The Petromac Conveyance System

The Petromac Conveyance System was developed to address the deployment limitations of conventional wireline logging tools in wellbores made difficult by ledges, washouts, cuttings and  high deviations.

Explorers use wireline log data to determine whether a well is commercial. Logging tools are lowered by cable into the wellbore to depths of  9,000 metres. The tools measure the properties of the subsurface rocks and fluids contained within the rock pores.

Petromac says about USD $8 billion is invested in wireline services annually. Roughly 85 per cent of wells are drilled at high angles - above 50 degrees.

Conventional wireline logging tools are seldom used for high-angle wells because obstacles and drag hinder the process downhole. About 23 per cent of wells are drilled at angles between 50 and 70 degrees and that’s the initial market Petromac aims to capture with its conveyance system.

It comprises two parts:

-          The Tool Taxi slips over the outside of a logging tool. Its wheels elevate the tool above the wellbore, so as not to drag or collect cutting debris. Taxis are secured off-centre and rotate the toolstring to find the lowest centre of gravity, so that sensors align with a side of the wellbore.

-          The Guide attaches to the bottom of a logging toolstring and points upwards so as to ski over any ledges. It allows the toolstring to pass seamlessly over a ledge 5 inches high - within an 8.5 inch hole - without holdup.

The wellbore environment was a challenge for development: drilling fluids are abrasive due to suspended cuttings; well temperatures can exceed 180 degrees Celsius and pressures can reach 30,000 psi.

Early Tool Taxi prototypes wore too quickly, necessitating customised bearings which are manufactured from tungsten carbide – a composite harder than quartz. The bearing technology continues to be developed to reduce friction - for better log data - and to facilitate conventional  logging operations up to 80 degrees deviation.

In New Zealand, the system has been used by TAG Oil, Todd Energy, Shell-Todd Oil Services, Greymouth Petroleum, KEA Petroleum and Mighty River Power. TAG used the system for a side-tracked well in Taranaki and says the Petromac tool is the best the company has used for this purpose.

Petromac invested $1.2 million in the conveyance system, supported partly by Callaghan Innovation in two funding rounds. The technology turned $600,000 profit in its first commercial year - 2014-2015 - and is estimated to have generated $1.5 million profit in the year just ended. Petromac expects profit to reach $20 million by 2020.

Both technologies have international patent applications. Petromac plans to market directly to oil companies, using the existing infrastructure of wireline logging companies as a third-party supplier. The company will retain ownership of the tools.

Auckland-based Petromac was founded by Steve McCormick, a petrophysicist for the oil industry. The company launched in May 2014 with contracts in Australia, the US, Asia and the Middle East. It has minor activities locally.

It expects to deploy to Argentina, Kazakhstan and Abu Dhabi as part of a five-year expansion plan.

Petromac sees its patents as a competitive advantage, and boasts a strong financial position with assets that include more than 100 devices and more than $1 million in cash and accounts receivable.

The Energy Technology of the Year award category is sponsored by Callaghan Innovation