Experimental Investigation into an Ultra-low-Friction Water-Based Drilling Fluid for Tight Gas Well: A Case Study of Tight Gas Well in Sichuan Basin, China

Water-based drilling fluid has the advantages of environmental protection and low cost, but the lubrication performance of water-based drilling fluid cannot reach the level of oil-based drilling fluid, which limits its application in unconventional oil and gas horizontal wells. By reducing the friction coefficient of the water-based continuous phase, we prepared an ultra-low-friction water-based drilling fluid (ULF-WBM) with the same lubrication performance as oil-based drilling fluid. Through a series of laboratory tests to evaluate the inhibition performance, filtration performance, and lubrication performance, the necessary inhibitors, tackifiers, and fluid loss additives were selected, and the formula of ULF-WBM was optimized. The results show that the low-friction continuous phase formed by SL and water, amino inhibitor, polymer additive, and potassium humate additive can effectively improve the lubrication, inhibition, rheology, and filtration properties of water-based mud. In addition, ULF-WBM has the advantages of good thermal stability and low friction for a long time. It has been applied to one well in tight gas horizontal wells and achieved good results. It is a guiding solution for water-based drilling fluid for unconventional horizontal wells.

Automated summary

Water-based drilling fluid has the advantages of environmental protection and low cost, but its lubrication performance is not as good as oil-based drilling fluid, which limits its application in unconventional oil and gas horizontal wells. By reducing the friction coefficient of the water-based continuous phase, an ultra-low-friction water-based drilling fluid (ULF-WBM) with the same lubrication performance as oil-based drilling fluid was developed. Through laboratory tests and optimization of the formula, ULF-WBM was proven to improve the lubrication, inhibition, rheology, and filtration properties of water-based mud. It has been successfully applied in a tight gas horizontal well, serving as a guiding solution for water-based drilling fluid in unconventional horizontal wells.