U.S. patent application number 10/499112 was filed with the patent office on 2006-05-25 for drilling method for maintaining productivity while eliminating perforating and gravel packing.
Invention is credited to Michael H. Johnson.
Application Number | 20060108114 10/499112 |
Document ID | / |
Family ID | 23338999 |
Filed Date | 2006-05-25 |
United States Patent
Application |
20060108114 |
Kind Code |
A1 |
Johnson; Michael H. |
May 25, 2006 |
Drilling method for maintaining productivity while eliminating
perforating and gravel packing
Abstract
A method for well construction and completion is disclosed.
First, a productive section of a well is drilled in the presence of
a fluid system that controls fluid losses, is substantially
non-damaging to the formation and includes particles in a particle
size distribution sufficient to form a low permeability filter cake
on a formation face and to allow the majority of the filter cake
particles to flow back into the borehole after well completion.
after drilling, a casing includes at least one and preferably a
plurality of extendable permeable elements or member is run in the
well so that the elements are positioned and aligned with sites in
the producing formation and once extended form production conduits
between the formation and an interior of the casing. A completed
borehole is also disclosed including a casing having production
conduits formed from the extendable members or elements.
Inventors: |
Johnson; Michael H.; (Katy,
TX) |
Correspondence
Address: |
ROBERT W STROZIER, P.L.L.C
PO BOX 429
BELLAIRE
TX
77402-0429
US
|
Family ID: |
23338999 |
Appl. No.: |
10/499112 |
Filed: |
December 18, 2002 |
PCT Filed: |
December 18, 2002 |
PCT NO: |
PCT/US02/40696 |
371 Date: |
December 22, 2004 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60341779 |
Dec 18, 2001 |
|
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Current U.S.
Class: |
166/276 ;
166/369 |
Current CPC
Class: |
E21B 43/11 20130101;
E21B 43/04 20130101; E21B 43/082 20130101 |
Class at
Publication: |
166/276 ;
166/369 |
International
Class: |
E21B 43/02 20060101
E21B043/02 |
Claims
1. A method of well construction and completion comprising:
drilling a well with a fluid system into a target formation or
reservoir, where the fluid system produces no filter cake or a
minimal filter cake on a surface of the target formation; inserting
into the well a casing string including at least one extendable
member so that the extendable member is positioned adjacent a site
in the target formation or reservoir, where the extendable members
have a sand control medium at their distal end, where the sand
control medium is adapted to minimize formation damage and
maximizing well productivity, while eliminating well perforation
and gravel packing; extending the member until the members contacts
the site in target formation or reservoir; and placing the well on
production.
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36. The method of claim 1, wherein the fluid system is a "Drill-In
Fluid."
37. The method of claim 1, wherein the fluid has a hydrostatic
pressure that is less than or equal to the pressure of the target
reservoir.
38. The method of claim 1, further comprising the step of:
circulating a solvent through the well after the placing step,
where the solvent is designed to remove portions of the filter cake
from the surface of the target formation, where the portions are
associated with the extendable members.
39. The method of claim 1, further comprising the step of:
cementing the casing in place.
40. The method of claim 39, further comprising the step of:
circulating a solvent through the well after the placing step,
where the solvent is designed to remove portions of the filter cake
from the surface of the target formation, where the portions are
associated with the extendable members.
41. The method of claim 39, wherein the extending step is after the
cementing step.
42. The method of claim 39, wherein the fluid system is a "Drill-In
Fluid."
43. The method of claim 42, wherein the fluid has a hydrostatic
pressure that is less than or equal to the pressure of the target
reservoir.
44. A method of well construction and completion comprising:
drilling a well with a first fluid system to a point above a target
reservoir; displacing the first fluid system with a second fluid
system, where the second fluid system produces no filter cake or a
minimal filter cake on a surface of the target formation; drilling
a remaining portion of the well into the target reservoir;
inserting into the well a casing string including at least one
extendable member so that the extendable member is positioned
adjacent a site in the target formation or reservoir, where the
extendable members have a sand control medium at their distal end,
where the sand control medium is adapted to minimize formation
damage and maximizing well productivity, while eliminating well
perforation and gravel packing; extending the member until the
member contacts the site in target reservoir; and placing the well
on production.
