Drilling Method and Apparatus

Abstract

Apparatus for drilling a borehole from a first subterranean location to a second subterranean location, comprises a casing (4) extending longitudinally inside a borehole, a conduit (6) extending longitudinally inside casing (4), and capable of being in sealing relationship therewith, at least one entry line (23,24) for liquid into the apparatus, a first annulus (22) between the casing (4) and conduit (6), at least one entry for liquid in the conduit, a tubing (14) having a first end and a second end (16), a remote controlled electrically powered drilling device (12) and remote controlled electrically powered pump, the device and pump being capable of being in fluid contact with the first end of the tubing (14), the second end (16) of the tubing (14) being inside the conduit (6) at a location more remote from the drilling device (12) than the entry for liquid in the conduit (6), with the conduit (6), tubing (14) and first end and second end (16) of the tubing (14) being adapted to provide routes for liquid contact between conduit (6) and drilling device (12), the routes being respectively internally and externally of the tubing (14).

Description

FIELD OF THE INVENTION[0001]The present invention relates to a method of drilling a borehole from a selected location in an existing wellbore penetrating a subterranean formation using a remotely controlled electrically operated drilling device wherein the drilling device is introduced into the existing wellbore through a conduit and water is pumped over the cutting surfaces of the drilling device using a remotely controlled electrically operated pumping means to cool the cutting surfaces and to transport drill cuttings away from the drilling device.BACKGROUND OF THE INVENTION[0002]In conventional methods of wellbore drilling a drill string including a drill bit at its lower end is rotated in the wellbore while drilling fluid is pumped through a longitudinal passage in the drill string, which drilling fluid returns to surface via the annular space between the drill string and the wellbore wall. There are certain restrictions to the drilling process, and particularly to the length of...

AI Technical Summary

Benefits of technology

[0021]One benefit of these more preferred embodiments is that the annulus has the sealing means such as a packer stopping flow out of the annulus at its bottom and directing it into the conduit thereby retaining the presence of the packer or other sealing means, which is highly desirable for safety and legal reasons.

[0060]The passage(s) in the conduit may be a slot or other pre-shaped hole, rectilinear or curved e.g. circular, which pre-shaped hole may be coverable by a sliding sleeve, adapted to be moved between two locations allowing or denying passage of liquid through the conduit wall. Its movement may be controlled e.g. from the surface by mechanical or electrical means. The benefit of using a coverable single slot is that the apparatus can easily alternate between use in lateral drilling with the slot open and use in normal oil production without gas lift with the slot closed.

Problems solved by technology

It is not suitable for producing wells, that are not producing because they are shut in or have insufficient formation pressures, or for water injection wells in water bearing formation, or barren formations bearing neither water or liquid hydrocarbon.

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