Method and system for predicting performance of a drilling system for a given formation

• US 6,408,953 B1
• Filed: 08/28/2000
• Issued: 06/25/2002
• Est. Priority Date: 03/25/1996
• Status: Expired due to Term

• Current Assignee: Halliburton Energy Services Incorporated (Halliburton Company)
• Original Assignee: Halliburton Energy Services Incorporated (Halliburton Company)
• Inventors: Pruitt, Gerald L., Weaver, Gary E., King, William W., Matthews, Oliver III, Goldman, William A.
• Primary Examiner(s): DANG, HOANG C
• Application Number:
  US09/649,495
• Time in Patent Office: 666 Days
• Field of Search: 175/39, 175/40, 175/57, 175/24, 702/9
• US Class Current: 175/39
• CPC Class Codes: E21B 12/02 Wear indicators
• CPC Class Codes: E21B 2200/22 Fuzzy logic, artificial intelligence, neural networks or the like
• CPC Class Codes: E21B 44/00 Automatic control systems specially adapted for drilling operations, i.e. self-operating systems which function to carry out or modify a drilling operation without intervention of a human operator, e.g. computer-controlled drilling systems; Systems specially adapted for monitoring a plurality of drilling variables or conditions
• CPC Class Codes: E21B 44/005 Below-ground automatic control systems
• CPC Class Codes: E21B 49/003 by analysing drilling variables or conditions E21B49/005 takes precedence; systems specially adapted for monitoring a plurality of drilling variables or conditions E21B44/00

Abstract

A method and apparatus for predicting the performance of a drilling system for the drilling of a well bore in a given formation includes generating a geology characteristic of the formation per unit depth according to a prescribed geology model, obtaining specifications of proposed drilling equipment for use in the drilling of the well bore, and predicting a drilling mechanics in response to the specifications as a function of the geology characteristic per unit depth according to a prescribed drilling mechanics model. Responsive to a predicted drilling mechanics, a controller controls a parameter in the drilling of the well bore. The geology characteristic includes at least rock strength. The specifications include at least a bit specification of a recommended drill bit. Lastly, the predicted drilling mechanics include at least one of bit wear, mechanical efficiency, power, and operating parameters. A display is provided for generating a display of the geology characteristic and predicted drilling mechanics per unit depth, including either a display monitor or a printer.

Claims

1. An apparatus for predicting the performance of a drilling system for the drilling of a well bore in a given formation, said apparatus comprising:

means for generating a geology characteristic of the formation per unit depth according to a prescribed geology model and outputting signals representative of the geology characteristic, the geology characteristic including at least rock strength;

means for inputting specifications of proposed drilling equipment for use in the drilling of the well bore, the specifications including at least a bit specification of a recommended drill bit;

means for determining a predicted drilling mechanics in response to the specifications of the proposed drilling equipment as a function of the geology characteristic per unit depth according to a drilling mechanics model and outputting signals representative of the predicted drilling mechanics, the predicted drilling mechanics including at least one of the following selected from the group consisting of bit wear, mechanical efficiency, power, and operating parameters;

means responsive to a predicted drilling mechanics output signal for controlling a control parameter in drilling of the well bore with the drilling system, the control parameter including at least one selected from the group consisting of weight-on-bit, rpm, pump flow rate, and hydraulics;

means for obtaining a measurement parameter in real time during the drilling of the well bore; and

means for history matching the measurement parameter with a back calculated value of the measurement parameter, wherein the back calculated value of the measurement parameter is a function of the drilling mechanics model and at least one control parameter, and wherein responsive to a prescribed deviation between the measurement parameter and the back calculated value of the measurement parameter, said control means performs at least one of the following selected from the group consisting of a) adjusts the drilling mechanics model, b) modifies control of a control parameter, and c) performs an alarm operation.

2. The apparatus of claim 1, further comprising:

means responsive to the geology characteristic output signals and the predicted drilling mechanics output signals for generating a display of the geology characteristic and predicted drilling mechanics per unit depth.

