U.S. patent application number 09/575882 was filed with the patent office on 2002-11-07 for deeply buried transmission line.
Invention is credited to Moss, Jeff H..
Application Number | 20020164212 09/575882 |
Document ID | / |
Family ID | 24302072 |
Filed Date | 2002-11-07 |
United States Patent
Application |
20020164212 |
Kind Code |
A1 |
Moss, Jeff H. |
November 7, 2002 |
Deeply buried transmission line
Abstract
A deeply buried transmission line and a method for installing
same wherein the majority of the line is buried at depth (e.g. up
to 5000 feet or more) well below conventionally buried lines. This
provide much greater security from either accidental or intentional
damage to the line. The line is initiated by drilling a wellbore in
a downward vertical direction to a first depth (e.g. about 500
feet) from spaced surface points before the respective wellbores
are curved into in a horizontal direction towards each other at a
second depth (e.g. about 5000 feet) where they ultimately
intersect. By drilling a wellbore downward from small, spaced
surface plots at either end of the line, only a small surface area
is affected during the installation of the line.
Inventors: |
Moss, Jeff H.; (The
Woodlands, TX) |
Correspondence
Address: |
Denise Y. Wolfs
ExxonMobil Upstream Research Company
P.O. Box 2189
Houston
TX
77252-2189
US
|
Family ID: |
24302072 |
Appl. No.: |
09/575882 |
Filed: |
May 22, 2000 |
Current U.S.
Class: |
405/155 ;
166/285; 175/61 |
Current CPC
Class: |
E21B 7/04 20130101 |
Class at
Publication: |
405/155 ;
166/285; 175/61 |
International
Class: |
E21B 007/04 |
Claims
What is claimed is:
1. A method for installing a deeply buried transmission line
between a first point and a second point which are spaced on the
surface of the earth, said method comprising: drilling a first
wellbore downward in a substantially vertical direction from said
first point to a first depth and then diverting said first wellbore
through a curved section and into a substantially horizontal
section which extends towards said second point at a second depth;
ceasing the drilling of said first wellbore before it reaches said
second point; drilling a second wellbore downward in a
substantially vertical direction from said second point to a first
depth and then diverting said second wellbore through a curved
section and into a substantially horizontal section which extends
towards said first wellbore at a second depth; and ceasing the
drilling of said second wellbore after it intersects said first
wellbore whereby the interconnected said first and said second
wellbores form said transmission line between said first and said
second points.
2. The method of claim 1 wherein said first depth of said first
wellbore is at least about 500 feet and said first depth of said
second wellbore is at least about 500 feet.
3. The method of claim 2 wherein said second depth of said first
wellbore is at least about 5000 feet and said second depth of said
second wellbore is at least about 5000 feet.
4. The method of claim 2 wherein said first point on the surface is
spaced from about 3000 feet to about 7000 feet from said second
point.
5. The method of claim 4 wherein said first point is located within
a first plot having a surface area of .+-.2 acres and said second
point is located within a second plot having a surface area of
.+-.2 acres.
6. The method of claim 1 including: casing said first wellbore and
said second wellbores with conduit to provide a continuous cased
passage between said first point and said second point.
7. The method of claim 6 wherein casing said first wellbore and
said second wellbores comprises: casing said first wellbore
throughout said substantially vertical direction with one or more
strings of casing; casing said second wellbore throughout its said
substantially vertical direction with one or more strings of
casing; and running a liner between said casing in said first
wellbore and said casing in said second wellbore.
8. The method of claim 7 including: cementing said casing in said
first and said second wellbores; and cementing said liner to
thereby provided a sealed passage between said first point and said
second point.
9. The method of claim 8 wherein said sealed passage provides a
flowpath for fluids.
10. The method of claim 8 including: extending a transmission cable
between said first point and said second point through said sealed
passage.
11. The method of claim 5 including: drilling a second first
wellbore for a second deeply buried transmission line downward
within said second plot from which said second wellbore of said
deeply buried transmission line is drilled; and connecting said
second wellbore to said second first wellbore within said second
plot.
