blended into a preservation treatment. In either case, GILSONITE dissolves easily in bitumen and achieves a uniform, easily workable product.
Gilsonite resin is often used by asphalt producers, road paving engineers and paving contractors who are concerned with PG specifications, high-performance and cost-effectiveness. Gilsonite, long known as a bitumen re-enforcer and strengthening agent, also offers a unique combination of high-performance and economy for high-stress paving, and preservation applications. Gilsonite is an approved mineral by the U.S. Food & Drug Administration for use in resinous and polymeric coatings that come into direct contact with food. Gilsonite falls under Section 175.300 (formerly Section 121.2514) of the FDA regulations, Part 3, subpart (iv), which lists Gilsonite as one of several approved natural resins. Besides being non-toxic, Gilsonite products are non-carcinogenic and non-mutagenic.

9.      Gilsonite Solubility
A variety of sophisticated analytical tests have been run on Gilsonite to characterize its unique properties. For reference, the test methods include vacuum thermal gravimetric analysis (TGA), nuclear magnetic resonance (NMR), Fourier transform infrared spectrometry (FTIR), vapor pressure osometry (VPO), high performance liquid chromatography (HPLC), rapid capillary gas chromatography (RCAP), and several fractionation techniques. H/C ratios and NMR analysis indicate the presence of a significant aromatic fraction. Most of the aromatics exist in stable, conjugated systems, probably porphyrin-like structures that relate to the geologic source of the product. The remainder of the product consists of long, paraffinic chains. A very unique feature of Gilsonite is its high nitrogen content, which is present mainly as pyrrole, pyridine, and amide functional groups. Phenolic and carbonyl groups are also present. The law oxygen content relative to nitrogen suggests that much of the nitrogen has basic functionality. This probably accounts for Gilsonite special surface wetting properties and resistance to free radical oxidation. The average molecular weight of Gilsonite is about 3000. This is very high relative to other asphalt products and to most synthetic resins. This may relate to Gilsonite "semi-polymeric" behavior when used as a modifying resin in polymeric and elastomeric systems. There is some reactive potential in Gilsonite. Crosslinking and addition type reactions have been observed. Gilsonite is known to react with formaldehyde compounds under certain conditions
Gilsonite is an important component of today's printing inks, paints & industrial coatings. Gilsonite is used as a hard resin and carbon black dispersant in a variety of coatings. Solutions of Gilsonite (sometimes called cutbacks or varnishes) are an excellent starting point for blending Gilsonite with other components of a final product formulation. Some formulators convert dry Gilsonite into liquid solution in their own facilities. Others will request a pre-made solution. Converting dry, granular Gilsonite to a liquid solution also provides the opportunity to remove the small amount of abrasive grit that occurs in natural asphalt. Stabilizing additives can also be added if a poor solvent is used or if high concentrations of Gilsonite are desired.
Solubility: Gilsonite is soluble in aliphatic, aromatic and chlorinated hydrocarbon solvents. It has limited solubility in most ketones, but is soluble in mixed aromatic solvents that contain a ketone component. Gilsonite is not soluble in water, alcohols, or acetone.Solution Preparation: Three basic procedures are used to dissolve Gilsonite. In each case, precautions for flammable materials should be used. Cold-cutting: Gilsonite is generally soluble in aliphatic and aromatic solvents at ambient temperatures. Some agitation should be used. The rate of solution will depend on the type of solvent, the type and severity of mixing, and the grade of Gilsonite. The solution rate can be increased by using a high shear mixer, such as a Cowles disperser. When a ball mill or a paddle mixer is used, lump grade Gilsonite is recommended. When high energy mixing is available, either lump or pulverized grades may be used. Care must be taken to avoid "dry balls" of undissolved solid when using pulverized grades. Hot-cutting: The rate of solution can be increased by heating. Steam coils or hot oil is preferred. Direct-fired heating can be hazardous. Care must be taken to avoid or make up for vaporized solvent.
Facilities for solvent containment are often necessary. The maximum processing temperature will depend on the boiling range of the solvent. Hot fluxing: Gilsonite can be hot fluxed into asphalts and high boiling oils. Once blended, the combination can then be let down with a solvent to reach the desired viscosity. This hot fluxing with another product can help overcome limitations of solubility. Selecting the correct blend or co-solvent can yield compatibility with a solvent that is normally of limited solubility. Hot Fluxing Procedure: Heat the oil to 200 °F or more. Most of the high boiling, law aromatic ink oils in use today will require a temperature of at least 300-330 °F. With good agitation, add dry Gilsonite at a rate that maintains constant dispersion of the particles until they dissolve. Be alert for foaming that can be caused by traces of moisture in the Gilsonite. Continue to agitate for 15 to 30 minutes beyond the point when the last of the Gilsonite particles is detected. The Gilsonite should now be completely dissolved and the solution ready for discharge. Filtration: The varnish must be filtered to remove the grit that is a natural component of Gilsonite. There are two common filtration methods. Each provides a different degree of cleanliness. Both methods are normally preceded by passing the hot varnish through a course wire screen (approx. 1/4") to remove any large stones. For a normal degree of cleanliness, the prescreened, hot varnish is passed through wire screen baskets of about 200 mesh (74 microns). Cloth bag filters can also be used, at a higher cost, when the company doesn’t have the personnel to clean the wire baskets. Disposal of the bags is also a consideration. Be careful to use bags that can tolerate elevated temperatures if hot cutting is performed.
For extra cleanliness, the prescreened, hot varnish is passed through cartridge filters of about 5 to 25 microns. These filters are also disposable. Viscosity Modification: Some Gilsonite solutions can be quite viscous at ambient temperature. Also, some solutions can steadily increase in viscosity over time. These characteristics are usually observed when using law aromatic oils with poor solvent power or when high percentages of Gilsonite are used. In these cases, small amounts of viscosity modifiers are often added to (1) keep the hot varnish sufficiently fluid for easy filtration and (2) to reduce and stabilize the ambient viscosity so the solution remains fluid until it is used. The following is a partial list of modifiers that are effective at stabilizing the viscosity of Gilsonite solutions.
Soft asphalt flux. This is often substituted for 15 to 20 % of the Gilsonite in the varnish. At this level, it reduces the softening point of the Gilsonite by about 30 °F. It should not be used when maximum hardness and rub resistance is desired, or when fast solvent release is required, or when restrictive health safety regulations are in effect.
Tridecyl alcohol (TDA). More volatile than some modifiers (a flash point of 180°F), but effective. Generally used at 3-10%, based on the Gilsonite content.
Low molecular weight alcohols. Examples are n-propanol and n-butanol. These are effective, but their high volatility usually restricts their use to fast drying systems or products that are stored and used at ambient temperature.
Tall oil fatty acids. These are mainly oleic and linoleic acids with small amounts of rosin acids present. They are used for their high flash point and law volatility. In some cases, stearic or oleic acid, or vegetable oils such as linseed or soya bean oil, can be substituted for tall oil fatty acids with comparable performance.
Surfactants. A wide variety of commercial surfactants are also effective. Care must be taken to avoid any undesirable side effects on the performance of the final product.
GILSONITE SOLUBILITY
Chemical Group
Item
Solubility
Aliphatic Hydrocarbons
VM&P Naphtha
S
----
Mineral Spirits
S
----
Solvents with KB
S
Aromatic Hydrocarbons
All
S
Alcohols
All
I
Chlorinated Hydrocarbons
All
S
Esters
Methyl Acetate
I
----
Ethyl Acetate
Slight
----
n-Butyl Acetate
Slight
Glycols
All
I
Glycol Ethers
All
I
Glycol Ether Esters
All
I
Ketones
Acetone
I
----
MEK
I
----
MIBK
I
Other Solvents
Carbon Disulfide
S
----
Carbon Tetrachloride
S

