Methods and apparatus for measuring formation properties

• US 20050257611A1
• Filed: 05/23/2005
• Published: 11/24/2005
• Est. Priority Date: 05/21/2004
• Status: Abandoned Application

• Current Assignee: Halliburton Energy Services Incorporated (Halliburton Company)
• Original Assignee: Halliburton Energy Services Incorporated (Halliburton Company)
• Inventors: Proett, Mark A., Dudley, James H., Beique, Jean Michel, Welshans, David, Fogal, James M., Marsh, Laban M., Hardin, John R. Jr., Hendricks, William Edward
• Application Number:
  US11/135,050
• Publication Number:
  US 20050257611A1
• Time in Patent Office: Days
• US Class Current: 73/152.220
• CPC Class Codes: E21B 49/10 using side-wall fluid samplers or testers

Abstract

This application relates to various methods and apparatus for rapidly obtaining accurate formation property data from a drilled earthen borehole. Quickly obtaining accurate formation property data, including formation fluid pressure, is vital to beneficially describing the various formations being intersected. For example, methods are disclosed for collecting numerous property values with a minimum of downhole tools, correcting and calibrating downhole measurements and sensors, and developing complete formation predictors and models by acquiring a diverse set of direct formation measurements, such as formation fluid pressure and temperature. Also disclosed are various methods of using of accurately and quickly obtained formation property data.

Claims

1. A method of measuring a formation property, the method comprising:

disposing a drill collar in a borehole at a first depth, the drill collar comprising a formation tester tool, a formation probe assembly, and at least a first sensor and a second sensor;

engaging the formation tester tool with an earth formation using the formation probe assembly;

selectively sampling at least one of the first and second sensors;

making at least a first and a second measurement; and

comparing the first measurement to the second measurement.

2. The method of claim 1 further comprising:

communicating a formation fluid to the first and second sensors;

communicating an annulus fluid to the first and second sensors; and

wherein making at least a first and second measurement comprises simultaneously measuring a plurality of pressure values of any one of the formation fluid and the annulus fluid, wherein at least one of the pressure values is measured by the first sensor and at least one of the pressure values is measured by the second sensor.

3. The method of claim 2 further comprising supplementing a formation fluid pressure from the first sensor with a formation fluid pressure from the second sensor.

4. The method of claim 2 further comprising supplementing an annulus fluid pressure from the first sensor with an annulus fluid pressure from the second sensor.

5. The method of claim 1 wherein making at least a first and a second measurement comprises measuring a first formation pressure using the first sensor and measuring a second formation pressure using the second sensor, the method further comprising:

correcting the first and second formation pressures; and

obtaining a first corrected formation pressure, wherein the first corrected formation pressure is substantially the same as an actual formation pressure.

6. The method of claim 5 wherein correcting the first and second formation pressures further comprises:

obtaining a first offset error by subtracting the second formation pressure from the first formation pressure; and

adding the first offset error to at least one of the first and second formation pressures.

7. The method of claim 1 wherein making at least a first and a second measurement comprises measuring a plurality of pressures with each of the first and second sensors, the method further comprising:

identifying at least one pressure value from the first sensor plurality of pressures; and

calibrating the second sensor to the at least one first sensor pressure value.

8. The method of claim 7 further comprising:

identifying at least two first sensor pressure values P_Q1 and P_Q2;

identifying at least two second sensor pressure values P_SG1 and P_SG2; and

correcting the second sensor pressure values using any one of;

P_{SG corrected}=P_off+(P_slope*P_SG); and


P_{SG corrected}=P_Q1−

(P_Q1−

P_Q2)/(P_SG1−

P_SG2)*(P_SG1−

P_SG2).

9. The method of claim 7 wherein the calibrating the second sensor to the at least one first sensor pressure value occurs during the measuring a plurality of pressures with each of the first and second pressure sensors.

10. The method of claim 7 further comprising:

disposing the drill collar at a plurality of depths in the borehole;

identifying at least one pressure value from the first sensor at each of the depths; and

continually calibrating the second sensor to the at least one first sensor pressure value for each of the depths.

11. The method of claim 7 further comprising:

disposing the drill collar at a plurality of depths in the borehole;

identifying at least one pressure value from the first sensor at each of the depths;

identifying at least one pressure value from the second sensor at each of the depths;

measuring at least one temperature value at each of the depths from a temperature sensor disposed adjacent the first and second sensors;

developing a plot of the pressure values versus the temperature value; and

continually calibrating the second sensor to the plot for each of the depths.

12. The method of claim 1 wherein:

the formation tester tool further includes embedded software; and

the comparing the first measurement to the second measurement occurs downhole using the formation tester tool embedded software.

13. The method of claim 1 wherein the second sensor is an LWD tool, the method further comprising:

imaging a portion of the borehole using the LWD tool;

wherein making a first measurement comprises identifying a first formation property of the imaged borehole portion;

wherein making a second measurement comprises pre-determining a formation property; and

adjusting the drill collar if the first formation property differs from the predetermined formation property.

14. The method of claim 13 further comprising:

orienting the formation tester tool toward a selected location;

disengaging the formation probe assembly from the formation;

imaging the selected location; and

verifying formation probe assembly engagement adjacent the selected location.

15. The method of claim 1 further comprising:

communicating a formation fluid through the formation probe assembly to at least the first sensor;

wherein making a first measurement comprises measuring a first formation fluid pressure;

pumping a drilling fluid down the borehole;

wherein making a second measurement comprises measuring a second formation fluid pressure while the pumping occurs; and

determining a difference between the first and second pressures.

