CH2M

HORIZONTAL DIRECTIONAL DRILLING

Meehan Drilling Ltd were awarded the project of installing a 580m remedial horizontal well for the main contractor CH2M. The ultimate client was Du Pont of Maydown, Londonderry.

In commencement of the pilot bore, an 200mm tri-cone bit was utilised for the pilot bore to ensure accuracy of the drilling profile. Our targets were to drill 580m at a maximum depth of 28 metres below ground level. The parameters of the profile were crucial to the success of the remedial well. Tolerances of plus / minus 1 metre were achieved. Operations were 24 hours to maintain the stability of the bore and productivity.

Geological conditions were not favourable, but our highly skilled crew of drill fluid engineers found the solution to achieve the perfect drilling mud. Environmentally friendly bentonite was mixed with fresh water (which had a balanced PH of 8.5) via a high shear pump. This produced the high viscosity required to allow progressive drilling.

Upon completion of the pilot bore, the stainless-steel product pipe of 150mm in diameter was installed over the 580 metres within 7 hours. The pipe was welded in 3 sections. The centre section was perforated with 0.3mm slotted sections to allow the water to permeate through and flow down the pipe to a collection point. From here, the water was transferred to a water treatment plant. After treatment, the clean water is returned to the nearby river Foyle.