The authors have previously developed and proposed methods to estimate the in situ rock strength and tooth wear while drilling with roller-cone bits [Karasawa et al., 2002, ASME J. Energy Resour. Technol. 124, pp. 125–132 (Pt. 1) 133–140 (Pt. 2)]. The purpose of this paper is to provide a follow-up to these two reports and to propose, for both previous methods, alternate techniques that can be more readily implemented in the field than those originally presented. The data presented in Part 1 of the previously mentioned work [1] were reanalyzed in order to find a new and simple parameter that can be used to estimate rock strength. This parameter uses only one set of data that consists of bit weight, torque, penetration rate, rotary speed, and bit diameter. It was also demonstrated that the effect of tooth wear on this new parameter is small. In addition, more practical methods, which employ two parameters, are derived and proposed to evaluate the tooth wear of roller-cone bits.

Issue Section:
Technical Papers
Keywords:
rocks, oil drilling, mechanical strength, wear
Topics:
Drilling, Rocks, Wear, Weight (Mass), Rollers, Torque
1.
Karasawa
,
H.
,
Ohno
,
T.
,
Kosugi
,
M.
, and
Rowley
,
J. C.
,
2002
, “
Methods to Estimate the Rock Strength and Tooth Wear While Drilling With Roller-Bits, Part 1: Milled-Tooth Bits
,”
ASME J. Energy Resour. Technol.
,
124
, pp.
125
–
132
.
2.
Karasawa
,
H.
,
Ohno
,
T.
,
Kosugi
,
M.
, and
Rowley
,
J. C.
,
2002
, “
Methods to Estimate the Rock Strength and Tooth Wear While Drilling With Roller-Bits, Part 2: Insert Bits
,”
ASME J. Energy Resour. Technol.
,
124
, pp.
133
–
140
.
3.
Teale
,
R.
,
1965
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The Concept of Specific Energy in Rock Drilling
,”
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,
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, pp.
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4.
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,
L. L.
, and
Bratcher
,
G. J.
,
1996
, “
A New Approach for Determining In-Situ Rock Strength While Drilling
,”
ASME J. Energy Resour. Technol.
,
118
, pp.
249
–
255
.
5.
Pessier, R. C., and Fear, M. J., 1992, “Quantifying Common Drilling Problems With Mechanical Specific Energy and a Bit-Specific Coefficient of Sliding Friction,” SPE 24584, presented at 67th ATCE of SPE, Washington, DC, pp. 373–388.
6.
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7.
Burgess, T. M., and Less, W. G., Jr., 1985, “Measuring the Wear of Milled Tooth Bits Using MWD Torque and Weight-on-Bit,” SPE/IADC 13475, presented at SPE/IADC 1985 Drilling Conference, New Orleans, pp. 453–462.
8.
Karasawa, H., Ohno, T., and Kosugi, M., 2003, “Methods to Evaluate Rock Strength and Tooth Wear in Real Time While Drilling,” Japanese Patent Application No. 2003-165886.
9.
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,
M. G.
,
1964
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How to Locate Performance Line When Drilling Response Is Low
,”
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), pp.
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,
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,
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,
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,”
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Copyright © 2004
 by ASME
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