Underreamer Eccentric (URE)
The Holte Percussion Underreamer is a two piece tool, a driver section & a bit section. The driver, or splined section fits into a down hole hammer.
The bit section has a pilot portion that is out of center to the rest of the bit and the drill string. As the hammer rotates, the pilot section tries to center itself. The friction of the nose of the bit on the wall of the well bore also helps pull the nose out from under the casing so it will drill a larger hole than the OD of the drive shoes on the casing.
The whole bit swings out and has a short heavy pin on the top side that fits into a pocket on the driver. A small portion of the air escapes between the wall of the driver pocket and the pin portion of the bit. This keeps the bit free from sticking in place so that a very minimum of reverse rotation will swing the bit back in alignment with the drill string for retraction.
The percussion underreamer along with a small compact Holte Casing Driver (which also serves as a diverter for water and air cuttings) will allow the casing to be placed easily in areas where it would have been a major struggle or next to impossible.
URE Underreamer is also available in a Drive Shoe Style for use without a Casing Driver. Both Eccentric Overburden Systems are available between 5″ – 12″.
The Holte Casing Driver (CD) was designed to be small and compact as well as hard hitting like a Down Hole Hammer (DHH). While the CD cycles fast like a DHH it is able to be designed around a much larger piston since it is above ground, in turn, deriving an extremely powerful impact for driving casing, allowing your DHH to run most efficiently since its energy is not absorbed trying to pull casing along with it.
The Holte Casing Driver is designed to be used with a DHH (Down The Hole Hammer) and underreamer, and is available in four sizes from an easily portable size for light duty rigs to a heavy duty size for the most extreme well and hole conditions.
The casing drive acts similar, in operation, to a down hole hammer. When the hole is first started and until gravity is not enough to make the casing follow the underreamer the casing driver sits inactive on top of the casing and acts as a water diverter. When the underreamer advances 1” ahead of the casing the CD anvil closes and the casing driver starts operating. The more the anvil is closed, the harder the casing driver hits. This happens when increased air pressure and volume feeds the casing driver which makes the piston operate faster and harder. The CD turns on and off automatically and runs only when the casing lags behind the underreamer, causing the anvil to close. There is only 1 1/4” of vertical movement of the CD anvil so the casing will always remain within 3” of the bit.
Maximize your underreaming with a Holte URE designed to have a wider cutting edge where you need it most. The Holte oval shape places more cutting edge on the bore hole wall. The URE Drive Shoe Style Underreamer is similar to the Casing driver style except the driver portion has a drive shoulder. This shoulder drives down the drive shoe that is welded to the casing. With this system, the down hole hammer is used to both drill and drive casing.
Eccentric Overburden Systems are available between 5″ – 12″.
UnderReamers Eccentric (URE) | Sizes & Part Numbers
|UnderReamers Eccentric (URE)|
|5" URE Driver: 4” IR Hammer DS Style/5" DS Bit Assembly||070105-0411|
|5" URE Driver: 4” IR Hammer CD Style/5 CD Full Bit Assembly||070105-0412-1|
|5" URE Driver: 4” IR Hammer CD Style/5" DS O/S Bit Assembly||070105-0412-2|
|5" URE Driver: 4" IR Hammer, Drive Shoe Style||100457|
|5" URE Driver: 4" IR Hammer, Casing Drive Style||100459|
|5" URE Driver: 4" Mission Hammer DS Style/5" DS Bit Assembly||070105-0421|
|5" URE Driver: 4" Mission Hammer CD Style/5" CS Full Bit Assembly||070105-0422-1|
|5” URE Driver: 4" Mission Hammer CD Style/5" CS O/S Bit Assembly||070105-0422-2|
|5" URE Driver: 4" Mission Hammer, Drive Shoe Style||100461|
|5" URE Driver: 4” Mission Hammer, Casing Driver Style||100463|
|5" URE Driver: 5” IR Hammer DS Style/5" DS Bit Assembly||070105-0511|
|5" URE Driver: 5" IR Hammer CD Style/5" CS Full Bit Assembly||070105-0512-1|
|5" URE Driver: 5" IR Hammer CD Style/5" CS O/Sl Bit Assembly||070105-0512-2|
|5" URE Driver: 5" IR Hammer, Drive Shoe Style||100458|
|5" URE Driver: 5” IR Hammer, Casing Drive Style||100460|
|5" URE Driver: 5” Mission Hammer DS Style/5" DS Bit Assembly||070105-0521|
|5" URE Driver: 5" Mission Hammer CD Style/5" CD Full Bit Assembly||070105-0522-1|
|5" URE Driver: 5" Mission Hammer CD Style/5 CS O/S Bit Assembly||070105-0522-2|
|5" URE Driver: 5" Mission Hammer, Drive Shoe Style||100462|
|5" URE Driver: 5” Mission Hammer, Casing Driver Style||100464|
|5" URE - Bit, Drive Shoe Style (Retaining Kit Included)||100465|
|5" URE - Bit, Casing Drive Style Full size (Retaining Kit Included)||100466|
|5" URE - Bit, Casing Drive Style Over Size (Retaining Kit Included)||100467|
|5" URE - Retaining Pin||100468|
|5" URE - Includes: Locking Pin, Spring, Rubber Plug and Glue||100469|
|5" URE - Ball Style Kit Drive Shoe||100960|
|5" URE - Ball Style Kit Casing Drive||100961|
|5" URE - Blow Tube/Foot Valve/Mission SD5||100470|