New cost-effective Gilsonite product provides crucial filtration control, maintains stable rheology
September 10, 2021
Ultra-deep wells and gypsum-salt formations present unique drilling challenges
The Sichuan Basin in southwest China is rich in ultra-deep natural gas and deep shale gas resources. Successful wells must be 7,000 to 8,000 meters (23,000 to 26,000 feet) deep. In addition, thick gypsum-salt rock formations present extreme engineering challenges, notably maintaining a stable rheological profile.
Other SBM additives fail to maintain stable fluid rheology
The client drilled with a synthetic-based mud (SBM) typically used in the region but was looking for a fluid loss control additive that would offer consistent performance while keeping emulsion strength and maintaining a stable rheological profile. Drilling fluid properties typically worsen when contaminated by highly pressurized brine in gypsum-salt formations. Therefore, consistent performance of additives is key.
New Gilsonite® product provides cost-effective filtration control, preserves other important fluid properties
The new Gilsonite® grade was used to replace other asphaltic additives that were less reliable and known to impact rheological values. A formulation with 8 ppb (pounds per barrel) of the new product provided adequate filtration control with no impact on rheology. In addition, it provided a cost-effective solution to improve the performance of the client’s SBM formulation. Gilsonite® uintaite is the only naturally occurring drilling fluid additive that prevents wellbore instability without affecting fluid rheology.
“Overall, we are pleased with the performance of the new Gilsonite® product, which is why we would like to promote it in China,” noted the client’s operations manager.