U.S. patent application number 14/353478 was filed with the patent office on 2015-10-29 for excavating deposits from an underground formation layer.
The applicant listed for this patent is Michael RUGGIER, Hendrik Martinus WENTINCK. Invention is credited to Michael RUGGIER, Hendrik Martinus WENTINCK.
Application Number | 20150308267 14/353478 |
Document ID | / |
Family ID | 44840162 |
Filed Date | 2015-10-29 |
United States Patent
Application |
20150308267 |
Kind Code |
A1 |
WENTINCK; Hendrik Martinus ;
et al. |
October 29, 2015 |
EXCAVATING DEPOSITS FROM AN UNDERGROUND FORMATION LAYER
Abstract
Deposits, such as coal, tar sand, heavy crude oil and/or
minerals are excavated from an underground formation layer (4)
by:--inserting a chain cutter string (11) into a 1st section (8, 9)
and a control cable (12) into a 2nd section (10) of a T-, V-, U-,
or L-shaped channel assembly (8, 9, 10) traversing the layer
(4);--connecting the control cable (12) to the chain cutter string
(11) at a branchpoint (13) of said 1st & 2nd sections (8, 9
& 10); and--pulling the chain cutter string (11) in a
continuous or oscillating manner through the first section (8,9)
while continuously pulling the control cable (12), such that the
chain cutter string (11) carves deposits from the layer (4) and the
control cable (12) optimizes the performance and reduces the risk
of breakage of the chain cutter string (11).
Inventors: |
WENTINCK; Hendrik Martinus;
(Rijswijk, NL) ; RUGGIER; Michael; (Aberdeen,
GB) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
WENTINCK; Hendrik Martinus
RUGGIER; Michael |
Rijswijk
Aberdeen |
|
NL
GB |
|
|
Family ID: |
44840162 |
Appl. No.: |
14/353478 |
Filed: |
October 20, 2011 |
PCT Filed: |
October 20, 2011 |
PCT NO: |
PCT/EP2011/068297 |
371 Date: |
March 26, 2015 |
Current U.S.
Class: |
299/10 |
Current CPC
Class: |
B28D 1/088 20130101;
E21B 43/305 20130101; E21C 29/14 20130101; E21B 43/30 20130101;
E21C 25/54 20130101; E21C 27/04 20130101; E21B 11/06 20130101; E21C
41/16 20130101; E21C 29/145 20130101; E21C 25/56 20130101 |
International
Class: |
E21C 29/14 20060101
E21C029/14; E21B 43/30 20060101 E21B043/30; E21C 41/16 20060101
E21C041/16; E21C 25/56 20060101 E21C025/56; E21C 27/04 20060101
E21C027/04 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 22, 2010 |
EP |
10188575.4 |
Sep 29, 2011 |
EP |
11183234.1 |
Claims
1. A method of excavating deposits from an underground formation
layer, comprising: drilling a well assembly, which penetrates the
underground formation layer at a first, a second and a third
location, which locations are triangularly spaced; drilling from
these locations a channel assembly that traverses the formation
layer and interconnects the locations; inserting a chain cutter
string into a first section of the channel assembly that is located
between the first and second locations; inserting a chain cutter
control cable from the third location into a second section of the
channel assembly; connecting the chain cutter control cable to the
chain cutter string at a branchpoint of the first and second
sections of the channel assembly; pulling the chain cutter string
through the first section of the channel assembly while exerting a
lateral force to the chain cutter string by the chain cutter
control cable such that the chain cutter string is pressed against
the wall of the first section of the channel assembly and is
thereby induced to carve deposits from the underground formation
layer; and flushing carved out deposits through the channel
assembly and the well assembly.
2. The method of claim 1, wherein during an initial or subsequent
moment of execution of the method: the first section of the channel
assembly extends as a substantially straight line between the first
and the second locations; the second section of the channel
assembly extends from the third location to the branchpoint, which
is formed by a midpoint of the first section of the channel
assembly, so that the channel assembly substantially has a T-shape;
and the chain cutter string is pulled through the first section
while the chain cutter string is pressed against the sidewall of
the first section by the chain cutter control cable and is pulled
by the chain cutter control cable towards the third location.
