In preparation for directional drilling, a wedge supported distally ahead of a tubular drill string is advanced along a parent hole. The wedge is connected to the drill string by a rigid link that extends along a central longitudinal axis through an annular cutting head. The wedge may be connected to the drill string via an inner dropper mechanism that can be engaged by a wireline lifting system. After locking the wedge at a kick-off point in the hole at a desired azimuth, the connection of the link is broken. The dropper mechanism can then be retrieved and replaced by an inner core tube, without moving the drill string. The drill string is then advanced to drill a daughter hole that branches from the parent hole on the azimuth determined by the wedge. Advantageously, there is no need to withdraw the drill string before drilling the daughter hole can commence.
E21B 23/04 - Apparatus for displacing, setting, locking, releasing or removing tools, packers or the like in boreholes or wells operated by fluid means, e.g. actuated by explosion
E21B 25/02 - Apparatus for obtaining or removing undisturbed cores, e.g. core barrels or core extractors the core receiver being insertable into, or removable from, the borehole without withdrawing the drilling pipe
E21B 47/024 - Determining slope or direction of devices in the borehole
In preparation for directional drilling, a wedge supported distally ahead of a tubular drill string is advanced along a parent hole. The wedge is connected to the drill string by a rigid link that extends along a central longitudinal axis through an annular cutting head. The wedge may be connected to the drill string via an inner dropper mechanism that can be engaged by a wireline lifting system. After locking the wedge at a kick-off point in the hole at a desired azimuth, the connection of the link is broken. The dropper mechanism can then be retrieved and replaced by an inner core tube, without moving the drill string. The drill string is then advanced to drill a daughter hole that branches from the parent hole on the azimuth determined by the wedge. Advantageously, there is no need to withdraw the drill string before drilling the daughter hole can commence.
E21B 23/04 - Apparatus for displacing, setting, locking, releasing or removing tools, packers or the like in boreholes or wells operated by fluid means, e.g. actuated by explosion
E21B 25/02 - Apparatus for obtaining or removing undisturbed cores, e.g. core barrels or core extractors the core receiver being insertable into, or removable from, the borehole without withdrawing the drilling pipe
E21B 47/024 - Determining slope or direction of devices in the borehole
In preparation for directional drilling, a wedge supported distally ahead of a tubular drill string is advanced along a parent hole. The wedge is connected to the drill string by a rigid link that extends along a central longitudinal axis through an annular cutting head. The wedge may be connected to the drill string via an inner dropper mechanism that can be engaged by a wireline lifting system. After locking the wedge at a kick-off point in the hole at a desired azimuth, the connection of the link is broken. The dropper mechanism can then be retrieved and replaced by an inner core tube, without moving the drill string. The drill string is then advanced to drill a daughter hole that branches from the parent hole on the azimuth determined by the wedge. Advantageously, there is no need to withdraw the drill string before drilling the daughter hole can commence.
E21B 23/01 - Apparatus for displacing, setting, locking, releasing or removing tools, packers or the like in boreholes or wells for anchoring the tools or the like
E21B 25/02 - Apparatus for obtaining or removing undisturbed cores, e.g. core barrels or core extractors the core receiver being insertable into, or removable from, the borehole without withdrawing the drilling pipe
In preparation for directional drilling, a wedge supported distally ahead of a tubular drill string is advanced along a parent hole. The wedge is connected to the drill string by a rigid link that extends along a central longitudinal axis through an annular cutting head. The wedge may be connected to the drill string via an inner dropper mechanism that can be engaged by a wireline lifting system. After locking the wedge at a kick-off point in the hole at a desired azimuth, the connection of the link is broken. The dropper mechanism can then be retrieved and replaced by an inner core tube, without moving the drill string. The drill string is then advanced to drill a daughter hole that branches from the parent hole on the azimuth determined by the wedge. Advantageously, there is no need to withdraw the drill string before drilling the daughter hole can commence.
E21B 25/02 - Apparatus for obtaining or removing undisturbed cores, e.g. core barrels or core extractors the core receiver being insertable into, or removable from, the borehole without withdrawing the drilling pipe
E21B 23/01 - Apparatus for displacing, setting, locking, releasing or removing tools, packers or the like in boreholes or wells for anchoring the tools or the like
patents
