Method for managing production from a hydrocarbon producing reservoir in real-time

1. A method of performing an oilfield operation of an oilfield having at least one wellsite, each wellsite having a wellbore penetrating a subterranean formation for extracting fluid from an underground reservoir therein, the method comprising:

obtaining a plurality of real-time parameters from a plurality of sensors disposed about the oilfield, the oilfield receiving command signals from a surface unit to perform the oilfield operation, wherein the plurality of real-time parameters comprise real-time flow rate data and real-time pressure data of the wellbore;

identifying a simulation session marked by identified transients in the plurality of real-time parameters, wherein the identified transients are identified using wavelet decomposition;

identifying, within the simulation session, a first time period during which the real-time flow rate data is not available and a second time period during which the real-time pressure data is not available;

obtaining offline flow rate data for the first time period by performing flow rate re-construction based on at least one selected from a group consisting of tubing head pressure measurement and bottom hole pressure measurement;

obtaining offline pressure data for the second time period based on historical data and spot measurement;

configuring, in the surface unit, a gridless analytical simulator for the simulation session to simulate the underground reservoir based on the plurality of real-time parameters supplemented by the offline flow rate data during the first time period and the offline pressure data during the second time period;

generating real-time simulation results of the underground reservoir and the at least one wellsite in real-time using the gridless analytical simulator; and

sending, from the surface unit, the command signals to the oilfield to manage the underground reservoir in real time by performing the oilfield operation, wherein the command signals are based on the real-time simulation results.

2. The method of claim 1 ,

wherein at least a portion of the oilfield is modeled as a vertically stacked system of a plurality of layers using a plurality of analytic solutions corresponding to the plurality of layers, and

wherein the gridless analytical simulator is based on coupling the plurality of analytic solutions to account for crossflow among the plurality of layers.

3. The method of claim 2 ,

wherein a flux field at an interface of the plurality of layers is obtained by solving a Fredholm integral equation, and

wherein a time evolution of the flux field is governed by a Volterra integral equation.

4. The method of claim 1 ,

wherein the oilfield comprises a plurality of wellsites, and

wherein the gridless analytical model is configured to simulate an interference effect from the plurality of wellsites.

5. The method of claim 1 , wherein the real-time simulation results are generated using at least one selected from a group consisting of a no-flow boundary condition, and a constant pressure boundary condition.

6. The method of claim 1 , wherein configuring the gridless analytical simulator comprises identifying a reservoir model based on at least one selected from a group consisting of a neural network method, a rate of change of the real-time pressure data, and a geological parameter.

7. The method of claim 1 ,

wherein the at least one wellsite comprises at least one selected from a group consisting of a horizontal well, a vertical well, and a deviated well, and

wherein the underground reservoir comprises a plurality of heterogeneous layers.

8. The method of claim 1 , wherein the underground reservoir is a naturally fractured reservoir.

9. The method of claim 1 , wherein hydraulic fracturing is performed for the at least one wellsite.

10. The method of claim 9 , wherein the wellbore comprises at least one selected from a group consisting of a finite conductivity hydraulic fracture and an infinite conductivity hydraulic fracture.

11. The method of claim 1 , wherein the wellbore is modeled as a line source in the gridless analytical simulator.

12. The method of claim 11 , further comprising:

simulating at least one selected from a group consisting of a wellbore storage effect and a finite wellbore radius by applying corrections to the gridless analytical simulator.

13. The method of claim 1 , wherein the real-time simulation results comprises at least one selected from a group consisting of reservoir pressure, flow rate, well skin, effective permeability, fracturing performance, well drainage area, compartmentalization, and well productivity.

14. The method of claim 1 , wherein performing the oilfield operation comprises at least one selected from a group consisting of anticipating an event, identifying an event, performing real-time diagnostics, performing real-time interpretation, performing real-time decision making, performing real-time corrective action, and forecasting performance of the wellsite and the reservoir in real-time.

15. The method of claim 1 , further comprising:

generating an alert based on comparing at least one of the plurality of real-time parameters to a pre-determined limit; and

classifying the alert according to a plurality of pre-determined alert levels,

wherein an alert level of the plurality of pre-determined alert levels dictates at least one selected from a group consisting of a proactive action and a reactive action.