3. The method of claim 1, wherein during an initial or subsequent
moment of execution of the method: the first section of the channel
assembly has a V-shape and has a first leg, which extends from the
first location towards the third location and a second leg, which
extends from the third location towards the second location and the
chain cutter string extends through the first and second legs of
the V-shaped first section of the channel assembly; the chain
cutter control cable is connected to the chain cutter string at the
third location, which location forms the branchpoint of the first
and second sections of the channel assembly; and the chain cutter
string is pulled through the first section.
4. The method of claim 3, wherein the chain cutter control cable is
gradually slackened while the chain cutter string is pulled through
the first section of the channel assembly, thereby controlling the
pressure between the chain cutter string and the sidewall of the
first section.
5. The method of claim 1, wherein the chain cutter string is pulled
sequentially from the first to the second location and from the
second to the first location to mine deposits from the underground
formation layer.
6. The method of claim 1, wherein the chain cutter string is an
endless chain, which carries a series of cutting elements and is
moved in a continuous motion through the first section of the
channel assembly to mine deposits from the underground formation
layer.
7. The method of claim 6, wherein the cutting elements are selected
from the group of mechanical cutters and/or hydraulic jets.
8. The method of claim 1, wherein the method is used to create at
least one high permeability plane in a viscous crude oil or tight
gas containing formation and/or in a formation comprising a flow
barrier, such as a shale layer with a low permeability.
9. The method of claim 1, wherein the method is used to mine
hydrocarbon deposits selected from the group of coal, oil shale,
tar sand and heavy crude from the subsurface formation layer.
10. The method of claim 9, wherein after mining a deposit from a
first triangular section of the subsurface formation layer between
the first, second and third locations an additional wellbore or
well section is drilled such that it penetrates the underground
formation layer at a triangularly spaced fourth location relative
to a pair of the first, second and third locations, and deposits
are mined from a second triangular section between the fourth
location and said pair of the first, second and third
locations.
11. The method of claim 10, wherein after mining a deposit from the
second triangular section of the subsurface formation layer a fifth
wellbore or section is drilled such that it penetrates the
underground formation layer at a fifth triangularly spaced location
relative to the third and fourth locations, and deposits are mined
from a third triangular section between the third, fourth and fifth
locations.
12. The method of claim 11, wherein after mining a deposit from an
n-th triangular section of the subsurface formation layer, wherein
n is a number that is larger than five, a further wellbore or
section is drilled such that it penetrates the underground
formation layer at another triangularly spaced location relative to
a pair of locations located at the outer periphery of the array of
n existing triangular sections, and deposits are mined from said
another triangular section between the n-th and said pair of
locations located at the outer periphery of the array of n existing
triangular sections.
Description
BACKGROUND OF THE INVENTION
[0001] The invention relates to a method for excavating deposits
from an underground formation layer.
[0002] Such a method is known from U.S. Pat. Nos. 2,796,129;
4,232,904; 4,442,896; 5,033,795 and 7,647,967.
[0003] In the methods known from these prior art references a chain
cutter string is pulled through a channel in an underground
formation layer, such as a coal seam, and the chain cutter is
simultaneously moved such that the cutters scrape material from the
wall of the channel.
[0004] In the method known from U.S. Pat. No. 4,232,904 a U-shaped
tunnel is bored into a substantially horizontal coal seam in a hill
such that an both an entrance and an exit hole are laterally
displaced along the front surface of the hill. A chain drive having
rotating cutters spaced therealong is then drawn through the tunnel
by a motor located outside the tunnel. The motor provides
continuous outward pressure on the chain, causing the blades to
rotate, thereby cutting the coal, thereby cutting the coal from the
inside back wall of the tunnel. Buckets mounted along the chain
remove the coal from the tunnel.
