Most yes, all no.
for example, Halliburton is fracturing in Australia and Europe:
http://www.halliburton.com/public/projects/pubsdata/Hydraulic_Fracturing/fluids_disclosure.html
The point is, it is not knowledge limited to companies that only work in the US.
The point is, it is not knowledge limited to companies that only work in the US.
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Fracking was invented here in the USA. As well a dozen other techniques to optimize the process that have sprung up in the last five years.
That said there are plenty of foreign companies —including chinese companies — working in partnership with american companies—operating in the Baaken, Eagle Ford, the permian basin and elsewhere with the goal of learning the technology and taking it back to their home countries and elsewhere.