System and method for flow control for high watercut oil production
| Title: | System and method for flow control for high watercut oil production |
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| Patent Number: | 5,205,310 |
| Publication Date: | April 27, 1993 |
| Appl. No: | 07/758,659 |
| Application Filed: | September 12, 1991 |
| Abstract: | Net oil production from a low volume high watercut well or other source of a water-oil mixture is accurately metered with systems which include a separator vessel which allows a water-oil mixture to collect and form a separate oil layer on top of the water and which has liquid level sensors and an oil detector which measures the presence of an oil layer. The sensors are arranged in such a way with associated control circuits so that the vessel does not discharge oil until a significant accumulation of an oil layer occurs in the vessel. The systems each include a liquid discharge conduit and a motor operated control valve connected to a logic circuit which receives signals from the level sensors and the oil detector to provide cyclic operation of the valve to discharge water from the vessel repeatedly until a relatively large quantity of oil collects and then discharges all of the oil prior to resumption of the operating cycle. |
| Inventors: | Kolpak, Miroslav M. (Plano, TX); Hetherington, William D. (Richardson, TX) |
| Assignees: | Atlantic Richfield Company (Los Angeles, CA) |
| Claim: | What is claimed is |
| Claim: | 1. A system for measuring the net oil production from a relatively high watercut source of a mixture of oil and water comprising |
| Claim: | a vessel including a conduit for admitting an oil-water mixture to said vessel, a space within said vessel for holding a quantity of oil and water mixture to allow a separate oil layer to accumulate above a layer of water in said space, and a discharge conduit for discharging both liquid oil and water from said vessel; |
| Claim: | valve means interposed in said discharge conduit for controlling the flow of liquid from said vessel; and |
| Claim: | control means for controlling the flow of liquid from said vessel through said discharge conduit so that said layer of water is discharged from said vessel through said discharge conduit and said separate oil layer is discharged from said vessel through said discharge conduit when a predetermined accumulation of said oil layer has occurred. |
| Claim: | 2. The system set forth in claim 1 wherein |
| Claim: | said control means includes first sensor means for sensing a maximum level of liquid in said vessel, second sensor means for sensing a level of liquid in said vessel below said first sensor means, oil detector, means for sensing an oil layer in said vessel in response to a falling level of liquid in said vessel, and a control circuit responsive to receiving signals from said sensor means and said oil detector means for controlling the operation of said valve means to discharge an accumulated oil layer from said vessel. |
| Claim: | 3. The system set forth in claim 2 wherein |
| Claim: | said oil detector means is mounted in said vessel at an elevation below said second sensor means. |
| Claim: | 4. The system set forth in claim 3 Wherein |
| Claim: | said oil detector means includes means for sensing when the liquid level in said vessel has decreased to a level at or below said oil detector means. |
| Claim: | 5. The system set forth in claim 4 wherein |
| Claim: | said control circuit includes first and second flip-flop circuits operably connected to an OR gate for providing a signal to effect opening of said valve when the liquid level reaches the elevation of said first sensor means or when the level of said liquid reaches the level of said first sensor means and said oil detector means detects the presence of oil in said space. |
| Claim: | 6. The system set forth in claim 5 wherein |
| Claim: | said control circuit includes an AND gate for receiving a signal from said oil detector means and said first sensor means for providing a signal to one of said flip-flop circuits to effect an output signal to said OR gate. |
| Claim: | 7. The system set forth in claim 2 including |
| Claim: | third sensor means for detecting a level of liquid in said vessel above said first sensor means, and means associated with said control circuit for receiving signals from said first sensor means, said second sensor means, said third sensor means and said oil detector means for controlling the flow of liquid from said vessel to discharge oil from said vessel when a predetermined oil layer has collected in said vessel between said oil detector means and said third sensor means. |
| Claim: | 8. The system set forth in claim 7 wherein |
| Claim: | said control circuit includes a timing circuit and means for providing a signal to effect opening of said valve means when said timing circuit is not providing a timing function, said first sensor determines a maximum level of liquid in said vessel and said oil detector means does not detect the presence of oil. |
| Claim: | 9. The system set forth in claim 7 wherein |
| Claim: | said control circuit includes means for effecting closure of said valve means when either a minimum level of liquid occurs in said vessel or said oil detector means senses the presence of an oil layer. |
| Claim: | 10. The system set forth in claim 9 wherein |
| Claim: | said control circuit includes means for activating a timing circuit upon closure of said valve means in response to a signal from said second sensor means or said oil detector means and means for effecting opening of said valve means in response to a signal from said first sensor means, said timing circuit and said oil detector means. |
| Claim: | 11. The system set forth in claim 2 wherein |
| Claim: | said control circuit includes timing means operable to receive a signal from said first sensor means and means for controlling said valve means to discharge only water from said vessel unless the time between sensing said maximum liquid level and the presence of oil at said oil detector means during a cycle of opening and closing said valve means is less than a predetermined amount. |
