Pumping under pressure

The UK is ‘going all out for shale’. Those were the words of prime minister David Cameron at the start of the year as he attempted to shore up support for ‘fracking’ — a controversial technique that he believes could help solve the country’s impending energy crisis.

Fracking — or hydraulic fracturing — involves shattering rock deep  in the Earth to release shale gas using high-pressure water, sand and chemicals. Its use has prompted fierce opposition from some sections  of the public over fears that it could trigger earthquakes and release damaging chemicals into the environment. But while the debate on fracking continues to rage in the UK, engineers in the US are developing technologies that could extract shale gas from increasingly difficult geological formations. The country has undertaken fracking in at least  17 states with more than 82,000 wells operating nationally.

The success of the shale industry owes a great deal to innovation in the pumps used to deliver fluid down to the well bore, as well as the growing supply chain. Early frac pumps were either triplex or quintuplex, operating with three or five pistons. They were used on vertical fracturing operations and typically ranged in horsepower capacity from 1,300–2,000bhp with pressure requirements often less than 10,000psi.