12. The method of claim 11 wherein said second wellbore and said
second first wellbore are spaced on the surface from each other at
a distance of about 20 feet.
13. A deeply buried transmission line extending between a first
point and a second point space on the surface of the earth, said
transmission line comprising: a first wellbore extending downward
from said first point in a substantially vertical direction to a
first depth and then in a substantially horizontal direction
towards said second point at a second depth; and a second wellbore
extending downward from said second point in a substantially
vertical direction to a first depth and then in a substantially
horizontal direction towards said first wellbore at a second depth
until said second wellbore intersects said first wellbore whereby
the intersected said first and second wellbores form said deeply
buried transmission line.
14. The deeply buried transmission line of claim 13 wherein said
first depth of said first wellbore is at least about 500 feet and
said first depth of said second wellbore is at least about 500
feet.
15. The deeply buried transmission line of claim 14 wherein said
second depth of said first wellbore is at least about 5000 feet and
said second depth of said second wellbore is at least about 5000
feet.
16. The deeply buried transmission line of claim 15 wherein said
first point on said surface is spaced from about 3000 feet to about
7000 feet from said second point on said surface.
17. The deeply buried transmission line of claim 16 wherein said
first point is located within a plot having a surface area of .+-.2
acres and said second point is located within a plot having a
surface area of .+-.2 acres.
18. The deeply buried transmission line of claim 13 including: at
least one string of casing in said first wellbore and extending
substantially throughout said vertical direction of said first
wellbore; at least one string of casing in said second wellbore and
extending substantially throughout said vertical direction of said
second wellbore; and a liner connecting said at least one string of
casing in said first wellbore and said at least one string of
casing in said second wellbore.
19. The deeply buried transmission line of claim 18 wherein said
transmission line is used to transport fluids.
20. The deeply buried transmission line of claim 18 including: a
transmission cable extending from said first point to said second
point through said at least one string of casing in said first
wellbore, said liner, and said at least one string of casing in
said second wellbore.
Description
DESCRIPTION
[0001] 1. Technical Field
[0002] The present invention relates to a transmission line buried
deep in the earth and in one of its aspects relates to a
transmission line (e.g. liquid pipeline, electrical power line,
communication line, etc.) and a method for installing the line deep
within the earth or beneath bodies of waters in order to protect
the line and reduce the disturbance to the surface during
installation and maintenance.
[0003] 2. Background of the Invention
[0004] In laying transmission lines across long distances, it is
common to bury the line in a trench which is only a few feet deep
(e.g. 20 feet or less) below the surface). For example, pipelines
for transporting hydrocarbons (i.e. crude oil, refined products,
etc.) are typically constructed by welding joints of pipe together
as they lay on the ground and then lowering the welded line into a
prepared trench. The trench is then filled with soil to bury the
line. However, since a trench must be dug along most of the length
of the pipeline, a large contiguous right-of-way on the surface is
required to install the line. Further, major environmental
disturbances and disruptions may occur during the ditching
operation and the installation of the line. This is also true for
buried electrical power or communication transmission lines where
long lengths of cable or the like are likewise buried just below
the ground in relative shallow trenches.
[0005] Since these transmission lines are buried relatively close
to the surface, they are susceptible to damage and/or destruction
from causes either unintentional and intentional. For example, it
is not uncommon for buried transmission lines to be unintentionally
severed while the surface is being excavated for roads, buildings,
other transmission lines, or the like. The accidental severance of
these lines can result in a major disaster in both property and
lives and can substantially paralyze a community or industry until
the lines are repaired. Likewise, in the modern political climate,
the relatively-shallow buried lines may also become targets for
espionage or sabotage by protesters or terrorists seeking to
disrupt the normal operations in a community.
[0006] Due to the long distances traversed by such lines, it is
extremely difficult and expensive to provide the necessary security
along their entire lengths, especially where the lines pass through
remote and/or rugged terrain. Accordingly, a need exists for a
transmission lie which is protected from damage by surface
excavations and which is secure from vandalism and/or sabotage over
most of its length.
