Drilling Fluid

Fluid Loss Control

The invention relates to a composition comprising an HPHT fluid loss control aid, stable at elevated temperatures and which also acts as an excellent shale stabilizer, bore hold lubricant, sealant for depleted sand, and wall cake conditioner. The HPHT fluid loss control aid broadly comprises a Gilsonite (asphaltite, asfaltit,Gilsonita,uintaite, natural asphalt, natural bitumen) which also contains a surfactant such as a nonionic surfactant.

The HPHT fluid loss control aid also contains a solubilized lignite such as causticized lignite and carbon black. The fluid loss control aid reduces HPHT filtrate loss, has good stability at elevated temperatures such as at 300 °F, stabilizes troublesome shales and decreases bore hole erosion, helps seal depleted sands, reduces torque and drag, causes no adverse effects on the flow properties of the properly conditioned drilling fluid, and lowers total well costs.
To achieve these and other advantages, and in accordance with the purpose of the invention, as embodied and broadly described, the invention comprises a composition comprising an HPHT fluid loss control aid stable at elevated temperatures, and which also acts as an excellent shale stabilizer, bore hole lubricant sealant for depleted sands, and wall cake conditioner.
The HPHT fluid loss control aid broadly comprises Gilsonite, an asphaltic material or solidified hydrocarbon produced by GLB (Global Leading Bitumen ) Gilsonite Company in Iran. The Gilsonite employed according to the present invention also contains a surfactant, especially, a nonionic surfactant.
Combination of these compounds as a HPHT fluid loss control aid, reduces HPHT filtrate loss has good stability at elevated temperatures such as at about 300 °F and sometimes as high as 400 °F, stabilizes troublesome shales and decreases bore hole erosion, helps seal depleted sands, reduces torque and drag, causes no adverse effects on the flow properties of the drilling fluid properly conditioned and lowers total well costs.
The invention also comprises a product made by combining the components of the composition as well as a product made by the process of adding the composition or product to a drilling fluid. Lastly, the invention comprises a process for controlling HPHT fluid loss in subterranean wells by adding the composition or product into a subterranean well.
Drilling fluids as used in the written description and the claims, include not only conventional drilling fluids or drilling muds including petroleum oil, synthetic oil and fresh water and salt water types as known in the art but also completion fluids and work over fluids.