Gilsonite is effective at sealing off permeable formations even when drilling such zones at a highly overbalanced pressure differential. In this manner, Gilsonite helps prevent the occurrence of stuck pipe and stuck logging tools across these zones. Gilsonit Natural Asphalt , Natural Bitumen , Hard Asphalt or Hard Asphaltum is used as a performance-enhancing agent for asphalt mixes. Iran Gilsonite-modified paving mixes achieve higher PG grades and incorporate perfectly into the asphalt blend with no need for high shear milling as is the case with many other modifiers.
Gilsonite is the preferred fluid loss control agent for use in oil based drilling fluids. It provides shale stabilization superior to other additives and also functions as a malleable plugging agent that effectively seals off permeable zones as they are drilled. Iran Gilsonite has an important characteristic of gilsonit is its softening-point temperature. In oil-base muds, it is used as a fluid-loss control agent. Being a hydrocarbon, it is naturally wetted by the oil. In water-base muds, it is used as a shale-stabilizing additive and is difficult to evaluate unless tested at or above its softening point. As a hydrocarbon, the powder must be coupled to water by using a glycol or similar water-wetter.
Gilsonite can partially or totally replace, or complement, the use of SBS polymers in modified asphalts at a fraction of the cost. Gilsonite-modified asphalts have higher stability, reduced deformation, reduced temperature susceptibility and increased resistance to water stripping than non-modified asphalts. Gilsonit is also used to make both solvent-based and emulsion pavement sealers with superior appearance and weathering properties.
Gilsonite additive is an asphaltene hydrocarbon in granular form. Its particle size varies between 4- and 100-mesh. Gilsonit additive is commonly used to control lost circulation. It is effective at bottomhole temperatures (BHTs) between 60° and 230°F (16° and 110°C). Typical additive concentrations range from 5- to 50-lb/sk of cement. The low specific gravity of Gilsonite additive helps improve its ability to control lost circulation. However, this feature can also cause the additive to separate to the top of thin slurries and slurries containing dispersants. Adding 2% or more bentonite to the slurry will help prevent separation.
The primary use of Gilsonite today is as an additive in drilling fluids and cementing slurries that are utilized in the drilling of oil and gas wells. It is also used in hard resin printing inks for newspapers and magazines, in producing sand molds used in the foundry industry, and as a modifying agent in asphalt used for road paving. Gilsonit is used in cementing slurries to provide density control, scouring action for mud removal, and to support compressive strength development. Gilsonit has a unique reaction with shale which improves cement bond development and strength.
Gilsonite also is an excellent fluid loss agent for use in water based drilling fluids. When pre-treated with a surfactant to enhance dispersion, Gilsonit provides the same benefits in water based fluids as it does in oil based fluids – fluid loss control, shale stabilization, and lost circulation prevention. Due to its high softening points (400450°F), Gilsonite is especially effective in drilling fluids used to drill in high temperature environments. Gilsonite provides excellent fluid loss control and shale stabilization even at these elevated bottom-hole temperatures.