U.S. patent application number 10/906241 was filed with the patent office on 2005-08-18 for method and apparatus for isolating and testing zones during reverse circulation drilling.
This patent application is currently assigned to PRESSSOL LTD.. Invention is credited to Livingstone, James I..
Application Number | 20050178562 10/906241 |
Document ID | / |
Family ID | 34885915 |
Filed Date | 2005-08-18 |
United States Patent
Application |
20050178562 |
Kind Code |
A1 |
Livingstone, James I. |
August 18, 2005 |
METHOD AND APPARATUS FOR ISOLATING AND TESTING ZONES DURING REVERSE
CIRCULATION DRILLING
Abstract
A zone isolating and testing apparatus comprising an isolation
tool and a downhole flow control means and a method of using such
apparatus is disclosed. The zone isolating and testing apparatus is
particularly useful for testing zones during reverse circulation
drilling using concentric drill string such as concentric drill
pipe or concentric coiled tubing. The isolation tool of the zone
isolating and testing apparatus comprises an expandable packer
means and is adapted to connect to concentric drill string near the
drilling means. The downhole flow control means of the zone
isolating and testing apparatus comprises two valves, one for
closing off the annulus between the inner tube and outer tube of
the concentric drill string and the other for closing off the inner
space of the inner tube. The downhole flow control means is also
adapted to connect to concentric drill string near the drilling
means. During testing, the isolation tool seals off the annulus
between the concentric drill string and the walls of the wellbore
and the downhole flow control means seals off either the annulus
between the inner tube and outer tube of the concentric drill
string or the inner space of the inner tube of the concentric drill
string.
Inventors: |
Livingstone, James I.;
(Calgary, CA) |
Correspondence
Address: |
BENNETT JONES
C/O MS ROSEANN CALDWELL
4500 BANKERS HALL EAST
855 - 2ND STREET, SW
CALGARY
AB
T2P 4K7
CA
|
Assignee: |
PRESSSOL LTD.
8 Lake Placid Bay SE
Calgary
CA
|
Family ID: |
34885915 |
Appl. No.: |
10/906241 |
Filed: |
February 10, 2005 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60521051 |
Feb 11, 2004 |
|
|
|
Current U.S.
Class: |
166/386 ;
166/187; 166/242.1; 166/316; 166/380 |
Current CPC
Class: |
E21B 21/12 20130101;
E21B 17/003 20130101; E21B 49/087 20130101; E21B 17/18 20130101;
E21B 49/08 20130101; E21B 33/12 20130101; E21B 34/06 20130101 |
Class at
Publication: |
166/386 ;
166/380; 166/242.1; 166/187; 166/316 |
International
Class: |
E21B 034/06 |
Claims
What is claimed is:
1. An apparatus for isolating a zone in a hydrocarbon formation for
testing flow of hydrocarbons, formation fluids and/or drill
cuttings during vertical, horizontal or directional reverse
circulation drilling of a wellbore using concentric drill string,
said concentric drill string comprising an inner tube situated
inside an outer tube and forming an annulus therebetween,
comprising: (a) an isolation tool having an expandable and
contractible packer means and adapted to be operably connected to
said concentric drill string; and (b) a downhole flow control means
having a plurality of valve means for controlling the flow of
hydrocarbons, formation fluids and drill cuttings through the
annulus, the inner tube or both and adapted to be operably
connected to said concentric drill string.
2. The apparatus of claim 1 wherein said concentric drill string
comprises joints of concentric drill pipe.
3. The apparatus of claim 1 wherein said concentric drill string
comprises concentric coiled tubing.
4. The apparatus of claim 1 wherein said downhole flow control
means is operably connected to said concentric drill string below
said isolation tool.
5. The apparatus of claim 1 wherein said downhole flow control
means is operably connected to said concentric drill string above
said isolation tool.
6. The apparatus of claim 2 wherein said isolation tool and said
downhole flow control means are separated from each other by one or
more joints of concentric drill pipe.
7. The apparatus of claim 1 wherein said inner tube is made of a
rubber material, rubber and steel, fiberglass or other composite
material and comprises electrical wires and said packer means of
said isolation tool expands or contracts by means of an electric
current delivered by the electrical wires of the inner tube.
