U.S. patent application number 12/923682 was filed with the patent office on 2011-04-07 for jet-drilling and completion process.
This patent application is currently assigned to IOR Canada Ltd.. Invention is credited to Conrad Ayasse.
Application Number | 20110079397 12/923682 |
Document ID | / |
Family ID | 43822305 |
Filed Date | 2011-04-07 |
United States Patent
Application |
20110079397 |
Kind Code |
A1 |
Ayasse; Conrad |
April 7, 2011 |
Jet-drilling and completion process
Abstract
A method of drilling a slim hole and inserting a slotted liner
into such hole drilled in an underground reservoir using
jet-drilling. The method enables jet-drilling to be effective in
unconsolidated subterranean formations, such as some petroleum
reservoirs. The method enables fluid injection or production to be
undertaken on individual jet-drilled holes or on groups of holes
drilled laterally at different vertical intervals in a vertical
well within an underground formation.
Inventors: |
Ayasse; Conrad; (Calgary,
CA) |
Assignee: |
IOR Canada Ltd.
Calgary
CA
|
Family ID: |
43822305 |
Appl. No.: |
12/923682 |
Filed: |
October 4, 2010 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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61272547 |
Oct 5, 2009 |
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Current U.S.
Class: |
166/369 ;
175/67 |
Current CPC
Class: |
E21B 7/18 20130101; E21B
41/0035 20130101 |
Class at
Publication: |
166/369 ;
175/67 |
International
Class: |
E21B 43/00 20060101
E21B043/00; E21B 7/18 20060101 E21B007/18 |
Claims
1. A method of creating lateral boreholes extending perpendicularly
outwardly from a well bore, comprising the steps of: placing a shoe
comprising a 90 degree curved member having an inner arcuate curved
passage, to which at one end is affixed coiled tubing, against a
side wall of said well bore; inserting a drilling bit into said
coiled tubing, and thereby deflecting said drilling bit via said
shoe against said side wall of said well bore; operating said
drilling bit to drill through said side wall in said well bore, and
thereafter removing said drilling bit; directing a jet drill member
and attached perforated liner member, in which is located a jetting
fluid feed line to said jet drill member, through said coiled
tubing; and supplying a fluid under pressure to said jet drill
member to drill a lateral borehole extending perpendicularly
outwardly from said well bore.
2. The method as claimed in claim 1 further comprising the step of
detaching said jetting fluid feed line from said jet drill member
and removing said jetting fluid feed line from said lateral
borehole.
3. The method as claimed in claim 1 further comprising the step,
after the step of supplying fluid under pressure to said jet drill
member, of severing said coiled tubing at said side wall of said
well bore.
4. The method as claimed in claim 1, further comprising the steps,
after the step of supplying fluid under pressure to said jet drill
member and after the step of detaching said jetting fluid feed line
from said jet drill member and removing said jetting fluid feed
line from the lateral borehole, of severing said coiled tubing at
said side wall of said well bore.
5. A method of creating at least one lateral borehole extending
perpendicularly outwardly from a pre-drilled vertical well bore
drilled in an underground formation, comprising the steps of:
attaching coil tubing to one end of a 90 degree curved member, said
curved member having an inner arcuate curved passage, attaching an
opposite end of said curved member against a side wall of said
vertical well bore; inserting a drilling bit into said coiled
tubing and into said curved member, and deflecting said drilling
bit via said arcuate curved passage against said side wall of said
well bore; operating said drilling bit to drill through said side
wall in said vertical well bore, and thereafter removing said
drilling bit from said curved member and said well bore; attaching
a jet drill apparatus to a perforated liner member; locating a
jetting fluid feed line co-axially within said perforated liner
member, and coupling said fluid feed line to said jet drill
apparatus so that said jet drill apparatus is in fluid
communication therewith; directing said jet drill apparatus and
attached perforated liner member, in which said jetting fluid feed
line is co-axially located, through said coiled tubing and said
curved member; and supplying a fluid under pressure to said jet
drill apparatus via said jetting fluid feed line and drilling a
lateral borehole extending perpendicularly outwardly from said
vertical well bore.
6. The method as claimed in claim 5 further comprising the step of
detaching said jetting fluid feed line from said jet drill member
and removing said jetting fluid feed line from said lateral
borehole.