[0005] In the method known from U.S. Pat. No. 4,442,896 a U-shaped
channel is drilled in a substantially vertical plane, whereupon the
chain cutter string is inserted into the U-shaped channel and
induced to make an oscillating movement while a tension force is
applied thereto, so that the chain cutter string scrapes material
from the upper wall of the U-shaped channel and thereby cuts a
substantially vertical cavity in the formation.
[0006] In the method known from U.S. Pat. No. 5,033,795 a
substantially horizontal U-shaped trench is digged in a formation
adjacent to a horizontal mineral deposit seam and a continuous
chain saw string is rotated between guide wheels mounted on a pair
caterpillar trucks that slowly move along the parallel legs of the
U-shaped trench, such that the chain cutter string cuts a
substantially horizontal cavity in the mineral deposit seam.
[0007] In the method known from U.S. Pat. No. 7,647,967 hydrocarbon
production from a subsurface oil reservoir is enhanced by inserting
a flexible linear cutting device, such as a segmented diamond wire
saw, into a pair of intersecting wellbores, to form a fissure
beginning a the intersection of the wellbores and extending along
the lower part of the length of the wellbores, which fissure
intersects with natural or previously formed fractures to enhance
the permeability and productivity of the subsurface oil
reservoir.
[0008] In the method known from U.S. Pat. No. 2,796,129 a
chaincutter assembly is inserted into a V-shaped horizontal tunnel
assembly arranged between three tri-angularly spaced vertical wells
and oil sand from a formation between these wells is mined by
pulling the chaincutter assembly up and down through the V-shaped
tunnel assembly until the chaincutter assembly forms a straight
line between two of the three wells. In case the chaincutter
assembly gets stuck in rocks or other blockages in the formation
then the only option to retrieve the chaincutter assembly is to
break it up and pull the broken pieces out of the wells.
[0009] A disadvantage of the known cutting methods is that there is
no provision to control the lateral pressure of the chain cutter
string against the formation or prevent it from sticking so there
is a risk of damage and breaking of the cutter chain due to an
overload.
[0010] Therefore there is a need to provide an improved method for
mining deposits from an underground layer wherein the lateral
pressure between the chain cutter string and the formation can be
controlled and there is a provision to release the chain when it
gets stuck.
SUMMARY OF THE INVENTION
[0011] In accordance with the invention there is provided a method
of excavating deposits from an underground formation layer,
comprising: [0012] drilling a first, second and third well, which
penetrate the underground formation layer at three triangularly
spaced locations; [0013] drilling from these locations a channel
assembly that traverses the formation layer and interconnects each
of the wells; [0014] inserting a chain cutter string into a first
section of the channel assembly that is located between the first
and second wells; [0015] inserting a chain cutter control cable
from the third well into a second section of the channel assembly;
[0016] connecting the chain cutter control cable to the chain
cutter string at a branchpoint of the first and second sections of
the channel assembly; [0017] pulling the chain cutter string
through the first section of the channel assembly while exerting a
lateral force to the chain cutter string by the chain cutter
control cable such that the chain cutter string is pressed against
the wall of the first section of the channel assembly and is
thereby induced to carve deposits from of the underground formation
layer; and [0018] flushing carved out deposits through the channel
assembly and at least one of the wells.
[0019] Optionally, during an initial or subsequent moment of
execution of the method: [0020] the first section of the channel
assembly extends as a substantially straight line between the first
well and the second well; [0021] the second section of the channel
assembly extends from the third well to the branchpoint, which is
formed by a midpoint of the first section of the channel assembly,
so that the channel assembly substantially has a T-shape; and
[0022] the chain cutter string is pulled through the first section
while the chain cutter string is pressed against the sidewall of
the first section by the chain cutter control cable and is pulled
by the chain cutter control cable towards the third well.