45. The method of claim 44, wherein the first fluid system is a
conventional drilling fluid and the second fluid system is a
"Drill-In Fluid."
46. The method of claim 45, wherein the second fluid system has a
hydrostatic pressure that is less than or equal to the pressure of
the target reservoir.
47. The method of claim 44, further comprising the step of:
circulating a solvent through the well after the placing step,
where the solvent is designed to remove portions of the filter cake
from the surface of the target formation, where the portions are
associated with the extendable members.
48. The method of claim 44, further comprising the step of:
cementing the casing.
49. The method of claim 48, further comprising the step of:
circulating a solvent through the well after the placing step,
where the solvent is designed to remove portions of the filter cake
from the surface of the target formation, where the portions are
associated with the extendable members.
50. The method of claim 48, wherein the extending step occurs after
cementing step.
51. The method of claim 48, wherein the first fluid system is a
convention drilling fluid and the second fluid system is a
"Drill-In Fluid."
52. The method of claim 51, wherein the second fluid system has a
hydrostatic pressure that is less than or equal to the pressure of
the target reservoir.
53. A well comprising a borehole and a casing inserted into the
borehole, where the casing includes at least one extendable member
having a retracted state and an extended state, where the casing is
designed to be positioned in the well so that the at least one
member is adjacent a site in a productive formation and when
extended forms a production conduit between the formation at sites
in a target formation having no filter cake or a minimal filter
cake on a surface thereof and an interior of the casing, where the
extendable members have a sand control medium at their distal end,
where the sand control medium is adapted to minimize formation
damage and maximizing well productivity, while eliminating well
perforation and gravel packing.
54. The well of claim 53, wherein the casing includes a plurality
of extendable members, each of the members being positioned
adjacent a site in the productive formation and each of the members
designed to form a productive conduit between the productive
formation and the interior of the casing.
55. The well of claim 53, further comprising a cement layer between
a formation face of the productive formation and an exterior
surface of the casing.
56. The well of claim 54, further comprising a cement layer between
a formation face of the productive formation and an exterior
surface of the casing.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] This invention relates to a method of drilling and
completing a well.
[0003] More particularly, this invention relates to a method for
placing a means of communication between a productive formation and
a well borehole without perforating and gravel packing the well
borehole at sites of production. The method also relates to
minimizing formation damage caused by conventional drilling,
perforating, and gravel packing. The method combines and integrates
elements of well drilling and construction with the well completion
in a manner to reduce time, improve safety, and maximize
productivity.
[0004] 2. Description of the Related Art
[0005] The search for oil and gas reserves has taken the industry
to remote sites including land, traditional offshore locations, and
offshore deepwater. Historically the cost for exploring and
developing hydrocarbons has been very high, and as the search for
hydrocarbons continues in more remote areas costs are escalating
because of the amount of equipment and personnel required in these
areas. Because of the escalating cost it is important, that
formation damage be minimized. Formation damage can negatively
affect productivity of the resulting wells. Productivity needs to
be as high as possible in order to ensure profitability. Also, it
is important to seek ways to reduce the time spent on well
construction and completion operations to minimize cost and if the
number of personnel and the amount of equipment can be reduced
safety inherently improves.
[0006] Many hydrocarbon reservoirs are by their very nature
unconsolidated rock and/or sandstone. These unconsolidated
formations may produce sand particles and other debris which can
cause well bore and surface facility problems as well as negatively
affecting the productivity of the well. Therefore, means of
preventing sand production have been developed throughout the
years.
[0007] One common method of well construction and completion is to
drill a borehole with conventional drilling fluids, run casing into
the borehole and cement the casing in place, displace the
conventional drilling fluids with a clear brine, filter the brine
and clean the borehole, run perforating guns in the well and
perforate the casing, remove the perforating guns and re-clean the
casing, re-filter to the clear brine fluids, run in the well with a
gravel pack screen assembly, use high-pressure pumps place gravel
pack sand between the gravel pack screen assembly into the
perforation tunnels and against the formation face. This is a
costly, time-consuming process.
