DrillTec undertook shoreline crossing works using horizontal directional drilling (HDD) as part of Apache Energy’s Devil Creek Development Project at Forty Mile Beach. The shoreline crossing works at Gnoorea Point will connect the offshore section of the pipeline with the onshore sections via a 1,850 m buried pipeline. Drilling operations under the shoreline commenced in late February and continued under 24 hour operations until August. The 350 tonne DrillTec rig was used to drill the bores.
The crossing was particularly challenging due to the nature of the ground formation. The initial 400 m of the alignment consisted of sand and weak sandstones which required a 28 inch casing to be installed to provide the necessary support for the forward reaming operations. The remainder of the crossing consisted of granites and a series of extremely hard dolerite dykes. During the drilling operations DrillTec welded and pre-tested the HDD product string ready for subsequent thrusting using the DrillTec-designed and built pipe thruster.
The final phase of thrusting involved a 250 m section of pipe being pushed onto the seabed, which was guided by a vessel offshore into the final position. After completion of the thrusting DrillTec performed the tie-in operations to the onshore section of pipe.
DrillTec is a specialist drilling company with expertise in hydrocarbon, geothermal and HDD (specialising in shore approaches) for the oil, gas and water industries. DrillTec has extensive worldwide experience and is currently undertaking projects in Europe, South Asia, Russia and the Middle East.