WBF System to Drill High-Temperature Deviated WellDownload PDF
Mitigate lost returns
Engineer a WBF system to provide SOBM-like performance, including:
ConocoPhillips (Grissik) Ltd. was seeking a mud system alternative for drilling a 12.25-in. intermediate section in one of their Suban Field wells in South Sumatra, Indonesia. Due to a relatively high pressure of 4,000 psi, a mud density of 13.0-13.5 ppg was required to successfully drill the section. The anticipated bottomhole static temperature (BHST) was 260-275° F, with a pump pressure limitation of 5,000 psi maximum. The well was planned to have up to a 54/55-degree angle of inclination, within a ± 3,280-ft (± 1,000-m) length of the Telisa Shale formation.
In the region’s offset wells, intermediate sections are normally drilled using synthetic oil-based mud (SOBM), which poses no major risks concerning shale stabilization, high-temperature exposure, insufficient lubricity, poor hole cleaning, high standpipe pressure, or barite sag in a deviated angle. However, the cuttings and leftover SOBM present other concerns, from environmental and hazardous waste cost management perspectives. In this drilling campaign, ConocoPhillips challenged Halliburton Baroid to provide a suitable water-based mud (WBM) system that would match the performance of SOBM, while minimizing impact to the environment and lowering waste management costs.
A customized HYDRO-GUARD® HT water-based fluid was formulated in the Baroid laboratory, introducing BaraVis® W-637 and BaraThin W-678 into the chemical mixture as the main viscosifier and thinner, respectively, to control the rheology in the system. Both additives worked synergistically with other components in the HYDRO-GUARD formulation to improve HPHT fluid loss control at 280° F, without affecting the rheological profile. This engineered solution was designed to support the drilling operation of a high-angle well, in both dynamic and static conditions.
In the Suban Field application, HYDRO-GUARD HT provided shale stabilization and lubricity, enabling a high rate of penetration (ROP) with low torque & drag. Rheological profiles were relatively low with acceptable tau 0, ensuring sufficient hole cleaning at a high inclination angle, and within the allowable standpipe pressure threshold. No hole cleaning issues occurred during drilling, circulating, and pipe tripping operations.
The HYDRO-GUARD HT mud system also proved to be stable during an unexpected 21-day static period due to rig shutdown during a Covid-19 outbreak. Following this period, the density of the mud after bottom-up demonstrated minimum to no barite sagging tendency.
Additionally, HYDRO-GUARD HT provided in-situ dewatering and cuttings handling process benefits. By processing the WBM cuttings and waste on location, the customer eliminated transportation and hazardous waste treatment costs that are usually incurred by a SOBM system.
Overall, ConocoPhillips was satisfied with the result, and this HYDRO-GUARD HT is now their benchmark performance for drilling the Telisa Shale formation.
Halliburton Baroid is at the forefront of the drilling and completion fluids industry.
Ready to take the next step?