[0008] There are many disadvantages from the above procedure. These
disadvantages can be broken into two categories; equipment and
process reliability, and formation damage mitigation or removal.
Fluid losses of the filtered brine can occur after perforating
necessitating the need for a means of fluid loss control which
generally entails pumping high viscosity polymer gel into the
formation. There have been instances where leaks have caused
perforating guns to low order detonate resulting in no or poor
perforating performance and expensive fishing operations to remove
the damaged perforating gun bodies. Also, gravel pack screens have
failed during the high-pressure pumping operation causing
additional fishing operations or worse the damage isn't discover
until the well is placed on production necessitating a workover of
the well.
[0009] Formation damage is also a problem during conventional well
construction and completion. Conventional drilling fluids can allow
filtrate and solid particles to invade the formation causing
restrictions in the productive pore spaces. Another source of
formation damage is the shaped charges or explosives used in
perforating. The energy from these explosives pushes the casing,
cement, and formation aside when creating the perforation tunnel.
This causes crushing of the formation matrix reducing the
permeability and flow potential of the formation. Additional damage
can come from the polymer gels used for controlling fluid losses
after formation perforation. One method currently used to over come
formation damage is hydraulic fracturing or frac packing. Frac
packing is an attempt to use high-pressure pumping and hydraulic
horse power to frac beyond any damage. Another method for formation
damage mitigation uses acid stimulation to try and remove or
dissolve formation damage caused by polymer gels or mud particle
invasion. However, most mud weighting materials are solid mineral
particles such as barite and bentonite that cannot be readily
dissolved.
[0010] The gravel pack assembly itself can serve as the restriction
in the well borehole. This may cause unnecessary pressure drops
which restrict production. Also, the gravel pack assembly may need
to be removed for remedial operations. The process of removing an
object from a well borehole is called fishing. These operations are
costly and time consuming and not always successful resulting in a
need to re-drill a portion of, or possibly the entire well.
[0011] Another common method of well construction and completion is
to drill a borehole and not run casing across the productive
formation. This type of well construction is termed barefoot or
openhole. Openhole completions are generally utilized after
horizontal well construction. The most common practice is to run a
screen assembly in the openhole section and not gravel pack on the
outside of the screen between the screen and the formation.
However, there has been an increasing number of openhole horizontal
gravel packs performed. Formation damage is mitigated by the use of
special drilling fluids termed "Drill-In-Fluids." A common problem
with this type of completion is the inability to isolate areas in
the completion that produce water. Water production can increase to
a point that limits hydrocarbon production rates. Isolating and
stopping areas of water production is made extremely difficult due
to not having cemented casing in-place to help control the flow of
water in the annulus between the screen and the formation. Also,
the screens run in the horizontal openhole generally contain a sand
control filter media. The horizontal openhole section can act as a
gravity separator during production. Because the unconsolidated
formation material is not kept in place with gravel pack sand in
the annulus between the screen and formation, it is free to move
during production. The produced fluids having a certain velocity
will carry smaller formation particles more easily and at a higher
velocity than the larger formation particles. Because the filter
media is usually designed on the midrange particle size based on
the overall particle size distribution of the formation, the
smaller formation particles tend to plug the screen's sand control
filter media instead of bridging on the surface of the filter media
with the larger formation particles. This plugging restricts the
production potential of the well and may cause a workover or loss
of hydrocarbon recovery from the reservoir.
[0012] Attempts to introduce devices which eliminate perforating
and gravel packing are not new and have been disclosed in the past.
Zandmer in U.S. Pat. No. 3,347,317 disclosed an extendable duct
with solid particles acting as a gravel pack medium. Johnson
disclosed an extendable device in PCT application publication
number WO9626350. These devices have not been widely used. These
devices trap drilling mud filter cake between the sand control
filter media and formation face which limit productivity due to
plugging of the formation and filter media The drilling fluids used
in the well construction process generally contain minerals such as
barite, bentonite, and/or clays in the form of solid particles.