16. A non-transitory computer readable medium, embodying instructions executable by a computer to perform method steps for an oilfield operation, the oilfield having at least one wellsite, each of the at least one wellsite having a wellbore penetrating a subterranean formation for extracting fluid from an underground reservoir therein, the instructions comprising functionality to:

obtain a plurality of real-time parameters from a plurality of sensors disposed about the oilfield, the oilfield receiving command signals from a surface unit to perform the oilfield operation, wherein the plurality of real-time parameters comprise at least one selected from a group consisting of real-time flow rate data and real-time pressure data of the wellbore;

identify a simulation session marked by identified transients in the plurality of real-time parameters, wherein the identified transients are identified using wavelet decomposition;

identify a first time period during which the real-time flow rate data is not available and a second time period during which the real-time pressure data is not available;

obtain offline flow rate data for the first time period by performing flow rate re-construction based on at least one selected from a group consisting of tubing head pressure measurement and bottom hole pressure measurement;

obtain offline pressure data for the second time period based on historical data and spot measurement;

configure, in the surface unit, a gridless analytical simulator for the simulation session to simulate the underground reservoir based on the plurality of real-time parameters supplemented by the offline flow rate data and the offline pressure data during the first time period and the second time period, respectively; and

generate real-time simulation results of the reservoir and the at least one wellsite in real-time using the gridless analytical simulator,

wherein the oilfield operation is performed to manage the underground reservoir in real time by receiving the command signals that are generated based on the real-time simulation results.

17. The non-transitory computer readable medium of claim 16 ,

wherein at least a portion of the oilfield is modeled as a vertically stacked system of a plurality of layers using a plurality of analytic solutions corresponding to the plurality of layers, and

wherein the gridless analytical simulator is based on coupling the plurality of analytic solutions to account for crossflow among the plurality of layers.

18. The non-transitory computer readable medium of claim 16 ,

wherein a flux field at an interface of the plurality of layers is obtained by solving a Fredholm integral equation, and

wherein a time evolution of the flux field is governed by a Volterra integral equation.

19. The non-transitory computer readable medium of claim 16 ,

wherein the oilfield comprises a plurality of wellsites, and

wherein the gridless analytical model is configured to simulate an interference effect from the plurality of wellsites.

20. The non-transitory computer readable medium of claim 16 , wherein the real-time simulation results are generated using at least one selected from a group consisting of a no-flow boundary condition, and a constant pressure boundary condition.

21. The non-transitory computer readable medium of claim 16 , wherein configuring the gridless analytical simulator comprises identifying a reservoir model based on at least one selected from a group consisting of a neural network method, a rate of change of the real-time pressure data, and a geological parameter.

22. The non-transitory computer readable medium of claim 16 ,

wherein the at least one wellsite comprises at least one selected from a group consisting of a horizontal well, a vertical well, and a deviated well, and

wherein the underground reservoir comprises a plurality of heterogeneous layers.

23. The non-transitory computer readable medium of claim 16 , wherein the underground reservoir is a naturally fractured reservoir.

24. The non-transitory computer readable medium of claim 16 , wherein hydraulic fracturing is performed for the at least one wellsite.

25. The non-transitory computer readable medium of claim 24 , wherein the wellbore comprises at least one selected from a group consisting of a finite conductivity hydraulic fracture and an infinite conductivity hydraulic fracture.

26. The non-transitory computer readable medium of claim 16 , wherein the wellbore is modeled as a line source in the gridless analytical simulator.

27. The non-transitory computer readable medium of claim 26 , the instructions further comprising functionality to:

simulating at least one selected from a group consisting of a wellbore storage effect and a finite wellbore radius by applying corrections to the gridless analytical simulator.

28. The non-transitory computer readable medium of claim 16 , wherein the real-time simulation results comprises at least one selected from a group consisting of reservoir pressure, flow rate, well skin, effective permeability, fracturing performance, well drainage area, compartmentalization, and well productivity.

29. The non-transitory computer readable medium of claim 16 , wherein performing the oilfield operation comprises at least one selected from a group consisting of anticipating an event, identifying an event, performing real-time diagnostics, performing real-time interpretation, performing real-time decision making, performing real-time corrective action, and forecasting performance of the wellsite and the reservoir in real-time.

30. The non-transitory computer readable medium of claim 16 , the instructions further comprising functionality to:

generating an alert based on comparing at least one of the plurality of real-time parameters to a pre-determined limit; and

classifying the alert according to a plurality of pre-determined alert levels,

wherein an alert level of the plurality of pre-determined alert levels dictates at least one selected from a group consisting of a proactive action and a reactive action.