Method of making well logging apparatus

• US 4,356,629 A
• Filed: 04/21/1980
• Issued: 11/02/1982
• Est. Priority Date: 04/21/1980
• Status: Expired due to Term

• Current Assignee: Exploration Logging Incorporated
• Original Assignee: Exploration Logging Incorporated
• Inventors: Jeter, John D., More, Henry S.
• Primary Examiner(s): Husar, Francis S.
• Assistant Examiner(s): Arbes, Carl J.
• Application Number:
  US06/141,769
• Time in Patent Office: 925 Days
• Field of Search: 29/846, 29/825, 29/885, 29/458, 175/50, 166/66, 427/96
• US Class Current: 29/885
• CPC Class Codes: E21B 17/003 with electrically conducting or insulating means E21B17/028 and E21B17/023 take precedence
• CPC Class Codes: E21B 47/01 Devices for supporting measuring instruments on drill bits, pipes, rods or wirelines; Protecting measuring instruments in boreholes against heat, shock, pressure or the like
• CPC Class Codes: F16F 15/08 with rubber springs grommet- or bushing-type resilient mountings F16F1/3732, F16F1/38; with springs made of rubber and metal arrangement of internal-combustion or jet-propulsion units B60K5/12; mounting of propulsion plants on vessels B63H21/30; mounting of vehicle drivers' cabs B62D33/0604
• CPC Class Codes: H01R 13/523 for use under water
• CPC Class Codes: H01R 2107/00 Four or more poles
• CPC Class Codes: H01R 24/58 Contacts spaced along longitudinal axis of engagement
• CPC Class Codes: H01R 43/24 Assembling by moulding on contact members
• CPC Class Codes: Y10T 29/49224 with coating
• CPC Class Codes: Y10T 29/49885 with coating before or during assembling

Abstract

A replaceable insulating sleeve is disposed around the lower end of a drill string used in drilling a well. The sleeve is restrained from rotating relative to the drill string, but can be released and quickly slipped off the drill string in the field to permit rapid replacement if damaged, or if alternate equipment is required. The sleeve carries sensing means for measuring a characteristic of formations penetrated by the well.

Claims

1. A method for making an electrode assembly adapted to slide on and off a drill string to be used in a well for measuring electrical resistivity of earth formations traversed by the well, the method including the steps of:

(a) forming a sleeve of insulating material by wrapping resin-coated fibers around an elongated and generally cylindrical mandrel, the mandrel having an exterior surface which converges toward one end so the sleeve is formed with an internal converging surface matching the external surface of the mandrel;

(b) embedding at least one electrical conductor in the sleeve;

(c) forming a recess in the outer surface of the sleeve to expose the embedded electrical conductor in the vicinity of the recess;

(d) depositing metal within the recess to at least partially fill it and make electrical contact with at least part of the exposed electrical conductor;

(e) curing the resin while the fibers are wrapped around the mandrel; and

(f) thereafter slipping the sleeve from the mandrel and thereafter slipping the sleeve onto a drill string having an external surface matching that of the mandrel.

2. A method according to claim 1 in which the formation of the recess includes forming an outwardly opening, circumferential groove in the outer surface of the sleeve.

3. A method according to claim 1 or 2 in which the external surface of the mandrel includes longitudinally extending grooves and splines with surfaces which converge toward one end of the sleeve.

4. A method for making a logging assembly adapted to slide on and off a drill string in a well for measuring a downhole characteristic in the well, the method including the steps of:

(a) forming a sleeve of insulating material by wrapping resin-coated fibers around an elongated and generally cylindrical mandrel, the mandrel having an exterior surface which converges toward one end so the sleeve is formed with an internal converging surface matching the external surface of the mandrel;

(b) embedding at least one electrical conductor in the sleeve;

(c) securing sensing means to the sleeve;

(d) connecting the electrical conductor to the sensing means;

(e) curing the resin while the fibers are wrapped around the mandrel; and

(f) thereafter slipping the sleeve from the mandrel and ther after slipping the sleeve onto a drill string having an external surface matching that of the mandrel.