Herrenknecht Vertical GmbH presents its first deep drilling rig

Conventional deep drilling systems are not always suitable for such projects, since they are mainly oriented towards the demands of oil and natural gas drilling. That's why the Federal Ministry for the Environment, Nature Conservation and Nuclear Safety has promoted the development of new a deep drilling rig as part of its energy research program. With the "HotRock 1" deep drilling rig presented today, Herrenknecht Vertical GmbH now offers the market a machine which is especially designed to meet the requirements of geothermal drillings.

Considerable noise reduction

The great improvement in noise protection during machine operation is one of the most important innovations. Drilling near inhabited areas is often necessary during geothermal projects. Thus, Herrenknecht Vertical GmbH's engineers integrated comprehensive noise protection measures even during the construction phase of the now completed "HotRock 1" deep drilling rig, which will bore to depths of 3,500m to 5,000m in densely populated areas. The noise pressure level of the 3 slush pumps was significantly reduced by enclosing them in casings, while each of the 1,540kVA generators driving the rig was equipped with optimized exhaust silencers and air flow routing. For the two hydraulic cylinders of the lifting unit, noise reduction was achieved by means of pulsation damping. All these noise protection measures in combination mean the expected noise pressure level at a distance of approx. 150m from the rig is about the same as a domestic TV or radio at normal listening volume.

Maximum safety

The issue of work safety generally plays an important role in the drilling industry. Therefore, Herrenknecht Vertical GmbH also focused on this aspect during the development of the new deep drilling rig. New standards can be set by integrating extensive automation processes (hands off technology). Here, the completely new pipe handling system is unique. All handling of the drilling rods (max. length 19m, max. weight 4.5t) is carried out by means of a pipe handling system. This facility uses a scratch buffer when lifting the rods from their bearings onto the more than 9m high working platform. The horizontal positioning of the rod bearings next to the drilling rig, together with the pipe handling system which can be controlled from the control platform, allows the pipe to be transported safely throughout the entire process. No personnel need work in the hazard zone during this process.

The principle of hands off technology is also applied when tightening or loosening the bolts of the rods. The drilling rods are joined to or separated from the vertical bolting unit using partially automated processes. Since this process is also controlled from the control platform, no personnel need work in the hazard area.

More economic efficiency in drilling

Herrenknecht Vertical GmbH's engineers also investigated the potential for reducing drilling costs when developing the new concept for the deep drilling rig. In geothermal projects the cost of boring drilling holes down to a depth of 5,000m represents the largest portion of the budget and most of the project risk. In order to reduce drilling costs, the electricity for the Herrenknecht Vertical deep drilling rig will be taken from the public power grid. The rig can additionally be operated with commercially available generators. The comprehensive energy management system of the "HotRock 1" and the relevant components makes for considerable savings.
In addition, the overall drilling area can be kept very small in comparison with conventional equipment. The area required to assemble the complete deep drilling rig is no more than approx. 30 x 80m.

The Herrenknecht Vertical unit is optimally equipped for use in geothermal projects. After final testing by the owner, HotRock GmbH (Karlsruhe), the deep drilling rig will be employed in the commercial zone of the municipality of Bellheim (southern Germany). The geothermal power plant which is planned there will later produce 5-6 MW of electric power.