Patent GB-1232517-A (GB)
IPC: E21B47/022
Filed: 1969-05-22
Abstract: 1,232,517. Borehole clinometer. BYRON JACKSON Inc. May 22, 1969 [June 24, 1968], No.26310/69. Heading G1F. [Also in Divisions E1 and E2] A signalling apparatus, adapted to be installed in a well drilling string, produces pressure signals in the well drilling fluid indicative of the inclination of the apparatus. During the flow of drilling fluid, shaft 13 is pushed into the instrument by fluid-pressure on knob 14, but on cessation of flow, the shaft 13 is expelled by spring 15 to an extent dependent on the inclination. On restarting fluid-flow knob 14 passes a number of pulse rings 7, each of which causes a pressure pulse to be transmitted to the surface, the number of pulses indicating the inclination. Pendulum 16 is supported by support 90 Fig.2C, screw threaded into holder 93 having a shoulder 94. A latch body 95 (which includes part 96 in Fig.2C) carries latches 109 and 123, the former engaging shoulder 94. When fluid-flow is ceased, shaft 13 moves upwards under the action of spring 15 and at the same time a coding rod 60, 74 is moved upwards by spring 60a. The coding rod 74 pulls latch body 95 upwards until pendulum 16 engages one of the stops 17, Figs. 1, 2C, the stop selected, and hence distance of upward travel depending on the inclination of the apparatus. Coding rod 74 moves further against the action of the spring actuated between boss 101 on the coding rod and stop 103 on the latch body. Boss 101 thus causes latch 123 to engage one of the stops 175 to 175f corresponding to the particular stop 17 engaged by pendulum 16. Further movement of coding rod 74 so that boss 101 abuts stop 103 causes latch 109 to be released from shoulder 94, and the pendulum is now caused to move downwardly and engage pendulum seat 19 by the action of spring 95b. The coding rod 60, 74 moves inside tube 75, Fig.2a, which is fixed relative to the drill, and a pair of stop balls 75a to 75f is cammed out of the tube 75 by cams 72a to 72f, corresponding to the location of latch 123 on stops 175a to 175f. If stop 175 is engaged by latch 123, none of the balls are cammed out, a fixed stop 75 corresponding to stop 175. Shaft 13 has an associated stop tube 77, Fig. 2b (not shown) which moves with shaft 13 upwardly between tubes 13 and 61, Fig.2a, and engages the selected pair of stop balls 75a to 75f or fixed stop 75 to limit outward movement of the shaft. The stop balls and associated cams on the coding rod are arranged so that the shaft moves a distance inversely proportional to the distance moved by the pendulum and latch body 95 i. e. a distance proportional to the inclination. The vertical position of stop rings 17, and hence the range of the instrument are adjustable. The instrument housing I is filled with oil and a piston 20 at the bottom permits pressure equalization with the drilling fluid during movement of the shaft. When the shaft moves upwardly, the oil in the housing I flows freely through valve 22, but when the shaft moves downwardly the oil has to flow through restrictions 48 Fig.2d (not shown) comprising perforated discs inside tube 18 to ensure that the shaft moves sufficiently slowly for the transmitted pulses to be separated. The restrictions may be by-passed by valve 43 in the event of a large pressure pulse on knob 14.