Rod pump optimization system

• US 4,854,164 A
• Filed: 05/09/1988
• Issued: 08/08/1989
• Est. Priority Date: 05/09/1988
• Status: Expired due to Fees

• Current Assignee: N/Cor Incorporated Arlington Texas
• Original Assignee: N To B Ltd.
• Inventors: Rhoads, Benjamin J.
• Primary Examiner(s): Levy, Stewart J.
• Assistant Examiner(s): O'Shea, Kevin D.
• Application Number:
  US07/191,381
• Time in Patent Office: 456 Days
• Field of Search: 73/151, 73/155, 73/863.02, 73/863.03, 73/864.34, 417/36, 417/44, 166/53, 166/68.5
• US Class Current: 73/152.29
• CPC Class Codes: E21B 47/009 Monitoring of walking-beam pump systems
• CPC Class Codes: E21B 47/113 using electrical indications; using light radiations

Abstract

An apparatus for measuring the quantity and flow rate of liquids in a flowing fluid stream containing liquids and gases such as found in oil well production, with an optional controller for oil well pumps to control the pumping period or speed based on pump displacement. Total number of tank fill events provide a precise measurement of total volume. Volumes are accumulated on a time base to determine flow rate and on the basis of strokes to determine pump displacement. Liquid measurement is accomplished without restriction to the flowing stream, even in the event of a valve failure. The filling of each tank with oil of low or high viscosity can be measured by level, hydrostatic pressure, or weight sensors. Measurement of total produced volumes are accumulated with the accuracy and repeatability needed when correlating producing wells with injection wells, and when diagnosing well problems. Flow rate or subsurface pump displacement is used to provide a means for pump-off control without the adjustment and calibration problems inherent in load sensing pump-off control systems. Combined pump-off and production measurements permit routine adjustment of idle-time when pumping period is controlled while flow and pump rates permit pump displacement measurements which are fundamental to effective speed control.

Claims

1. A liquid measurement apparatus for measuring liquid quantities in a fluid flow stream containing both liquids and gases and comprising

two containers each of which has an inlet and outlet line for the flowing fluids and a connecting conduit between the two containers to allow any gases contained in said fluid flow stream to separate in either of said two containers to pass to the other while accumulating liquids in one of said two containers and

a mechanism on the said inlet and outlet lines of the said two containers to alternately divert said flowing fluids to and from the said two containers such that fluid is flowing into one of said two containers while simultaneously discharging from the other and

a sensing means located in each of the said two containers to detect when a quantity of liquids accumulate in the one of said two containers into which fluids are flowing and to provide a signal when said quantity of liquids has accumulated and

a control and recording means to accept said signals alternately from both said sensing means to record said liquid quantity signals when liquids alternately accumulate in each of said two containers to divert said flowing fluids to and from the opposite of the said two containers when said control and recording means receives a signal from said sensing means from either of said two containers.

2. The liquid measurement apparatus of claim 1 wherein the said mechanism on said inlet and outlet lines of said two containers is a pneumatically operated valve that will alternately divert said flowing fluids to and from said two containers such that fluid is flowing into one of said two containers while simultaneously discharging from the other with said pneumatically operated valve constructed so as to be operated by a single pneumatic operator and such that no position of the valve or pneumatic operator will restrict said flowing fluids from the inlet to the outlet of said liquid measurement apparatus.

3. The liquid measurement apparatus of claim 1 wherein the said mechanism on said inlet and outlet lines of said two containers is an electric motor operated valve that will alternately divert said flowing fluids to and from said two containers such that fluid is flowing into one of said two containers while simultaneously discharging from the other with said electric motor operated valve constructed so as to be operated by a single electric motor and such that no position of the valve or electric operator will restrict said flowing fluids from the inlet to the outlet of said liquid measurement apparatus.

4. The liquid measurement apparatus of claim 1 wherein said sensing means for each of the said two containers is a level sensing means consisting of a float that will provide an electrical signal when the liquid level in the said two containers reaches the level in the said containers at which the float is positioned.

5. The liquid measurement apparatus of claim 1 wherein said sensing means for each of the said two containers is a hydrostatic head sensing switch that will provide an electrical signal when the hydrostatic head of each of said two containers accumulates liquids which exceed the fixed and adjustable limit of the hydrostatic head switch.

6. The liquid measurement apparatus of claim 1 wherein said sensing means for each of the said two containers is a weight sensing means whereby each of the sensing means will provide an electrical signal when the increase in weight of either of the two said containers exceeds a fixed but adjustable weight limit caused by liquids accumulating in either of said two containers.

