Electric Impulse Technology: Long Run Drilling in Hard Rocks

Abstract

The costs of drilling in hard rock depend significantly on the available drilling technology. Conventional drill bits are especially adapted to the needs of the oil and gas industry but they are limited for drilling in crystalline formations. The Electric Impulse Technology offers a promising alternative for this purpose. The splitting effect of electrical explosions inside the rock is used to destroy the rock instead of working mechanical against the compressive strength of the rock. In a project funded by the BMWi (project number 0325253) a drill head was developed, which consists of a pulse power source of up to 500 kV and electrodes for a 12 ¼″ borehole. The drill head is designed for downhole pressures up to 1000 bar and temperatures up to 200 °C. A test stand has been implemented at the TU Dresden. Drilling tests under borehole like conditions could be performed. Drilling speeds of 1 m/h could be proven. The follow-up project started in the end of 2014. The drill head will be optimized and the power supply will be designed. The total system will be used in a test well and investigated.