3. The apparatus of claim 2, wherein said display generating means includes at least one of the following selected from the group consisting of a) a display monitor and b) a printer, wherein the display of the geology characteristic and predicted drilling mechanics per unit depth includes a printout.

4. The apparatus of claim 1, wherein said geology characteristic generating means further generates at least one of the following additional characteristics selected from the group consisting of log data, lithology, porosity, and shale plasticity.

5. The apparatus of claim 1, wherein said proposed drilling equipment input specification means further includes inputting at least one additional specification of proposed drilling equipment selected from the group consisting of down hole motor, top drive motor, rotary table motor, mud system, and mud pump.

6. The apparatus of claim 1, wherein the operating parameters include at least one of the following selected from the group consisting of weight-on-bit, rotary rpm (revolutions-per-minute), cost, rate of penetration, and torque.

7. The apparatus of claim 6, further wherein rate of penetration includes instantaneous rate of penetration (ROP) and average rate of penetration (ROP-AVG).

8. The apparatus of claim 2, wherein the display of the geology characteristic includes at least one graphical representation selected from the group consisting of a curve representation, a percentage graph representation, and a band representation, and

the display of the predicted drilling mechanics includes at least one graphical representation selected from the group consisting of a curve representation, a percentage graph representation, and a band representation.

9. The apparatus of claim 8, wherein said display generating means includes at least one of the following selected from the group consisting of a) a display monitor and b) a printer, wherein the display of the geology characteristic and predicted drilling mechanics per unit depth includes a printout.

10. The apparatus of claim 8, further wherein the at least one graphical representation of the geology characteristic and the at least one graphical representation of the predicted drilling mechanics are color coded.

11. The apparatus of claim 8, wherein rock strength is expressed in the form of at least one of the following representations selected from the group consisting of a curve representation, a percentage graph representation, and a band representation, wherein

the curve representation of rock strength includes confined rock strength and unconfined rock strength, further wherein an area between respective curves of confined rock strength and unconfined rock strength is graphically illustrated and represents an increase in rock strength as a result of a confining stress, and

the band representation of rock strength provides a graphical illustration indicative of a discrete range of rock strength at a given depth, further wherein the band representation of the rock strength is coded, including a first code representative of a soft rock strength range, a second code representative of a hard rock strength range, and additional codes representative of one or more intermediate rock strength ranges.

12. The apparatus of claim 8, wherein said geology characteristic generating means further generates at least one of the following additional characteristics selected from the group consisting of log data, lithology, porosity, and shale plasticity, and

the operating parameters include at least one of the following selected from the group consisting of weight-on-bit, bit rpm (revolutions-per-minute), cost, rate of penetration, and torque.

13. The apparatus of claim 12, wherein

log data is expressed in the form of a curve representation, the log data including any log suite sensitive to lithology and porosity, and

lithology is expressed in the form of a percentage graph for use in identifying different types of rock within the given formation, the percentage graph illustrating a percentage of each type of rock at a given depth, and

porosity is expressed in the form of a curve representation, and

shale plasticity is expressed in the form of at least one of the following representations selected from the group consisting of a curve representation, a percentage graph representation, and a band representation, wherein

the curve representation of shale plasticity includes at least one curve of shale plasticity parameters selected from the group consisting of water content, clay type, and clay volume, further wherein shale plasticity is determined from water content, clay type, and clay volume according to a prescribed shale plasticity model, and

the band representation of the shale plasticity provides a graphical illustration indicative of a discrete range of shale plasticity at a given depth, further wherein the band representation of the shale plasticity is coded, including a first code representative of a low shale plasticity range, a second code representative of a high shale plasticity range, and additional codes representative of one or more intermediate shale plasticity ranges.

