In the GOA, a major operator needed to drill all wells in the third phase of a field’s life at a stable 265 degF while maintaining the ability to drill through 5,000-psi overbalanced pressure. The field had been previously produced and is significantly depleted as a result. The goal was to achieve densities as high as 15.6-lbm/galUS while maintaining both production and injectivity according to the operator’s standards.
SLB recommended the DIPRO high-density divalent reservoir drill-in fluid, which uses optimal bridging particle distributions and formulations without the need for biopolymers. This fluid is suitable for reservoir drill-in fluids in divalent brines ranging from 11.5 to 17.0 lbm/galUS, enabling customized formulations with ultralow-permeability filtercakes that are easily removed. It showed over 90% return permeability in core testing and demonstrated high-pressure performance up to 9,300 psi in laboratory settings before adding wellbore strengthening material.
The 6¼- × 7-in reservoir section was drilled to a TD of 30,403 ft without any issues related to drilling fluid properties. The stability of the fluid properties highlights the advantages of the low ECD achieved with the DIPRO high-density divalent reservoir drill-in fluid.
Additionally, the fluid demonstrated long-term stability for more than 40 days downhole and proved its ability to be reconditioned for reuse between wells. Field data confirmed high-pressure performance with 7,200-psi overbalance during operations. Additionally, all LWD data were successfully acquired, eliminating the need for wireline operations.