7. The method as claimed in claim 5 further comprising the step,
after the step of supplying fluid under pressure to said jet drill
member, of severing said coiled tubing at said side wall of said
well bore.
8. The method as claimed in claim 5, further comprising the steps,
after the step of supplying fluid under pressure to said jet drill
member and after the step of detaching said jetting fluid feed line
from said jet drill member and removing said jetting fluid feed
line from the lateral borehole, of severing said coiled tubing at
said side wall of said well bore.
9. A method of creating at least one lateral borehole extending
perpendicularly outwardly from a pre-drilled vertical well bore
drilled in an underground formation, comprising the steps of:
attaching coil tubing to one end of a 90 degree curved member
having an inner arcuate curved passage, attaching an opposite end
of said curved member against a side wall of said vertical well
bore; inserting a drilling bit into said coiled tubing and into
said curved member, and deflecting said drilling bit via said
arcuate curved passage against said side wall of said well bore;
operating said drilling bit to drill through said side wall in said
vertical well bore, and thereafter removing said drilling bit from
said curved member and said well bore; coupling a jet drill
apparatus to a jetting fluid feed line so as to be in fluid
communication therewith; locating said jetting fluid feed line
co-axially within a perforated liner member, and attaching said
perforated liner member to said jet drill apparatus or said jetting
fluid line so that said perforated liner member moves with said jet
drill jet drill apparatus; and directing said jet drill apparatus
and said perforated liner member in which said jetting fluid feed
line is co-axially located, through said coiled tubing and said
curved member; and supplying a fluid under pressure to said jet
drill apparatus via said jetting fluid feed line and drilling a
lateral borehole extending perpendicularly outwardly from said
vertical well bore.
10. The method as claimed in claim 9 further comprising the step of
detaching said jetting fluid feed line from said jet drill
apparatus and removing said jetting fluid feed line from said
lateral borehole.
11. The method as claimed in claim 10 further comprising the step,
after the step of supplying fluid under pressure to said jet drill
apparatus, of severing said coiled tubing at said side wall of said
well bore.
12. The method as claimed in claim 10, further comprising the
steps, after the step of supplying fluid under pressure to said jet
drill member and after the step of detaching said jetting fluid
feed line from said jet drill apparatus and removing said jetting
fluid feed line from the lateral borehole, of severing said coiled
tubing at said side wall of said well bore.
13. A method of recovering liquid hydrocarbons from an underground
formation, comprising the steps of: (i) creating a vertical well;
(ii) creating lateral boreholes extending perpendicularly outwardly
from said vertical well by: (a) placing a shoe comprising a 90
degree curved member having an inner arcuate curved passage, to
which at one end is affixed coiled tubing, against a side wall of
said well bore; (b) inserting a drilling bit into said coiled
tubing, and thereby deflecting said drilling bit via said shoe
against said side wall of said well bore; (c) operating said
drilling bit to drill through said side wall in said well bore, and
thereafter removing said drilling bit; (d) directing a jet drill
member and attached perforated liner member, in which is located a
jetting fluid feed line to said jet drill member, through said
coiled tubing; (e) supplying a fluid under pressure to said jet
drill member to drill a lateral borehole extending perpendicularly
outwardly from said well bore; and (f) repeating the process to
create a number of boreholes extending radially and horizontally
outwardly from said vertical well; (iii) allowing hydrocarbons to
flow into said lateral boreholes; and (iv) pumping said
hydrocarbons to surface.
Description
RELATED APPLICATIONS
[0001] Priority is claimed from U.S. Provisional Application
61/272,547 filed Oct. 5, 2009 entitled "Jet-Drilling And Completion
Process" listing Conrad Ayasse as inventor. Such provisional
application is incorporated herein by reference.
FIELD OF THE INVENTION
[0002] The invention relates to a method for recovering
hydrocarbons from a well bore, and more particularly to a method
for drilling lateral recovery bores in a vertical well using
jet-drilling.
BACKGROUND
[0003] Jet-drilling is an established rock drilling method. Lateral
holes ranging in diameter from about 0.5 inches to 3 inches or more
are drilled out laterally from a vertical wellbore and can extend
horizontally for up to 100 meters or more into the formation. For
petroleum recovery, these holes provide reservoir fluid flow
channels and can increase petroleum recovery rates from a reservoir
or they can be used to improve fluid infectivity into a formation
as in a water disposal well. Jet-drilled holes are left as `open
holes` which means that there is no liner placed in the hole.