These particles form a filter cake on the formation face as the
well is drilled. These filter cakes have a leak off rate which
allows filtrate and smaller particles to enter the pore spaces of
the formation and can cause considerable damage to a formation's
productivity. The same filter cake can plug the sand control filter
media utilized in the devices described above. In another invention
disclosed by Reinhardt in U.S. Pat. No. 5,425,424, no gravel pack
median is used in these extendable ducts. However, productivity is
maximized by performing a hydraulic fracture treatment after
extending the perforation ducts. Hydraulic fracturing is a method
of bypassing formation damage and/or improving conductivity between
the productive formation and the well borehole.
[0013] Therefore, there is a need for a method of well construction
and completion that minimizes formation damage, maximizes well
productivity, and provides a means of formation isolation. Further,
there is a need for a method that minimizes time spent during well
completion and that improves process reliability and safety. For
cased and cemented wells, there is a further need to integrate well
construction and completion processes eliminating well perforation
and gravel packing operations, while maximizing formation
productivity. The present invention answers these needs in a cross
disciplined integration of well construction (drilling) and
completion processes to maximize formation productivity.
SUMMARY OF THE INVENTION
[0014] The present invention provides a method for drilling and
completing a well, where the method achieves improved formation
productivity without the need for well perforation and gravel
packing.
[0015] The present invention provides a method of well construction
and completion including the steps of drilling an interval of a
well into or into and through a productive formation in the
presence of a fluid system adapted to control fluid loss, to be
substantially non-damaging to the productive formation, and to form
a filter cake having substantial flow back properties minimizing
adverse affects on formation productivity. After the productive
interval is drilled, a casing string including at least one and
preferably a plurality of laterally extendable members having a
sand control medium associated therewith is run into the well so
that the members can be deployed to contact sites in the productive
interval, i.e., the extendable members are positioned and aligned
within the productive formation interval of the well. After the
casing has been properly run into the well, the members are
extended such that each member comes into contact with the filter
cake and/or the productive formation at their associated sites,
where the contacting in sufficient to allow productive formation
fluids to flow through the member into the casing and out of the
well. Once the members are deployed forming production conduits
between an interior of the casing and the formation, the casing is
cemented in place. After casing cementing, production
tubing/equipment is run into the well borehole and the well is
placed on production.
[0016] The present invention provides a method of well construction
and completion including the steps of drilling an interval of a
well into or into and through a productive formation in the
presence of a fluid system characterized by having a hydrostatic
pressure equal to or less than the formation pressure to minimize
or eliminate the formation of a filter cake on the formation face,
so called under balanced or near balanced drilling. After the
productive interval is drilled, a casing string including at least
one and preferably a plurality of laterally extendable members
having a sand control medium associated therewith is run into the
well so that the members can be deployed to contact sites in the
productive interval, i.e., the extendable members are positioned
and aligned within the productive formation interval of the well.
After the casing has been properly run into the well, the members
are extended such that each member comes into contact with the
filter cake and/or the productive formation at their associated
sites, where the contacting in sufficient to allow productive
formation fluids to flow through the member into the casing and out
of the well. Once the members are deployed forming production
conduits between an interior of the casing and the formation, the
casing is cemented in place. After casing cementing, production
tubing/equipment is run into the well borehole and the well is
placed on production.
[0017] The present invention provides a method of well construction
and completion including the steps of drilling a first interval of
a well through non-productive formations in the presence of a first
fluid system. Prior to drilling into or into and through a
productive formation, the first drilling fluid is replaced with a
second fluid system adapted to control fluid loss, to be
substantially non-damaging to the productive formation, and to form
a filter cake having substantial flow back properties minimizing
adverse affects on formation productivity. After fluid system
replacement, a second interval of the well is drilled into or into
and through a productive formation in the presence of the second
fluid system. After the productive interval is drilled, a casing
string including at least one and preferably a plurality of
laterally extendable members having a sand control medium
associated therewith is run into the well so that the members can
be deployed to contact sites in the productive interval, i.e., the
extendable members are positioned and aligned within the productive
formation interval of the well. After the casing has been properly
run into the well, the members are extended such that each member
comes into contact with the filter cake and/or the productive
formation at their associated sites, where the contacting in
sufficient to allow productive formation fluids to flow through the
member into the casing and out of the well. Once the members are
deployed forming production conduits between an interior of the
casing and the formation, the casing is cemented in place. After
casing cementing, production tubing/equipment is run into the well
borehole and the well is placed on production.
