AMC BOS™ saves 77% in operational costs compared to traditional cementing method

AMC BOS™ reduced drilling fluids needed by 50%, eliminated the need for a costly, time consuming cementing/grouting and improved the average bit life used. The new solution delivered significant productivity improvements to the operation at the Resolution Copper site in Arizona, USA.

Challenge

After a successful trial on another hole at the Resolution Copper Mine in Arizona, AMC was assigned a dedicated hole to trial of the AMC Borehole Optimisation System™ (AMC BOS™) to improve efficiencies across the full course of drilling.

The crew had been facing a variety of issues in the region with sections of the whitetail conglomerate formation breaking free and causing constant reaming and excessive wear on bits. Drilling through the other troubling formation; cretaceous volcanic sediment, resulted in excessive clay leaching and swelling of the ground, causing the rods to stick and pinch. These unpredictable and unstable formations contributed to excessive drill bit wear from the repeated reaming and rod tripping. The increase in rod tripping increased exposure to hazards for the crew on site.

Results

  • Eliminated cost of cementing/grouting, vacuum truck and displacement of contaminated drilling fluids
  • Improved rig productivity by 4 days, contributing to considerable cost savings
  • 50% reduction in drilling fluids used on-site, allowing drillers to focus on drilling and not mixing mud
  • Improved site safety – less exposure to injury due to unnecessary rod trips for prematurely worn drill bits
  • Significant torque reduction – up to 27%
  • Over 50% improvement in bit life, only 4 bits used from the cut-out wedge at 3,428ft to the bottom of the 6,770ft borehole.

Solution

Due to AMC’s success on the original hole, a three month trial was to be conducted with the new AMC BOS™. The AMC BOS™ is a rapid descent, dual action in-hole casing unit which delivers a measured amount of AMC BOS FIX™ at regular intervals down the borehole. The AMC BOS UNIT™ deploys the AMC BOS FIX™ at precise locations from the bottom of the drill string into the strata and migrates into the annulus to develop a plasticising membrane on the borehole wall.

Due to formation instability in the area, the drill crew had previously implemented cementing/grouting to cure a borehole. Carrying out a cement squeeze raises the challenge of disposing of 20,000 gallons of contaminated fluids, and then requiring vacuum trucks to haul the contaminated drilling fluids off-site. In comparison, AMC’s system proved more cost effective, with an estimated 77% saving compared to the traditional method.

In addition to the 77% saving in costs associated with a potential cement squeeze, there was also a significant productivity improvement. With the new AMC BOS™ in place, it enabled the crew to improve their rig productivity by 4 days over the course of drilling the borehole.

There was a significant increase in fluid returns once the new system was in place. It was not uncommon for the fluid returns to reach only a maximum of 30% prior to the introduction of the AMC BOS™, now close to 80% returns had been achieved with the new system in place. Circulation was lost on six separate occasions throughout the duration of the program and each time was regained due to targeted injections from the the AMC BOS™.

Prior to the introduction of the AMC BOS™, there were eight individual products being used on each hole. The new system provided a 50% reduction in products used, allowing the crew on-site to focus drilling through the tough formation rather than mixing mud.
Before
After

Project Outcome

In comparison to using the traditional cementing/grouting methods, the AMC BOS™ provided a number of operational efficiencies on site, proving to be a highly cost-effective. The solution provided the following significant operational efficiencies;

  • Reduced rig utilisation by 4 days, contributing to considerable cost savings
  • Saved significant time compared to the traditional grouting/cementing method due to the fast setting and inexpensive AMC BOS FIX™
  • Eliminated the cement squeeze cost, vacuum truck and displacement of contaminated drilling fluids
  • Improved site safety - reduced exposure to hazards due to unnecessary rod trips of prematurely worn drill bits
  • Significant torque reduction – up to 27%
  • Over 50% improvement in bit life, only 4 bits used from the cut-out wedge at 3,428ft to the bottom of the 6,770ft borehole.
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