Since the introduction of the first 400 tonne modular rig in the Netherlands, Germany and Spain, more equipment is now in operation in large infrastructure projects. Herrenknecht is now placed among the leading manufacturers of HDD equipment, supplying the complete package (drill rig, mud pumps, recycling units, transfer pumps, tools, drill pipe, etc.) from one source together with full technical support to maximise performance.
Special design modular rigs permit easy transportation as well as site set-up without the need for mobile cranes. For a 400 tonne rig, transportation can be made in 20 ft shipping containers with a maximum piece weight of 28 tonnes.
Trailer rigs offer fast mobilisation where access to the drill site is possible by road. Crawler rigs offer excellent manoeuvrability for difficult access. Basic frame rigs are also available to complete the four different styles of rig offered, all of which utilise rack and pinion power transmission. State of the art closed circuit hydraulic systems permit constant speed operation of the diesel engine prime mover with subsequent economies of fuel consumption.
Three trailer type rigs are currently in operation on the East – West gas pipeline in China where a 760 m long crossing (813 mm diameter) was completed in only one week.
Tight deadlines for completion of the 1,760 km long BTC pipeline (a double 46 and 42 in. oil and gas pipeline) from Baku in Azerbaijan, via Tbilisi in Georgia, to Ceyhan in Turkey by end of 2004 employ a further two 250 tonne rigs and high pressure mud pumps.
Proven performance in the high temperatures of Asia as well as extreme low temperatures (approx. minus 40oC) in Khanty Mansisk, Siberia, demonstrate the high reliability of these new rigs.
Yet another 250 tonne trailer rig is currently on route to Moscow to undertake two river crossings in the capital city of Russia.
New Developments in HDD technology
Further developments are underway to extend the range of soil conditions in which HDD techniques may be applied. Push Pull Technology (PPT) combines HDD and microtunnelling to offer a new equipment variant capable of completing large diameter bores in a single reaming operation. Field trials for installation of 1,000 mm diameter pipe have proven the technique through difficult gravel layers.
2004 also sees the first of a new range of thruster units. These all hydraulic operated devices can be used with pipes in the range 32 to 48 in. providing up to 500 tonnes additional thrust in emergency cases.
Worldwide experience in rental of microtunnelling equipment is now further extended to include for rental of HDD rigs and ancillary equipment, as well as the new PPT technology and thrusters in the near future.