Methods of hydraulically fracturing a subterranean formation

Patent metadata

Field	Value
Publication number	US-9336416-B2
Application number	US-201313956471-A
Country	US
Kind code	B2
Filing date	Aug 1, 2013
Priority date	Jan 29, 2007
Publication date	May 10, 2016
Grant date	May 10, 2016

Abstract

A hydraulic fracture design model that simulates the complex physical process of fracture propagation in the earth driven by the injected fluid through a wellbore. An objective in the model is to adhere with the laws of physics governing the surface deformation of the created fracture subjected to the fluid pressure, the fluid flow in the gap formed by the opposing fracture surfaces, the propagation of the fracture front, the transport of the proppant in the fracture carried by the fluid, and the leakoff of the fracturing fluid into the permeable rock. The models used in accordance with methods of the invention are typically based on the assumptions and the mathematical equations for the conventional 2D or P3D models, and further take into account the network of jointed fracture segments. For each fracture segment, the mathematical equations governing the fracture deformation and fluid flow apply. For each time step, the model predicts the incremental growth of the branch tips and the pressure and flow rate distribution in the system by solving the governing equations and satisfying the boundary conditions at the fracture tips, wellbore and connected branch joints. An iterative technique is used to obtain the solution of this highly nonlinear and complex problem.

First claim

The invention claimed is:

1. A method of performing a fracture treatment, said method comprising:
acquiring subterranean formation layer geomechanical properties;
providing pumping parameters for fracturing the subterranean formation;
predicting a propagation of a network of fractures in the formation, and a flow rate and pressure distribution throughout the network of fractures based on the acquired geomechanical properties and the pumping parameters;
designing a fracturing fluid and a fracturing treatment schedule based upon the predicting; and,
injecting the fracturing fluid into a wellbore according to the fracturing treatment schedule.

2. The method of claim 1 , wherein the geomechanical properties include at least one of an elasticity property of the formation and a deformation property of the formation.

3. The method of claim 1 , further comprising predicting if each fracture will grow and in which direction the fracture will branch.

4. The method of claim 1 , wherein the predicting comprises solving governing deformation and flow equations.

5. The method of claim 1 , further comprising inputting the geomechanical properties of the formation into a model.

6. The method of claim 5 , wherein the model is selected from the group consisting of a 2D Perkins-Kern-Nordren (2D PKN) model, a Radial (RAD) model, a planar 3D model, a Khristianovich-Geertsma-de Klerk (KGD) model, a Pseudo-3D (P3D) model, and a full 3D model.

7. The method of claim 1 , wherein predicting the propagation of the network of fractures further comprises dividing at least one fracture segment of the network of fractures into a plurality of elements to form a fracture grid.

8. The method of claim 1 , wherein predicting the propagation of the network of fractures is performed before or during the fracture treatment, and achieved by modeling progression of the fracture in small time increments with the fracture growing in length in small steps.

9. The method of claim 8 , wherein said predicting further comprises, at each time increment, solving the flow rate and pressure distribution throughout the network of fractures to further satisfy boundary conditions at tips of propagating branches and at a wellbore communicating with the subterranean formation, and the continuity, and flow rate balance at each joint connecting more than one branch.

10. The method of claim 1 , further comprising using a production simulator to predict productivity increase for the subterranean formation.

11. The method of claim 1 , further comprising selecting an optimum fracturing fluid composition to achieve a fracture propagation objective.

12. The method of claim 1 , wherein the subterranean formation comprises a natural fracture network.

13. The method of claim 12 , further comprising providing a description of the natural fracture network.

14. The method of claim 1 , wherein pumping parameters comprise at least one of a pump rate and pump time.

15. A method of fracturing a subterranean formation, the method comprising:
inputting a geomechanical property of the formation into a model;
inputting pumping parameters for fracturing the subterranean formation into the model;
simulating a propagation of a network of fractures in the formation;
predicting a flow rate and pressure distribution throughout the network of fractures based on the acquired geomechanical properties and the pumping parameters;
designing a fracturing fluid and a fracturing treatment schedule based upon the predicting; and,
injecting the fracturing fluid into a wellbore according to the fracturing treatment schedule.

16. The method of claim 15 , wherein the geomechanical property includes at least one of an elasticity property of the formation and a deformation property of the formation.

17. The method of claim 15 , further comprising predicting if each fracture will grow and in which direction the fracture will branch.

18. The method of claim 15 , further comprising selecting an optimum fracturing fluid to achieve the simulated fracture propagation result.

19. The method of claim 15 , further comprising fracturing the subterranean formation.

20. The method of claim 15 , wherein the model is selected from the group consisting of a 2D Perkins-Kern-Nordren (2D PKN) model, a Radial (RAD) model, a planar 3D model, a Khristianovich-Geertsma-de Klerk (KGD) model, a Pseudo-3D (P3D) model, and a full 3D model.

21. The method of claim 15 , wherein said simulating is performed before or during the fracture treatment, and achieved by modeling progression of the fracture in small time increments with fracture growing in length in small steps.

22. The method of claim 21 , wherein said simulating further comprising, at each time increment, solving the flow rate and pressure distribution throughout a fracture system to satisfy boundary conditions at tips of propagating branches and at a wellbore communicating with the subterranean formation, and the continuity, and flow rate balance at each joint connecting more than one branch.

23. The method of claim 15 , wherein said predicting further comprises solving governing deformation and flow equations.

24. The method of claim 15 , wherein said simulating further comprises dividing at least one fracture segment of the network of fractures into a plurality of elements to form a fracture grid.

25. The method of claim 15 , further comprising using a production simulator to predict productivity increase for the subterranean formation.

26. The method of claim 15 , wherein the subterranean formation is a natural fracture network.

27. The method of claim 26 , further comprising inputting a description of the natural fracture network into the model.

Assignees

• Schlumberger Technology Corp

Inventors

• Weng Xiaowei
• Siebrits Edward

Classifications

• G06G7/57

  for fluid flow (G06G7/50 takes precedence){; for distribution networks} · CPC title

• G06F30/28 Primary

  using fluid dynamics, e.g. using Navier-Stokes equations or computational fluid dynamics [CFD] · CPC title

• E21B43/26

  by forming crevices or fractures · CPC title

• E21B43/267

  reinforcing fractures by propping · CPC title

• G06G7/50 Primary

  for distribution networks, e.g. for fluids (G06G7/62 takes precedence) · CPC title