[0004] Typically a coiled tubing from the surface is attached to a
"shoe" and the shoe is located at the desired side-entry point in a
vertical well. The shoe is a curved opening that abuts the well
wall and contains a curved opening. A steel-drilling bit is lowered
through the coiled tubing from the surface and is sufficiently
flexible the make the sharp 90.degree. bend at the shoe to reach
the well wall. The drilling bit is activated from the surface and
drills out a hole in the steel well wall and through any outer
cement that may be placed outside the wall. After the drilling bit
is withdrawn, a jet-drilling nozzle is lowered inside the coiled
tubing. The nozzle is attached to a slim flexible jet-fluid
delivery tubing conduit that can carry a high-pressure jet-drilling
liquid from the surface to the nozzle. The Jet-drilling fluid can
be formation water which is delivered to the nozzle at high
pressure in the range of up to approximately 15,000 psi. The fluid
exits the nozzle at the tip and blasts a hole in the rock ahead of
the nozzle, while also exiting backwards from the side of the
nozzle to provide a forward propulsion force. This latter force
pulls the entire assembly forward as the hole advances in the rock.
It also washes drilling debris back to the horizontal well, where
it falls to the bottom of the vertical wellbore. In some
operations, the shoe can be quickly rotated and/or lowered to
enable horizontal holes to be drilled horizontally in any desired
direction and at low cost relative to traditional large-diameter
horizontal well drilling.
[0005] In a consolidated rock the jet-drilled holes are stable and
permanent. However, in an un-consolidated rock the hole can
collapse and be of little use, so a way is needed to stabilize
jet-drilled holes in un-consolidated rock formations.
SUMMARY OF THE INVENTION
[0006] The present invention solves the problem of borehole
collapse in unconsolidated formations.
[0007] The method of the present invention provides for Jet-drilled
boreholes in un-consolidated subterranean formation which are
stabilized and remain permanently open by using the forward drive
energy of a jet nozzle to drag a perforated liner into the borehole
while the borehole is being drilled.
[0008] At the completion of the jet drilling the jet-drilling
nozzle and jet-fluid delivery tubing can be left in the borehole,
or the tubing can be detached from the nozzle and recovered at the
surface. The perforated liner may extend to the surface or be
severed inside the vertical well. The liner perforation dimensions
are chosen to enable exclusion of formation solids while permitting
entry of formation fluids.
[0009] Accordingly, in a first broad aspect of the method of the
present invention for creating a borehole extending perpendicularly
outwardly from a well bore, such method comprises the steps of:
[0010] placing a shoe comprising a 90 degree curved member having
an inner arcuate curved passage, to which a one end is affixed
coiled tubing, against a side wall of said well bore;
[0011] inserting a drilling bit into said coiled tubing, and
thereby deflecting said drilling bit via said shoe against said
side wall of said well bore;
[0012] operating said drilling bit to drill through said side wall
in said well bore, and thereafter removing said drilling bit;
[0013] directing a jet drill member and attached perforated liner
member, in which is located a jetting fluid feed line to said jet
drill member, through said coiled tubing; and
[0014] supplying a fluid under pressure to said jet drill member to
drill a lateral borehole extending perpendicularly outwardly from
said well bore.
[0015] In a further broad aspect of the method of the present
invention of creating at least one lateral borehole extending
perpendicularly outwardly from a pre-drilled vertical well bore
drilled in an underground formation, such method comprises the
steps of:
[0016] attaching coil tubing to one end of a 90 degree curved
member, said curved member having an inner arcuate curved
passage,
[0017] attaching an opposite end of said curved member against a
side wall of said vertical well bore;
[0018] inserting a drilling bit into said coiled tubing and into
said curved member, and deflecting said drilling bit via said
arcuate curved passage against said side wall of said well
bore;
[0019] operating said drilling bit to drill through said side wall
in said vertical well bore, and thereafter removing said drilling
bit from said curved member and said well bore;
[0020] attaching a jet drill apparatus to a perforated liner
member;
[0021] locating a jetting fluid feed line co-axially within said
perforated liner member, and coupling said fluid feed line to said
jet drill apparatus so that said jet drill apparatus is in fluid
communication therewith;
[0022] directing said jet drill apparatus and attached perforated
liner member, in which said jetting fluid feed line is co-axially
located, through said coiled tubing and said curved member; and
[0023] supplying a fluid under pressure to said jet drill apparatus
via said jetting fluid feed line and drilling a lateral borehole
extending perpendicularly outwardly from said vertical well
bore.