[0018] The present invention provides a method of well construction
and completion including the steps of drilling a first interval of
a well through non-productive formations in the presence of a first
fluid system. Prior to drilling into or into and through a
productive formation, the first drilling fluid is replaced with a
second fluid system characterized by having a hydrostatic pressure
equal to or less than the formation pressure to minimize or
eliminate the formation of a filter cake on the formation face.
After fluid system replacement, a second interval of the well is
drilled into or into and through a productive formation in the
presence of the second fluid system, so called under balanced or
near balanced drilling. After the productive interval is drilled, a
casing string including at least one and preferably a plurality of
laterally extendable members having a sand control medium
associated therewith is run into the well so that the members can
be deployed to contact sites in the productive interval, i.e., the
extendable members are positioned and aligned within the productive
formation interval of the well. After the casing has been properly
run into the well, the members are extended such that each member
comes into contact with the filter cake and/or the productive
formation at their associated sites, where the contacting in
sufficient to allow productive formation fluids to flow through the
member into the casing and out of the well. Once the members are
deployed forming production conduits between an interior of the
casing and the formation, the casing is cemented in place. After
casing cementing, production tubing/equipment is run into the well
borehole and the well is placed on production.
[0019] The methods of this invention can also include steps
designed to remove or reduce the filter cake deposited on the
formation face during the drilling operation by pumping a solvent
into the well for a time sufficient to remove some or substantially
all of the filter pack. The filter pack removal step can occur
before or after member extension or before or after well
cementing.
[0020] The present invention further provides a completed well
including a casing string including at least one and preferably a
plurality of extended members having a sand control medium
associated therewith, where the members extend out from the casing
and contact sites in a productive formation forming production
conduits through which formation fluid flow into an interior of the
casing and out of the well. The member includes a casing fitting,
an inner sleeve having inner sleeve stops and an outer sleeve
having outer sleeve stops, where the sleeves are movable from a
retracted state to an extended state when a sufficient hydraulic
pressure is applied to the members.
DESCRIPTION OF THE DRAWINGS
[0021] The invention can be better understood with reference to the
following detailed description together with the appended
illustrative drawings in which like elements are numbered the
same:
[0022] FIG. 1 is a schematic illustrating drilling a well to a
point above the anticipated productive formations;
[0023] FIG. 2 depicts a schematic illustrating drilling through a
productive formation with a "Drill-In Fluid" including a logging
while drilling tool which can be used to determine the depth and
length of productive formations;
[0024] FIG. 3 depicts a schematic illustrating the benefits of
using a "drill-in-fluid" drilling fluid vs. a conventional drilling
fluid;
[0025] FIG. 4 depicts a schematic illustrating running the
extendable devices on the casing and positioning them across from
the productive formation;
[0026] FIG. 5 depicts a schematic illustrating extending the
devices to contact the formation face and centralize the
casing;
[0027] FIG. 6 illustrates the casing been cemented into place;
and
[0028] FIG. 7 depicts a schematic illustrating the well in a
producing mode.
DETAILED DESCRIPTION OF THE INVENTION
[0029] The inventor has found that an oil and/or gas well can be
drilled and completed without the need for formation perforation
and gravel packing using a casing including at least one, but
preferably a plurality of extendable members adapted to form
production conduits between a productive formation and an interior
of the casing. The members are hydraulically extendable from a
retracted stated to an intended state and include a casing fitting,
an inner sleeve, inner sleeve stops, an outer sleeve and outer
sleeve stops, where the sleeve are movable between the retracted
state and the extended state to form a telescoping conduit. In the
extended state a distal end of the member is designed to contact a
site on a face of a productive formation, where the contact is
sufficient to allow fluid flow from the formation through an
interior of the extended member and into an interior of the
casing.
