Reducing Torque and Drag with Asphaltic Additives

Torque and drag limit how far and how fast you can drill, especially in deviated and horizontal wells. Asphaltic additives such as gilsonite and sulphonated asphalt help reduce friction.

How they work

Fine asphaltic particles form a slick, thin filter cake on the wellbore wall and coat the drill string. This provides boundary lubrication between steel and rock.

Benefits

• Lower rotating torque
• Lower pick-up and slack-off drag
• Smoother sliding with motors
• Reduced risk of differential sticking

Combining with lubricants

Asphaltic additives can be used with liquid lubricants. They also improve filter cake quality, which reduces sticking risk.

Dosage

3–6 lb/bbl of sulphonated asphalt in water-based mud or gilsonite in oil-based mud.

Measuring results

Track torque and drag trends before and after treatment, and compare with friction factor models.

Measuring friction

Drilling engineers compare actual hook loads and torque with modelled values to estimate friction factors. A drop in friction factor after treatment shows the additive is working.

Typical approach

Benefits

Lower torque allows longer laterals, better weight transfer to the bit and less wear on the drill string.

See also preventing differential sticking.