New Product Bulletin No. 1
March 1, 2002

Stabilized Core Barrel Outer Tubes

The purpose of using a stabilized core barrel outer tube in wireline core drilling is to assist in minimizing the degree of drill hole angular deviation in target or deep hole drilling situations. The increased stability that these products provide will result in less vibration, a straighter drill hole and better core recovery.

These tools are used in place of conventional blank core barrel outer tubes or all-steel, fluted (milled) core barrel outer tubes and are available in the AQ, BQ, NQ and HQ wireline sizes. When used in conjunction with a stabilized adapter coupling and stabilized locking coupling, a stabilized outer tube adds considerable rigidity to the core barrel assembly by limiting the amount of potential flexing that can occur between the bit and core barrel back-end, particularly under higher bit loads. An advantage of these stabilized outer tubes is that they have an inherently lower degree of fluid passage restriction between the stabilizing elements and the hole wall than do all-steel fluted outer tubes. This allows the fluid and cuttings from the bit and reaming shell to be ejected freely and results in less wear on their steel tool bodies.

Typically, all 10 foot or 3 metre stabilized outer tubes are supplied with 3 full matrix body stabilizer ring elements that are cast onto the steel tool body for maximum bond strength and tool integrity. In addition, these stabilizer ring elements feature spiral waterway canals that both effectively clear the bit cuttings and provide full 360° hole contact.

These tools are intended to stabilize and not cut. Therefore, they are purposely not set with any natural or synthetic diamond materials. The stabilizer ring elements on these tools are set with angular-shaped tungsten-carbide particles that are embedded into a tough, abrasion resistant matrix body. In addition, the set diameters of all of these tools are slightly smaller than that of the companion reaming shell but are slightly larger than that of the companion core bit.