Since 2000, Japan has drilled nearly three dozen exploratory well holes in the Nankai Trough.

FORBES

The Deepwater Horizon rig was leased to oil giant BP to drill an exploratory well.

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Ocean had mixed success last year, with modest commercial success at one exploratory well in the deepwater Gulf and two failures.

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It is due in Cuban waters by the end of the year, contracted by Spain's Repsol to drill an exploratory well.

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When seismic surveys show that there is a good chance of finding oil, companies set about the delicate process of drilling an exploratory well.

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First to use it will be the Spanish oil company Repsol YPF, which plans to drill an exploratory well around 100km (62 miles) from the Florida Keys.

BBC: The Scarabeo 9 rig

This was an exploratory well.

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The BP Deepwater Horizon well was an exploratory rather than a production well, so the oil to be extracted from this was not planned on -- that was not planned to go online immediately.

WHITEHOUSE: Press Briefing

Increasing oil production takes quite a few years, involving time spent on seismic studies, exploratory drilling, production drilling, as well as construction of infrastructure for transportation and refining.

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Representative TANCREDO: Well, once I see the degree to which my exploratory committee has any degree of success, once I see that, then I'll be able to know a lot more about whether my earlier statement was accurate.

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