7. An apparatus for determining actual liquid displacement quantities of a subsurface reciprocating oil well pumping system to detect changes in actual liquids displaced by the pump over short and long time periods for the purpose of analyzing and managing pump and reservoir performance comprising

an electronic apparatus for receiving electrical signals representative of a quantity of liquids being pumped from some liquid measurement apparatus and

a select and display means for said electronic apparatus to select and display data associated with the reception of said electrical signals representative of a quantity of liquids being pumped and

a select and limit entry means for said electronic apparatus to select and enter timing limits associated with the reception of said electrical signals representative of a quantity of liquids being pumped and timing limits associated with the on and off control of the pumping system and

a monitoring means for said electronic apparatus to monitor elapsed time and/or number of pumping strokes between said electrical signals representative of a quantity of liquids being pumped to detect when said elapsed time and/or number of pumping strokes between said electrical signals representative of a quantity of liquids being pumped exceeds fixed but adjustable timing limits and

a control means for said electronic apparatus to turn off said oil well pumping system when said monitoring means detects when said elapsed time and/or number of pumping strokes between electrical signals representative of a quantity of liquids being pumped exceeds said limit and to leave said oil well pumping system turned off for a fixed but adjustable time limit before restarting said oil well pumping system.

8. The apparatus of claim 7 wherein said electronic apparatus includes a recording means to record the following elapsed times

(a) said elapsed time and number of pumping strokes between said electrical signals representative of a quantity of liquids being pumped for the current operating oil well pumping system run cycle and a plurality of previous run cycles

(b) elapsed time and number of pumping strokes between the restarting of said oil well pumping system after said oil well pumping system has been turned off by said control means for said time limit and the reception of first said electrical signal representative of a quantity of liquids being pumped for the current run cycle and a plurality of previous run cycles

(c) elapsed time and number of pumping strokes between the restarting of said oil well pumping system by said control means and the time said oil well pumping system is turned off by said control means for the current run cycle and a plurality of previous run cycles.

9. The apparatus of claim 8 wherein said electronic apparatus will accumulate and record said elapsed times of said oil well pumping system run cycles for a plurality of time intervals.

10. The apparatus of claim 7 wherein said electronic apparatus includes a recording means of accumulating and recording received said electrical signals representative of a quantity of liquids being pumped for the current run cycle of said oil well pumping system and a plurality of previous run cycles.

11. The apparatus of claim 10 wherein said recording means of said electronic apparatus will accumulate and record received electrical signals representative of a quantity of liquids being pumped for a plurality of time intervals.

12. An apparatus for determining actual liquid displacement quantities of a subsurface reciprocating oil well pumping system to detect changes in actual liquids displaced by the pump over short and long time periods for the purpose of analyzing and managing pump and reservoir performance comprising

an electronic apparatus for receiving electrical signals representative of a quantity of liquids being pumped (from some liquid measurement apparatus) and for receiving electrical status signals indicating said oil well pumping system is running or not running and

a select and display means for said electronic apparatus to select and display data associated with the reception of said electrical signals representative of a quantity of liquids being pumped and data associated with said electrical status signals indicating said oil well pumping system is running or not running and

a select and limit entry means for said electronic apparatus to select and enter limits associated with the reception of said electrical signals representative of a quantity of liquids being pumped and

a monitoring means for said electronic apparatus to monitor elapsed time and number of pumping strokes between said electrical signals representative of a quantity of liquids being pumped to detect an event when said elapsed time and/or number of pumping strokes between said electrical signals representative of a quantity of liquids being pumped exceeds fixed but adjustable preset limits and

a recording means for said electronic apparatus to record said number of electrical signals, elapsed times associated with said electrical signals, with said event detected by said monitoring means, and said electrical status signals for the current run cycle and a plurality of previous run cycles with the cycles being controlled by an external manually adjustable interval timer including

(a) said elapsed time and number of pumping strokes between said electrical signals representative of a quantity of liquids being pumped

(b) elapsed time and number of pumping strokes between the reception of said status signal indicating said oil well pumping system is running and the reception of the first said electrical signal representative of a quantity of liquids being pumped

(c) elapsed time and number of pumping strokes between the reception of said status signal indicating said oil well pumping system is running and the time said monitoring means detects said event when said elapsed time and/or number of pumping strokes between said electrical signals representative of a quantity of liquids being pumped exceeds said preset elapsed limit

(d) elapsed time and number of pumping strokes between the reception of said status signal indicating said oil well pumping system is running and the time of reception of said status signal indicating said oil well pumping system is not running

(e) elapsed time between the time of reception of said status signal indicating said oil well pumping system is not running and the time of reception of said status signal indicating said oil well pumping system is running.

13. The apparatus of claim 12 wherein said recording means of said electronic apparatus will accumulate and record said electrical signals representative of a quantity of liquids being pumped and number of pumping strokes separately during each of the following elapsed times of the current run cycle and a plurality of previous run cycles with the cycles being controlled by an external manually adjustable interval timer

(a) the elapsed time from the reception of said electrical status signal indicating the said oil well pumping system is running until the time said monitoring means detects said event when said elapsed time between electrical signals representative of a quantity of liquids being pumped exceeds said preset elapsed limit

(b) the elapsed time from when said monitoring means detects said event when said elapsed time and/or number of pumping strokes between said electrical signals representative of a quantity of liquids being pumped exceeds said preset limit until reception of said electrical status signal indicating said oil well pumping system is not running

(c) the elapsed time from the reception of said electrical status signal indicating said oil well pumping system is running until reception of said electrical status signal indicating said oil well pumping system is not running.