[0023] Alternatively or subsequently, during an initial or
subsequent moment of execution of the method: [0024] the first
section of the channel assembly has a V-shape and has a first leg,
which extends from the first well towards the third well and a
second leg, which extends from the third well towards the second
well and the chain cutter string extends through the first and
second legs of the V-shaped first section of the channel assembly;
[0025] the chain cutter control cable is connected to the chain
cutter string at the location where the third well penetrates the
formation layer, which location forms the branchpoint of the first
and second sections of the channel assembly; and [0026] the chain
cutter string is pulled through the first section.
[0027] In the latter case the chain cutter control cable is
gradually slackened while the chain cutter string is pulled through
the first section of the channel assembly, thereby controlling the
pressure between the chain cutter string and the sidewall of the
first section.
[0028] The chain cutter string may be pulled sequentially from the
first to the second well and from the second to the first well to
mine deposits from the underground formation layer.
[0029] The chain cutter string is an endless chain, which carries a
series of cutting elements and is moved in a continuous motion
through the first section of the channel assembly and the first and
second wells to mine deposits from the underground formation layer
and the cutting elements may be selected from the group of
mechanical cutters and/or hydraulic jets.
[0030] The method according to the invention may be used to create
at least plane with a high permeability in a viscous crude oil
containing formation in order to Enhance Oil Recovery (EOR)
therefrom and/or to mine hydrocarbon deposits selected from the
group of coal, oil shale, tar sand and heavy crude from the
subsurface formation layer and/or for other purposes.
[0031] These and other features, embodiments and advantages of the
method and according to the invention are described in the
accompanying claims, abstract and the following detailed
description of non-limiting embodiments depicted in the
accompanying drawings, in which description reference numerals are
used which refer to corresponding reference numerals that are
depicted in the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0032] FIG. 1 is a schematic three-dimensional view of a chain
cutter assembly that is operated in accordance with the method
according to the present invention;
[0033] FIG. 2 is a top view of a chain cutter assembly, which moves
in a single direction through a first section of a subsurface
channel assembly;
[0034] FIG. 3 is a top view of a chain cutter assembly, which makes
an oscillating movement to excavate rock from the wall of a first
section of a subsurface channel assembly;
[0035] FIG. 4 is a schematic vertical sectional view of an assembly
of two wells, which define three triangularly spaced locations
between which a triangularly shaped cavity is carved using the
method according to the invention;
[0036] FIG. 5 is a schematic vertical sectional view of a
multilateral well assembly, which defines three triangularly spaced
locations between which a triangularly shaped cavity is carved
using the method according to the invention;
[0037] FIG. 6 is a schematic vertical sectional view of another
multilateral well assembly, which defines three triangularly spaced
locations between which a triangularly shaped cavity is carved
using the method according to the invention; and
[0038] FIG. 7 is a schematic vertical sectional view of a H-shaped
multilateral well assembly, which defines four rectangularly spaced
locations between which a rectangularly shaped cavity is carved
using the method according to the invention.
DETAILED DESCRIPTION OF THE DEPICTED EMBODIMENTS
[0039] FIG. 1 shows a triangular well assembly comprising first,
second and third well 1,2 and 3, which penetrate a underground
formation layer 4, such as a mineral, coal, tar sand or heavy oil
containing seam, at three triangularly spaced locations 5,6 and
7.
[0040] A channel assembly 8,9 and 10 traverses the formation layer
4 and interconnects each of the wells 1,2 and 3 at these locations
5,6 and 7.
[0041] A chain cutter string 11 is inserted via the first and
second wells 1 and 2 into a first section 8, 9 of the channel
assembly that extends between the first and second wells 1 and
2.
[0042] A chain cutter control cable 12 extends from the third well
3 into a second section 10 of the channel assembly and is connected
to the chain cutter string 11 at a branchpoint 13 of the first and
second sections 8,9 and 10 of the channel assembly.
[0043] During normal use the chain cutter string 1 may be moved in
a continuous or oscillating mode through the first section 8,9 of
the channel assembly while exerting a lateral force to the chain
cutter string 11 by the chain cutter control cable 12 such that the
chain cutter string 11 is pressed against the wall of the first
section 8,9 of the channel assembly and is thereby induced to carve
deposits from of the underground formation layer 4.