14. The apparatus of claim 8, wherein bit wear is determined as a function of cumulative work done according to a prescribed bit wear model and expressed in the form of at least one of the following representations selected from the group consisting of a curve representation and a percentage graph representation, wherein

the curve representation of bit wear may include bit work expressed as specific energy level at the bit, cumulative work done by the bit, and optional work losses due to abrasivity, and

the percentage graph representation is indicative of a bit wear condition at a given depth, further wherein the percentage graph of bit wear is coded, including a first code representative of expired bit life, and a second code representative of remaining bit life.

15. The apparatus of claim 8, wherein bit mechanical efficiency is determined as a function of a torque/weight-on-bit signature for the given bit according to a prescribed mechanical efficiency model and expressed in the form of at least one of the following representations selected from the group consisting of a curve representation and a percentage graph representation, wherein

the curve representation of bit mechanical efficiency includes total torque and cutting torque at the bit, and

the percentage graph representation of bit mechanical efficiency graphically illustrates total torque, total torque including cutting torque and frictional torque components, further wherein the percentage graph representation of bit mechanical efficiency is coded, including a first code for illustrating cutting torque, a second code for illustrating frictional unconstrained torque, and a third code for illustrating frictional constrained torque.

16. The apparatus of claim 15, wherein mechanical efficiency is further represented in the form of a percentage graph illustrating drilling system operating constraints that have an adverse impact upon mechanical efficiency, the drilling system operating constraints corresponding to constraints that result in an occurrence of frictional constrained torque, the percentage graph further for indicating a corresponding percentage of impact that each constraint has upon the frictional constrained torque component of the mechanical efficiency at a given depth, wherein

the drilling system operating constraints can include maximum torque-on-bit (TOB), maximum weight-on-bit (WOB), minimum and maximum bit revolutions-per-minute (RPM), maximum penetration rate (ROP), in any combination, and an unconstrained condition, further wherein the percentage graph representation of drilling system operating constraints on mechanical efficiency is coded, including different codes for identifying different constraints.

17. The apparatus of claim 8, wherein power is expressed in the form of at least one of the following representations selected from the group consisting of a curve representation and a percentage graph representation, wherein

the curve representation for power includes power limit and operating power level, the power limit corresponding to a maximum power to be applied to the bit and the operating power level including at least one of the following selected from the group consisting of constrained operating power level, recommended operating power level, and predicted operating power level, and

the percentage graph representation of power illustrates drilling system operating constraints that have an adverse impact upon power, the drilling system operating constraints corresponding to those constraints that result in a power loss, the power constraint percentage graph further for indicating a corresponding percentage of impact that each constraint has upon the power at a given depth, further wherein the percentage graph representation of drilling system operating constraints on power is coded, including different codes for identifying different constraints.

18. The apparatus of claim 2, further comprising:

means for generating a display of details of proposed drilling equipment along with the geology characteristic and predicted drilling mechanics, the proposed drilling equipment including at least one recommended bit selection used in predicting the performance of the drilling system.

19. The apparatus of claim 18, wherein first and second bit selections are recommended for use in a predicted performance of the drilling of the well bore, further wherein the first and second bit selections are identified with respective first and second identifiers, the first and second identifiers being displayed with the geology characteristic and predicted drilling mechanics, further wherein the positioning of the first and second identifiers on the display is selected to correspond with portions of the predicted performance to which the first and second bit selections apply, respectively.

20. The apparatus of claim 2, further comprising:

a bit selection change indicator for indicating that a change in bit selection from a first recommended bit selection to a second recommended bit selection is required at a given depth on the display of geology characteristics and predicted drilling mechanics.

