US2026009326A1PendingUtilityA1
Computer-implemented method for identifying the position of a hole or a crack in a drill string and computer-readable storage material
Assignee: PETROLEO BRASILEIRO SA PETROBRASPriority: Jul 4, 2024Filed: Jun 27, 2025Published: Jan 8, 2026
Est. expiryJul 4, 2044(~17.9 yrs left)· nominal 20-yr term from priority
Inventors:TOBISAWA RODRIGO YUGI IKUTAMARTINS ANDRE LEIBSOHNGONCALVES DA SILVA FABIO RODRIGUESDE SOUZA CRUZ MARCELO
E21B 44/00E21B 2200/20E21B 47/117E21B 47/10
41
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Claims
Abstract
The present invention relates to a computer-implemented method for identifying the position of a hole or a crack in a drill string, comprising the steps of identifying a pressure drop in the standpipe and/or a drop in the rotation of the turbine of the continuous logging instrument; obtaining the head losses in the bottom-hole assembly; calibrating the head losses inside the drill string; and calculating the distance from the hole or crack to the bottom-hole assembly.
Claims
exact text as granted — not AI-modified1 . A computer-implemented method for identifying the position of a hole or a crack in a drill string, the computer-implemented method comprising:
identifying a pressure drop in a standpipe and/or a drop in a rotation of a turbine of a continuous logging instrument; obtaining head losses in a bottom-hole assembly (BHA); calibrating the head losses inside the drill string; and calculating a distance (Lx) from the hole or the crack in the drill string to the BHA, from the equation:
Δ
P
fric
SP
→
Pint
=
[
Δ
P
DP
Q
1
m
*
(
L
pwd
-
L
bha
)
]
-
[
Δ
P
DP
Q
1
m
*
(
L
x
)
]
+
[
Δ
P
DP
Q
2
m
*
(
L
x
)
]
+
[
Δ
P
bha
Q
2
]
wherein:
ΔP fric SP→Pint is head loss inside the drill string between a standpipe pressure sensor and a pressure while drilling (PWD) sensor using flow rate before a leak (Q1);
Δ
P
DP
Q
1
m
is head loss per meter inside the drill string using the flow rate before the leak (Q1):
Δ
P
DP
Q
2
m
is head loss per meter inside the drill string using flow rate after a leak section (Q2);
ΔP bha Q2 is head loss through the BHA using the flow rate after the leak section (Q2);
L bha is distance between a start of the BHA and the standpipe pressure sensor; and
L pwd is distance between the standpipe and the BHA.
2 . The computer-implemented method of claim 1 , wherein the head losses in the BHA are obtained through a shallow test comprising:
collecting or estimating a plurality of data, the plurality of data comprising:
data on solids density (rho_ShT);
data on the fluid flow rate when passing through the drill string before identifying the hole or crack (Q1);
data on a head loss in a drill bit (DP_pwd, ΔP bit ) after identifying the hole or the crack;
data on a total pressure drop during the shallow test (DP_ShalT);
data on the head loss of the BHA completely inside a well;
data on the head loss of the BHA partially inside the well; and
data on the head loss of the BHA along a portion of the drill string inside the well.
3 . The computer-implemented method of claim 1 , wherein the calibrating step comprises:
collecting samples of pressure and flow rate points at each end of the drill string, wherein each of the samples comprises:
flow rate of a drill fluid (Q);
pressure in the standpipe (SPP);
pressure inside the BHA (P internal );
depth of a drill bit;
equivalent static density (ESD); and
pressure in an annulus (P annulus );
adjusting an efficiency of an inlet flow (Q1); comparing actual and calculated values of the head losses in the drill string; and correcting the actual and calculated values by using a correction factor.
4 . The computer-implemented method of claim 1 , wherein the head loss inside the drill string is obtained from a difference between a pressure read in the standpipe (P standpipe ) and a pressure inside the BHA (P internal ), discounting effects of hydrostatics and fluid compressibility.
5 . The computer-implemented method of claim 3 , wherein the correction factor is obtained by applying the least squares method to the pressure and flow rate points at each end of the drill string where the samples are collected.
6 . A computer-readable storage media comprising a set of computer-readable instructions stored therein, wherein the set of computer-readable instructions are configured to be executed by a computer to perform the computer-implemented method of claim 1 .Join the waitlist — get patent alerts
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