Sensor and data transmission in measurement whilst drilling

摘要

An apparatus for measuring whilst drilling, possibly for use in steerable drilling includes a housing 1 and motor rota 4 and motor stator 3. A bent subassembly 7 is present at the lower end of the apparatus, the subassembly 7 providing a small angular deviation between the housing unit axis and an axis defined by the bent subassembly. An output shaft 10 extends within the bent assembly 7 for driving the bit and a torsion bar or flexible shaft 6 connects the rotor 4 to the output shaft 10. A sensor and data transmission assembly 5 is located on the main housing 1 in a parallel relationship with said torsion bar or flexible shaft 6 and extends generally the same longitudinal distance along the main housing 1 as the torsion bar or flexible shaft 6. The sensor and transmission assembly 5 can be an electric field communication type for short range data communication in a borehole.