Claims
- 1. A method for measuring a formation pressure, comprising:
lowering a formation testing tool to a first selected measuring position in a borehole; extending a nozzle through a mud cake layer on a surface of a formation, forming a seal between the mud cake layer and a sealing surface of the nozzle, the nozzle penetrating into the formation to expose a tip of the nozzle to the formation pressure; releasing the tip of the nozzle to expose a passage in the nozzle to the formation pressure; and communicating the formation pressure through the nozzle to a pressure sensor.
- 2. The method of claim 1, further comprising:
transmitting pressure data generated by the pressure sensor to the earth's surface.
- 3. The method of claim 1, wherein the formation testing tool is included in a drill string.
- 4. The method of claim 4, wherein the lowering, extending, and communicating are performed during a drilling operation.
- 5. The method of claim 1, further comprising:
adjusting a density of a drilling fluid in response to a formation pressure determined by measurements made by the pressure sensor.
- 6. The method of claim 1 further comprising urging the formation testing tool toward a wall of the borehole on a same side thereof as the nozzle, the urging performed during or prior to extension of the nozzle.
- 7. The method as defined in claim 1 further comprising retracting the nozzle, moving the tool to a second selected measuring position, and repeating the extending, releasing and communicating.
- 8. A formation testing tool positionable in a wellbore having a sidewall, comprising:
a nozzle extendable from the tool into a mudcake layer lining the sidewall of the wellbore, the nozzle having a duct therethrough in pressure communication with a pressure sensor in the tool, the nozzle defining an outer surface adapted to sealingly engage the mudcake; and a tip at an end of the nozzle, the tip adapted to restrict access to the duct whereby mudcake particles are prevented from entering the duct during formation testing.
- 9. The formation testing tool of claim 8 wherein the tip has a plurality of pores therethrough, the pores having a diameter smaller than the particle size of the mudcake.
- 10. The formation testing tool of claim 8 wherein the tip is positioned in the duct at the end of the nozzle, the tip movable between an extended and retracted position for selectively restricting entry into the duct.
- 11. The formation testing tool of claim 10 further comprising an actuator for extending and retracting the tip.
- 12. The formation testing tool of claim 11 further comprising a lock pin for securing the tip in position.
- 13. The formation testing tool of claim 8, further comprising a telemetry unit adapted to transmit data from the sensor to the earth's surface.
- 14. The formation testing tool of claim 8, wherein the testing tool is adapted to be coupled to a drill-string.
- 15. A formation testing tool, comprising:
a tool body adapted for movement through a wellbore; an actuator disposed in the tool body, the actuator coupled to a nozzle, the actuator adapted to move the nozzle from a retracted position to an extended position; and a nozzle tip disposed in an end of the nozzle, the tip coupled to a lock adapted to maintain the tip in the end of the nozzle during extension of the actuator, the lock adapted to release the tip after extension the actuator, the nozzle having a duct therethrough in pressure communication with a pressure sensor in the tool, the duct opened upon release of the nozzle tip.
- 16. The formation testing tool of claim 15, wherein the nozzle comprises a sealing surface adapted to form a seal with a mud cake layer when the nozzle is in the extended position.
- 17. The formation testing tool of claim 15, further comprising a telemetry unit adapted to transmit data from the sensor to the earth's surface.
- 18. The formation testing tool of claim 15, wherein the testing tool is adapted to be coupled to a drill-string.
- 19. A formation testing tool, comprising:
a tool body adapted for movement through a wellbore; an actuator disposed in the tool body and adapted to move a nozzle from a retracted position to an extended position, the nozzle in the extended position penetrating through a mud cake layer by an amount necessary to expose a tip of the nozzle to formation pressure; and a tip in an axial end of the nozzle, the tip having pores with a diameter smaller than a particle size in the mud cake layer, the nozzle having a passage therethrough in pressure communication with a pressure sensor in the tool, the passage opened upon positioning of the nozzle tip.
- 20. The formation testing tool of claim 19, wherein the nozzle comprises a sealing surface adapted to form a seal with a mud cake layer when the nozzle is in the extended position.
- 21. The formation testing tool of claim 19, further comprising a telemetry unit adapted to transmit pressure data from the tool to the earth's surface.
- 22. The formation testing tool of claim 19, wherein the testing tool forms part of a drill-string.
- 23. A method for measuring a formation pressure, comprising:
lowering a formation testing tool to a first selected measuring position in a borehole; extending a nozzle through a mud cake layer on the sidewall of the borehole to form a seal between the mud cake layer and a sealing surface of the nozzle, the nozzle having a tip at an end thereof and a passage therethrough, the tip adapted to restrict access to the passage; positioning the tip of the nozzle to expose a passage in the nozzle to the formation pressure; and communicating the formation pressure through the nozzle to a pressure sensor.
- 24. The method of claim 23 wherein the step of extending comprises extending a nozzle through a mud cake layer on the sidewall of the borehole to form a seal between the mud cake layer and a sealing surface of the nozzle, the nozzle having a porous tip at an end thereof and a passage therethrough, the tip having pores with diameters smaller than the particle size of the mudcake to prevent entry of mudcake particle into the passage.
- 25. The method of claim 24 wherein the step of positioning comprises positioning the porous tip of the nozzle into the invaded zone to expose a passage in the nozzle to the formation pressure.
- 26. The method of claim 23 wherein in the step of extending comprises extending a nozzle through a mud cake layer on the sidewall of the borehole to form a seal between the mud cake layer and a sealing surface of the nozzle, the nozzle having a retractable tip in an end thereof and a passage therethrough, the retractable tip movable between an extended and a retracted position for restrict access to the passage.
- 27. The method of claim 26 wherein the step of positioning comprises retracting the retractable tip of the nozzle to expose a passage in the nozzle to the formation pressure.
- 28. The method of claim 23, further comprising:
transmitting pressure data generated by the pressure sensor to the earth's surface.
- 29. The method of claim 23, wherein the formation testing tool is included in a drill string.
- 30. The method of claim 29, wherein the lowering, extending, and communicating are performed during a drilling operation.
- 31. The method of claim 23, further comprising:
adjusting a density of a drilling fluid in response to a formation pressure determined by measurements made by the pressure sensor.
- 32. The method of claim 23 further comprising urging the formation testing tool toward a wall of the borehole on a same side thereof as the nozzle, the urging performed during or prior to extension of the nozzle.
- 33. The method as defined in claim 23 further comprising retracting the nozzle, moving the tool to a second selected measuring position, and repeating the extending, releasing and communicating.
- 34. The method of claim 23 further comprising repeating the steps of extending positioning and communicating for each nozzle.
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority from Provisional Application No. 60/298,164, filed Jun. 13, 2001, the contents of which is hereby incorporated by reference in its entirety.
Provisional Applications (1)
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Number |
Date |
Country |
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60298164 |
Jun 2001 |
US |