U.S. patent number 11,008,851 [Application Number 16/809,600] was granted by the patent office on 2021-05-18 for ultrasonic wellbore anti-collision monitoring system and monitoring method.
This patent grant is currently assigned to SOUTHWEST PETROLEUM UNIVERSITY. The grantee listed for this patent is SOUTHWEST PETROLEUM UNIVERSITY. Invention is credited to Qian Li, Qifu Xiao, Hu Yin.
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United States Patent |
11,008,851 |
Yin , et al. |
May 18, 2021 |
Ultrasonic wellbore anti-collision monitoring system and monitoring
method
Abstract
The present invention discloses an ultrasonic wellbore
anti-collision monitoring system, comprising a downhole ultrasonic
monitoring device and a ground control system, wherein the
ultrasonic monitoring device includes a cylindrical body, at least
three centralizers are fixed on the cylindrical body at an equal
interval, the mounting groove 1 is cut into the cylindrical body
surface between two adjacent centralizers, one electrically
controlled expansion device is installed in the groove 1 and
includes electric push rods placed horizontally and a ribbed plate
perpendicular to the electric push rods, the bottom ends of the
electric push rods are fixedly connected to the bottom surface of
the mounting groove, the front ends of the electric push rods are
connected with the ribbed plate, the mounting groove 2 is cut into
the ribbed plate, and one ultrasonic transducer is installed in the
groove 2. The ground control system controls the ultrasonic
transducer to emit S wave and receive the reflected wave, and
calculates the distance between the two wells by monitoring the
time difference between the emission time and the reflection time
in combination with the travel velocity of S wave in the formation.
The wellbore anti-collision monitoring system is simple in
structure and easy in monitoring operation.
Inventors: |
Yin; Hu (Chengdu,
CN), Xiao; Qifu (Chengdu, CN), Li; Qian
(Chengdu, CN) |
Applicant: |
Name |
City |
State |
Country |
Type |
SOUTHWEST PETROLEUM UNIVERSITY |
Sichuan |
N/A |
CN |
|
|
Assignee: |
SOUTHWEST PETROLEUM UNIVERSITY
(Chengdu, CN)
|
Family
ID: |
69658271 |
Appl.
No.: |
16/809,600 |
Filed: |
March 5, 2020 |
Foreign Application Priority Data
|
|
|
|
|
Dec 3, 2019 [CN] |
|
|
201911216691.8 |
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
E21B
47/0224 (20200501); E21B 47/107 (20200501); E21B
47/14 (20130101) |
Current International
Class: |
E21B
47/0224 (20120101); E21B 47/107 (20120101); E21B
47/14 (20060101) |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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201460860 |
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May 2010 |
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CN |
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104781503 |
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Jul 2015 |
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CN |
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105986810 |
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Oct 2016 |
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CN |
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107642355 |
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Jan 2018 |
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CN |
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109083632 |
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Dec 2018 |
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CN |
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109667550 |
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Apr 2019 |
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CN |
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110275223 |
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Sep 2019 |
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CN |
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2474130 |
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Apr 2011 |
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GB |
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WO-2007014446 |
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Feb 2007 |
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WO |
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WO-2009073008 |
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Jun 2009 |
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WO |
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WO-2015099790 |
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Jul 2015 |
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WO |
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WO-2017044103 |
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Mar 2017 |
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WO |
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Other References
First Office Action in Chinese Application No. 201911216691.8 dated
Apr. 10, 2020, 20 pages. cited by applicant.
|
Primary Examiner: Gay; Jennifer H
Attorney, Agent or Firm: Jin; Yuqin
Claims
We claim:
1. An ultrasonic wellbore anti-collision monitoring system,
comprising a downhole ultrasonic monitoring device and a ground
control system, wherein the ultrasonic monitoring device includes a
cylindrical body, a lifting cap is arranged on the top of the
cylindrical body, and a lifting bail for connecting ground
drawworks is arranged on the top of the lifting cap; at least three
centralizers are fixed on the cylindrical body at an equal
interval, a first mounting groove is cut into a cylindrical body
surface between two adjacent centralizers of the at least three
centralizers, an electronically controlled expansion device is
installed in the first mounting groove and includes electric push
rods placed horizontally and a ribbed plate perpendicular to the
electric push rods, bottom ends of the electric push rods are
fixedly connected to a bottom surface of the first mounting groove,
front ends of the electric push rods are connected with the ribbed
plate, a second mounting groove is cut into the ribbed plate, and a
ultrasonic transducer is installed in the second mounting groove;
the electronically controlled expansion device is connected to the
ground control system to control an extension and a retraction of
the electric push rods; when the electric push rods are retracted,
a horizontal protruding height of the ultrasonic transducer
protruding from the surface of the cylindrical body is smaller than
horizontal heights of the two adjacent centralizers adjacent to the
ultrasonic transducer; when the electric push rods are extended,
the horizontal protruding height of the ultrasonic transducer
protruding from the surface of the cylindrical body is equal to the
horizontal heights of the two adjacent centralizers adjacent to the
ultrasonic transducer, and the ultrasonic transducer is close to a
wellbore casing; the ground control system controls the ultrasonic
transducer to emit an S wave and receive a reflected wave, and
calculate a distance between a well being drilled and a well
adjacent to the well being drilled by monitoring a time difference
between an emission time and a reflection time in combination with
a travel velocity of the S wave in the formation; and the two
adjacent centralizers adjacent to the ultrasonic transducer are
made of a hard material, and a remainder of the at least three
centralizers is made of an elastic material; the cylindrical body
is connected with the lifting cap, and the lifting bail is arranged
on the top of the lifting cap and connected with the ground
drawworks to lift the ultrasonic monitoring device up and down; the
at least three centralizers include four centralizers in an
elongated shape and with axes parallel to the axis of the
cylindrical body.
