Automatic data retrieval system for pumping wells

• US 3,921,152 A
• Filed: 07/23/1973
• Issued: 11/18/1975
• Est. Priority Date: 06/01/1972
• Status: Expired due to Term

• Current Assignee: Harold E. Schwartz Jr, James L. Hagar
• Original Assignee: Harold E. Schwartz Jr, James L. Hagar
• Inventors: Hagar, James L., Schwartz, Harold E. Jr.
• Primary Examiner(s): Shaw, Gareth D.
• Assistant Examiner(s): Thomas, James D.
• Application Number:
  US05/381,847
• Time in Patent Office: 848 Days
• Field of Search: 340/172.5,150,163R 235/151.3 166/65
• US Class Current: 702/43
• CPC Class Codes: E21B 47/007 Measuring stresses in a pipe string or casing for locating blocked portions of pipes E21B47/09
• CPC Class Codes: E21B 47/009 Monitoring of walking-beam pump systems

Abstract

Measurements of the load conditions on a plurality of pumping wells are made by strain gauges mounted on the pumping wells. A field-located remote terminal unit is connected to each of the plurality of pumping wells. Upon command from a centrally located computer, the remote terminal unit stores the load condition measurements from a pumping well selected by the computer. At some later time the computer retrieves the load condition measurements stored in the remote terminal unit.

Claims

1. A well monitoring system for measuring operating conditions at a plurality of pumping wells of the type having a crank shaft and a sucker rod string and means to reciprocate the sucker rod string to operate a downhole pump as the crank shaft revolves, comprising:

a. at least two transducers connected to each of said pumping wells, a first transducer generating a load signal representative of the changing load conditions on the sucker rod string during pumping and a second transducer generating a timing pulse at least once during each pumping stroke of the sucker rod string representative of the rate of rotation of said crank shaft, b. a central computer for generating a plurality of monitor commands, each monitor command identifying a selected one of said pumping wells, and a retrieval command, and c. a remote terminal unit coupled to said transducers and to said central computer, comprising;

1. a frequency-to-digital converter, 2. a digital storage unit connected to the output of said frequency-to-digital converter, 3. means responsive to each of said monitor commands for selectively connecting the first transducer at the pumping well identified by a monitor command to said frequency-todigital converter and the second transducer at the same pumping well to said digital storage unit, whereby the load signal from the selected pumping well is converted to a digital signal by the frequency-to-digital converter and whereby the timing signal from the selected pumping well enables the digital storage unit to store the digital signal from the frequency-to-digital converter at a data rate dependent upon the rate of rotation of the crank shaft of the selected pumping well, and 4. means responsive to said retrieval command from the computer for enabling the digital signals to be clocked out of the digital storage unit into said computer at a data rate that is independent of the rates of rotation of the crank shafts of the pumping wells.

2. a digital storage unit connected to the output of said frequency-to-digital converter,

3. The system of claim 2 wherein said retrieval command is a plurality of sequential address codes, each code identifying a particular one of said storage registers and wherein said storage unit further includes a decoder which decodes each address code and enables the particular storage register identified by that address code to transfer its digital contents to said computer, whereby the computer receives digital signals representing the load conditions at said pumping wells at a data rate determined by the frequency at which said computer issues said address codes.

4. means responsive to said retrieval command from the computer for enabling the digital signals to be clocked out of the digital storage unit into said computer at a data rate that is independent of the rates of rotation of the crank shafts of the pumping wells.

5. The system of claim 4 wherein each of said monitor commands is a binary signal in which one of its two states energizes the relay to which it is coupled.

6. A method of measuring operating conditions at a plurality of pumping wells of the type having a crank shaft and a sucker rod string and means to reciprocate the sucker rod string to operate a downhole pump as the crank shaft revolves, comprising the steps of:

a. generating a load signal representative of the changing load conditions on the sucker rod string of each well during pumping, b. generating a timing pulse at least once during each pumping stroke of the sucker rod string of each well representative of the rate of rotation of the crank shaft, c. generating a plurality of monitor commands, each monitor command identifying a selected one of said pumping wells, d. converting the load signal from the pumping well identified by the monitor command to a digital signal, and e. storing said digital signal in a digital storage unit at the data rate of said timing pulses from the identified pumping well.

7. The method of claim 6 further including the steps of:

a. generating a retrieval command, b. generating clock pulses, and c. transferring said digital signals out of said storage unit in response to said retrieval command, said transfer being at the data rate of said clock pulses.