Disperses more in water and generates less viscosity compared with PHPA.
An operator was drilling an exploratory well in Argentina's Bajada del Toro field. To improve reservoir understanding, the operator planned to collect high-resolution measurements and formation samples in the 17 1/2-in and 12 1/4-in sections. The operator divided the logging runs into three sets: resistivity, spontaneous potential (SP), gamma ray (GR), caliper, and dipolar sonic; magnetic resonance and Dielectric Scanner multifrequency dielectric dispersion service; and MDT modular formation dynamics tester.
Multiple logging runs required well stability for extended periods of time—the operator needed to ensure proper mud weight and inhibition so the well would not close in or become unstable. In addition to these technical requirements, the drilling fluid needed to meet strict environmental regulations, because the well was located near an aquifer zone.
Schlumberger selected the HydraGlyde high-performance water-based drilling fluid system with potassium sulfate, HydraSpeed ROP-enhancing primary lubricant, and HydraCap encapsulating additive for its excellent lubricity and inhibitory characteristics.
The operator aimed to drill each section with an average ROP of 30 to 50 m/h with no HSE incidents. While planning the well, however, the drilling team discovered that the rig had only two primary shakers, which would reduce planned flow rates, ROP, and hole cleaning efficiency. Schlumberger proposed using the onsite mud cleaner as a third primary shaker to handle the volume of cuttings from both sections.
The operator drilled the 17 1/2-in section to 605-m [1,984-ft] TD at an ROP of up to 50 m/h. After running the first two logs, Schlumberger observed some restrictions due to lack of density. The team performed a calibration trip as planned and increased fluid density to 1,200 kg/m3 [10 lbm/galUS] before running the third log set. Formation fluid samples were collected at 535 m [1,755 ft], 461 m [1,512 ft], and 302 m [990 ft].
After reaching 1,050-m [3,444-ft] TD in the 12 1/4-in section, the operator cleaned the hole and increased the fluid density to 1,250 kg/m3 [10.4 lbm/galUS] before successfully completing all three logging runs. The operator took formation samples at 1,018 m [3,339 ft], 933 m [3,060 ft], 798 m [2,617 ft], and 671 m [2,200 ft] with no issues.
The HydraGlyde fluid system delivered ROP, hole cleaning, and stability similar to oil-based mud with the economic and environmental benefits of a water-based drilling fluid. Despite the drilling challenges, the operator drilled and logged both sections 1.2 days ahead of schedule. In addition, Schlumberger was able to eliminate a planned calibration trip and reuse more than 85% of the drilling fluid from the 17 1/2-in section in the 12 1/4-in section. These efficiencies helped reduce costs in each section by 2% and 14%, respectively.
Challenge: Meet HSE requirements while drilling and logging an exploration well in the Neuquén Basin.
Solution: Use the HydraGlyde high-performance water-based drilling fluid system to maximize drilling performance while reducing risks.