Patent ID: 7487846
Filing Date: 2009-02-10
Classification: E21B

Abstract:
1. A method of drilling a borehole from a selected location in an existing wellbore penetrating a subterranean earth formation having at least one hydrocarbon bearing zone wherein the existing wellbore is provided with a casing and a hydrocarbon fluid production conduit is arranged in the existing wellbore in sealing relationship with the wall of the casing, the method comprising: passing a remotely controlled electrically operated drilling device suspended on a cable that encases at least one wire and/or segmented conductor for transmitting electricity or electrical signals, from the surface through the hydrocarbon fluid production conduit to the selected location in the existing wellbore; operating the drilling device such that cutting surfaces on the drilling device drill a new wellbore section from the selected location in the existing wellbore thereby generating drill cuttings wherein at least a lower section of the cable from which the drilling device is suspended lies within a length of tubing having a first end that is in fluid communication with a fluid passage in the drilling device and a second end that extends into the hydrocarbon fluid production conduit and wherein during operation of the drilling device, a first stream of produced fluid flows directly to the surface through the hydrocarbon fluid production conduit and a second stream of produced fluid is pumped over the cutting surfaces of the drilling device via a remotely controlled electrically operated downhole pumping means and the drill cuttings are transported away from the drilling device entrained in the second stream of produced fluid.