System and method for integrated wellbore stress, stability and strengthening analyses

Patent metadata

Field	Value
Publication number	US-9803475-B2
Application number	US-201414249052-A
Country	US
Kind code	B2
Filing date	Apr 9, 2014
Priority date	Apr 9, 2014
Publication date	Oct 31, 2017
Grant date	Oct 31, 2017

Abstract

Systems and methods for an integrated wellbore stress, stability and strengthening analysis are disclosed. An integrated geomechanical tool can be used to analyze and evaluate stress along the length of the wellbore to identify a safe drilling mud weight window and help identify troublesome zones in the wellbore. Fracture length may then be predicted in the identified troublesome zones by using a stress tensor calculated during the stress analysis. The calculated fracture length may be used to perform a strengthening analysis. After performing strengthening analysis, mud loss may be predicted based on predicted fracture size calculated during the stress, stability and strengthening analyzes.

First claim

What is claimed is:

1. A method implemented with one or more processors and a drilling system, the method comprising:
receiving, at the one or more processors, a plurality of input parameters, each input parameter relating to at least one of a wellbore, a formation in which the wellbore is drilled, and a drilling operation used to drill the wellbore with the drilling system;
generating, with the one or more processors, a geomechanical model of the wellbore based on one or more of the received input parameters;
identifying, with the one or more processors, one or more troublesome zones of the wellbore by performing a stress and stability analysis for the wellbore using the generated model based on one or more of the received input parameters to produce one or more stress and stability analysis output parameters;
performing, with the one or more processors, a strengthening analysis for the wellbore using the generated model based on one or more of the received input parameters and one or more of the stress and stability analysis output parameters to produce one or more strengthening analysis output parameters;
performing, with the one or more processors, a mud loss analysis for the wellbore using the generated model based on one or more of the received input parameters and one or more of the strengthening analysis output parameters to produce one or more mud loss analysis output parameters; and
drilling the wellbore in the formation with the drilling operation by operating the drilling system using the one or more strengthening analysis output parameters and the one or more mud loss analysis output parameters to strengthen the one or more identified troublesome zones during drilling.

2. The method of claim 1 , wherein drilling the wellbore by operating the drilling system comprises drilling the wellbore with a drill string and a drill bit; circulating drilling fluid through the drill string and the drill bit; and mitigating loss of the drilling fluid by performing wellbore strengthening.

3. The method of claim 2 , wherein performing the wellbore strengthening comprises sealing one or more existing natural fractures and/or induced fractures with a lost circulation material.

4. The method of claim 3 , wherein sealing the one or more fractures comprises determining a dimension of a fracture at a wellbore location and selecting the lost circulation material having a suitable particle size distribution to seal the fracture at the wellbore location.

5. The method of claim 2 , wherein performing the wellbore strengthening comprises increasing a fracture gradient at a wellbore location; inducing a fracture at the wellbore location with the increased fracture gradient; and sealing the induced fracture.

6. The method of claim 5 , wherein inducing the fracture at the wellbore location with the increased fracture gradient comprises exerting pressure of mud weight that exceeds the fracture gradient at the wellbore location and controlling a size of the induced fracture and an increase in the fracture gradient based on a determined amount of mud weight and/or a type of lost circulation material used at the wellbore location.

7. The method of claim 1 , wherein the stress and stability analysis comprises a simple stress and stability analysis and an advanced stress and stability analysis.

8. The method of claim 1 , wherein the one or more of the received input parameters used for the stress and stability analysis comprise one or more of temperature parameters, temperature parameters that are time dependent, and mud cake effects.

9. The method of claim 1 , wherein the one or more stress and stability analysis output parameters comprise one or more of a safe mud weight window and a fracture length.

10. The method of claim 1 , wherein the one or more strengthening analysis output parameters comprise one or more of a fracture width distribution and a fracture re-initiation pressure.

11. The method of claim 1 , further comprising updating a mud weight window for the wellbore based on one or more of the strengthening analysis output parameters.

12. The method of claim 1 , wherein the one or more mud loss analysis output parameters provide information about one or more of loss of fluid in a natural fracture, loss of fluid in the formation, and loss of fluid in an induced fracture.

13. The method of claim 1 , wherein each of the stress and stability, strengthening and mud loss analysis can be run separately or in multiple combinations.

14. The method of claim 1 , wherein drilling the wellbore comprises measuring one or more stress and stability output parameters; and performing a calibration procedure by comparing at least one of the one or more stress and stability analysis output parameters to the one or more measured stress and stability analysis parameters to calculate a difference between the at least one of the one or more stress and stability analysis output parameters and the one or more measured stress and stability analysis parameters, and using the calculated difference for calibration purposes of the stress and stability analysis.

15. The method of claim 1 , wherein drilling the wellbore comprises measuring one or more strengthening analysis parameters; and performing a calibration procedure by comparing at least one of the one or more strengthening analysis output parameters to the one or more measured strengthening analysis parameters to calculate a difference between the at least one of the one or more strengthening analysis output parameters and the one or more measured strengthening analysis parameters, and using the calculated difference for calibration purposes of the strengthening analysis.

16. The method of claim 1 , wherein receiving the input parameters comprises obtaining the one or more input parameters in one or more of a well log, a leak-off test, a mini-fracture test, real-time information for the wellbore being drilled, pre-drilled information from another wellbore, and an assumed value based on available information.

17. The method of claim 1 , wherein generating the geomechanical model of the wellbore comprises incorporating a transient thermo-poro-elastic algorithm that takes into account wellbore temperature and/or mudcake effects.

18. The method of claim 1 , wherein performing the strengthening analysis for the wellbore comprises simulating a plurality of wellbore strengthening scenarios having one or more of fracture widths, fracture lengths, and lost circulation materials that are different.

19. A drilling system for drilling a wellbore in a formation with a drilling operation, the drilling system comprising:
a memory;
a display device; and
a processor operatively coupled to the memory and the display device and adapted to execute program code stored in the memory to:
receive a plurality of input parameters, each input parameter relating to at least one of the wellbore, the formation, and the drilling operation;
generate a geomechanical model of the wellbore based on one or more of the received input parameters;
perform a stress and stability analysis for the wellbore using the generated model based on one or more of the received input parameters to produce one or more stress and stability analysis output parameters;
identify one or more troublesome zones of the wellbore based on the stress and stability analysis;
perform a strengthening analysis for the wellbore using the generated model based on one or more of the received input parameters and one or more of the stress and stability analysis output parameters to produce one or

Assignees

• Weatherford Lamb Inc
• Weatherford Tech Holdings Llc

Inventors

• Shahri Mojtaba P
• Safariforoshani Mohammadreza
• Mutlu Ovunc
• Oar Trevor
• Karimi Mojtaba

Classifications

• E21B49/006 Primary

  Measuring wall stresses in the borehole · CPC title

• E21B49/003

  by analysing drilling variables or conditions (E21B49/005 takes precedence; systems specially adapted for monitoring a plurality of drilling variables or conditions E21B44/00) · CPC title

• E21B21/003 Primary

  Means for stopping loss of drilling fluid (plastering the borehole wall E21B33/138) · CPC title