8. The apparatus of claim 1 wherein said packer means comprises an
inflatable ring.
9. The apparatus of claim 8 wherein said inflatable ring expands or
contracts by pumping fluids into or out of the inflatable ring.
10. The apparatus of claim 1 wherein said isolation tool and said
downhole flow control means are further adapted to be connected to
each other.
11. A method for isolating a zone in a hydrocarbon formation for
testing flow of hydrocarbons, formation fluids and/or drill
cuttings during vertical, horizontal or directional reverse
circulation drilling of a wellbore using concentric drill string,
said concentric drill string comprising an inner tube situated
inside an outer tube and forming an annulus therebetween,
comprising: (a) sealing off an outside annulus formed between a
wall of said wellbore and an outer surface of said concentric drill
string to form an isolated testing zone; (b) sealing off one of
said annulus between the outer tube and the inner tube of the
concentric drill string or said inner space of the inner tube of
the concentric drill string; (c) allowing hydrocarbons, formation
fluids and/or drill cuttings present in said isolated testing zone
to flow through the other of said annulus between the outer tube
and the inner tube of the concentric drill string or said inner
space of the inner tube of the concentric drill string to the
surface of said wellbore; and (d) measuring the amount of
hydrocarbons, formation fluids and/or drill cuttings present in
said isolated testing zone.
12. The method of claim 11 wherein the outside annulus is sealed
off by means of an isolation tool comprising an expandable and
contractible packer means.
13. The method of claim 12 wherein said packer means is expanded
and contracted by means of an electrical current.
14. The method of claim 12 wherein said packer means is expanded
and contracted by means of addition of fluid into or removal of
fluid from the packer means.
15. The method of claim 11 wherein the annulus between the outer
tube and the inner tube of the concentric drill string or the inner
space of the inner tube of the concentric drill string is sealed
off by means of a downhole flow control means comprising a
plurality of valve means.
16. The method of claim 111 wherein said concentric drill string
comprises joints of concentric drill pipe.
17. The method of claim 11 wherein said concentric drill string
comprises concentric coiled tubing.
Description
[0001] This application claims the benefit of U.S. Provisional
Application No. 60/521,051, filed Feb. 11, 2004.
FIELD OF USE
[0002] The present invention relates to an apparatus and method for
isolating and testing individual zones in a vertical, directional
or horizontal wellbore during drilling. More particularly, the
present invention relates to a zone isolating and testing apparatus
and method of use thereof to allow testing of isolated zones for
flow of hydrocarbons, formation fluids and drill cuttings during
vertical, horizontal or directional reverse circulation drilling of
wellbores using concentric drill pipe, concentric coiled tubing, or
the like.
BACKGROUND OF THE INVENTION
[0003] The oil and gas industry uses various methods to test the
productivity of wells prior to completing a well (see, for example,
U.S. Pat. No. 4,898,236). After drilling operations have been
completed and a well has been drilled to total depth or prior to
reaching total depth in the case of multi-zoned discoveries, it is
common to test the zone to estimate future production of oil and
gas. Current technologies used for testing reservoirs such as drill
stem testing (DST) are often too expensive to test multi-zone
reservoirs, particularly at shallow depths. Furthermore, isolating
and testing zones using conventional packer technology can be slow,
expensive and sometimes difficult to set and then release.
[0004] Traditionally the DST process involves flowing a well
through a length of drill pipe reinserted through the static
drilling fluid. The bottom of the pipe will attach to a tool or
device with openings through which fluid can enter. This perforated
section is placed across an anticipated producing formation and
sealed off with packers, frequently a pair of packers place above
and below the formation. This packing off technique permits an
operator to test only an isolated section or cumulative
section.
[0005] The present invention allows a fast, safe and economic way
to isolate and test zones during reverse circulation drilling,
alleviating the need to first remove the drill pipe used for
drilling and then reinsert a length of drill pipe for testing.
SUMMARY OF THE INVENTION
[0006] A zone isolating and testing apparatus comprising an
isolation tool and a downhole flow control means and a method of
using such apparatus is disclosed. The zone isolating and testing
apparatus is particularly useful for testing zones during reverse
circulation drilling using concentric drill string, e.g.,
concentric drill pipe, concentric coiled tubing and the like, said
concentric drill string comprising an inner tube and an outer tube
forming an annulus therebetween. Thus, the zone isolating and
testing apparatus is preferably operably connected to a concentric
drill string.
