Gilsonite, also known as uintaite or asphaltum, is a natural resinous hydrocarbon that is commonly used in various industries, including the drilling fluid industry. It is primarily used to enhance the performance of drilling fluids by improving their rheological properties, filtration control, and shale stabilization. Here are some methods of using gilsonite in drilling fluids:
- Gilsonite as a Rheology Modifier: Gilsonite can be used as a rheology modifier to adjust the viscosity and gel strength of drilling fluids. It can be added directly to the drilling fluid system to increase its thickness and provide better suspension of cuttings. The dosage of gilsonite will depend on the desired rheological properties of the drilling fluid.
- Gilsonite as a Filtration Control Agent: Gilsonite is an effective filtration control agent that helps reduce fluid loss and prevent excessive invasion of drilling fluids into the formation. It forms a thin, impermeable filter cake on the wellbore wall, reducing fluid loss and stabilizing the wellbore. Gilsonite can be added to the drilling fluid system at a concentration suitable for the specific drilling conditions.
- Gilsonite for Shale Stabilization: Shale formations can be prone to swelling and instability when exposed to drilling fluids. Gilsonite can be used as a shale stabilizer to prevent shale hydration and minimize wellbore instability. It forms a thin, hard film on the shale surfaces, reducing water adsorption and preventing swelling. The concentration of gilsonite required for shale stabilization will depend on the shale characteristics and drilling conditions.
- Gilsonite as a Lost Circulation Material: In situations where drilling fluids encounter fractures or highly permeable zones, gilsonite can be used as a lost circulation material (LCM) to seal off the loss zones and prevent excessive fluid loss. It can be mixed with other LCM materials and added to the drilling fluid to bridge and seal the fractures, reducing fluid loss and maintaining wellbore integrity.
When using gilsonite in drilling fluids, it is important to consider the compatibility with other additives and chemicals in the system. Proper testing and evaluation should be performed to determine the optimal concentration and application method based on the specific drilling conditions and objectives. It is also advisable to follow the guidelines and recommendations provided by the Gilsonite manufacturer.