2. The ultrasonic wellbore anti-collision monitoring system
according to claim 1, wherein an upper part of the cylindrical body
is provided with a cable hole through which a cable is connected to
the ground control system and the downhole ultrasonic monitoring
device.
3. A monitoring method using an ultrasonic wellbore anti-collision
monitoring system, wherein an ultrasonic monitoring device is
lowered by drawworks into a well adjacent to a well being drilled
and emits an S wave perpendicular to a casing wall of the well
adjacent to the well being drilled; under such condition, during a
travel the S wave encounters a drilling fluid in the well being
drilled, and cannot continue to travel, but is reflected back along
an original path, and a ground control system calculates a distance
S between the well being drilled and the well adjacent to the well
being drilled by monitoring a time difference T between an emission
time and a reflection time of the S wave and a travel velocity V of
the S wave in the formation; the calculation formula is .times.
##EQU00004## for different types of well intervals, operations are
as follows: a real-time monitoring mode adopted for a wellbore
anti-collision monitoring in a vertical interval, including the
following steps: Step a1: calculating a vertical depth a of a
measuring point according to inclination and azimuth measured by
MWD of the well being drilled; Step a2: lowering the ultrasonic
monitoring device by the drawworks to the vertical depth a
calculated in step a1; Step a3: controlling electric push rods to
be extended by the ground control system to move an ultrasonic
transducer close to a casing wall of the well adjacent to the well
being drilled, and then the ultrasonic transducer emitting the S
wave and receiving the reflected waves, and transmitting the
emitted and reflected wave signals to the ground control system to
calculate the distance between the well being drilled and the well
adjacent to the well being drilled; Step a4: after completing Steps
a1 to a3, controlling the electric push rods to be retracted by the
ground control system, lowering the ultrasonic monitoring device by
the drawworks until the ultrasonic monitoring device moves down 2
meters into the well adjacent to the well being drilled and then
stopping lowering ultrasonic monitoring device, a lowering speed of
the ultrasonic monitoring device being the same as a drilling speed
of the well being drilled, and then repeating Steps a3 and a4 in
turn to continue to measure the distance between the well being
drilled and the well adjacent to the well being drilled in the
vertical interval; Step a5: after measuring the distance between
the well being drilled and the well adjacent to the well being
drilled in the vertical interval, controlling the electric push
rods to be closed by the ground control system, starting up the
drawworks to lift up the ultrasonic monitoring device and lift the
ultrasonic monitoring device away from a wellhead; wellbore
anti-collision monitoring for a deflection interval including the
following steps: Step b1: obtaining downhole inclination and
azimuth measured by the MWD of the well being drilled; Step b2:
calculating, by anti-collision scanning, a nearest distance between
the well being drilled and the well adjacent to the well being
drilled, working out a vertical depth a and an azimuth b of a
nearest point of the well being drilled to the well adjacent to the
well being drilled, and then calculating a monitoring azimuth c of
the well adjacent to the well being drilled; if a currently
measured azimuth is 0.degree. to 180.degree., c=360.degree.-b; if
the currently measured azimuth is 180.degree. to 360.degree., c=b;
Step b3: using a compass to determine a position d of the measured
azimuth c measured at the wellhead of the well adjacent to the well
being drilled, and aligning the position of the ultrasonic
transducer with the position d; Step b4: lowering the ultrasonic
monitoring device by the drawworks to the vertical depth a
according to the requirements set forth in Step b3; Step b5:
controlling the electric push rods to be extended by the ground
control system to move the ultrasonic transducer close to the
casing wall of the well adjacent to the well being drilled, and
then the ultrasonic transducer emitting the S wave and receiving
the reflected waves, and transmitting the emitted and reflected
wave signals to the ground control system to calculate the distance
between the well being drilled and the well adjacent to the well
being drilled; after that, lifting up the ultrasonic monitoring
device and lifting the ultrasonic monitoring device away from the
wellhead to monitor a next point, and repeating Steps b1 to b5, a
real-time monitoring and single-point accurate measurement adopted
for an anti-collision monitoring of an interval with higher risk of
collision, including the following steps: Step c1: calculating a
vertical depth a of a measuring point according to inclination and
azimuth measured by the MWD of the well being drilled; Step c2:
lowering the ultrasonic monitoring device by the drawworks to the
vertical depth a calculated in Step c1; Step c3: controlling the
electric push rods to be extended by the ground control system to
move the ultrasonic transducer close to the casing wall of the well
adjacent to the well being drilled, and then the ultrasonic
transducer emitting the S wave and receiving the reflected waves,
and transmitting the emitted and reflected wave signals to the
ground control system to calculate the distance between the well
being drilled and the well adjacent to the well being drilled; Step
c4: after completing Steps c1 to c3, controlling the electric push
rods to be retracted by the ground control system, lowering the