| Claim: | 12. The system set forth in claim 11 wherein |
| Claim: | said second sensor means is disposed for sensing liquid generally at the same level as said oil detector means in said vessel. |
| Claim: | 13. The system set forth in claim 2 wherein |
| Claim: | said second sensor means is disposed for sensing a liquid level in said vessel between the level sensed by said first sensor means and said oil detector means. |
| Claim: | 14. The system set forth in claim 13 including |
| Claim: | third sensor means disposed in said vessel for sensing a liquid level below said second sensor means and operable to effect closing of said valve means. |
| Claim: | 15. The system set forth in claim 14 wherein |
| Claim: | said control circuit includes means operable to receive signals from said sensor means and said oil detector means, respectively, for opening said valve means on an increasing liquid level in said vessel and closing said valve means when said oil detector means detects said oil layer after said liquid level has been sensed by said second sensor means. |
| Claim: | 16. The system set forth in claim 14 wherein |
| Claim: | said control circuit includes means operable to receive signals from said sensor means and said oil detector means, respectively, for opening said valve means on an increasing liquid level in said vessel and closing said valve means when said liquid level is sensed by said third sensor means if said oil detector means senses said oil layer before said liquid level is sensed by said second sensor means. |
| Claim: | 17. The system set forth in claim 1 wherein |
| Claim: | said discharge conduit is connected to means for measuring the water content of a liquid flowstream flowing through said discharge conduit. |
| Claim: | 18. A method for measuring net oil production from a source of a mixture of oil and water comprising |
| Claim: | providing a vessel including a conduit for admitting an oil-water mixture to said vessel, said vessel including a space for holding a quantity of oil and water to allow a separate oil layer to accumulate above a volume of water in said vessel, a discharge conduit for discharging liquid from said vessel, valve means interposed in said discharge conduit for controlling the flow of liquid from said vessel and control means for controlling the operation of said valve means to discharge liquid from said vessel, said control means including first sensor means for sensing a first liquid level in said vessel, second sensor means for sensing a second liquid level in said vessel below said first sensor means, oil detector means for sensing said oil layer and third sensor means for sensing a third liquid level below said second sensor means; |
| Claim: | causing said valve means to discharge liquid from said vessel if the liquid level increases in said vessel to the level of said first sensor means; and |
| Claim: | causing said valve means to close at a selected one of a condition wherein said liquid level decreases to a level sensed by said second sensor means and said liquid level decreases to a level sensed by said third sensor means if said oil detector means senses said oil layer prior to the liquid level decreasing to the level sensed by said second sensor means. |
| Claim: | 19. A method for measuring net oil production from a source of a mixture of oil and water comprising |
| Claim: | providing a vessel including a conduit for admitting an oil-water mixture to said vessel, said vessel including a space for holding a quantity of oil and water to allow a separate oil layer to accumulate above a volume of water in said vessel, a discharge conduit for discharging liquid from said vessel, valve means interposed in said discharge conduit for controlling the flow of liquid from said vessel and control means for controlling the operation of said valve means to discharge liquid from said vessel, said control means including first sensor means for sensing a first liquid level in said vessel, second sensor means for sensing a second liquid level in said vessel below said first sensor means and oil detector means for sensing said oil layer; |
| Claim: | causing said valve means to open to discharge liquid from said vessel when said liquid level increases to the level of said first sensor means; and |
| Claim: | causing said valve means to close when a selected one of a condition occurs wherein said oil layer is detected at said oil detector means and said liquid level decreases to the level of said second sensor means when a cycle of opening said valve means and closing said valve means occurs more than once during a predetermined period of time. |
| Claim: | 20. A method for measuring net oil production from a source of a mixture of oil and water comprising |
| Claim: | causing said valve means to open when the liquid level in said vessel increases to the level of said first sensor means; and |
| Claim: | causing said valve means to close at a selected one of a condition wherein said oil layer is detected by said oil detector means after the liquid level has decreased to a level below said second sensor means and said liquid level decreases to a level sensed by said third sensor means when said oil layer is detected at said oil detector means before said liquid level has decreased to the level of said second sensor means. |
| Current U.S. Class: | 137/2; 137/172 |
| Current International Class: | B01D 17025 |
| Patent References Cited: | 2051180 August 1936 Ruzicka 2701602 February 1955 Crawford 2984360 May 1961 Smith 3202167 August 1965 DeYoung |
| Primary Examiner: | Cohan, Alan |
| Attorney, Agent or Firm: | Martin, Michael E. |
| Accession Number: | edspgr.05205310 |
| Database: | USPTO Patent Grants |
| Language: | English |
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