Geothermal energy is one of the cleanest forms of energy to satisfy the growing global demand. Many countries around the world, including the USA, have a huge potential of untapped geothermal energy. Enhanced Geothermal Systems (EGS) technology is needed to economically utilize this resource. If hot rock is sufficiently fractured with continuous channels interconnecting large volumes of rock, a very large surface area is created that enables to economically extract geothermal energy from deep in the ground. The US Department of Energy (DOE) spearheads research and innovation in tools and technologies required for a successful exploitation of such EGS reservoirs where the temperature can exceed even 300°C.
To effectively utilize EGS resources, an array of injector and producer wells must be accurately placed in the formation fracture network. This requires a directional drilling system capable of high temperature whereas most commercial services for directional drilling systems are rated at 175°C. Deeper drilling will generally become more common in the future for new reservoirs and therefore high temperature drilling technology will be equally useful to the oil and gas industry.
We will discuss the development of a 300°C directional drilling positive displacement motor. Emphasis is put on design and manufacturing challenges of the multi-lobe metal only power section.
With the assembly and successful test of two complete tools in a test well at the Baker Hughes Experimental Test Area (BETA) in Oklahoma a major mile stone has been accomplished. Additional tests on the motor test bench in Celle (Germany) have been conducted to further improve durability. The utilization of the tools in a commercial geothermal well is planned for the second half of 2014.