[0007] The isolation tool of the zone isolating and testing
apparatus comprises an expandable packer means and is adapted to
connect to concentric drill string near the drilling means. When
the packer means of the isolation tool is in the expanded position,
the isolation tool is in the "closed position" and when the packer
means is in the contracted position the isolation tool is in the
"open position". In a preferred embodiment, the expansion of the
packer means is controlled by an electric current for quicker
opening and closing of the isolation tool.
[0008] It is understood in the art that the area of the zone tested
will be dictated by the distance the isolation tool is placed away
from the drilling means. In some instances where the bands of the
pay zones are known to be quite broad the isolation tool and the
drilling means can be separated from one another by several joints
of concentric drill string.
[0009] The downhole flow control means of the zone isolating and
testing apparatus comprises two valves, one for closing off the
annulus between the inner tube and outer tube of the concentric
drill string and the other for closing off the inner space of the
inner tube. The downhole flow control means is also adapted to
connect to concentric drill string near the drilling means. In one
embodiment, the isolation tool and downhole flow control means are
connected to each other. However, it is understood that these two
components may be separated from one another by one or more joints
of concentric drill string.
[0010] During the drilling process, the isolation tool is in the
open position, i.e. the packer means is contracted. When the tool
is in the open position it does not significantly restrict the flow
of hydrocarbons, as the outside diameter of the isolation tool when
in the open position is preferably equal to or less than the
outside diameter of the concentric drill string. However, it is
understood that the outside diameter of the open isolation tool can
also be greater than the outside diameter of the concentric drill
string and still not significantly restrict the flow of
hydrocarbons.
[0011] The downhole flow control means is also in the complete open
position during drilling, i.e., both valves are open. This allows
drilling fluid to be pumped down either the annulus or inner space
of the concentric drill string and exhaust drilling fluid and drill
cuttings to be removed through the other of said annulus or inner
space.
[0012] However, when testing is required during the reverse
circulation drilling process, the isolation tool is in the closed
position, i.e. the packer means expands to abut the adjacent
wellbore walls. Further, one of the two valves of the downhole flow
control means is also in the closed position. Which valve will be
closed is dependent upon whether drilling fluid is being pumped
through the annulus or the inner space. For example, if drilling
fluid were being pumped down the annulus then during testing the
annulus valve would be closed.
[0013] Thus, during testing, the zone of the wellbore below the
isolation tool is shut off or isolated from the portion of the
wellbore above the tool as the expanded packer means will not allow
hydrocarbons to flow passed it. The materials present in the
isolated zone can then flow through either the annulus or inner
space to the surface of the well for testing.
[0014] The disclosed invention has one or more of the following
advantages over conventional isolation packer technology and drill
stem testing:
[0015] when drilling vertical, directional, and/or horizontal
wellbores, individual zones can be isolated and tested much quicker
and cheaper without having to interrupt drilling for extended
periods of time;
[0016] open hole testing provides very valuable production
data;
[0017] zones which may otherwise be damaged by testing fluids when
using drill stem testing can now be tested without damage as
testing fluids are not necessary;
[0018] easier to measure the flow of formation fluids into a
zone;
[0019] decisions on well stimulation can be made while the well is
being drilled; and
[0020] more accurate information on reservoir pressure,
temperature, flow rate etc. can be obtained from individual
zones.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021] FIG. 1 is a schematic of one embodiment of the isolation
tool of the present invention.
[0022] FIGS. 2a and 2b is a schematic of the isolation tool in the
open and closed position, respectively.
[0023] FIG. 3 is a schematic of the downhole blow out
preventor.
[0024] FIG. 4 is a schematic of the surface drilling and testing
equipment used in the present invention.
[0025] FIG. 5 is a schematic of the inner drill string of
concentric drill string of the present invention.
[0026] FIG. 6 is a schematic of one embodiment of the zone
isolating and testing apparatus typically used with concentric
drill pipe.
[0027] FIG. 7 is a schematic of one embodiment of the zone
isolating and testing apparatus typically used with concentric
coiled tubing.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0028] A zone isolating and testing apparatus comprising an
isolation tool and a downhole flow control means and method of
using such apparatus will now be described with reference to the
following preferred embodiment.