ultrasonic monitoring device by the drawworks until the ultrasonic
monitoring device moves down 2 meters into the well adjacent to the
well being drilled and then stopping lowering ultrasonic monitoring
device, a lowering speed of the ultrasonic monitoring device being
the same as a drilling speed of the well being drilled, and then
repeat Steps c3 and c4 to conduct real-time monitoring; in the
process of the real-time monitoring, if there is a trend of
collision between the well being drilled and the well adjacent to
the well being drilled, that is, the distance between the well
being drilled and the well adjacent to the well being drilled is
continuously decreased, switching to a precise measurement mode,
and lifting up the ultrasonic monitoring device and lifting the
ultrasonic monitoring device away from the wellhead as follows:
Step d1: obtaining downhole inclination and azimuth measured by the
MWD of the well being drilled; Step d2: calculating, by
anti-collision scanning, a nearest distance between the well being
drilled and the well adjacent to the well being drilled, working
out a vertical depth a and an azimuth b of a nearest point of the
well being drilled to the well adjacent to the well being drilled,
and then calculating a monitoring azimuth c of the well adjacent to
the well being drilled; if a currently measured azimuth is
0.degree. to 180.degree., c=360.degree.-b; if the currently
measured azimuth is 180.degree. to 360.degree., c=b; Step d3: using
a compass to determine a position d of the measured azimuth c
measured at the wellhead of the well adjacent to the well being
drilled, and aligning the position of the ultrasonic transducer
with the position d; Step d4: lowering the ultrasonic monitoring
device by the drawworks to the vertical depth a according to the
requirements set forth in Step d3; Step d5: controlling the
electric push rods to be extended by the ground control system to
move the ultrasonic transducer close to the casing wall of the well
adjacent to the well being drilled, and then the ultrasonic
transducer emitting the S wave and receiving the reflected waves,
and transmitting the emitted and reflected wave signals to the
ground control system to calculate the distance between the well
being drilled and the well adjacent to the well being drilled;
after that, lifting up the ultrasonic monitoring device and lifting
the ultrasonic monitoring device away from the wellhead to monitor
a next point, and repeating Steps c1 to c4.
Description
CROSS REFERENCE
This application claims priority of Chinese Patent Application No.
201911216691.8 filed on Dec. 3, 2019, the entire contents of which
are hereby incorporated by reference.
TECHNICAL FIELD
The present invention relates to the technical field of oil and gas
drilling, in particular to a technical monitoring device and a
monitoring method for real-time monitoring the distance between two
wells by ultrasonic wave.
BACKGROUND
With the more intensive development of various oilfields, the
development of remaining oil and marginal oil reservoir in old
oilfields has become an important way to increase reserves and
production. As a result, there are more adjustment wells,
progressive development wells, and cluster wells developed in the
oilfields, and more special wells gradually drilled in the
oilfields, increasing the density of well patterns, reducing the
distance between wells, drilling more layered exploitation wells,
and increasing the development of cluster wells in urban areas,
etc. At the same time, it is an important measure for reserve and
production improvement to find thin bed reservoir and
hard-to-recover reserves in high-density well gaps in old
oilfields. With the wide application of non-conventional wells in
major oilfields, the number of cluster wells is increasing, and the
distance between wells is getting smaller and smaller. In the
process of drilling cluster wells or adjusting wells in old
oilfields, there is an increase in the collision of two wells in
the vertical interval and deviated interval, and frequent
occurrence of abandoned footage and repeated construction. The
environmental problems and economic losses caused by wellbore
collision may be catastrophic.
Therefore, it is more and more important to evaluate the wellbore
track and avoid the risk of wellbore collision. The collision
prevention is the core issue to ensure the safe and rapid
construction of dense wellhead cluster well groups. The collision
prevention is involved in pre-drilling preparation, engineering
design, construction and other aspects of dense wellhead cluster
well groups. During the drilling process, the uncertainty of the
geological target and kick-off rate of the formation has brought
certain difficulties to the construction of cluster wells. There
are unpredictable risks. How to keep the distance between the drill
bit and the adjacent well within the safe distance has become a key
problem in cluster well development. For well areas with dense
wellbores, the collision prevention between the wellbore tracks is
the core issue to ensure the safe and rapid construction of dense
wellhead cluster well groups. In the existing method, the distance
between two wells can be calculated only by scanning, and there is
error between the theoretical calculation value and the actual
value.
SUMMARY
An object of the present invention is to provide a monitoring
system and a monitoring method to monitor the distance between the
two wells in real time by ultrasonic wave to solve the problem
found in the calculation of distance of two wells by existing
scanning method and the error between the theoretical calculation
value and the actual value, which is used for the ultrasonic
anti-collision monitoring of the wellbore.
