Setting
Media Luna is located in the Guerrero Gold belt. The commercially viable ore is in a skarn deposit, where the skarn is the result of contact metamorphism between the sedimentary formations (primarily limestone and siltstone), and intrusive bodies.
AZIWELL has been working with Torex Gold at the property since 2018, using the N-size AZIDRILL® Directional Core Drilling tool.
More details about the challenging environment and how the N-size AZIDRILL® was used can be read in the #25 issue (11/23) of Coring Magazine.
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Developing a revolutionary tool
The existing technology for drilling H-size holes is rather limited: mud motors, or wedges (continuous or static). Both options lack one critical element: continuous curvature with core recovery.
Not only does a Directional Core Barrel recover, as the name suggests, a core sample, but the decrease in contact surface between the rock and the drill bit leads to higher production rates, which is always an important factor for cutting costs in an exploration project.
To further add to the list of benefits, it has the same water consumption as traditional Conventional Core Barrels, making it exceedingly more environmentally friendly to use over mud motors.
In order to address these needs of the industry, AZIWELL has developed the H-size AZIDRILL®, which recovers N2 core samples with a diameter of 50.6mm (2”). It is the world’s first commercially available H-size Directional Core Barrel.
Carrying out the test
Due to the long collaboration between Torex Gold and AZIWELL, the parties showed interest in field testing the new tool at Minera Media Luna. For the test to reflect exactly a real-life scenario, two directional holes were planned that had to hit commercially relevant targets. In short, the test did not just simulate a real-life scenario, but proved to be one.
To plan the trajectory of the boreholes, AZIWELL’s NAVIGATOR planning software was used. Two targets were chosen by Torex Gold, with total depths of 341.85 and 432.85 meters respectively. Two mother holes were to be drilled initially, followed by two curves, each planned with a dogleg severity of 5 degrees.
For the first target, a mother hole was initially drilled to a depth of 223.6 meters. After which, the AZIDRILL® was lowered and the first commercial directional drillhole with core recovery in H-size began on the 18th of October, 2023. It took a couple of days to adjust the tool and reach the desired dogleg severity. However, once the settings were figured out and the proper adjustments were made, the production rate shot up to 33 meters of curve which were drilled during the 6th day, in the desired direction and with the correct dogleg severity, nonetheless.
The needed inclination and azimuth were reached on the first hours of the 7th day, with a total curve length of 107.95 meters.
The second target needed a much shorter curve, ending with a total of 58.6 meters, taking just 4 days and a few hours to complete.
Below you can find the tables with the daily production for the two curves:
Table 1 - Daily production break-down for the 1st curve
18 Oct 4.65m
19 Oct 6m
20 Oct 17.6m
21 Oct 16.1m
22 Oct 21.6m
23 Oct 33m
24 Oct 6m
Table 2 - Daily production break-down for the 2nd curve
2 Nov 0.4m
3 Nov 12.15m
4 Nov 14.4m
5 Nov 10.1m
6 Nov 21.5m
