________________ A joint research project funded by the Federal Ministry for Environment, Nature Conservation and Nuclear Safety (BMU) is creating the foundations for the safe design of drilling rigs and, in particular, the development mud pumps in collaboration with Herrenknecht. The aim is to increase the reliability and operational safety of deep drilling rigs and, at the same time, to reduce the operating costs. The development focuses are, in particular, an integrated global diagnostic system and a damper system for efficient pulsation damping in the mud pumps.
An early detection system to minimize risks and drilling costs
The German Federal Government has set itself the goal of increasing the percentage of geothermal energy in the overall energy consumption of the Federal Republic of Germany considerably in the next few years. The plan is to use geothermal energy more widely in the future, to increase the energy yield and to reduce the set-up and operating costs. Therefore, early detection of wear is of great importance to reduce costs in geothermal plants. According to the Federal Gazette, developing equipment, devices and machines "that function reliably, energy-efficiently and with low maintenance needs under the typical high geothermal temperatures, pressures and corrosive conditions" constitutes a major contribution to this cost reduction. This applies in particular to the development of pumps. Wear in the pump systems can lead to malfunctions and unplanned breakdowns during a geothermal drilling process. Therefore, the development of an early detection system is in the interests of the plant operator and of all other parties involved in order to keep the costs and the risks as low as possible.
Special importance is given to the modernization and further development of the drilling technology. The lack of a state-of-the-art method as well as high drilling costs are currently highly limiting factors. The drilling processes represent the most expensive factor in geothermal projects. To reduce these processes is therefore a key aspect for the further extension of geothermal energy in Germany. Drilling processes present the greatest risk for investors, because the feasibility of a project is only known after a first drill has been carried out. Through a comprehensive adaptation and further development of the technology, and the resulting minimization of the drilling time, a cost minimization can also be achieved.
The aim: to avoid unexpected failures of the mud pumps.
The use of displacement pumps in deep drilling rigs has proven its worth in recent years. The borehole safety is primarily dependent on a functioning flushing circuit. To avoid the sudden failure of mud pumps, the study will first examine to what extent wear can be automatically diagnosed through early detection and notification of failures. Furthermore, the possibility of changing the method in favor of a pressure-side pulsation dampening will be examined: The currently employed gas-prestressed pulsation dampers could be replaced with a different physical procedure for reducing the pressure-side pulsation.
Developing the foundations for the reliable design of the mud pumps and an overall diagnostic system increases the reliability of the entire deep drilling rig. Ultimately, the early detection of occurring damage is essential to increase safety for borehole, plant and personnel. Only more extensive knowledge about the state of the mud pump will help reduce maintenance measures in a targeted manner.
The continuous further development and adaptation of drilling technology to the needs of future projects is one of the main factors securing the competitive edge of German companies in the use of low-enthalpy geothermal reservoirs in deep geothermal energy.