Downhole pressure and/or temperature gauges

• US 4,805,448 A
• Filed: 08/18/1987
• Issued: 02/21/1989
• Est. Priority Date: 08/20/1986
• Status: Expired due to Fees

• Current Assignee: Drexel Equipment UK Ltd (NOV, Inc.)
• Original Assignee: Drexel Equipment UK Ltd (NOV, Inc.)
• Inventors: Armell, Richard A.
• Primary Examiner(s): LaRoche, Eugene R.
• Assistant Examiner(s): Ham, Seung
• Application Number:
  US07/086,677
• Time in Patent Office: 553 Days
• Field of Search: 73/151, 73/152, 73/706, 73/756, 73/732-742, 464/57, 464/60, 464/162
• US Class Current: 73/152.53
• CPC Class Codes: E21B 47/06 Measuring temperature or pressure
• CPC Class Codes: G01D 5/04 using levers; using cams; using gearing
• CPC Class Codes: G01K 5/326 using a fluid container connected to the deformable body by means of a capillary tube
• CPC Class Codes: G01L 7/043 with mechanical transmitting or indicating means

Abstract

A pressure or temperature gauge includes a Bourdon tube which is coupled via a shaft to transmit rotation to a stylus carried by the shaft which makes a record on a cylindrical chart which moves axially of the shaft at a constant rate. The shaft is divided into two sections which are joined together by a flexible coupling; the upper section of the shaft is mounted for angular displacement about its longitudinal axis by the thrust bearing. One section has an integrally formed axial extension which is received in a recess in the facing end portion of the other shaft section. This construction of the stylus shaft allows the angular motion produced by the coiling and uncoiling of the Bourdon type generally through an angle less than 360° to be faithfully transmitted without any axial motion of the shaft which would give rise to erroneous recording of pressure or temperature readings in relation to time.

Claims

1. In an assembly for continuously monitoring down-hole pressure or temperature parameters in an oil or gas well or other remote location accessible only along a narrow passageway,

means defining a sensing element having a longitudinal axis and two further axes each orthogonal to the longitudinal axis, the sensing element being subject to angular deflection about the longitudinal axis over a limited range in response to any change in the parameter being measured and motion in the direction of the longitudinal axis of the sensing element,

means for recording on a continuous basis the said changes in the parameter sensed by the sensing element and converted to said angular deflection,

elongate means coupling the sensing element and the continuous recording means,

means supporting the elongate means at spaced locations along the length of the elongate means, the supporting means including

an elongate housing, and

a compliant device interposed along the length of the elongate coupling means, said compliant device exhibiting torsional rigidity such that the angular deflection of the sensing element is transmitted with high precision to the recording means while any motion of the sensing element in the direction of said longitudinal axis is accommodated by the compliant device substantially without transmission of the motion of the sensing element in the direction of the longitudinal axis of the sensing element.

4. An assembly according to claim 1, wherein the compliant device comprises

a first end part,

a second end part, and

a helical connection part, interconnecting the said first and second parts, and

means for securing the first and second parts to the elongate coupling means.

5. An assembly according to claim 4, wherein said first and second end parts are each of hollow cylindrical form.

6. An assembly according to claim 4 wherein the securing means comprise set bolts extending parallel to the axis of the elongate coupling means, and

flange means on the elongate means by which the compliant device is secured to the elongate means.

7. An assembly according to claim 6 wherein the elongate means comprises

a first shaft section, and

a second shaft section,

one shaft section being received for relative axial movement in the second shaft section.

8. An assembly according to claim 1 wherein the housing comprises a tubular member to one end of which, remote from the recording means, the sensing element is secured.

9. An assembly according to claim 8 comprising a further housing coaxial with the tubular member, the further housing including external screw thread means by which it can be mounted.

12. An assembly according to claim 9 wherein the first and second parts are of hollow cylindrical form.

2. In an assembly for monitoring over a required time period down-hole pressure or temperature parameters in an oil or gas well or other remote location accessible only along a narrow bore,

means defining a sensing element of helical form having a longitudinal axis and two further axes each orthogonal to the longitudinal axis the helical sensing element being subject to angular motion in the direction of the longitudinal axis,

chart means for recording the said changes in the parameter sensed by the helical sensing element and converted to said angular deflection,

elongate shaft means coupling the helical sensing element and the chart recording means,

means for supporting the elongate shaft means at spaced locations along the length of the elongate shaft means, the supporting means including

an elongate housing, and

bearing means interposed between the internal housing wall and the elongate shaft means at each of said spaced locations, and

a selective motion transmitting device interposed along the length of the elongate shaft coupling means, said motion transmitting device exhibiting torsional rigidity such that the angular deflection of the sensing element is transmitted with high precision to the chart recording means while any motion in the direction of said longitudinal axis of the helical sensing element resultant from the parameter being monitored is accommodated by the selective motion transmitting device substantially without transmission of motion along said longitudinal axis to the recording means,

the assembly serving to record over a predetermined time period the parameter sensed by the said helical sensing element substantially without error resultant from the effect of the said motion of the sensing element in the direction of the longitudinal axis of the helical sensing element.

10. An assembly according to claim 2, wherein the compliant device comprises

a first end part,

a second end part, and

a helical connection part, interconnecting the said first and second parts, and

means for securing the first and second parts to the elongate coupling means.

13. An assembly according to claim 10 wherein the first and second parts are of hollow cylindrical form.

3. In an assembly for continuously monitoring over a required period of time down-hole pressure or temperature parameters in an oil or gas well or other remote location accessible only along a narrow passageway,

a helical Bourdon tube having a longitudinal axis and two further axes each orthogonal to the longitudinal axis, the Bourdon tube being subject to angular deflection over a limited range in response to any change in the parameter being measured and motion in the direction of the longitudinal axis,

stylus and chart means for recording on a continuous basis the said changes in the parameter sensed by the Bourdon tube,

an elongate two-part shaft for coupling the Bourdon tube and the stylus,

means for supporting the elongate shaft at spaced locations along the length of the elongate shaft, the supporting means including

an elongate hollow, cylindrical housing,

bearings spaced along the length of the shaft and mounted on the inner wall of the housing, and

a selective motion transmitting device interposed between the two parts of the shaft, said selective motion-transmitting device exhibiting torsional rigidity such that the angular deflection of the Bourdon tube is transmitted with high precision to the stylus while any motion of the Bourdon tube in the direction of said longitudinal axis is accommodated by the motion-transmitting device substantially without transmission of the axial motion in the direction of the longitudinal axis to the stylus,

the assembly serving to record over a predetermined time period the parameter sensed by the Bourdon tube substantially without error resultant from the effect of the motion of the Bourdon tube in the direction of the longitudinal axis of the Bourdon tube.

11. An assembly according to claim 3 wherein the selective-motion transmitting device comprises

a first end part,

a second end part, and

a helical connection part, interconnecting the said first and second parts, and

means for securing the first and second parts to the elongate two-part shaft.