An aspect of the present disclosure provides an ultrasonic wellbore
anti-collision monitoring system. The ultrasonic wellbore
anti-collision monitoring system includes a downhole ultrasonic
monitoring device and a ground control system. The ultrasonic
monitoring device includes a body. A connection member for
connecting ground drawworks is arranged on the top of the body. At
least three centralizers are fixed on a body surface, and an
electrically controlled expansion device is installed in the body
surface between two adjacent centralizers. The electrically
controlled expansion device includes one or more electric push rods
placed horizontally and a ribbed plate perpendicular to the one or
more electric push rods, bottom ends of the one or more electric
push rods are connected to the body, front ends of the one or more
electric push rods are connected to the ribbed plate, and an
ultrasonic transducer is installed on the ribbed plate. The
electronically controlled expansion device is connected to the
ground control system to control the extension and retraction of
the one or more electric push rods, when the one or more electric
push rods are retracted, a horizontal protruding height of the
ultrasonic transducer is smaller than horizontal heights of two
centralizers adjacent to the ultrasonic transducer, when the one or
more electric push rods are extended, the horizontal protruding
height of the ultrasonic transducer is equal to the horizontal
heights of the two centralizers adjacent to the ultrasonic
transducer, and the ultrasonic transducer is close to the wellbore
casing. The ground control system controls the ultrasonic
transducer to emit S wave and receive the reflected wave, and
calculates the distance between the two wells by monitoring the
time difference between the emission time and the reflection time
in combination with the travel velocity of S wave in the
formation.
In some embodiment, material hardness of the two centralizers
adjacent to the ultrasonic transducer is greater than material
hardness of other centralizers.
The ultrasonic wellbore anti-collision monitoring system disclosed
by the present invention includes downhole ultrasonic monitoring
device and ground control system. The ultrasonic monitoring device
includes a cylindrical body, a lifting cap is arranged on the top
of the body, and a lifting bail for connecting the ground drawworks
is arranged on the top of the lifting cap. The preferred structure
is that the upper end of the cylindrical body is provided with a
box, the lifting cap is provided with a pin, the body is connected
with the lifting cap by thread, and a lifting bail is arranged on
the top of the lifting cap and connected with the ground drawworks
to lift up and lower the ultrasonic monitoring device.
At least three centralizers are fixed with an equal interval on the
surface of the cylindrical body, preferably four strip
centralizers. The axis of the strip centralizers is parallel to the
axis of the cylindrical body. The mounting groove 1 is cut into the
cylindrical body surface between two adjacent centralizers, one
electrically controlled expansion device is installed in the groove
1 and includes electric push rods placed horizontally and a ribbed
plate perpendicular to the electric push rods, the bottom ends of
the electric push rods are fixedly connected to the bottom surface
of the mounting groove, the front ends of the electric push rods
are connected with the ribbed plate, the mounting groove 2 is cut
into the ribbed plate, and one ultrasonic transducer is installed
in the groove 2.
In some embodiments, there is at least one electric push rod that
is synchronized to expand and retract and is connected to the
ribbed plate in a uniform distribution. At least one electric push
rod can always make the upper surface of the ribbed plate or the
ultrasonic transducer in the mounting groove 2 parallel to the axis
of the cylindrical body, so that the ultrasonic transducer can be
close to the wellbore casing.
In some embodiments, there are three electric push rods including
an electric push rod 1, an electric push rod 2, and an electric
push rod 3; the front end of the electric push rod 1 is connected
to a geometric center point of the ribbed plate; and the electric
push rod 2 and the electric push rod 3 are respectively located on
different sides of the electric push rod 1 and are connected to the
ribbed plate in an equidistant distribution.
The ultrasonic transducer is used to generate ultrasonic S wave (SH
wave) and receive the reflected S wave. Ultrasonic S wave can only
travel in solid media, and cannot travel and be reflected back in
liquids and air. The ultrasonic S wave may include a horizontally
polarized S wave (SH wave), which does not undergo waveform
conversion and travels in simple SH waveform in the whole travel
process, which makes the SH wave is not interfered by other waves
during the travel process. With the increase of travel distance,
the attenuation of this wave is much smaller than other waves.
Therefore, this wave is most suitable for detecting the distance
between two wells.
The electronically controlled expansion device is connected to the
ground control system to control the extension and retraction of
the electric push rod. When the electric push rods are retracted,
the horizontal protruding height of the ultrasonic transducer is
smaller than the horizontal height of two centralizers adjacent to
it. When the electric push rods are extended, the horizontal
protruding height of the ultrasonic transducer is equal to the
horizontal height of two centralizers adjacent to it, and the
ultrasonic transducer is close to the wellbore casing. The ground
control system controls the ultrasonic transducer to emit S wave
and receive the reflected wave, and calculate the distance between
the two wells by monitoring the time difference between the
emission time and the reflection time in combination with the
travel velocity of S wave in the formation. The two centralizers
adjacent to the ultrasonic transducer are made of hard material,
and the rest are made of elastic material. The upper part of the
cylindrical body is provided with a cable hole through which the
cable is connected to the ground control system and the downhole
ultrasonic monitoring device.