21. An method for predicting the performance of a drilling system for the drilling of a well bore in a given formation comprising:

generating a geology characteristic of the formation per unit depth according to a prescribed geology model and outputting signals representative of the geology characteristic, the geology characteristic including at least rock strength;

obtaining specifications of proposed drilling equipment for use in the drilling of the well bore, the specifications including at least a bit specification of a recommended drill bit;

determining a predicted drilling mechanics in response to the specifications of the proposed drilling equipment as a function of the geology characteristic per unit depth according to a drilling mechanics model and outputting signals representative of the predicted drilling mechanics, the predicted drilling mechanics including at least one of the following selected from the group consisting of bit wear, mechanical efficiency, power, and operating parameters;

controlling a control parameter in drilling of the well bore with the drilling system in response to a predicted drilling mechanics output signal, the control parameter including at least one selected from the group consisting of weight-on-bit, rpm, pump flow rate, and hydraulics;

obtaining a measurement parameter in real time during the drilling of the well bore; and

history matching the measurement parameter with a back calculated value of the measurement parameter, wherein the back calculated value of the measurement parameter is a function of at least one of the following selected from the group consisting of the drilling mechanics model and at least one control parameter, and responsive to a prescribed deviation between the measurement parameter and the back calculated value of the measurement parameter, said controlling step further for performing at least one of the following selected from the group consisting of a) adjusting the drilling mechanics model, b) modifying control of a control parameter, and c) performing an alarm operation.

22. The method of claim 21, further comprising:

generating a display of the geology characteristic and predicted drilling mechanics per unit depth in response to the geology characteristic output signals and the predicted drilling mechanics output signals.

23. The method of claim 22, wherein generating a display includes using at least one of the following selected from the group consisting of a) a display monitor and b) a printer, wherein the display of the geology characteristic and predicted drilling mechanics per unit depth includes a printout.

24. The method of claim 21, wherein generating the geology characteristic includes generating at least one of the following additional characteristics selected from the group consisting of log data, lithology, porosity, and shale plasticity.

25. The method of claim 21, wherein obtaining the proposed drilling equipment input specifications further includes obtaining at least one additional specification of proposed drilling equipment selected from the group consisting of down hole motor, top drive motor, rotary table motor, mud system, and mud pump.

26. The method of claim 21, wherein the operating parameters include at least one of the following selected from the group consisting of weight-on-bit, bit rpm (revolutions-per-minute), cost, rate of penetration, and torque.

27. The method of claim 26, further wherein rate of penetration includes instantaneous rate of penetration (ROP) and average rate of penetration (ROP-AVG).

28. The method of claim 22, wherein displaying the geology characteristic includes displaying at least one graphical representation selected from the group consisting of a curve representation, a percentage graph representation, and a band representation, and

displaying the predicted drilling mechanics includes displaying at least one graphical representation selected from the group consisting of a curve representation, a percentage graph representation, and a band representation.

29. The method of claim 28, wherein generating a display includes using at least one of the following selected from the group consisting of a) a display monitor and b) a printer, wherein the display of the geology characteristic and predicted drilling mechanics per unit depth includes a printout.

30. The method of claim 28, further wherein the at least one graphical representation of the geology characteristic and the at least one graphical representation of the predicted drilling mechanics are color coded.

31. The method of claim 28, wherein rock strength is expressed in the form of at least one of the following representations selected from the group consisting of a curve representation, a percentage graph representation, and a band representation, wherein

the curve representation of rock strength includes confined rock strength and unconfined rock strength, further wherein an area between respective curves of confined rock strength and unconfined rock strength is graphically illustrated and represents an increase in rock strength as a result of a confining stress, and

the band representation of rock strength provides a graphical illustration indicative of a discrete range of rock strength at a given depth, further wherein the band representation of the rock strength is coded, including a first code representative of a soft rock strength range, a second code representative of a hard rock strength range, and additional codes representative of one or more intermediate rock strength ranges.

32. The method of claim 28, wherein generating the geology characteristic further includes generating at least one of the following additional characteristics selected from the group consisting of log data, lithology, porosity, and shale plasticity, and

the operating parameters include at least one of the following selected from the group consisting of weight-on-bit, bit rpm (revolutions-per-minute), cost, rate of penetration, and torque.

