Basically, you can drill as deep as you want. A “deep hole” hydraulic core drilling rig can drill down to 2 500 m with H-size (96 mm) coring today. The weight of the drill string sets the limit of how deep you can drill. The rods also have a limitation of load to take.
Similar depth limitation is valid for Wassara. Keep in mind that the number of bit changes makes the hole less easy to core drill in later. We do recommend changing the bit once per borehole. The borehole depth you can reach with two bits is very much dependent on the formation.