Method of calibrating fracture geometry to microseismic events

1. A method of performing a fracture operation at a wellsite, the wellsite positioned about a subterranean formation having a wellbore therethrough and a fracture network therein, the fracture network comprising natural fractures, the wellsite stimulated by injection of an injection fluid with proppant into the fracture network, the method comprising:

generating wellsite data comprising natural fracture parameters of the natural fractures and obtaining measurements of microseismic events of the subterranean formation;

modeling hydraulic fractures of the fracture network based on the wellsite data and defining a hydraulic fracture geometry of the hydraulic fractures;

generating a stress field of the hydraulic fractures using a geomechanical model based on the wellsite data;

determining shear failure parameters comprising a failure envelope and a stress state about the fracture network;

determining a location of shear failure of the fracture network from the failure envelope and the stress state; and

calibrating the hydraulic fracture geometry by comparing the modeled hydraulic fractures and the locations of shear failure against the measured microseismic events.

2. The method of claim 1 , further comprising adjusting the natural fracture parameters based on the calibrating.

3. The method of claim 1 , further comprising stimulating the wellsite by injecting the injection fluid into the fracture network.

4. The method of claim 3 , further comprising adjusting the stimulation operation based on the calibrating.

5. The method of claim 1 , further comprising adjusting the wellsite data by selectively repeating the method based on the calibrating.

6. The method of claim 1 , wherein the determining a stress field comprises performing numerical simulations.

7. The method of claim 1 , wherein the determining shear failure parameters comprises determining a stress state at one of: along the natural fractures, along the hydraulic fractures, and along a rock medium about the natural fractures.

8. The method of claim 1 , wherein the geomechanical model comprises one of: a two dimensional displacement discontinuity method, a three dimensional displacement discontinuity method, finite element numerical geomechanics code, and a finite difference code.

9. The method of claim 8 , wherein the two dimensional displacement discontinuity method comprises:

providing a three dimensional correction factor;

validating the two dimensional displacement discontinuity method against a three dimensional finite difference solution; and

computing stresses acting on the fracture network.

10. The method of claim 8 , wherein the three dimensional displacement discontinuity method comprises:

discretizing the discrete fracture network into a plurality of elements;

generating an induced stress at a point by superimposing stresses from all fracture elements of the fracture network; and

applying a coordinate transform.

11. The method of claim 1 , wherein the calibrating comprises performing a failure assessment and calibration against the microseismic events.

12. The method of claim 1 , wherein the calibrating comprises:

generating plots of failure parameters by applying the stress field to points in three dimensional space;

generating stress parameters at and/or along the natural fractures based on shear stresses of failure conditions;

comparing stress parameters with microseismic locations and moment tensor attributes;

computing stresses at observed microseismic event locations; and

comparing predicted failure comprising shear slippage against the microseismic events.

13. The method of claim 12 , wherein the failure envelope is a Mohr-Coulomb failure envelope and wherein the stress state is a Mohr circle.

14. A method of performing a fracture operation at a wellsite, the wellsite positioned about a subterranean formation having a wellbore therethrough and a fracture network therein, the fracture network comprising natural fractures, the wellsite stimulated by injection of an injection fluid with proppant into the fracture network, the method comprising:

generating wellsite data comprising natural fracture parameters of the natural fractures and obtaining measurements of microseismic events of the subterranean formation;

modeling hydraulic fractures of the fracture network based on the wellsite data and defining a hydraulic fracture geometry of the hydraulic fractures;

generating a stress field of the hydraulic fractures using a geomechanical model based on the wellsite data;

determining shear failure parameters comprising a failure envelope and a stress state about the fracture network;

determining a location of shear failure of the fracture network from the failure envelope and the stress state; and

calibrating the hydraulic fracture geometry by comparing the modeled hydraulic fractures and the locations of shear failure against the measured microseismic events; and

adjusting the natural fracture parameters operation based on the calibrating.

15. The method of claim 14 , further comprising performing a stimulation operation comprising stimulating the wellsite by injecting the injection fluid into the fracture network.

16. The method of claim 14 , further comprising adjusting the stimulation operation based on the calibrating.

17. A method of performing a fracture operation at a wellsite, the wellsite positioned about a subterranean formation having a wellbore therethrough and a fracture network therein, the fracture network comprising natural fractures, the wellsite stimulated by injection of an injection fluid with proppant into the fracture network, the method comprising:

performing a stimulation operation comprising stimulating the wellsite by injecting the injection fluid into the fracture network;

generating wellsite data comprising natural fracture parameters of the natural fractures and obtaining measurements of microseismic events of the subterranean formation;

modeling hydraulic fractures of the fracture network based on the wellsite data and defining a hydraulic fracture geometry of the hydraulic fractures;

generating a stress field of the hydraulic fractures using a geomechanical model based on the wellsite data;

determining shear failure parameters comprising a failure envelope and a stress state about the fracture network;

determining a location of shear failure of the fracture network from the failure envelope and the stress state; and

calibrating the hydraulic fracture geometry by comparing the modeled hydraulic fractures and the locations of shear failure against the measured microseismic events.

18. The method of claim 17 , further comprising adjusting the natural fracture parameters operation based on the calibrating.

19. The method of claim 17 , further comprising adjusting the stimulation operation based on the calibrating.

20. The method of claim 17 , further comprising measuring the wellsite data and the microseismic events at the wellsite.