[0030] This invention broadly relates to methods for drilling and
completing a well including the step of drilling a productive
interval of a well with a fluid system selected from the group
consisting of a fluid system adapted to control fluid loss, to be
substantially non-damaging to the productive formation, and to form
a filter cake having substantial flow back properties minimizing
adverse affects on formation productivity, a fluid system
characterized by having a hydrostatic pressure equal to or less
than the formation pressure to minimize or eliminate the formation
of a filter cake on the formation face and mixtures or combinations
thereof. After drilling into or into and through the productive
formation, casing including at least one and preferably a plurality
of extendable members having a sand control medium associated
therewith is run into the well so that the extendable members are
positioned and aligned within the productive formation so that when
extended the member form production conduits between sites of the
productive formation and an interior of the casing. After proper
casing positioning, the member are extended hydraulically to form
the conduits and the casing is cemented in place. After cementing,
the well can be placed on production. Alternatively, cementing of
the casing can proceed extending of the member to form permeable
elements or production conduits.
[0031] The present invention also broadly relates to a completed
oil and/or gas well including a casing having at least one, but
preferably a plurality of, extendable member formed within sections
of the casing, where the sections of the casing are positioned in
productive formation so that the extendable members can form
production conduits or permeable elements at desired sites within
the productive formation once extended. The present invention also
broadly relates to a producing oil and/or gas well including a
casing having at least one, but preferably a plurality of,
extendable member formed within sections of the casing, where the
sections of the casing are positioned in productive formation and
where the extendable members are extended to form production
conduits or permeable elements at desired sites within the
productive formation. The extendable members include a casing
fitting adapted to secure the member to a portion of the wall of a
casing section, an inner sleeve, an inner sleeve stop, an outer
sleeve, an outer sleeve stop and a sand control medium disposed in
a distal section of an interior of the inner sleeve, where the
sleeves are designed to move from a retracted state to an extended
state to form a telescoping conduit and a distal end is designed to
contact a site of a productive formation forming a production
conduit with the sand control medium interposed between the
formation and an inner of the casing.
[0032] The productive formations can be identified during well
construction by utilizing logging while drilling tools or openhole
electric logs. These tools identify the productive formations depth
and thickness of the productive formations. The extendable members
which will replace the perforation and gravel pack completion are
spaced out on the casing string to allow them to be aligned with
the productive formations as determine by the well logs. Depending
on the expected productivity of the formation generally between 1
and 12 extendable members per foot may be required to effectively
drain a reservoir. In many cases 4 extendable members per foot will
be adequate. The casing is then run into the borehole such that the
extendable members are positioned opposite the productive
formation. The extendable members are extended mechanically, or
hydraulically or a combination of mechanical and hydraulic means.
This allows the devices to come in contact with the filter cake and
formation face. Also, the devices will help centralize the casing
in the borehole. The casing is then cemented. The production
tubing/equipment is then run into the well. Depending on the type
of "Drill-In Fluid" used in the drilling process, the well may be
placed on production or solvents pumped to remove the filter cake.
If the well has been drilled in an under balanced or near balanced
condition, there should be little if any filter cake to remove.
[0033] Suitable fluid systems for using in drilling the intervals
of a well that penetration into or into and through a productive
formation include, without limitation, any fluid system comprises a
fluid carrier and particles, where the particles have a particle
size distribution for forming a low permeability filter cake on a
formation face as the well is drilled and where the particle size
distribution is designed so that a majority of the particles in the
filter cake flow back into the casing through a sand control filter
medium associated with the extendable members and minimizing
adverse affects on formation productivity. One such fluid system
for drilling the productive formation is disclosed in U.S. Pat. No.
