Using Spiral Stabilizer Subs To Keep RC Drill Holes On Target By Minimising Deviation

Introduction – Spiral Stabilizer Sub Case Study

The drilling industry is always looking for improvements in tools and techniques for quality, efficiency and cost improvements. Problems with hole deviation arise from time to time but can be contained and eliminated with the right equipment and right drill string configuration.

Deviation when drilling deep reverse circulation holes

Harlsan was approached by a customer regarding problems they had drilling 360m deep reverse circulation holes. Some of the holes had deviated more than 5 degrees off the intended azimuth when measured at the bottom of the hole. As the RC holes were to be used as pre-collars for much deeper diamond drilling they needed to be as accurate as possible. The customer had used conventional dig-out & stabiliser subs to try and counter the problem of deviation but they have had mixed, inconsistent results.

Spiral stabilizer sub solutions for drill hole deviation

In response to the customers problem we supplied specifically designed spiral subs for hole stabilization and hole deviation reduction. The drilling benefit was immediate with hole deviation being bought under control resulting in consistent and repeatable drilling results. The customer was very satisfied with the outcome.

How spiral subs work

Our spiral subs are engineered to marry the benefits of dig-out and stabilizer sub with advanced manufacturing capabilities. The spiral arc hard facing tracks an exact mathematical curve around the body of the sub and it’s the engineered characteristics of this curve that lead to the spiral subs ability to control deviation.

Application support for spiral stabilizer subs on your drilling rig

There are a range of options to consider when setting up a spiral sub on a drill string. The suitability of the options will depend on a number of factors specific to the drill rig and the drilling conditions. For example, a successful configuration for some customers is a 500mm spiral sub above the hammer sub, followed by a 3m lead rod and a second 500m spiral sub. The experience Harlsan has had helping others drillers will be a valuable asset in helping you chose the correct set up.

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About Harley Hollier

Harley Hollier has had extensive experience in the reverse circulation drilling industry as a director of Harlsan Industries. Harley’s current industry roles incorporate the engineering, research and development of innovative reverse circulation drilling equipment and supporting customers with drilling application and solution development. He can be contacted on Ph. +61 8 9021 1288 (GMT +8 Hours) or email:
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