Downhole perforation tools are used for well completion. They puncture holes in the casing or liner, which creates a channel between the pay zone and the wellbore resulting in a clean channel for easy flow. It is critical that the perforated holes are debris free to allow for efficient fluid flow.
There are many different types of perforation methods such as bullet gun, abrasive, water jets and shaped charge. These utilise either explosive chemical reactions to perforate the wellbore liner or high-pressured hydraulics fluid to abrase the liner and form the flow channels. The method that our motor is designed for is for perforation through drilling or mechanically puncturing holes into the wellbore liner with mechanical penetration.
Guideline for the figure
(a) Through-casing perforation
(b) Through-tubing perforation (TTP)
(c) Tubing-conveyed perforation (TCP)
The motor was designed to achieve the following specifications.
| Parameter | Value |
| Dimension (Length & Diameter) | 360mm x ⌀63.5mm |
| Motor Type | 3-Phase BLDC |
| Nominal voltage, Vdc | 600 V |
| Maximum torque | 6 Nm |
| Maximum speed | 3000 RPM |
| Maximum input current | 4.2 A |
| Output power | 1.8 kW |
| Maximum operating temperature | 180℃ |
| Ambient temperature | 150℃ |
| Motor Internal Environment | Oil filled – 10 000 PSI |
| Shaft Dimension | ⌀10 mm |
| Feedback Device | Resolver |
| Cooling | Passive oil cooled |
| Drive Mode | Trapezoidal |
| Maximum drive frequency | 48 kHz |
The motor must perform in a very harsh environment. Experiencing high temperatures up to 180°C and pressures of 10,000 PSI.
A high temperature resolver has been attached to the rotor shaft to provide positional feedback to the motor drive unit.
It is critical to align the resolver rotor and stator either mechanically or be able to apply an offset in the software. This will allow the motor drive to access maximum torque at 0 RPM (or a greater initial acceleration) and will allow the motor to reach top speed faster. Any misalignments could result in lower torque output or an increased ramp up time.