[0024] In yet a still further broad aspect of the method of the
present invention of creating at least one lateral borehole
extending perpendicularly outwardly from a pre-drilled vertical
well bore drilled in an underground formation, such method
comprises the steps of:
[0025] attaching coil tubing to one end of a 90 degree curved
member having an inner arcuate curved passage,
[0026] attaching an opposite end of said curved member against a
side wall of said vertical well bore;
[0027] inserting a drilling bit into said coiled tubing and into
said curved member, and deflecting said drilling bit via said
arcuate curved passage against said side wall of said well
bore;
[0028] operating said drilling bit to drill through said side wall
in said vertical well bore, and thereafter removing said drilling
bit from said curved member and said well bore;
[0029] coupling a jet drill apparatus to a jetting fluid feed line
so as to be in fluid communication with each other;
[0030] locating said jetting fluid feed line co-axially within a
perforated liner member, and attaching said perforated liner member
to said jet drill apparatus or said jetting fluid line so that said
perforated liner member moves with said jet drill jet drill
apparatus; and
[0031] directing said jet drill apparatus and said perforated liner
member in which said jetting fluid feed line is co-axially located,
through said coiled tubing and said curved member; and
[0032] supplying a fluid under pressure to said jet drill apparatus
via said jetting fluid feed line and drilling a lateral borehole
extending perpendicularly outwardly from said vertical well
bore.
[0033] In a refinement of each of the above methods, the method
further comprising the step of detaching said jetting fluid feed
line from said jet drill apparatus and removing said jetting fluid
feed line from said lateral borehole.
[0034] In an alternative refinement of each of the above methods,
the method further comprises the step, after the step of supplying
fluid under pressure to said jet drill member, of severing said
coiled tubing at said side wall of said well bore.
[0035] In a combination of refinements, the method of the present
invention further comprises the steps, after the step of supplying
fluid under pressure to said jet drill member and after the step of
detaching said jetting fluid feed line from said jet drill member
and removing said jetting fluid feed line from the lateral
borehole, of severing said coiled tubing at said side wall of said
well bore.
[0036] Finally, in a further broad aspect of the invention, such
invention comprises a method of recovering liquid hydrocarbons from
an underground formation, comprising the steps of:
[0037] (i) creating a vertical well;
[0038] (ii) creating lateral boreholes extending perpendicularly
outwardly from said vertical well by: [0039] (a) placing a shoe
comprising a 90 degree curved member having an inner arcuate curved
passage, to which at one end is affixed coiled tubing, against a
side wall of said well bore; [0040] (b) inserting a drilling bit
into said coiled tubing, and thereby deflecting said drilling bit
via said shoe against said side wall of said well bore; [0041] (c)
operating said drilling bit to drill through said side wall in said
well bore, and thereafter removing said drilling bit; [0042] (d)
directing a jet drill member and attached perforated liner member,
in which is located a jetting fluid feed line to said jet drill
member, through said coiled tubing; and [0043] (e) supplying a
fluid under pressure to said jet drill member to drill a lateral
borehole extending perpendicularly outwardly from said well
bore;
[0044] (iii) allowing hydrocarbons to flow into said lateral
boreholes; and
[0045] (iv) pumping said hydrocarbons to surface.
BRIEF DESCRIPTION OF THE DRAWINGS
[0046] Further advantages and permutations will appear from the
following detailed description of various non-limiting embodiments
of the invention, taken together with the accompanying drawings, in
which:
[0047] FIG. 1 is a schematic view of a jet drilling apparatus being
used in the method of the prior art, with a jet nozzle being used
to drill toward the left-hand side of the page;
[0048] FIG. 2 is a schematic view of a jet-drilling apparatus being
used in the method of the present invention, showing the manner of
inserting a perforated liner into a horizontal well bore utilizing
a jet nozzle, with a jet nozzle being used to drill toward the
left-hand side of the page;
[0049] FIG. 3 is a schematic view of the completion of the vertical
well when the perforated liners are terminated at the vertical
well;
[0050] FIG. 4 is a schematic view of a plurality of
horizontally-drilled holes in a vertical well, each of said
horizontal bores having a perforated liner; and
[0051] FIG. 5 is a detail view of a single horizontal well of FIG.
