Formation testing in managed pressure drilling
First Claim
1. A method of testing an earth formation, comprising:
- circulating a drilling fluid in a wellbore formed in the earth formation;
ceasing circulation of the drilling fluid;
then incrementally opening a choke while drilling into the earth formation and circulation of the drilling fluid are ceased, thereby reducing pressure in the wellbore;
detecting an influx in the wellbore due to the reducing pressure in the wellbore;
verifying the pressure in the wellbore with a pressure sensor in the wellbore; and
wherein incrementally opening the choke is performed multiple times and ceases when the influx is detected.
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Accused Products
Abstract
A method of testing an earth formation can include incrementally opening a choke while drilling into the formation is ceased, thereby reducing pressure in a wellbore, and detecting an influx into the wellbore due to the reducing pressure in the wellbore. Another method of testing an earth formation can include drilling into the formation, with an annulus between a drill string and a wellbore being pressure isolated from atmosphere, then incrementally opening a choke while drilling is ceased, thereby reducing pressure in the wellbore, detecting an influx into the wellbore due to the reducing pressure in the wellbore, and determining approximate formation pore pressure as pressure in the wellbore when the influx is detected. Drilling fluid may or may not flow through the drill string when the influx is detected. A downhole pressure sensor can be used to verify pressure in the wellbore.
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Citations
16 Claims
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1. A method of testing an earth formation, comprising:
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circulating a drilling fluid in a wellbore formed in the earth formation; ceasing circulation of the drilling fluid; then incrementally opening a choke while drilling into the earth formation and circulation of the drilling fluid are ceased, thereby reducing pressure in the wellbore; detecting an influx in the wellbore due to the reducing pressure in the wellbore; verifying the pressure in the wellbore with a pressure sensor in the wellbore; and wherein incrementally opening the choke is performed multiple times and ceases when the influx is detected. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method of testing an earth formation, the method comprising:
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drilling into the earth formation, with an annulus between a drill string and a wellbore being pressure isolated from atmosphere; circulating a drilling fluid in the wellbore; ceasing circulation of the drilling fluid; then incrementally opening a choke while drilling is ceased, thereby reducing pressure in the wellbore; detecting an influx into the wellbore due to the reducing pressure in the wellbore; determining approximate formation pore pressure as pressure in the wellbore when the influx is detected; verifying the pressure in the wellbore with a pressure sensor in the wellbore; and wherein incrementally opening the choke is performed multiple times and ceases when the influx is detected. - View Dependent Claims (11, 12, 13, 14, 15, 16)
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Specification