Controlling high-pressure production trap separation efficiency

1. A computer-implemented method, comprising:

implementing a feedback control scheme including controlling a separation efficiency for a high-pressure production trap (HPPT) by manipulating a demulsifier concentration, including:

determining, as a function of temperature and based on correlations of historical process data, a minimum target separation efficiency and a maximum target separation efficiency;

identifying a target separation efficiency that is between the minimum target separation efficiency and the maximum target separation efficiency; and

adjusting a demulsifier dosage, used in calculating the separation efficiency, between a minimum demulsifier concentration and a maximum demulsifier concentration, the adjusting including:

when the separation efficiency is below the target separation efficiency, adjusting, using a PID controller, the demulsifier dosage upward but not to exceed a maximum dosage concentration; and

when the separation efficiency is above the target separation efficiency, adjusting, using the PID controller, the demulsifier dosage downward above a minimum dosage concentration.

2. The computer-implemented method of claim 1 , wherein identifying the target separation efficiency includes receiving, from an operator, input specifying an increase to an expected separation performance by a certain margin.

3. The computer-implemented method of claim 1 , wherein the minimum demulsifier concentration and the maximum demulsifier concentration are determined through correlations and are a function of temperature.

4. The computer-implemented method of claim 1 , further comprising:

determining that an upset has occurred in a dehydrator; and

using another PID controller having more aggressive tuning than a current PID controller to override the demulsifier concentration to mitigate the upset.

5. The computer-implemented method of claim 1 , further comprising: determining efficiency calculations that are based on reconciled values to account for instrument measurement errors and closure of a water balance.

6. The computer-implemented method of claim 1 , wherein adjusting the demulsifier dosage includes maintaining the demulsifier dosage regardless of crude and water flow oscillations.

7. The computer-implemented method of claim 6 , wherein maintaining the demulsifier dosage includes using a controlled variable used as a demulsifier concentration, a manipulated variable used as a demulsifier flow set point, and disturbances variables including a dry crude flow oscillation, a produced water flow oscillation, and a demulsifier flow oscillation.

8. A non-transitory, computer-readable medium storing one or more instructions executable by a computer system to perform operations comprising:

implementing a feedback control scheme including controlling a separation efficiency for a high-pressure production trap (HPPT) by manipulating a demulsifier concentration, including:

determining, as a function of temperature and based on correlations of historical process data, a minimum target separation efficiency and a maximum target separation efficiency;

identifying a target separation efficiency that is between the minimum target separation efficiency and the maximum target separation efficiency; and

adjusting a demulsifier dosage, used in calculating the separation efficiency, between a minimum demulsifier concentration and a maximum demulsifier concentration, the adjusting including:

when the separation efficiency is below the target separation efficiency, adjusting, using a PID controller, the demulsifier dosage upward but not to exceed a maximum dosage concentration; and

when the separation efficiency is above the target separation efficiency, adjusting, using the PID controller, the demulsifier dosage downward above a minimum dosage concentration.

9. The non-transitory, computer-readable medium of claim 8 , wherein identifying the target separation efficiency includes receiving, from an operator, input specifying an increase to an expected separation performance by a certain margin.

10. The non-transitory, computer-readable medium of claim 8 , wherein the minimum demulsifier concentration and the maximum demulsifier concentration are determined through correlations and are a function of temperature.

11. The non-transitory, computer-readable medium of claim 8 , the operations further comprising:

determining that an upset has occurred in a dehydrator; and

using another PID controller having more aggressive tuning than a current PID controller to override the demulsifier concentration to mitigate the upset.

12. The computer-readable medium of claim 8 , the operations further comprising: determining efficiency calculations that are based on reconciled values to account for instrument measurement errors and closure of a water balance.

13. The computer-readable medium of claim 8 , wherein adjusting the demulsifier dosage includes maintaining the demulsifier dosage regardless of crude and water flow oscillations.

14. The computer-readable medium of claim 13 , wherein maintaining the demulsifier dosage includes using a controlled variable used as a demulsifier concentration, a manipulated variable used as a demulsifier flow set point, and disturbances variables including a dry crude flow oscillation, a produced water flow oscillation, and a demulsifier flow oscillation.

15. A computer-implemented system, comprising:

a computer memory; and

a hardware processor interoperably coupled with the computer memory and configured to perform operations comprising:

implementing a feedback control scheme including controlling a separation efficiency for a high-pressure production trap (HPPT) by manipulating a demulsifier concentration, including:

determining, as a function of temperature and based on correlations of historical process data, a minimum target separation efficiency and a maximum target separation efficiency;

identifying a target separation efficiency that is between the minimum target separation efficiency and the maximum target separation efficiency; and

adjusting a demulsifier dosage, used in calculating the separation efficiency, between a minimum demulsifier concentration and a maximum demulsifier concentration, the adjusting including:

when the separation efficiency is below the target separation efficiency, adjusting, using a PID controller, the demulsifier dosage upward but not to exceed a maximum dosage concentration; and

when the separation efficiency is above the target separation efficiency, adjusting, using the PID controller, the demulsifier dosage downward above a minimum dosage concentration.

16. The computer-implemented system of claim 15 , wherein identifying the target separation efficiency includes receiving, from an operator, input specifying an increase to an expected separation performance by a certain margin.

17. The computer-implemented system of claim 15 , wherein the minimum demulsifier concentration and the maximum demulsifier concentration are determined through correlations and are a function of temperature.

18. The computer-implemented system of claim 15 , the operations further comprising:

determining that an upset has occurred in a dehydrator; and

using another PID controller having more aggressive tuning than a current PID controller to override the demulsifier concentration to mitigate the upset.

19. The computer-implemented system of claim 15 , the operations further comprising: determining efficiency calculations that are based on reconciled values to account for instrument measurement errors and closure of a water balance.

20. The computer-implemented system of claim 15 , wherein adjusting the demulsifier dosage includes maintaining the demulsifier dosage regardless of crude and water flow oscillations.