4 which has been drilled by the method of the present invention,
showing a perforated liner being introduced to the horizontal
wellbore during the jet-drilling process.
DESCRIPTION OF THE PREFERRED EMBODIMENT
[0052] Similar items in each of FIGS. 1-5 with identical function
are identified with the same reference number.
[0053] FIG. 1 shows a jet-drilling nozzle 1 being used in the
jet-drilling method of the prior art, typically reserved for
consolidated formations, having a jet-fluid delivery tube 2, which
is caused to create a hole 10 in a formation 20.
[0054] Interstitial space 3 within hole 10 conducts fluids to
surface (not shown) when the hole 10 is stable, such as for
consolidated rock, but which hole 10 will become blocked with the
collapse of the hole when rock in the formation 20 is
unconsolidated.
[0055] In operation, jetting fluid 4 exits the front of the nozzle
1 and blast the rock in formation 20 to create an open hole 10.
Jetting fluid 5 which exits the nozzle 1 from the side of nozzle 1
creates a forward drive force that pulls nozzle 1 and the jet-fluid
delivery tube 2 forward, while simultaneously flushing the drilling
debris back along open interstitial space 3 to a vertical well 12
where it can fall to a sump.
[0056] FIG. 2 shows the method of the present invention for
drilling a bore 10 in a formation using a jet-drilling nozzle 1 and
jet-fluid delivery tubing 2, while simultaneously inserting a
perforated well liner 6 into the resulting bore 10 in formation 20.
Perforated liner 6 is attached directly or indirectly to jet-nozzle
1. Again, in operation, jetting fluid 4 exits the front of the
nozzle 1 and blasts rock in formation 20 to create an open hole 10.
Jetting fluid 5 which exits the nozzle 1 from the side of nozzle 1
creates a forward drive force that pulls nozzle 1 and the jet-fluid
delivery tube as well as the perforated liner 6 attached to the
jet-nozzle 1 forward, while simultaneously flushing the drilling
debris back along open interstitial space 3 to a vertical well 12
where it can fall to a sump.
[0057] Perforated liner 6 is of a design that will permit the entry
of fluids, such as liquid hydrocarbons, but not solids. Such design
may comprise a series of small apertures or perforations within
perforated liner 6, or a combination of apertures in combination
with screens (not shown). However, other designs of perforated
liners 6 may be used as are known to persons of skill in the art. A
fluid flow space 7 inside the perforated liner 6, for delivering
produced fluids to the vertical well 12 and thence to the surface,
is provided. This fluid flow space 7 is enlarged upon the
(optional) detachment of jet-fluid delivery tubing 2 from jet
nozzle 1 and removal of the jet-fluid delivery tubing 2 to surface
at the completion of the borehole drilling and liner insertion
process.
[0058] Referring to FIG. 2 and FIG. 3, FIG. 3 depicts a completed
vertical well 12, having a series of individual separate left-side
lateral bores 10 each with an associated perforated liner 6 and a
similar series of individual separate right-side lateral bores 10,
each likewise having an associated perforated liner 6. Each of
lateral bores 10 and the respective associated perforated liners 6
terminate at the vertical well 12. In order for this to have
occurred, after the step of terminating the supply of the jet fluid
4,5 to the jet drilling nozzle 1 upon each lateral borehole 10
being drilled, the jet drill nozzle 1 is decoupled from the jet
fluid delivery tubing 2 via known methods such as unscrewing, or
decoupling via a "on-off" tool (not shown), and the jet fluid
delivery tubing 2 is removed from the borehole 10, leaving the
perforated liner 6 remaining in borehole 10. Packers 30, 32, and 34
isolate various zones A, B, C and D respectively in vertical well
bore 12. Hydrocarbons flowing into boreholes 10 are collected in
respective isolated zones A, B, C, and D of vertical wellbore 12.
Feeding tubes B', C', and D' deliver fluids to surface from
respective zones B, C, and D.