SUMMARY OF THE INVENTION
[0007] The present invention provides a deeply buried transmission
line and a method for installing the line wherein the majority of
the line is buried at depth (e.g. up to 5000 feet or more) which is
significantly deeper than more conventionally buried transmission
lines (e.g. about 20 feet). This provide much greater security for
the transmission line from either accidental or intentional damage
during its operational life. Further, the transmission line of the
present invention is initiated in a substantially straight down
direction at both ends so that the line is well below surface
obstructions and other buried objects before it is kicked off in a
horizontal direction. This greatly reduces, if not eliminates, the
danger of the line striking or otherwise damaging other structures,
i.e. other buried transmission lines).
[0008] Still further, the present transmission line only affects a
relatively small surface area during installation, operation, and
maintenance. That is, the present transmission line is initiated at
either ends from small surface area plots (e.g. .+-.2 acres) which
are spaced from each other by long distances (e.g. up to 7000 feet
or more). By requiring only widely-spaced, small areas on the
surface to install and maintain the transmission line, the amount
of disruption, etc. to the surface is minimized. Also, these small
plots can easily be secured which, in turn, can substantially
reduce damage due to vandalism and/or sabotage.
[0009] More particularly, the present invention provides a deeply
buried transmission line and a method for installing the line
between a first point and a second point which are spaced on the
surface of the earth. Basically, a first wellbore (i.e. target
well) is drilled downward in a substantially vertical direction
from the first point to a first depth (e.g. about at least 500
feet) and is then diverted through a curved section into a
substantially horizontal section which extends towards said second
point at a second depth (e.g. about 5000 feet).
[0010] Subsequent to or concurrent therewith, a second wellbore
(i.e. capture well) is drilled downward in a substantially vertical
direction from the second point to a first depth (e.g. about at
least 500 feet) and then is diverted towards the first wellbore at
a second depth (e.g. about 5000 feet) until the second wellbore
intersects the first wellbore. The intersected or interconnected
wellbores now form a deeply buried transmission line between said
first and said second points on the surface which, in turn, can be
spaced from about 3000 feet to about 7000 feet from each other.
[0011] Both the first wellbore and the second wellbore is typically
cased throughout substantially at least their respective vertical
sections with at least string of casing (e.g. conductor casing,
surface casing, intermediate casing, etc.) which, in turn, can be
connected with a liner to provide a continuous cased and sealed
passage between the first point and said second point. The strings
of casing and the liner can be cemented within the wellbores as
will be understood in the art. The completed line can be used as a
pipeline for fluids or can be used as a buried passage for a
transmission cable (e.g. power, communication, etc.) between the
first and second points on the surface.
[0012] If more than one span of the deeply buried transmission line
is needed to cover a prescribed distance, additional spans can be
completed in the same way as described above. The next span is
installed by drilling another first wellbore (i.e. target well)
from the same surface plot as that used in drilling the second
wellbore (i.e. target well) of the previous span of the
transmission line. The next span is then completed and the second
wellbore of the previous span of transmission line is connected or
manifolded to the next first wellbore of the next span of
transmission line. This procedure is repeated until enough spans
have been installed to complete the transmission line over the
desired distance. Since the manifolded wellbores of adjacent spans
lie in close proximity to each other (e.g. about 20 feet apart) and
since the upper ends of the wellbore are the only exposed portions
of the line at the surface, security for the entire line can be
maintained by merely patrolling and/or monitoring the spaced,
surface plots.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] The actual construction, operation, and apparent advantages
of the present invention will be better understood by referring to
the drawings which are not necessarily to scale and in which like
numerals identify like parts and in which:
[0014] FIG. 1 is a perspective elevational view, partly in section,
of one span of the deeply buried transmission line in accordance
with the present invention;
[0015] FIGS. 2A-2C are perspective elevational views, partly in
section, of the sequence of steps followed in constructing and
installing the transmission line of the present invention;
[0016] FIG. 3 is a perspective elevational view, partly in section,
of the surface manifold which connects two adjacent spans of the
transmission line of FIGS. 2A-2C together; and
[0017] FIG. 4 is a detailed, sectional view of one span of the
transmission line of the present invention.
