The right gear for drilling

University of Bath engineers are using technology developed to make gear changes in automatic cars smoother to drill for oil 9.5 kilometres underground.

The Powertrain & Vehicle Research Centre (PVRC) team’s £175,000 project aims to make more efficient, cheaper and smaller drilling systems to access hard to reach oil reservoirs. It will use Continually Variable Transmission (CVT) automatic powertrains.

In CVT, the traditional system of gears is replaced by a pulley system that allows an infinite variability between highest and lowest gears with no discrete steps or shifts. This means that cars with a CVT no longer have engines that ‘rev’ as the driver accelerates; they are always in the perfect ‘gear’.

The project is being funded by InterSyn Technologies in Houston, Texas, which makes a proprietary version of CVT called the Milner Continually Variable Transmission (MCVT). The MCVT is more compact than belt driven units and can be operated using ‘by-wire’ control techniques.

“For oilfield applications, CVT technology offers a number of advantages over traditional transmission methods,” said CVT expert Dr Sam Akehurst from the PVRC.

Stuart Schaaf, President of InterSyn Technologies, said, “As the system drills through layers of rocks, the CVT provides directional control of the drilling system and allows the operator to position the oil well for optimal production of the hydrocarbons in the reservoir.

“Because the CVT is significantly smaller and simpler than traditional power transmission and control systems, the drill system as a whole can be made more cost effectively. This allows for the system to be used in a broader cross section of wells around the world.”

InterSyn has funded a £120,000 CVT test rig at the PVRC that will allow Dr Akehurst to develop computer models of the complex mechanical operations of the CVTs developed for oil drilling and then test them on InterSyn’s prototype transmissions.