With the an-collision monitoring method by the ultrasonic wellbore
anti-collision monitoring system, the main technical solution is
that the nearest area (vertical depth) between two adjacent wells
is found out by anti-collision scanning, the ultrasonic monitoring
device is lowered by the drawworks to the specified vertical depth
(where the two wells are closest) in the well adjacent to the well
under drilling, the ultrasonic transducer is supported on the
casing wall of the adjacent well, the ultrasonic monitoring device
is controlled by the ground control system to emit S wave
perpendicular to the casing wall of the adjacent well, the S wave
encounters the drilling fluid in the well under drilling during the
travel, and cannot continue to travel, but is reflected back along
the original path, and the ground control system calculates the
distance S between the two wells by monitoring the time difference
T between the emission time and the reflection time of the S wave
and the travel velocity V of the S wave in the formation; the
calculation formula is
.times. ##EQU00001##
The monitoring mode varies with the type of well interval. The
details are described as follows:
(1) For the wellbore anti-collision monitoring in the vertical
interval, the real-time monitoring mode is adopted, including the
following steps:
Step 1: Calculate the vertical depth a of measuring point with
track calculation software according to inclination and azimuth
measured by MWD of the well under drilling;
Step 2: Lower the ultrasonic monitoring device by the drawworks to
the vertical depth a calculated in Step 1;
Step 3: Control the opening of the electric push rods with the
ground control system to make the ultrasonic transducer close to
the casing wall in the adjacent well, and then the ultrasonic
transducer emits S wave and receives the reflected waves at the
same time, and transmits the emitted and reflected wave signals to
the ground control system to calculate the distance between the two
wells;
Step 4: After completing Steps 1 to 3, control the closing of the
electric push rods with the ground control system, lower the
ultrasonic monitoring device by the drawworks at a velocity that is
same with drilling rate of the well under drilling until it runs
into the well 2 m deep, and then repeat Steps 3 and 4 in turns to
continue to measure the distance between the two wells in the
vertical interval;
Step 5: After the measurement is completed, control the closing of
the electric push rods with the ground control system, start up the
drawworks to lift up the ultrasonic monitoring device and lift it
away from the wellhead.
(2) For the wellbore anti-collision monitoring in the kick-off
interval, the precise measurement mode is adopted, including the
following steps:
Step 1: Calculate the track parameter with track calculation
software according to downhole inclination and azimuth measured by
MWD of the well under drilling;
Step 2: Calculate the nearest distance between the well under
drilling and the adjacent well by anti-collision scanning, work out
the vertical depth a and azimuth b of the nearest point of the well
under drilling to the adjacent well, and then calculate the
monitoring azimuth c of the adjacent well; if the currently
measured azimuth is 0.degree. to 180.degree., c=360.degree.-b; if
180.degree. to 360.degree., c=b;
Step 3: Use a compass to determine the position d of the measured
azimuth c measured at the wellhead of the adjacent well, to align
the position of the ultrasonic transducer with the position d;
Step 4: Lower the ultrasonic monitoring device by the drawworks to
the vertical depth a according to the requirements set forth in
Step 3;
Step 5: Control the opening of the electric push rods with the
ground control system to make the ultrasonic transducer close to
the casing wall in the adjacent well, and then the ultrasonic
transducer emits S wave and receives the reflected waves at the
same time, and transmits the emitted and reflected wave signals to
the ground control system to calculate the distance between the two
wells; after that, lift up the ultrasonic monitoring device and
lift it away from the wellhead to monitor the next point, and
repeat Steps 1 to 5.
(3) For the anti-collision monitoring of the interval with higher
risk of collision, the real-time monitoring+single-point accurate
measurement is adopted, including the following steps:
Step 1: Calculate the vertical depth a of measuring point with
track calculation software according to inclination and azimuth
measured by MWD of the well under drilling;
Step 2: Lower the ultrasonic monitoring device by the drawworks to
the vertical depth a calculated in Step 1;
Step 3: Control the opening of the electric push rods with the
ground control system to make the ultrasonic transducer close to
the casing wall in the adjacent well, and then the ultrasonic
transducer emits S wave and receives the reflected waves at the
same time, and transmits the emitted and reflected wave signals to
the ground control system to calculate the distance between the two
wells;
Step 4: After completing Steps 1 to 3, control the closing of the
electric push rods with the ground control system, lower the
ultrasonic monitoring device by the drawworks at a velocity that is
same with drilling rate of the well under drilling until it runs
into the well 2 m deep, and then repeat Steps 3 and 4 to conduct
real-time monitoring;
Step 5: In the process of real-time monitoring, if there is a trend
of collision between the two wells, that is, the distance between
the two wells is continuously decreased, switch to the precise
measurement mode, and lift up the ultrasonic monitoring device and
lift it away from the wellhead as follows:
Step 51: Calculate the track parameter with track calculation
software according to downhole inclination and azimuth measured by
MWD of the well under drilling;
Step 52: Calculate the nearest distance between the well under
drilling and the adjacent well by anti-collision scanning, work out
the vertical depth a and azimuth b of the nearest point of the well
under drilling to the adjacent well, and then calculate the
monitoring azimuth c of the adjacent well; if the currently
measured azimuth is 0.degree. to 180.degree., c=360.degree.-b; if
180.degree. to 360.degree., c=b;
Step 53: Use a compass to determine the position d of the measured
azimuth c measured at the wellhead of the adjacent well, to align
the position of the ultrasonic transducer with the position d;
Step 54: Lower the ultrasonic monitoring device by the drawworks to
the vertical depth a according to the requirements set forth in
Step 3;
Step 55: Control the opening of the electric push rods with the
ground control system to make the ultrasonic transducer close to
the casing wall in the adjacent well, and then the ultrasonic
transducer emits S wave and receives the reflected waves at the
same time, and transmits the emitted and reflected wave signals to
the ground control system to calculate the distance between the two
wells; after that, lift up the ultrasonic monitoring device and
lift it away from the wellhead to monitor the next point, and
repeat Steps 1 to 5.
Compared with the prior art, the present invention has the
following beneficial effects:
The ultrasonic monitoring wellbore anti-collision monitoring system
disclosed by the present invention is advantaged by simple
structure, low cost, and real-time monitoring of distance between
two adjacent wells. It is used to prevent the wellbore collision of
two adjacent wells, and provide more accurate monitoring results
than the existing scanning method.