[0044] Carved out deposits may be flushed from the channel assembly
8,9, 10 by injecting water, steam and/or another fluid into the
third well 3 and discharging a slurry comprising the stream of the
injected fluid and cuttings of carved out deposits via one or both
of the other wells 1,2. It may be advantageous to reverse or
alternate the direction in which the fluid flows through the
channel and well assembly 1,2,3,8,9,10.
[0045] FIG. 1 shows that during an initial moment of execution of
the method the first section 8,9 of the channel assembly extends as
a substantially straight line between the first well 1 and the
second well 2. In this situation the second section 10 of the
channel assembly extends from the third well 3 to the branchpoint
13, which is formed by a midpoint of the first section 8,9 of the
channel assembly, so that the channel assembly 8,9,10 substantially
has a T-shape. In the situation shown in FIG. 1 the chain cutter
string 11 is pulled through the first section 8,9 while the chain
cutter string 11 is pressed against the sidewall of the first
section 8,9 by the chain cutter control cable 11 and is pulled by
the chain cutter control cable towards the third well as shown by
arrow 14.
[0046] Alternatively, during an initial or subsequent moment of
execution of the method the first section of the channel assembly
has a V-shape as illustrated by dotted lines 18, 19 and has a first
leg 18, which extends from the first well 1 towards the third well
3 and a second leg 19, which extends from the third well 3 towards
the second well 2 and the chain cutter string 11 extends through
the first and second legs 18, 19 of the V-shaped first section of
the channel assembly. After drilling of the V-shaped channel
assembly the chain cutter control cable 12 is connected to the
chain cutter string 11 at or near the location 7 where the third
well 3 penetrates the formation layer 4, which location 7 then
forms the branchpoint 13 of the first and second sections 12, 18,
19 of the channel assembly, whereupon the chain cutter string is
pulled in a continuous or oscillating mode through the first
section 18,19 to carve out deposits from the underground formation
layer 4.
[0047] In that situation chain cutter control cable 12 is gradually
slackened while the chain cutter string 11 is pulled through the
first section of the channel assembly, thereby controlling the
pressure between the chain cutter string and the sidewall of the
first section 8,9.
[0048] It will be understood that the chain cutter assembly may be
pulled up and down by the chain cutter control cable 12 such that
subsequently triangularly shaped slices are carved from the
formation layer 4, which slices are within the triangle formed by
the first and second sections 8,9, 18 and 19 of the channel
assembly shown in FIG. 1.
[0049] After a substantial part of the deposits contained in the
part of the formation layer 4 within the triangle within the
sections 8,9, 18 and 19 are removed a fourth well 15 may be drilled
and be connected by a third channel section 16 to the existing
channel section 19, whereupon the chain cutter string may be
inserted into the section 19 and the chain cutter control cable may
be inserted via the fourth well 15 into the third channel section
16, whereupon the chain cutter string 11 may be moved in a
continuous or oscillating manner through the existing channel
section 19 and moved towards the fourth well 15 by the chain cutter
control cable 12 until a triangular section of the formation layer
4 between the channel section 19 and lines 20 and 21 is carved from
the formation layer.
[0050] The process of drilling further wells and carving further
triangular sections of the formation layer 4 adjacent to existing
channel sections 8,9,19,19,20,21 may be repeated in a similar
manner as described with reference to the fourth well 15 in FIG.
1.
[0051] It will be understood that the use of a chain cutter control
cable 12 that controls the lateral pressure between the chain
cutter string 11 and the wall of the channel assembly will optimize
the cutting performance of the cutters mounted on the chain cutter
string 11 and will reduce the risk of breaking of the chain cutter
string 11 and provide a possibility to relieve it when stuck. It
will further be understood that water, steam and or other fluid
injection hoses may be connected to the chain cutter string 11
and/or chain cutter control cable 12 to flush carved out cuttings
from the channel and well assembly, thereby reducing the risk of
plugging of the channel and well assembly.