33. The method of claim 32, wherein

log data is expressed in the form of a curve representation, the log data including any log suite sensitive to lithology and porosity,

lithology is expressed in the form of a percentage graph for use in identifying different types of rock within the given formation, the percentage graph illustrating a percentage of each type of rock at a given depth,

porosity is expressed in the form of a curve representation, and

shale plasticity is expressed in the form of at least one of the following representations selected from the group consisting of a curve representation, a percentage graph representation, and a band representation, wherein

the curve representation of shale plasticity includes at least one curve of shale plasticity parameters selected from the group consisting of water content, clay type, and clay volume, further wherein shale plasticity is determined from water content, clay type, and clay volume according to a prescribed shale plasticity model, and

the band representation of the shale plasticity provides a graphical illustration indicative of a discrete range of shale plasticity at a given depth, further wherein the band representation of the shale plasticity is coded, including a first code representative of a low shale plasticity range, a second code representative of a high shale plasticity range, and additional codes representative of one or more intermediate shale plasticity ranges.

34. The method of claim 28, wherein bit wear is determined as a function of cumulative work done according to a prescribed bit wear model and expressed in the form of at least one of the following representations selected from the group consisting of a curve representation and a percentage graph representation, wherein

the curve representation of bit wear may include bit work expressed as specific energy level at the bit, cumulative work done by the bit, and optional work losses due to abrasivity, and

the percentage graph representation is indicative of a bit wear condition at a given depth, further wherein the percentage graph representation of bit wear is coded, including a first code representative of expired bit life, and a second code representative of remaining bit life.

35. The method of claim 28, wherein bit mechanical efficiency is determined as a function of a torque/weight-on-bit signature for the given bit according to a prescribed mechanical efficiency model and expressed in the form of at least one of the following representations selected from the group consisting of a curve representation and a percentage graph representation, wherein

the curve representation of bit mechanical efficiency includes total torque and cutting torque at the bit, and

the percentage graph representation of bit mechanical efficiency graphically illustrates total torque, total torque including cutting torque and frictional torque components, further wherein the percentage graph representation of bit mechanical efficiency is coded, including a first code for illustrating cutting torque, a second code for illustrating frictional unconstrained torque, and a third code for illustrating frictional constrained torque.

36. The method of claim 35, wherein mechanical efficiency is further represented in the form of a percentage graph illustrating drilling system operating constraints that have an adverse impact upon mechanical efficiency, the drilling system operating constraints corresponding to constraints that result in an occurrence of frictional constrained torque, the percentage graph further for indicating a corresponding percentage of impact that each constraint has upon the frictional constrained torque component of the mechanical efficiency at a given depth, wherein

the drilling system operating constraints can include maximum torque-on-bit (TOB), maximum weight-on-bit (WOB), minimum and maximum bit revolutions-per-minute (RPM), maximum penetration rate (ROP), in any combination, and an unconstrained condition, and

the percentage graph representation of drilling system operating constraints on mechanical efficiency is coded, including different codes for identifying different constraints.

37. The method of claim 28, wherein power is expressed in the form of at least one of the following representations selected from the group consisting of a curve representation and a percentage graph representation, wherein

the curve representation for power includes power limit and operating power level, the power limit corresponding to a maximum power to be applied to the bit and the operating power level including at least one of the following selected from the group consisting of constrained operating power level, recommended operating power level, and predicted operating power level, and

the percentage graph representation of power illustrates drilling system operating constraints that have an adverse impact upon power, the drilling system operating constraints corresponding to those constraints that result in a power loss, the power constraint percentage graph further for indicating a corresponding percentage of impact that each constraint has upon the power at a given depth, further wherein the percentage graph representation of drilling system operating constraints on power is coded, including different codes for identifying different constraints.

38. The method of claim 22, further comprising:

generating a display of details of proposed drilling equipment along with the geology characteristic and predicted drilling mechanics, the proposed drilling equipment including at least one recommended bit selection used in predicting the performance of the drilling system.