16. The method of claim 15 further comprising:

disposing the drill collar near the distal end of a drill string, the distal end of the drill string having a drill bit for drilling the borehole to the first depth; and

calculating a property using the pressure difference.

17. The method of claim 1 further comprising:

communicating a formation fluid through the formation probe assembly to the first sensor;

sending a pressure pulse into the borehole;

wherein making a first measurement comprises measuring the pressure pulse at a location in an annulus of the borehole;

wherein making a second measurement comprises measuring the pressure pulse at the first sensor;

comparing the annulus pressure pulse measurement and the first sensor pressure pulse measurement; and

calculating a formation property.

18. The method of claim 17 wherein the pressure pulse is sent from a second formation probe assembly disposed on the drill collar.

19. The method of claim 1 wherein making at least a first and a second measurement comprises measuring a pressure using the first sensor and obtaining a second measurement using the second sensor, the method further comprising:

correcting the pressure using the second measurement.

20. The method of claim 19 further comprising:

drawing a formation fluid into the formation probe assembly, wherein the pressure comprises a formation pressure and the second measurement comprises a formation temperature; and

compensating the formation pressure for thermal effects using the formation temperature.

21. The method of claim 1 wherein making at least a first and a second measurement comprises measuring a pressure using the first sensor and obtaining a second measurement using the second sensor, the method further comprising:

correcting the second measurement using the pressure.

22. The method of claim 1 further comprising:

drawing a formation fluid into the formation probe assembly, wherein the first measurement comprises a formation pressure and the second measurement comprises a formation fluid resistivity; and

calculating a formation fluid saturation.

23. The method of claim 1 further comprising:

disposing the drill collar near the distal end of a drill string, the distal end of the drill string having a drill bit for drilling the borehole to the first depth;

wherein the first measurement is made at the first depth;

retracting the formation probe assembly;

pulling the drill string up the borehole to a second depth above the first depth;

engaging the formation probe assembly with the formation at the second depth; and

wherein the second measurement is made at the second depth.

24. The method of claim 23 further comprising at least one of correcting a formation model, supplementing a pore pressure prediction model, and calibrating a pore pressure prediction model.

25. A method of measuring a formation property, the method comprising:

disposing a drill collar in a borehole at a first depth, the drill collar comprising a formation tester tool, a formation probe assembly and a first sensor;

engaging the formation tester tool with an earth formation using the formation probe assembly;

making at least a first measurement; and

adjusting the first measurement.

26. The method of claim 25 wherein:

making a first measurement comprises measuring a first pressure with the first sensor; and

the adjusting the first measurement comprises improving an accuracy of the first pressure relative to an actual formation pressure.

27. The method of claim 26 wherein the improving an accuracy of the first pressure further comprises:

inputting a plurality of pressure values into the first sensor, the pressure values representing a full first pressure input range;

obtaining a plurality of output pressure values;

determining a transducer effect on the output values;

establishing at least two calibration tables based on the transducer effect; and

interpreting the first pressure using at least one of the calibration tables.

28. The method of claim 26 wherein the improving an accuracy of the first pressure further comprises:

providing a second sensor having a pressure range, wherein the second sensor pressure range differs from a first sensor pressure range;

measuring a second pressure using the second sensor; and

wherein the second pressure is outside the first sensor pressure range.

29. The method of claim 25 further comprising:

disposing the formation probe assembly at a first location and the first sensor at a second location;

communicating a fluid to the first sensor through a flow line between the formation probe assembly and the first sensor;

wherein making a first measurement comprises measuring a first pressure with the first sensor; and

wherein adjusting the first measurement comprises correcting the first pressure to an actual pressure at the first location.

30. The method of claim 29 wherein the correcting the first pressure further comprises:

determining a pressure difference between the first and second locations; and

subtracting the pressure difference from the first pressure.

31. The method of claim 25 wherein the engaging the formation tester tool occurs at a first location immediately after the drill bit intersected the first location and before a mudcake is formed on the borehole wall.

32. The method of claim 31 further comprising determining a formation quality and taking a corrective action comprising at least one of casing the borehole, changing a drilling mud property, and continuing drilling.

33. A method of measuring a formation property, the method comprising:

disposing a drill collar in a borehole, the drill collar comprising a formation tester tool, a formation probe assembly and a sensor;

engaging the formation tester tool with a formation using the formation probe assembly;

injecting a fluid from the formation probe assembly into the formation; and

measuring a pressure.

34. The method of claim 33 further comprising calculating a formation property, the formation property at least one of mud cake permeability and formation mobility.

35. The method of claim 33 further comprising:

fracturing the formation; and

wherein the measured pressure comprises a fracture pressure.

36. A method of measuring a formation property, the method comprising:

disposing a drill collar in a borehole at a first depth, the drill collar comprising a formation tester tool and a formation probe assembly having an extendable probe;

extending the probe;

engaging the probe with an earth formation;

maintaining a substantially non-flow condition within the formation probe assembly; and

measuring a formation property.

37. The method of claim 36 wherein measuring a formation property further comprises:

recording a pressure response to the probe engagement; and

determining a formation property.

38. The method of claim 36 wherein measuring a formation property further comprises:

indicating a first position of the probe;

indicating a second position of the probe;

measuring a distance between the first and second probe positions; and

determining a formation property.