10.  Gilsonite Compatibility
Adhesive/ coating system
Compatibility
Adhesive/ coating system
Compatibility
Natural rubber
FAIR
Ethylene/vinyl acetate
GOOD
Cellulose esters
POOR
SBS rubber
EXCELLENT
Phenolic
GOOD
Polychloroprene rubber
EXCELLENT
Resorcinol formaldehyde
FAIR
Nitrile rubber
FAIR
Urea formaldehyde
GOOD
Butyl rubber/polyisobutylene
GOOD
Melamine formaldehyde
GOOD
Silicone
GOOD
Alkyd
GOOD
Polyurethane
FAIR
Epoxy
FAIR
Vinyl ethers
GOOD
Polyurethane
FAIR
Resinates
GOOD
Acrylic
FAIR
Resin modified
EXCELLENT
Unsaturated polyester
FAIR
C9 aromatic
GOOD
Polyaromatic
GOOD
DCPD
EXCELLENT
Acrylic acid diester
POOR
Terpene
EXCELLENT
Polyvinyl acetate
FAIR
Terpene phenolic
GOOD
Polyvinyl alcohol
FAIR
Phenolic modified
GOOD
Polyvinyl chloride
GOOD
maleic-fumaric modified
EXCELLENT
Acrylic
FAIR
Alkyd
GOOD
Polyamide
POOR
Shellac
POOR
Phenoxy
POOR



11.  Typical Gilsonite Laboratory Test

TEST
UNIT
SAM-1
SAM-2
SAM-3
SAM-4
ENRICHED
Ash
wt%
12.4
14.88
4.71
1.87
0
Moisture
wt%
0.12
0.14
0.15
0.18
0.10
Volatile
wt%
68.9
71.6
68.45
72.6
75.0
Fixed Carbon
wt%
18.7
13.52
26.51
25.25
30
Density
g/qcm
1.18
1.21
1.12
1.08
1.10
Softening point
c
190-200
230-245
180-195
200-210
160
Flash point
c
430
440
410
430
430
Sulphur
wt%
1.77
3.74
0.74
0.67
1