BEST KNOWN MODE FOR CARRYING OUT THE INVENTION
[0018] Referring more particularly to the drawings, FIG. 1
illustrates a typical span of a deeply-buried, transmission line 10
in accordance with the present invention. As used herein,
"transmission line" is intended to cover both fluid-conveying lines
(e.g. pipelines) and power or data lines (e.g. electrical,
telephone, etc.). As illustrated in FIG. 1, one span of line 10
extends over a significant distance or length "L" between a first
surface point A and a second surface point B which, in turn, may
lie on opposite sides of major surface obstructions (e.g. buildings
11, body of water 12, and/or a wooded area 13). Deeply buried line
10 will typically lie at a maximum depth "D" of up to about 5000
feet over the majority of its length "L".
[0019] Since the distance "L" between points A and B is normally
substantial (e.g. up to about 7 miles or more), only a relatively
small number of relatively small, surface-area plots 14 (e.g. about
.+-.2 acres) will be required for installing and maintaining line
10 over long distances. Further, since plots 14 are small in
surface area and are spaced at long intervals (e.g. up to 7 miles
or more), only a small portion of the surface along line 10 will be
disturbed (i.e. only at each plot 14) during installation of line
10. Still further, since line 10 can only be reasonably accessed
from the surface at each of plots 14, line 10 can be secured
against vandalism and/or sabotage by merely securing or patrolling
the plots 14 spaced along line 10.
[0020] As will be more fully explained below, line 10 has a
substantially vertical section V (FIG. 4) at either end which
extends downward from the surface 15 at points A and B,
respectively, to a significant depth before line 10 curves through
a "sail angle" zone S and into a substantially horizontal section H
which, in turn, extends between and connects the two vertical
sections together. By initiating the line 10 in a downward vertical
direction for a significant depth (e.g. about .+-.500 feet), the
line 10 will be below any object buried near the surface at most
conventional depths (e.g. other transmission lines, foundations for
buildings, most bodies of water, etc.) before the line is directed
into its horizontal direction, thereby substantially eliminating
any chance that line 10 will contact, damage or be impeded by any
such near-surface objects. The actual depth of vertical section V
in a particular application will depend on a variety of factors,
e.g. the ultimate length of span 10, geological strata in the area,
fresh water zones to be protected, the required size of line 10,
governmental regulations, etc.).
[0021] Referring now to FIGS. 2A-2C and 4, the preferred method for
installing transmission line 10 is illustrated. First, a target
well T is drilled from surface plot 14 at point A by using
conventional, known directional drilling techniques. Target well T
is initiated in substantial downward, vertical direction for a
significant depth (e.g. .+-.500 feet). As will be fully understood
in this art, the vertical section V.sub.a of well T is cased and
cemented with conventional conductor string 20A and surface casing
21A (FIG. 4). Again, using conventional and well known directional
drilling techniques, target well T is then diverted through a "sail
angle" section S into the desired horizontal direction towards
point B.
[0022] By using known and commercially-available techniques (e.g.
measurements-while-drilling, gyroscopic surveying, etc.), the
wellbore of well T can be accurately "steered" from the surface
through the "sail angle" zone S.sub.a and horizontal section H to
its final destination (i.e. point X). While the distance from point
A will vary with a particular application, typically, point X will
lie approximately 2/3rds of the distance to point B. Of course,
wellbore T can be cased and cemented with one or more intermediate
strings (e.g. 22A, 22B) during the drilling of well T as is
typically done in the drilling of directional wells.
[0023] Once target well T has been drilled or concurrent therewith,
a capture well C is initiated on plot 14 at point B (FIG. 2A).
