Dresser Industries, Inc.

Thomas C Gaynor

M Vikram Rao

Chen-Kang David Chen

Roger Boulton

A bottom hole assembly,for drilling a deviated borehole includes a positive displacement motor,having a substantially uniform diameter motor housing outer surface without stabilizers extending radially therefrom. The motor housing,has a fixed bend therein between an upper power section,and a lower bearing section,. The long gauge bit,powered by the motor,has a bit face,with cutters,thereon and a gauge section,having a uniform diameter cylindrical surface,. The gauge section,has an axial length at least 75% of the bit diameter. The axial spacing between the bit face and the bend of the motor housing is less than ten times the bit diameter. According to the method of the present invention, fluid is pumped through the downhole motor to rotate the bit at a speed of less than 350 rpm. A substantial portion of the curved borehole section may be drilled while sliding rather than rotating the motor housing.

Growing community of inventors

Aberdeen, United Kingdom

Thomas C Gaynor