METHOD TO DETECT CASING POINT IN A WELL FROM RESISTIVITY AHEAD OF THE BIT
First Claim
1. A method of determining a casing point in an uncased interval of a well being drilled using a drilling mud, the method comprising:
- a) drilling an uncased interval of a well with a drilling mud using a drill bit and drill string at known dip and azimuth angles toward a region of interest in a known subterranean formation without the bit entering the region; and
b) using formation resistivity markers obtained from resistivity measurements obtained while drilling one or more offset wells to identify one or more casing points in the uncased interval of the well while the drill bit advances toward but does not penetrate the region of interest while drilling the well.
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Abstract
Methods are described using resistivity measurements obtained while drilling one or more offset wells using a drilling mud to guide drilling of one or more uncased intervals of a well to identify a casing point or points in the uncased intervals of the well. Resistivity data is gathered during drilling the offset well and prior to penetrating a region of interest of a known subterranean formation. The drill string in the uncased interval of the well progresses toward the region of interest, using resistivity data at similar depths to identify a casing point while the drill bit advances toward but does not penetrate the region. In certain embodiments resistivity may also be obtained in front of the drill bit in the uncased interval of the well and used in conjunction with the offset well resistivity data to identify casing points in the uncased intervals of the well.
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Citations
20 Claims
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1. A method of determining a casing point in an uncased interval of a well being drilled using a drilling mud, the method comprising:
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a) drilling an uncased interval of a well with a drilling mud using a drill bit and drill string at known dip and azimuth angles toward a region of interest in a known subterranean formation without the bit entering the region; and b) using formation resistivity markers obtained from resistivity measurements obtained while drilling one or more offset wells to identify one or more casing points in the uncased interval of the well while the drill bit advances toward but does not penetrate the region of interest while drilling the well. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method of determining a casing point in an uncased interval of a well during drilling of the well using a drilling mud, the method comprising:
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a) drilling an uncased interval of a well with a drilling mud using a drill bit, a drill string, and a resistivity apparatus at known dip and azimuth angles toward a region of interest in a known formation without the bit entering the region; b) measuring resistivity in front of the drill bit in the uncased interval of the well using the resistivity apparatus; c) using formation resistivity markers obtained from resistivity measurements obtained while drilling one or more offset wells in conjunction with the resistivity measured in front of the drill bit in the uncased interval of the well to identify one or more casing points in the uncased interval of the well while the drill bit advances toward but does not penetrate the region of interest while drilling the uncased interval of the well. - View Dependent Claims (11, 12, 13, 14, 15)
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16. A method of using resistivity measurements obtained while drilling one or more subterranean offset wells in drilling a subterranean uncased interval of a well using a drilling mud, the method comprising:
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a) drilling one or more offset wells; b) obtaining formation resistivity markers from resistivity measurements obtained while drilling at least one of the offset wells; c) drilling an uncased interval of a well with a drilling mud using a drill bit and drill string at known dip and azimuth angles toward a region of interest in the formation without the bit entering the region of interest; and d) using the formation resistivity markers obtained from step (b) to identify one or more casing points in the uncased interval of the well while the drill bit advances toward but does not penetrate the formation while drilling the uncased interval of the well. - View Dependent Claims (17, 18, 19, 20)
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Specification