Capture well C is drilled downward through vertical section V.sub.b
and is cased with conductor string 20B and surface casing string
21B at the appropriate times. Again, using known and available
technology, capture well C is then steered through "sail angle"
zone S.sub.b and horizontal section H until it intersects target
well T. There are several systems available for the accurate
drilling and positioning one well bore in relation to a second
wellbore; i.e. methods for drilling (a) substantially parallel
wellbores for steam-assisted gravity drainage wells, (b) offset
wells to intersect and kill blowouts or fires in adjacent wells;
(c) etc..
[0024] Such technology and services are commercially available from
a variety of contractors; e.g. Vector Magnetics Inc., Ithaca N.Y.;
Gyrodata Corp., Houston, Tex.. For example, a sonde(s) 25 (FIG.
2A), e.g. magnetic, acoustic, etc., may be lowered into target well
T which can be sensed when properly directing the drilling of
capture well C into intersection with target well T. Again, capture
well C can be cased with one or more intermediate strings 22B, 23B,
as needed during the drilling of well C.
[0025] Once wells T and C intersect, sonde(s) 25 are removed and
the capture well C is cleaned out all the way to casing shoe 24A at
the end of intermediate casing string 23A. The wellbore is now
complete between points A and B. The wellbore, including horizontal
section and ghost hole G, is then preferably filled with a
completion fluid, e.g. gel-type drilling mud, to aid in running a
liner 30 between intermediate casing strings 23A and 23B. Liner 30
is installed through capture well C using known techniques which
are routinely used for casing horizontal wellbores.
[0026] The liner 30 is lowered through intermediate casing string
23B in capture well C, across horizontal section H and into
intermediate casing string 23A in target well T. Casing 30 is of
sufficient length to span between casing shoes 24A and 24B and
extend for a short distance into both of the respective
intermediate casing strings. Depending on the particular
application, liner 30 may range from about 3000 feet or less to
about 7000 feet or more. Preferably, liner 30 is then cemented in
place by using standard well cementing procedures.
[0027] If line 10 is to be used to transport fluids (e.g. gas or
liquid) between points A and B, it is now ready for operation. The
fluids will flow through in either direction through the completed,
sealed pipeline comprised of intermediate casing string 23A, liner
30, and intermediate casing string 23B. If line 10 is comprised of
more than one span, the upper ends of adjacent capture wells C and
target well T will be manifolded together at the surface with an
appropriate connection 40 (FIG. 3).
[0028] That is, both a target well T of one span of line 10 and a
capture well C for an adjacent span of line 10 are drilled on the
same plot 14. This can be done by separate drilling rigs or it can
be done merely moving the same drilling rig over on plot 14 after a
first span is completed. The surface ends of wells T and C will be
spaced a short distance Z (e.g. about 20 feet or so) from each
other within the small plot 14 (e.g. .+-.2 acres). Also, plots 14
may also include pump or compressor stations, treatment stations,
etc., which are normally associated with fluid pipelines.
[0029] If transmission line 10 is to be used for power, data, or
communication lines, a power or data transmission cable (not shown)
would be extended through the completed wellbore (i.e. intermediate
casing 23A, liner 30, and intermediate casing 23B) between points A
and B. This could be done by attaching the cable or a pull line to
a "pig" (i.e. piston) and then forcing the pig from point A to
point B by pumping fluid behind the pig such as is done in
"pigging" operations used in cleaning the pipelines. Once the pig
arrived at point B, the cable can then be "spliced" to a span of
cable in an adjacent wellbore similarly explained above in relation
to FIG. 3.
[0030] It can be seen that since the majority of transmission line
10 is "buried" at a significant depth (e.g. about 500 feet or
greater), the only effective surface exposure of transmission line
10 is within the spaced plots 14. Since each plot 14 is of small
surface area (e.g. .+-.2 acres) and since each plot is spaced from
the other by a significant distance (e.g. up to 7000 feet or more),
security enclosures can easily be provided for each plot and each
plot can be monitored and/or patrolled which greatly increases the
safety and security of the overall transmission line 10.
* * * * *