Other advantages, objectives and characteristics of the present
invention will be partly embodied by the following description, and
partly understood by those skilled in the art through research and
practice of the present invention.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1: Schematic Diagram of Vibration Direction of SH Wave and SV
Wave; (a) Schematic Diagram of Vibration Direction of SH Wave, (b)
Schematic Diagram of Vibration Direction of SV Wave
FIG. 2: Schematic Diagram of Distance between Adjacent Wells under
Ultrasonic Monitoring
FIG. 3: Schematic Diagram of Ultrasonic Wellbore Anti-collision
Monitoring System
FIG. 4: Structure Diagram of Ultrasonic Monitoring Device
FIG. 5: Structure Diagram of Electronically Controlled Expansion
Device of Ultrasonic Monitoring Device
FIG. 6: Top View of Ultrasonic Monitoring Device
FIG. 7: Schematic Diagram of Wellhead Orientation of Two Adjacent
Wells
Explanation of numbers marked in the figure:
1--ultrasonic monitoring device, 2--ground control system,
3--drilling fluid, 4--drilling tool, 5--emitted wave, 6--reflected
wave, 11--cylindrical body, 12--lifting cap, 13--lifting bail,
14--centralizer, 15--mounting groove 1, 16--electric push rod,
17--ribbed plate, 18--bolt, 19--mounting groove 2, 20--ultrasonic
transducer, 21--bolt, 22--cable hole.
DETAILED DESCRIPTION
In the following detailed description of the preferred embodiments
of the present invention, reference is made to the accompanying
drawings. It is to be understood that the preferred embodiments
described herein are only used to illustrate and interpret the
present invention and are not intended to limit the present
invention.
I. The monitoring principle of the ultrasonic monitoring wellbore
anti-collision monitoring system in the present invention is
described as follows:
S wave normal probe comprises two parts: emitting and receiving
ultrasonic wave. The distance between the adjacent well and the
well under drilling can be calculated according to the time
difference between emitting and receiving.
The ultrasonic probe is a reversible acoustic-electric conversion
element. Direct piezoelectric effect: the process of converting
electrical signal into ultrasonic signal is an ultrasonic emission
process. Inverse piezoelectric effect: the process of converting
ultrasonic signal into electrical signal is an ultrasonic receiving
process.
Ultrasonic S waves are divided into horizontally polarized S wave
(SH wave) and vertically polarized S wave (SV wave), as shown in
FIG. 1. In the testing industry, if the vibration direction of S
wave is parallel to the workpiece surface, it is defined as SH wave
(FIG. 1a); if perpendicular to the workpiece surface, it is defined
as SV wave (FIG. 1b).
In the traveling process, ultrasonic SV wave will be converted into
refracted P wave and refracted SH wave. In the detection, all kinds
of waves will interfere with each other, and the wave will be
attenuated greatly. Therefore, this wave is not suitable for
detecting the distance between two wells. Compared with SV waves,
SH wave will not be converted in the whole traveling process. In
the detection, only SH wave will travel and will be attenuated
slightly. Therefore, this wave is suitable for detecting the
distance between two wells.
As shown in FIG. 2, the present invention adopts ultrasonic S wave
probe. Ultrasonic S wave is emitted perpendicular to the surface of
the casing of the adjacent well, and travels in the formation. If
encountering the drilling fluid in the well under drilling, S wave
cannot continue to travel, but is reflected back by drilling fluid
along the original path. The ground control system calculates the
distance S between the two wells by monitoring the time difference
T between the emission time and the reflection time of the S wave
and the travel velocity V of the S wave in the formation; the
calculation formula is
.times. ##EQU00002## Refer to Table 1 for the travel velocity of
ultrasonic wave (S wave and P wave).
TABLE-US-00001 TABLE 1 Travel Velocity of Ultrasonic S Wave and P
Wave Travel velocity of Travel velocity of S Density Radius Medium
P wave (m/s) wave (m/s) (kg/) (cm) Wellbore 1500 -- 1000 6 fluid
Exploring 5900 3300 7800 7 tube Cement 2800 1700 1900 10 Formation
3600 2200 2300 .infin.
II. The device structure of the ultrasonic wellbore anti-collision
monitoring system disclosed by the present invention is as
follows:
As shown in FIG. 3, the ultrasonic wellbore anti-collision
monitoring system includes ultrasonic monitoring device (1) which
is placed in adjacent well and ground control system (2). In the
figure, 3 is the drilling fluid, 4 is the drilling tool, 5 is the
emitted wave, and 6 is the reflected wave.
The structure of the ultrasonic monitoring device 1 is shown in
FIGS. 4 to 6, including a cylindrical body (11), a lifting cap (12)
arranged on the top of the body, and a lifting bail (13) arranged
on the top of the lifting cap for connecting the ground drawworks.
The preferred structure is that the upper end of the cylindrical
body is provided with a box, the lifting cap is provided with a
pin, the body is connected with the lifting cap by thread, and a
lifting bail is arranged on the top of the lifting cap and
connected with the ground drawworks to lift up and lower the
ultrasonic monitoring device.