[0029] FIG. 1 schematically illustrates the isolation tool 30 of
the zone isolating and testing apparatus and means for attaching
the isolation tool 30 between two pieces of concentric drill string
45 and 47. Concentric drill string 45 and 47 both comprise an inner
tube 57 and an outer tube 59. Concentric drill string is designed
such that at one end of concentric drill string is a threaded pin
end and at the other end is a threaded box end. Thus, pieces of
concentric drill string can be connected end to end by screwing the
threaded pin end of the new piece of concentric drill string to be
added into the box end of the drill string below.
[0030] As can be seen in FIG. 1, concentric drill string 45 has
threaded pin end 31 at its bottom end and concentric drill string
47 has threaded box end 35 at its top end. Isolation tool 30 is
adapted to be inserted between concentric drill string 45 and 47 by
means of threaded box end 37 and threaded pin end 33. Thus,
threaded pin end 31 of concentric drill string 45 screws into
threaded box end 37 and threaded pin end 33 screws into threaded
box end 35 of concentric drill string 47.
[0031] Isolation tool 30 further comprises packer means 39. Packer
means 39 can be expanded or contracted by any means known in the
art, for example, by means of an electric current flow path as
shown in FIG. 5. In another embodiment, the packer means comprises
an inflatable ring which can be inflated and deflated by pumping
various types of fluid into and out of the ring.
[0032] FIGS. 2a and 2b schematically illustrate the isolation tool
30 attached to the concentric drill string in the open and closed
position, respectively. During drilling the isolation tool 30 is in
the open position and during testing it is in the closed
position.
[0033] When packer means 39 is contracted or deflated as shown in
FIG. 2a, the isolation tool 30 is in the open position and
hydrocarbons can flow freely through the wellbore annulus 43 formed
between the outer wall of the concentric drill string and the
wellbore wall 41. When packer means 39 is expanded or inflated as
shown in FIG. 2b, the packer means 39 is forced against wellbore
wall 41 thereby closing annulus 43 to hydrocarbon movement above or
below the packer means 39. Thus, the testing region below the
packer is isolated from the surface of the wellbore.
[0034] In order to test for hydrocarbon flow, formation fluids,
drill cuttings and the like present in the testing zone, the
isolation tool is used in conjunction with a downhole flow control
means or downhole blow out preventor (downhole BOP) as shown in
FIG. 3. In FIG. 3, downhole BOP 10 is shown attached to the lower
end of concentric drill string 47 by threaded pin end 72 of
concentric drill string 47 screwing into threaded box end 70 of
downhole BOP 10.
[0035] In this embodiment, downhole BOP 10 comprises two valve
means 3 and 5 for shutting off the flow of drilling fluid,
exhausted drilling fluid, drill cuttings and/or hydrocarbons
through one or the other of the outer annulus 7 formed between
inner tube 57 and outer tube 59 of concentric drill string 47 and
inner space 9 of inner tube 57. It is understood that other
downhole flow control means can also be used, for example, the
downhole flow control means as described in U.S. Patent
Applications Publication Nos. 20030155156 and 20030173088,
incorporated herein by reference.
[0036] Thus, in one embodiment of the invention, the isolation tool
30 and the downhole BOP 10 of the zone isolating and testing
apparatus can be separated by a single joint of concentric drill
string 47. However, it is understood that in some instances the
isolation tool and downhole BOP can be directly threaded or
connected by other connection means to each other. Further, it can
be appreciated that the orientation of the two components is not
critical; in some instances it may be desirable to have the
downhole BOP attached to the bottom of the concentric drill string
first and the isolation tool connected either directly or by means
of one or more joints of concentric drill string below the downhole
BOP.
[0037] It is understood that the drilling means (not shown) can be
either directly attached to the bottom of the downhole flow control
means, the isolation tool, other downhole tools or an intervening
joint of concentric drill string. In general, however, the drilling
means is attached to the last in the series of downhole tools.