[0059] Perforated liner 6 will be of sufficient material strength
and thickness to resist collapse of unconsolidated rock in a
borehole 10. For such reason liner 6 will typically be of a hard,
but somewhat flexible material, such as Kevlar, to permit bending
from the vertical to the horizontal. In some cases steel may need
to be used in instances where it is desired that fluid flow into
borehole 10 via such liner 6 for subsequent collection,
particularly if borehole diameter is small and liner 6 must
accordingly be as thin as possible to preserve borehole diameter
and at the same time have numerous and sufficiently-sized
perforations to allow ingress of fluid. However the perforations
are of insufficient size and number to weaken the liner 6 to a
sufficient extent that liner 6 has insufficient strength to
substantially resist collapse due weight of to unconsolidated rock
in formation 20.
[0060] FIG. 4 is a view of a vertical well 12 similar to the
vertical well 12 of FIG. 3, but without the use of packers 30, 32,
or 34, having similar lateral boreholes 10. Jet drilled boreholes
10 within vertical well 12, permit the separate injection of fluids
into formation 20 via coil tubing 40, or alternatively permit the
flow of fluids from the formation 20 through perforated liners in
boreholes 6, through curved arcuate "shoes" 42, and thereafter via
coil tubing 40 to surface.
[0061] FIG. 5 is a detailed view of a borehole 10 shown in FIG. 4
at the time of drilling is the borehole 10 of FIG. 4, and is
perhaps best illustrative of the method of the present invention
for creating lateral boreholes 10 extending perpendicularly
outwardly from a well bore 12.
[0062] In this regard FIG. 5 shows a vertical well 12 drilled in
subterreanean formation 20. Shoe 42, having coil tubing 42 attached
thereto has been placed against the steel vertical well side wall
12' of vertical well 12 at the desired entry point during the
initial drilling of aperture 16 in steel vertical well side wall
12' (as described below). Perforated liner 6 is coupled to an
non-perforated liner segment 50, which may extend to surface within
coil tubing 40, to collect liquid hydrocarbons which may have
drained into borehole 10.
Example 1
[0063] The method of the invention in creating a borehole in a
non-consolidated rock formation 20 will now be described, with
reference to FIG. 5.
[0064] Firstly, in order to ready the vertical well 12 for the
borehole drilling operation shown in FIG. 5 an initial first series
of steps of creating an aperture 16 in the side of a vertical well
12 is carried out, and is hereinafter described as follows.
[0065] A shoe 42, which is affixed at the end of a coiled tubing
40, is placed against the steel vertical well side wall 12' of
vertical well 12 at the desired entry point. Shoe 42 is a steel
device having a 90 degree curved inner arcuate passage 43, as shown
in FIG. 5. A drilling bit (not shown), typically of steel or
titanium-coated steel, is lowered from the surface into the coiled
tubing 40 and is deflected at the shoe 42 from the vertical to the
horizontal direction. The steel drilling bit drills out an aperture
16 through the vertical well steel sidewall 12' and through any
cement that may have been emplaced outside vertical well 12, and
reaches into the rock formation 20. The steel drilling bit is
thereafter retracted, and the assembly described in FIG. 1, namely
a jet nozzle 1 with a jet fluid delivery tube 2, and an attached
perforated liner 6, is lowered into the coiled tubing 40 for the
purpose of jet-drilling a horizontal borehole 10 in formation. 20,
extending perpendicularly outwardly from vertical well 12. The
jet-drilling assembly comprising high-pressure jet nozzle 1 with an
attached jetting liquid delivery tubing 2 permits the nozzle 1 to
spray liquid 4, 5 in two main directions: ahead with liquid spray 4
to pulverize rock and create a borehole 10, as well as direct
liquid spray 5 sideways and backwards to provide a driving force
that moves the jet nozzle 1, jetting fluid delivery tubing 2, and
attached perforated liner 6 forward and into borehole 10, while
simultaneously flushing drilling debris back towards the vertical
well 12 along coiled tubing 40, and to surface or to a sump in the
vertical well. Drilling pressures with respect to supplied fluid
4,5 may be up to 15,000 psi or even higher.
[0066] In the operation of this invention, perforated liner 6 is
attached at or nearby the jet nozzle 1 as shown in FIGS. 2 and 5.
Liner 6 and jetting-liquid delivery tubing 2 which is inside the
liner 6 are fed in at the surface as the assembly of nozzle 1,
jetting-liquid feed line 2 and perforated liner 6 simultaneously
advance in the borehole 10 while jet-drilling.