The surface of the cylindrical body (11) is fixed with 4 strip
centralizers (14), and the axis of the strip centralizers is
parallel to the axis of the cylindrical body. The mounting groove 1
(15) is cut into the cylindrical body surface between two adjacent
centralizers, one electrically controlled expansion device is
installed in the groove 1 and includes three electric push rods
(16) placed horizontally and a ribbed plate (17) perpendicular to
the electric push rods. For example, the electric push rods can be
those produced by Shandong Jinniu Transmission Technology Co.,
Ltd., or other electric push rods with a similar structure. the
bottom ends of the electric push rods are fixedly connected to the
bolts (18) on the bottom of the mounting groove 1, the front ends
of the three electric push rods are fixedly connected with the
ribbed plate, the mounting groove 2 (19) is cut into the ribbed
plate, and the ultrasonic transducer (20) is fixed and installed in
the groove 2 by the bolts (21). The front end of the ultrasonic
transducer protrudes from the surface of the ribbed plate. The
ultrasonic transducer is used to generate ultrasonic S wave (SH
wave) and receive the reflected S wave. Ultrasonic S wave can only
travel in solid media, and cannot travel and be reflected back in
liquids and air. The ultrasonic S wave does not undergo waveform
conversion and travels in simple SH waveform in the whole travel
process, which makes the SH wave is not interfered by other waves
during the travel process. With the increase of travel distance,
the attenuation of this wave is much smaller than other waves.
Therefore, this wave is most suitable for detecting the distance
between two wells.
The electronically controlled expansion device is connected to the
ground control system to control the extension and retraction of
the electric push rod. There is at least one electric push rod that
is synchronized to expand and retract and is connected to the
ribbed plate in a uniform distribution. The present disclosure does
not limit a count of the electric push rods. Taking three electric
push rods as an example, the three electric push rods may include
an electric push rod 1, an electric push rod 2, and an electric
push rod 3. As shown in FIG. 5, the front end of the electric push
rod 1 is connected to a geometric center point of the ribbed plate,
and the electric push rod 2 and the electric push rod 3 are
respectively located on different sides of the electric push rod 1
and are connected to the ribbed plate in an equidistant
distribution. The three electric push rods are extended and
retracted at the same time. When the electric push rods are closed,
they are in the retracted state, the ribbed plate coincides with
the surface of the cylindrical body, and the horizontal protruding
height of the ultrasonic transducer is smaller than the horizontal
height of two centralizers adjacent to it. When the electric push
rods are opened, they are in the extended state, the horizontal
protruding height of the ultrasonic transducer is equal to the
horizontal height of two centralizers adjacent to it, and the
ultrasonic transducer is just close to the wellbore casing. At this
time, the ground control system controls the ultrasonic transducer
to emit S wave and receive the reflected wave, and calculates the
distance between the two wells by monitoring the time difference
between the emission time and the reflection time in combination
with the travel velocity of S wave in the formation. The two
centralizers adjacent to the ultrasonic transducer are made of hard
material, and the rest are made of elastic material, so that they
are not easy to deform under the action of external force and
capable of effectively protecting the ultrasonic sensor when the
device is lifted or lowered. The other two centralizers have low
hardness and are easy to deform under the action of external force.
The upper part of the cylindrical body is provided with a cable
hole 22 through which the cable is connected to the ground control
system and the downhole ultrasonic monitoring device.
III. With the an-collision monitoring method by the ultrasonic
wellbore anti-collision monitoring system, the main technical
solution is that the ultrasonic monitoring device is lowered by the
drawworks to the specified vertical depth (where the two wells are
closest) in the well adjacent to the well under drilling, the
ultrasonic transducer is supported on the casing wall of the
adjacent well, the ultrasonic monitoring device is controlled by
the ground control system to emit S wave perpendicular to the
casing wall of the adjacent well, the S wave encounters the
drilling fluid in the well under drilling during the travel, and
cannot continue to travel, but is reflected back along the original
path, and the ground control system calculates the distance S
between the two wells by monitoring the time difference T between
the emission time and the reflection time of the S wave and the
travel velocity V of the S wave in the formation; the calculation
formula is
.times. ##EQU00003##
Monitoring mode varies with the type of well interval. The details
are described as follows:
(1) It is very important to prevent the wellbore from collision in
the vertical interval, and the collision prevention of the vertical
interval is the basis of all works. The inclination of the vertical
interval is small, the azimuth changes greatly, and the azimuth
change does not affect the measurement. For the wellbore
anti-collision monitoring in the vertical interval, the real-time
monitoring mode is adopted, including the following steps:
Step 1: Calculate the vertical depth a of measuring point with
track calculation software according to inclination and azimuth
measured by MWD of the well under drilling;
Step 2: Lower the ultrasonic monitoring device by the drawworks to
the vertical depth a calculated in Step 1;
Step 3: Control the opening of the electric push rods with the
ground control system to make the ultrasonic transducer close to
the casing wall in the adjacent well, and then the ultrasonic
transducer emits S wave and receives the reflected waves at the
same time, and transmits the emitted and reflected wave signals to
the ground control system to calculate the distance between the two
wells;
Step 4: After completing Steps 1 to 3, control the closing of the
electric push rods with the ground control system, lower the
ultrasonic monitoring device by the drawworks at a velocity that is
same with drilling rate of the well under drilling until it runs
into the well 2 m deep, and then repeat Steps 3 and 4 in turns to
continue to measure the distance between the two wells in the
vertical interval;
Step 5: After the measurement is completed, control the closing of
the electric push rods with the ground control system, start up the
drawworks to lift up the ultrasonic monitoring device and lift it
away from the wellhead.
