PEMEX was drilling the 8½-in section of a 3D development well in HT formations offshore Mexico and expected to encounter static temperatures exceeding 165 degC [329 degF] and pressures up to 15,000 psi. With no commercially available RSS rated beyond 175 degC [347 degF], PEMEX selected a packed BHA. The possibility of veering off track was known to be a risk with the packed BHA, but PEMEX determined that a temperature-related tool failure was a greater risk.
While drilling, the BHA encountered very abrasive formations and veered off track. Lacking precise directional control and unable to reach the desired target, PEMEX pulled the BHA out of hole. To drill this section to planned TD, PEMEX needed a tool that could recover the tangent section and withstand the formations’ elevated temperatures.
SLB used the PowerDrive ICE™ ultraHT rotary steerable system (RSS) to steer the wellbore to target while withstanding the high temperatures and pressures of the field.
We steered azimuth from 77° to 57° to reach target of 3D well, increased ROP by 16%, as compared to the previous ROP record in this field, and saved 9 days of rig time and USD 1.35 million.
During the drilling of the 8½-in section, a field test of the PowerDrive ICE ultraHT RSS concluded, and the tool became available. SLB recommended using the ultraHT RSS to correct the trajectory of the borehole and drill the section to TD.
Rated to 200 degC [392 degF], the PowerDrive ICE RSS is specifically designed to improve reliability in wells with extreme heat. At the time the well was drilled, the operating windows of all commercially available RSSs were limited by the plastic components in their electronic circuit boards. These parts begin to deteriorate, melt, and cause downhole failure at 180 degC [356 degF]. Designed with proprietary ultraHT-rated electronics that are ruggedized for downhole use and a bias unit with metal-to-metal seals, the PowerDrive ICE RSS provides operators with precise directional control in HT and ultraHT environments.
PEMEX used the PowerDrive ICE RSS to improve the azimuth of this wellbore from 77° to 57°. This RSS drilled the wellbore from 6,160-m [20,210-ft] MD to section TD at 6,340-m [20,800-ft] MD and encountered temperatures that reached 163 degC [325 degF] while drilling and 173 degC [343 degF] while static. The maximum pressure was 16,000 psi.
The PowerDrive ICE system performed reliably in these harsh conditions and increased ROP by 16%, saving PEMEX 9 operating days and USD 1.35 million. The RSS achieved an average ROP of 3.84 m/h [12.59 ft/h], setting a record for the field. Previously, the highest average ROP for an 8½-in section in this field was 3.30 m/h [10.82 ft/h], which was drilled using a conventional motor. PEMEX plans to use the PowerDrive ICE RSS in three future HT offshore wells.
