Russian drilling technologies. Conclusion. Russia shares technical know-how with US. D.E. Gaddy. OGJ, 8 March 1999, 97(10), 51, 52, 54--56.
Consideration is given to two technologies which should hold promise for future technology-transer programmes. Electric downhole motors and their advantages over conventional mud motors and turbodrills are examined. Hydraulic independence, diagnostics and control, information technology, design and development being discussed. The use of retractable drill bits are described, details being given of transport, drilling modes, and operation. 4 refs.