(2) If there is collision risk between the well under drilling and
the adjacent well in the kick-off interval, collision prevention
and obstacle avoidance are particularly important. At this time, it
is necessary to not only ensure that the kick-off rate meets the
design requirements, but also consider the risk of collision with
the adjacent well. There are errors in the measured data of MWD and
in the calculated results of the track calculation software.
Therefore, it is particularly important to accurately measure the
distance between the two adjacent wells. For the wellbore
anti-collision monitoring in the kick-off interval, the precise
measurement mode is adopted, including the following steps:
Step 1: Calculate the track parameter with track calculation
software according to downhole inclination and azimuth measured by
MWD of the well under drilling;
Step 2: Calculate the nearest distance between the well under
drilling and the adjacent well by anti-collision scanning, work out
the vertical depth a and azimuth b of the nearest point of the well
under drilling to the adjacent well, and then calculate the
monitoring azimuth c of the adjacent well; if the currently
measured azimuth is 0.degree. to 180.degree., c=360.degree.-b; if
180.degree. to 360.degree., c=b. It should be noted that if the
azimuth of the well under drilling is in the range of 0.degree. to
180.degree., the monitoring device is also lowered according to the
azimuth of the well under drilling, and the orientation of the
device is exactly opposite to that of the well under drilling;
Step 3: Use a compass to determine the position d of the measured
azimuth c measured at the wellhead of the adjacent well, to align
the position of the ultrasonic transducer with the position d;
Step 4: Lower the ultrasonic monitoring device by the drawworks to
the vertical depth a according to the requirements set forth in
Step 3;
Step 5: Control the opening of the electric push rods with the
ground control system to make the ultrasonic transducer close to
the casing wall in the adjacent well, and then the ultrasonic
transducer emits S wave and receives the reflected waves at the
same time, and transmits the emitted and reflected wave signals to
the ground control system to calculate the distance between the two
wells; after that, lift up the ultrasonic monitoring device and
lift it away from the wellhead to monitor the next point, and
repeat Steps 1 to 5.
(3) For the anti-collision monitoring of the interval with higher
risk of collision, real-time monitoring+single-point accurate
measurement is adopted. The purpose of real-time monitoring is to
monitor the collision trend of adjacent wellbores. For well
intervals with a tendency to collide, an accurate measurement mode
is used to accurately measure the distance between two wells,
including the following steps:
Step 1: Calculate the vertical depth a of measuring point with
track calculation software according to inclination and azimuth
measured by MWD of the well under drilling;
Step 2: Lower the ultrasonic monitoring device by the drawworks to
the vertical depth a calculated in Step 1;
Step 3: Control the opening of the electric push rods with the
ground control system to make the ultrasonic transducer close to
the casing wall in the adjacent well, and then the ultrasonic
transducer emits S wave and receives the reflected waves at the
same time, and transmits the emitted and reflected wave signals to
the ground control system to calculate the distance between the two
wells;
Step 4: After completing Steps 1 to 3, control the closing of the
electric push rods with the ground control system, lower the
ultrasonic monitoring device by the drawworks at a velocity that is
same with drilling rate of the well under drilling until it runs
into the well 2 m deep, and then repeat Steps 3 and 4 to conduct
real-time monitoring;
Step 5: In the process of real-time monitoring, if there is a trend
of collision between the two wells, that is, the distance between
the two wells is continuously decreased, switch to the precise
measurement mode, and lift up the ultrasonic monitoring device and
lift it away from the wellhead as follows:
Step 51: Calculate the track parameter with track calculation
software according to downhole inclination and azimuth measured by
MWD of the well under drilling;
Step 52: Calculate the nearest distance between the well under
drilling and the adjacent well by anti-collision scanning, work out
the vertical depth a and azimuth b of the nearest point of the well
under drilling to the adjacent well, and then calculate the
monitoring azimuth c of the adjacent well; if the currently
measured azimuth is 0.degree. to 180.degree., c=360.degree.-b; if
180.degree. to 360.degree., c=b;
Step 53: Use a compass to determine the position d of the measured
azimuth c measured at the wellhead of the adjacent well, to align
the position of the ultrasonic transducer with the position d;
Step 54: Lower the ultrasonic monitoring device by the drawworks to
the vertical depth a according to the requirements set forth in
Step 3;
Step 55: Control the opening of the electric push rods with the
ground control system to make the ultrasonic transducer close to
the casing wall in the adjacent well, and then the ultrasonic
transducer emits S wave and receives the reflected waves at the
same time, and transmits the emitted and reflected wave signals to
the ground control system to calculate the distance between the two
wells; after that, lift up the ultrasonic monitoring device and
lift it away from the wellhead to monitor the next point, and
repeat Steps 1 to 5.
The above are only the preferred embodiments of the present
invention, and are not intended to limit the present invention in
any form. Although the present invention has been disclosed as
above with the preferred embodiments, it is not intended to limit
the present invention. Those skilled in the art, within the scope
of the technical solution of the present invention, can use the
disclosed technical content to make a few changes or modify the
equivalent embodiment with equivalent changes. Within the scope of
the technical solution of the present invention, any simple
modification, equivalent change and modification made to the above
embodiments according to the technical essence of the present
invention are still regarded as a part of the technical solution of
the present invention.
* * * * *