[0052] Furthermore fluid injection hoses may be used to inject a
filler and/or tailings into the created cavity in order to inhibit
subsidence of the overburden.
[0053] FIG. 2 depicts a top view of a detail of the cutting
mechanism of a continuous chain cutter assembly 50, 51 that is
moving in one direction.
[0054] The continuous chain cutter assembly 50,51 traverses a first
section 53 of a channel assembly that is located between a region
of disturbed rock 61 and an undisturbed rock formation 60. The
chain cutter assembly 50,51 comprises cutting blades 51 that are
mounted on chain sections 50, which chain sections 50 are pivotably
interconnected by connector pins 52.
[0055] At a branchpoint 53a the first section 53 is connected to a
second section 62 of the channel assembly 53,62, at which
branchpoint 53a the chain cutter string 50,51 is connected to a
control device 54.
[0056] The control device 54 comprises a connection assembly 40 to
apply a controlled pulling force to the chain cutter string 50,51.
The control device 54 controls the pressure of clamp blades 41a,41b
to fixate the position of the control device 54 in the horizontal
borehole 62 while cutting, like fixation devices known as friends'
or `camalots` in mountain climbing. The teeth on the clamp blades
41a,41b penetrate into the undisturbed rock formation 60 when
pulling on the chain 50,51. The clamp blades 41a,41b have a wide
operating range with respect to width of the second section 62 of
the channel assembly they are in.
[0057] The clamp blades 41a, 41b are mounted on a common shaft 41
and connected by strings 43 to a motor assembly 44 that can pull
the strings 43 to relieve the clamp blades 41a, 41b from the wall
of the horizontal borehole 62.
[0058] The connection assembly further comprises a spring 45 which
is connected by a connecting rod 46 to a shaft 48 which rotatably
carries a guide wheel 47 provided with cutter blades 49, which
intermesh with the cutting blades 51 of the chain cutter string
50,51 to control the lateral pulling force exerted by the control
device 54 on the chain cutter string 50,51.
[0059] The guide wheel 46 thereby accurately guides and presses the
cutter blades 51 of the chain cutter string 50, 51 against the
undisturbed rock formation 60. It will be understood that the wheel
47 may have more teeth than four and may have a corresponding
larger diameter.
[0060] Optionally hydraulic jets can be mounted on the control
device 54 to facilitate movement in forward and/or backward
direction.
[0061] FIG. 3 is a top view of a chain cutter assembly 80,81, which
makes an oscillating movement to excavate soil from the wall of a
first section 75 of a subsurface channel assembly 75,76.
[0062] FIG. 3 depicts how a control device 70,74 is connected to a
chain cutter string 80,81 which cuts rock and/or hydrocarbon
containing material in an oscillating manner from an undisturbed
rock, shale oil, tar sand, viscous crude, tight gas and/or coal
containing formation 77.
[0063] The control device 70,74 is arranged in a second section 76
of the subsurface channel assembly 75,76 and comprises a connection
bar 70, which is connected by a pin 71 to a connection rod 74,
which is slideably arranged within a cylindrical housing 83 in
which a spring 84 is arranged and which housing 83 is connected to
a chain cutting string control cable 94.
[0064] The control device 70,74 furthermore comprises a pin 71 to
connect the connection bar 70 to the connection rod 74 in a
pivotable manner and optionally a cutting blade 72 which is
arranged at the end of the connection bar 70. A pin 73 pivotably
connects the cutting chain 80 to the connection rod 70. In this
case the cutting chain 80 is a cable 80 of two parts with eyes at
the end 82a and 82b and connected to pin 73. Here four cutting
blades 81 are mounted over the complete circumference of the
cable.
[0065] The control device 70, 74 shown in FIG. 3 may have the same
fixation device 41a,41b and motor assembly 44 as shown in FIG.
