If our new Combi 300 thought it was going to have an easy life, it was mistaken. It Initially drilled a test borehole through the magnesian limestone at our depot in Seaham County Durham to familiarise the drillers with the controls. It coped well handling the difficult broken and powdery strata drilling a 225mm borehole to 110mbgl. It was then sent to a proper job, to drill a Water monitoring borehole to a proposed depth of 600mbgl.
This was more of a challenge and would test the machine’s capability.
The borehole was drilled through the Triassic Formation to 90mbgl at 460mm diameter. A 300mm steel casing then installed and the annulus fully grouted.
The Permian Formation was then drilled at 290mm diameter to 175mbgl. A 240mm steel casing was now installed and the annulus grouted throughout.
Coal Measures Formation was now drilled to 580mbgl. A 150mm steel casing was now installed with the annulus grouted.
The borehole was then advanced to target depth of 610mbgl at 145mm Ø. The borehole was tested for verticality at regular intervals during construction and was completed at 89.6 degrees. Only 0.4 degrees off vertical – excellent accuracy!!
The rig handled the project without any difficulty and judging by the controls, could easily have deepened the borehole to 700mbgl. Our young drillers Scott, Jake and Sam achieved their personal record depth.
For more information on Drilcorp’s Combi 300 drill, contact our UK-based team today via our online form or call the team on 0808 175 5228.