[0067] When the jet-drilling is completed, there are several
choices.
[0068] Firstly, the jet drilling assembly comprising the jet nozzle
1, jetting fluid delivery tubing 2, and perforated liner 6 can be
left in the borehole 10, and the liner 4 and coiled tubing 40 can
be put on production at the surface. Any borehole hole collapse
will be limited by the perforated liner and fluids which enter the
liner 6 and flow to the surface or to a pump placed downhole. The
jetting fluid delivery tubing 2 inside liner 6 provides only minor
obstruction to fluid flow in either direction since there will
remain ample open fluid flow area 7 inside the liner 6.
[0069] Alternatively, in a more preferred embodiment, the
jetting-liquid delivery tubing 2 is detached from nozzle 1 as
described above, or alternatively by a break-away device or
procedure such as strong pulling on the delivery tubing 2. This
will leave the liner 6 completely clear, and the shoes 42 can also
be removed. Therefore the invention can be employed for fluid
production from a reservoir 20 or for fluid injection as may occur
in water disposal, and it may be employed in both consolidated rock
or un-consolidated rock. The material of construction for the liner
6 must have sufficient strength to hold back sand from borehole
collapse and sufficient flexibility to make the sharp turn from
vertical to horizontal at the shoe 42. A number of materials are
candidates, such as steel mentioned above, but also perforated
Kevlar tubing, particularly where fluid (such as water) is being
supplied to borehole 10 and not being withdrawn. In order to
maintain maximum strength a favored embodiment for perforation is
small holes of a size appropriate to exclude sand or other grains,
but to permit fluid passage. The methodologies for determining the
maximum perforation size are well known to those skilled in the
art.
[0070] FIG. 3 shows the embodiment wherein the coil tubing 40 and
shoe 42 (see FIG. 5) is severed at the vertical well 12. Fluids
entering the vertical wellbore 12 from boreholes 10a & 10b
admix in the annular space of the vertical well 12 with access to
the surface. These fluids are segregated from others by a packer
30. Fluids entering from holes 10c & 10d are admixed in annular
space B, and can rise to the surface via tubing B' and are
segregated by packers 30 & 32. Fluids entering from boreholes
10e and 10f admix in annular area C, and get to the surface via
tubing C' and are segregated by packers 32 & 34. Finally,
fluids entering vertical well 12 via boreholes 10g and 10h admix in
annular area D, and get to the surface via tubing D', and are
segregated by packer 34 and the bottom of the vertical well 12''.
Therefore segregated fluid flow to and from multiple zones A, B, C,
and D can be achieved, even in un-consolidated or
poorly-consolidated formations. This can be exploited in certain
enhanced oil recovery processes. For example in a gravity-stable
miscible gas flooding project, solvent gas can be injected in an
upper zone and oil produced from a lower zone.
Example 2
[0071] A preferred embodiment for maximizing the oil recovery rate
at low cost is to eliminate the packers 30, 32, & 34 and
tubings B', C' and D' shown in FIG. 3 and let fluids flow into the
wellbore 12 from all boreholes 10a-10f. The mixture can then be
pumped to the surface via a standard production tubing. The
jet-liquid feed line 2 can be pulled out and the perforated liner 6
cut at the intersection of the vertical well bore 12 and borehole
10, or such feed line 2 can be left in place.
Example 3
[0072] In this example, as shown in FIG. 4 and FIG. 5, the shoe 42
and coiled tubing 40 assembly is retained after creation of
aperture 16 and drilling of boreholes 10, and each liner 6 that is
emplaced in the jet-drilled borehole 10 while drilling thereby
retains direct access via coil tubing 40 to the surface. The
jet-liquid feed line 2 can be left in the liner 6 or removed as
described in Example 1. Details of this embodiment are shown in
FIGS. 4 and 5. This embodiment provides the greatest flexibility
because every jet-drilled wellbore 10 is individually accessible
and can have many uses. This configuration eliminates the need for
downhole packers.
[0073] Although the disclosure describes and illustrates preferred
embodiments of the method of the present invention, it is
understood that the invention is not limited to these particular
embodiments. Many variations and modifications will now occur to
those skilled in the art. For a full definition of the invention,
reference is to be made to the appended claims.
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