14. The apparatus of claim 13 wherein said recording means of said electronic apparatus will, in addition, separately accumulate and record said elapsed times during previous run cycles being controlled by an external manually adjustable interval timer for a plurality of time intervals.

15. The apparatus of claim 14 wherein said recording means of said electronic apparatus will, in addition, separately accumulate and record said electrical signals representative of a quantity of liquids being pumped for said elapsed times during previous run cycles controlled by an external manually adjustable interval timer for a plurality of time intervals.

16. A liquid measurement apparatus for measuring liquid quantities of fluids pumped by a subsurface reciprocating oil well pumping system when said fluids contain both liquids and gases with said liquid measurement apparatus including a means to determine liquid displacement quantities of said pumping system to detect changes in said liquid displacement for the purpose of analyzing and managing pump and reservoir performance comprising

two containers each of which has an inlet and outlet line for the pumped fluids and a connecting conduit between the two containers to allow any gases contained in said pumped fluids to pass from either of said two containers to the other while accumulating liquids in the opposite of said two containers and

a mechanism on the said inlet and outlet lines of the said two containers to alternately divert said flowing fluids to and from the said two containers such that fluid is being pumped into one of said two containers while simultaneously discharging from the other and

a sensing means for each of the said two containers to provide analog signals representative of the quantity of liquids present in each of said two containers and

an electronic apparatus to accept and process said analog signals from each of said sensing means of said two containers to determine actual liquid displacement of said oil well pumping system for some preset and adjustable plurality of strokes of the subsurface reciprocating pumping system and

a select and display means for said electronic apparatus to select and display data associated with the processing of said analog signals to determine actual pump displacement and the volume of liquids pumped over a plurality of time intervals and number of strokes of the subsurface pump and

a select and limit entry means for said electronic apparatus to select and enter limits associated with the processing of said analog signals and the control of said oil well pumping system to improve performance and

a control means for said electronic apparatus to cause said mechanism on the inlet and outlet lines to said two containers to divert said pumped fluids to and from the opposite of said two containers when the number of strokes of the pumping system equals preset entered limits and

a control means for said electronic apparatus to cause said oil well pumping system to be shut down when the actual liquid displacement of said reciprocating pumping system falls below an adjustable entered limit.

17. The apparatus of claim 16 wherein said electronic apparatus includes a recording means to record the following

(a) quantity of liquids pumped by said subsurface reciprocating pump for the plurality of strokes determined by entered limits

(b) average displacement quantity per stroke for the plurality of strokes determined by entered limits

(c) displacement efficiency of said subsurface reciprocating pump system with respect to theoretical subsurface pump displacement and with respect to actual attainable pump displacement with known submergence and known pump inefficiencies during filling of each of said two containers for the plurality of strokes determined by entered limits for a plurality of said two container filling events that occur from the starting of the pumping system to the stopping of the pumping system and over specified plurality of time intervals

(d) displacement efficiencies when the subsurface pumping system is initially installed in the well and at specified time intervals during the operating life of the pumping system or until repairs or modifications are made to the pumping system

(e) quantities of liquids pumped, number of strokes required for pumping said quantities of liquid pumped, number of pump system start to stop cycles, time pump system was running and time pump system was stopped for specified time intervals and specified number of pump system start to stop cycles.

18. The apparatus of claim 16 wherein said mechanism on said inlet and outlet lines of said two containers to divert said flowing fluids is a pneumatically actuated diverting mechanism constructed such that flow of fluids from the inlet to the outlet of the said two containers cannot be restricted because of the position of the diverter mechanism or the position of the pneumatic operator.

19. The apparatus of claim 16 wherein said mechanism on said inlet and outlet lines of said two containers to divert said flowing fluids is an electric motor actuated diverter mechanism constructed such that a single electric motor will actuate the diverter mechanism for both of two said containers and such that flow of fluids from the inlet to the outlet of said two containers cannot be restricted because of the position of the diverter mechanism or the position of the electric motor driving the diverter mechanism.

20. The apparatus of claim 16 wherein said sensing means of each of said two containers is a level sensing means that provides analog signals representative of the level of liquids in each of said two containers.

21. The apparatus of claim 16 wherein said sensing means is a hydrostatic head sensing means that provides analog signals representative of the hydrostatic head in each of the two said containers.

22. The apparatus of claim 16 wherein said sensing means for each of said two containers is a weight sensing means that provides analog signals representative of the weight of each of said two containers and their fluid contents.