2.
[0066] Optionally, the width of the cutters 81 of the oscillating
cutter assembly shown in FIG. 3 may vary over the length of the
chain leaving pillar like supported structures in the formation
61.
[0067] It will further be understood that the wells 1,2 and 3 shown
in FIG. 1 may have a tilted, non-vertical, orientation and that the
triangular area to be cut away in the plane defined by the channel
assemblies 8-10,53,62,75 and 76 shown in FIGS. 1-3 may be adapted
to foreseen subsidence.
[0068] It will also be understood that the channel assemblies
8-10,53,62,75 and 76 shown in FIGS. 1,2 and 3 may define a dipped,
non-horizontal, plane to facilitate flushing of the cutting
deposits to the bottom of one of the wells 1,2 or 3 in which a
slurry pump may be arrange to remove the cutting deposits to the
earth surface.
[0069] It will further be understood that the three wells 1,2,3 and
channel assembly 8,9,10 may be drilled by known deviated and or
river-crossing drilling technologies, wherein the first and second
wells 1,2 and the first and second sections 8,9 of the channel
assembly are drilled as a single U-shaped well having two entrances
at the earth surface and the third well 3 and third section of the
channel assembly 10 are drilled as a single J-shaped well, which is
drilled towards the branchpoint 13 by known navigation and
homing-in techniques.
[0070] Finally, it will be understood that the first or second well
1 or 2 may be located above the branchpoint 13 so that the first
and second sections of the channel assembly 8-10 have a L-shaped
configuration instead of the T-shaped configuration shown in FIG.
1. This alternative L-shaped configuration may be attractive if the
control cable 12,62,94 also has cutting capabilities provided by
jets and/or cutting elements (not shown) mounted on the control
cable 12,62,94.
[0071] Fraccing is widely used in the oil and gas industry to
generate vertical fluid conduit planes to improve hydrocarbon
production. But, there are circumstances that it cannot be done or
is less effective. Examples are high permeable, vuggy reservoirs
and subsurface formations where the risk is high that the fracture
penetrates into a sedimentary layer causing problems.
[0072] Also, it can be advantageous to make a fracture with a
relative large fracture aperture to fill the fracture with a gel,
cement or other material to create a baffle for fluid flow of
substantial areal dimensions. One application is the control of
water ingress from an active aquifer, with or without pollutants,
another is a sufficient wide fracture for viscous oil production or
tight or shale gas production.
[0073] The chain cutter as described with reference to FIGS. 1-3
could in these cases be an alternative enabling technology.
[0074] In the case that the planes to be cut out are predominantly
vertical, simpler well configurations can be applied as illustrated
in the following figures.
[0075] FIG. 4 shows a configuration with two wells 400 and 405
which start vertical from the surface 420 and deviate from vertical
further downwards.
[0076] The oscillating chain cutter 401 is anchored in the bottom
by anchor 403 of well 400 via spring 404. The spring can freely
rotate in the plane of cutting. The chain cutter control device 407
which controls the lateral force of the chain cutter on the rock is
connected to the chain cutter via a guide wheel 408. This wheel can
be provided with cutter blades. The chain cutter control device can
be similar as the one shown in FIG. 2 of the original patent
application. The chain cutter control device 407 is pulled upwards
by the control cable 406. The control cable is guided in bends in
the well at locations as 415 by appropriate mechanical means, such
as guiding wheels (not drawn) to avoid unnecessary friction and
deterioration of well and control cable. Guiding wheel 402 for the
chain cutter is mounted in well 400 for similar reasons.
[0077] After drilling wells 400 and 405 with well intervention at
location 413, the chain cutter is along line 410 and connected to
the control device at this location. While pulling on the control
cable, the oscillating chain cutter progresses from dashed dotted
line 410 to dashed dotted line 411 to dashed dotted line 412.
[0078] It is obvious from FIG. 4 that there is little to no lateral
control on the chain cutter when the chain cutter operates in the
accentuated area 414. Pending on rock properties and other factors,
operation in this area requires consideration and, if needed, the
size of this area should be limited by choosing a proper location
of guiding wheel 402.