[0038] During reverse circulation drilling with concentric drill
string, both valves 3 and 5 of the downhole BOP 10 are in the open
position (not shown). In one embodiment, drilling fluid is pumped
from surface equipment through the annulus 7 formed between the
inner tube 57 and outer tube 59 and exhausted drilling fluid, drill
cuttings and/or hydrocarbons 19 flow through the inner space 9 to
the surface of the wellbore. It is understood that drilling fluid
could also be pumped from surface through the inner space 9 and
exhausted drilling fluid, drill cuttings and/or hydrocarbons
removed through the annulus 7.
[0039] When drilling is stopped for testing, the isolation tool 30,
which is located at or near the downhole BOP, is put in the closed
position as shown in FIG. 2b to isolate the testing region below
the packer means. In the instance where drilling fluid is being
pumped down the annulus 7 and exhausted drilling fluid, drill
cuttings and/or hydrocarbons flow through the inner space 9 to the
surface of the wellbore, valve means 3 of the downhole BOP 10 is
also put in the closed position as shown in FIG. 3, as no fluids
are being flowed from surface equipment during testing.
[0040] Valve means 5, however, remains in the open position as
shown in FIG. 3 thereby allowing hydrocarbons, formation fluids
and/or drill cuttings (collectively referred to as reference 19 in
FIG. 3) present in the isolated zone to flow to surface. Well flow
test equipment known in the art will be able to determine the
hydrocarbon content of the isolated testing area. Optionally, a
surface blow out preventor (surface BOP, not shown) is provided to
shut off the flow of hydrocarbon from the annulus between the drill
string and the wellbore walls that may be present in the zone above
the packer means.
[0041] FIG. 4 schematically shows the surface equipment used during
drilling and testing. Drilling rig 70 is equipped with well testing
equipment 74. The hydrocarbons in the test region flow through the
inner space of the inner tube of the concentric drill string and
then through the choke manifold system as shown in 72. Well flow
test equipment can also be located at the end of blewie line 78.
Surface BOP 76 ensures that there is no escape of hydrocarbons to
the surface through the annulus formed between the drill string and
the wellbore walls.
[0042] The isolation tool is preferably powered by an electric
current for quicker opening and closing operations. FIG. 5 is a
schematic of a portion of concentric drill string having threaded
pin end 31 at one end. The outer tube has been removed to reveal
inner tube 57, which is preferably made of a rubber type material,
rubber/steel, fiberglass or composite material, capable of
withstanding the forces and pressures of the drilling operations.
Inner tube 57 further comprises electrical wires 51 that allow the
flow of the electric current. Wire coils 53 and 55 are compressed
in each end of the concentric drill string when two pieces of
concentric drill string are torqued (screwed) together. This
provides the electric current to operate the isolation tool, e.g.,
to expand or contract the packer means as needed.
[0043] Other means of operating the isolation tool could include
fiber optic cables, radio frequency and electric magnetic forces.
When using concentric coiled tubing the isolation tool can be
operated using small diameter capillary tubes which transmit
hydraulic or pneumatic pressure to an actuator at or near the
tool.
[0044] FIG. 6 shows one embodiment of the assembled zone isolating
and testing apparatus of the present invention, which is typically
used with concentric drill pipe. In this embodiment, the isolation
tool 30 and the downhole BOP 10 are spatially separated by means of
a single joint of concentric drill pipe 47. Typically, the drilling
means (not shown) is attached either directly to the downhole BOP
10 or to other downhole tools that can be attached to the downhole
BOP. It may be desirable, however, particularly in instances where
the bands of the pay zones are known to be quite broad (i.e., 40 ft
or greater), to have the isolation tool and the drilling means
separated even further by additional joints of concentric drill
string.
[0045] FIG. 7 shows another embodiment of the assembled zone
isolating and testing apparatus, which is typically used when the
concentric drill string comprises a continuous length of concentric
coiled tubing having a continuous length of inner coiled tubing and
a continuous length of outer coiled tubing. In this embodiment, the
isolation tool 30 is connected to the bottom of the concentric
coiled tubing 65 by connection means known in the art. The downhole
BOP 10 is then connected to the isolation tool 30 by similar
connection means known in the art.
[0046] The foregoing disclosure and description of the invention
are illustrative and explanatory thereof. Various changes in the
size, shape and materials as well as the details of the illustrated
construction may be made without departing from the spirit of the
invention.
* * * * *