39. The method of claim 38, wherein first and second bit selections are recommended for use in a predicted performance of the drilling of the well bore, further wherein the first and second bit selections are identified with respective first and second identifiers, the first and second identifiers being displayed with the geology characteristic and predicted drilling mechanics, further wherein the positioning of the first and second identifiers on the display is selected to correspond with portions of the predicted performance to which the first and second bit selections apply, respectively.

40. The method of claim 22, further comprising:

indicating that a change in bit selection from a first recommended bit selection to a second recommended bit selection is required at a- given depth on the display of geology characteristics and predicted drilling mechanics.

41. A computer program stored on a computer-readable medium for execution by a computer for predicting the performance of a drilling system in the drilling of a well bore of a given formation, said computer program comprising:

instructions for generating a geology characteristic of the formation per unit depth according to a prescribed geology model and outputting signals representative of the geology characteristic, the geology characteristic including at least rock strength;

instructions for obtaining specifications of proposed drilling equipment for use in the drilling of the well bore, the specifications including at least a bit specification of a recommended drill bit;

instructions for determining a predicted drilling mechanics in response to the specifications of the proposed drilling equipment as a function of the geology characteristic per unit depth according to a drilling mechanics model and outputting signals representative of the predicted drilling mechanics, the predicted drilling mechanics including at least one of the following selected from the group consisting of bit wear, mechanical efficiency, power, and operating parameters;

instructions for controlling a control parameter in drilling of the well bore with the drilling system in response to a predicted drilling mechanics output signal, the control parameter including at least one selected from the group consisting of weight-on-bit, rpm, pump flow rate, and hydraulics;

instructions for obtaining a measurement parameter in real time during the drilling of the well bore; and

instructions for history matching the measurement parameter with a back calculated value of the measurement parameter, wherein the back calculated value of the measurement parameter is a function of at least one of the following selected from the group consisting of the drilling mechanics model and at least one control parameter, and said instructions for controlling the control parameter further including instructions, responsive to a prescribed deviation between the measurement parameter and the back calculated value of the measurement parameter, for performing at least one of the following selected from the group consisting of a) adjusting the drilling mechanics model, b) modifying control of a control parameter, and c) performing an alarm operation.

42. The computer program of claim 41, further comprising:

instructions for generating a display of the geology characteristic and predicted drilling mechanics per unit depth in response to the geology characteristic output signals and the predicted drilling mechanics output signals.

43. The computer program of claim 42, wherein generating a display includes using at least one of the following selected from the group consisting of a) a display monitor and b) a printer, wherein the display of the geology characteristic and predicted drilling mechanics per unit depth includes a printout.

44. The computer program of claim 41, wherein generating the geology characteristic includes generating at least one of the following additional characteristics selected from the group consisting of log data, lithology, porosity, and shale plasticity.

45. The computer program of claim 41, wherein obtaining the proposed drilling equipment input specifications further includes obtaining at least one additional specification of proposed drilling equipment selected from the group consisting of down hole motor, top drive motor, rotary table motor, mud system, and mud pump.

46. The computer program of claim 41, wherein the operating parameters include at least one of the following selected from the group consisting of weight-on-bit, bit rpm (revolutions-per-minute), cost, rate of penetration, and torque.

47. The computer program of claim 46, further wherein rate of penetration includes instantaneous rate of penetration (ROP) and average rate of penetration (ROP-AVG).

48. The computer program of claim 42, wherein displaying the geology characteristic includes displaying at least one graphical representation selected from the group consisting of a curve representation, a percentage graph representation, and a band representation, and

displaying the predicted drilling mechanics includes displaying at least one graphical representation selected from the group consisting of a curve representation, a percentage graph representation, and a band representation.

49. The computer program of claim 48, wherein generating a display includes using at least one of the following selected from the group consisting of a) a display monitor and b) a printer, wherein the display of the geology characteristic and predicted drilling mechanics per unit depth includes a printout.

50. The computer program of claim 48, further wherein the at least one graphical representation of the geology characteristic and the at least one graphical representation of the predicted drilling mechanics are color coded.