[0079] Alternatively, spring 404 is a pneumatic or electrically
driven actuator, or is replaced by a guiding wheel. In the latter
case the chain cutter string returns through well 400 to the
surface allowing for a continuous (non-oscillating) movement of the
chain cutter.
[0080] FIG. 5 shows a single vertical well 500 with a side track
505. Two anchors 503 and 509 fixate two guiding wheel 504 and
spring 510 for the oscillating chain cutter 501. The chain cutter
control device 507 which controls the lateral force of the chain
cutter on the rock is connected to control cable 506 and to the
chain cutter via a guide wheel 508. Optionally, this wheel can be
provided with cutter blades. The chain cutter control device can be
similar as the one shown in FIG. 2 of the original patent
application. Guiding wheels at location 502 or equivalent
mechanical means reduce friction and avoid unlimited deterioration
of the well and control cable 508. The cutting starts at the top of
the intersection as denoted by the dashed dotted line 511 and the
chain cutter and the chain cutter control gradually move downwards
until dashed dotted line 512 is reached. Alternatively, spring can
be replaced by an oscillating electric or pneumatic actuator or a
guiding wheel. In the latter case the chain cutter string returns
through the side track 505 and well 500 to the surface allowing for
a continuous (non-oscillating) movement of the chain cutter.
[0081] FIG. 6 shows a configuration somewhat similar to the one
shown in FIG. 5 but with two springs 604 and 610. The oscillating
chain cutter has now two chains 601A and 601B that are connected to
these springs via two small guiding wheels at the exit of the
anchors. It is an option to house the springs in the anchors to
minimize negative impact of debris. Two integrated guiding wheels
608 with cutting blades are connected to the chain cutting control
device 607 that is gently lowered during cutting using control
cable 606 and/or the weight of this device and/or actuators shown
in FIG. 2 of the original patent application. The cutting starts at
the top of the intersection as denoted by the dashed dotted line
611 and the chain cutter and the chain cutter control gradually
move downwards until dashed dotted line 612 is reached.
[0082] Optionally, control cable 606 is left out and the lowering
of the control device is activated and controlled by changing the
operating mode of the cutting chains 601A and 601B since they can
be operated in phase and out of phase. A mechanical device in the
control unit act on frictional differences between the control
device and the chain cutters in this case. Optionally, the springs
604 and 610 can be replaced by an oscillating electric or pneumatic
actuator as in the examples given before.
[0083] FIG. 7 shows a configuration with one vertical wells 700 and
a vertical well 705 with side track 711. This may be advantageous
if the distance between the two wells is large compared to the
depth. The two anchors 703 and 709 fixate two wheels 704 and 710 to
guide control cables 706 and 707. The end of these control cables
are connected to guiding wheels 708 and 709 for the chain cutter
701. The chain cutter can oscillate or move continuously. By
putting tension on the control cables the lateral force of the
cutter on the rock can be increased while cutting. The cutting
chain starts along the original side track 711 until it reaches the
dashed dotted line 712. The guiding wheels 708 and 709 can move
somewhat to each other as a result from the force balance.
Optionally, sliding cases in the well bore below these guiding
wheels can maintain the center of these wheels in the well bore.
These sliding cases are not drawn in FIG. 7.
[0084] It will be understood that when the cutting operations start
the side track 711 form a first section of the channel assembly and
the lower parts of the vertical wells 700 and 705 form a second and
third part of the channel assembly and that each of the control
cables 706 and 707 forms a chain cutter control cable which
controls the lateral force between the chain cutter assembly 712
and the bottom of the side track 711 from which formation particles
are carved out by the oscillating or continuously rotating chain
cutter assembly 712.
[0085] There is no limitation to tilt the cutting plane in FIGS. 4,
5, 6 and 7 from pure vertical to a plane outside the plane of the
drawing.
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