5,504,062 to Johnson, incorporated herein by reference. Those
skilled in the art will recognize that these types of fluid systems
have the ability to minimize filtrate and particle invasion into
the formation. U.S. Pat. No. 5,504,062 also disclosed, a
formulation of particle sizes that protect the formation and flow
back through conventional gravel pack media with minimal damage to
the production potential of a formation. These fluids have been
designed for use in openhole well construction; more particularly
they are used for openhole horizontal drilling. Other fluid systems
are disclosed U.S. Pat. Nos. 4,620,596, 4,369,843; and 4,186,803 to
Mondshine, incorporated herein by reference. The fluid system
includes sized salt particles; which protect the formation during
well construction and workover operations. The fluids disclosed by
Mondshine have been applied as drilling fluids in horizontal
openhole well construction. If the fluids disclosed by Mondshine
are used in the present invention, a solvent would be required to
reduce the filter cake particle sizes or completely dissolve the
salt particles in the filter cake. These particular fluids are of
interest in the invention because the solvent may come from conate
water, water already present in the formation, which would dissolve
the salt particles insitu and eliminate having to pump an acid or
solvent into the well prior to production. While the use of the
fluids mentioned above are preferred embodiments for the inventive
method, the use of these fluid systems should not be interpreted as
a limitation. As new polymers and fluid formulations are tested and
become available in the market which protect the formation and have
the ability to be dissolved or sufficiently flow back through the
gravel pack filter medium to maximize productivity. These fluids,
which are used in well construction for drilling openhole
horizontal wells, are a class of drilling fluids known as "Drill-In
Fluids."
[0034] Referring to FIG. 1, a drilling vessel or platform 2
including a drilling rig 1. A subsea blowout preventer stack 3 may
be positioned on an ocean floor 3a in offshore application. The
well casing string 45 includes a conductor elements 4, a surface
element 5, and an intermediate element 6. As is well understood by
those of ordinary skill in the art, the casing string is placed in
boreholes and then cemented in place. As is shown in FIG. 1,
drilling of a well borehole 50 is continued to a target reservoir
16. The drilling assembly 55 includes of a drill string 7, logging
while drilling formation evaluation sensors 8, a drilling motor 9,
a drill string stabilizer 10, and a drill bit 11. As is shown in
FIG. 1, the bottom hole assembly 12, includes the logging while
drilling formation evaluation sensors 8, the drilling motor 9, the
drill string stabilizer 10, and the drill bit 11.
[0035] As shown in FIG. 1, the bottom hole assembly 12 has
intersected a marker formation 15. The marker formation 5 is a
selected geological indicator that is reached prior to the borehole
50 intersecting the target formation 16. The marker formation 15
provides an indication of the additional drilling depth needed
drill from a current bottom hole position 14 to the target
formation 16. When the bottom hole position 14 is approximately 200
to 500 feet above the target formation 16, conventional drilling
mud is displaced with a "Drill-In Fluid" selected to protect the
formation in the target reservoir 16 during drilling into or into
and through the target formation 16. The "Drill-In Fluid" displaces
the conventional mud by pumping the "Drill-In Fluid" into the drill
string 7 pushing the conventional drilling fluid out of the
borehole 45 via return up an annulus space 13.
[0036] Referring now to FIG. 2, drilling of the borehole 50 is
continued and extended into or into and through the target
reservoir 16 using the "Drill-In Fluid". The bottom of the well 14
is now shown extended through the target reservoir 16.
[0037] Referring now to FIG. 3, the target reservoir 16 has a
formation matrix 27 including solid particles 18 and pore spaces
17. The pore spaces 17 are the area in the formation that generally
contains oil, gas, and/or water. Looking at FIG. 3B, an example of
what can happen to a formation matrix 28 is graphically depicted if
a conventional drilling fluid is used to drill into and through the
target reservoir or formation 16. As can be seen in the formation
matrix 28, a filter cake 19 has been formed from on a face 28a of
the matrix 28 and mud filtrate and solid particles have invaded the
pore spaces 17 which can cause a reduction in well productivity.
Looking at FIG. 3C, a formation matrix 29 is shown depicting the
use of a "Drill-In Fluid" for drilling within the target reservoir
16, which forms a filter cake 20 with little or no invasion of
particulate into the pore spaces 17 protecting the formation matrix
29. This type of fluid will minimize any negative effects on
productivity.
[0038] After reaching the total depth 14 as shown in FIG. 2, the
drill string 7 and bottom hole assembly 12 are pulled from the
borehole 45. Casing is run into the well. The casing will have
extendable members positioned such that when the casing reaches the
bottom of the borehole 14 the extendable members are positioned and
aligned with sites in the target reservoir 16.
[0039] Referring now to FIG. 4, a section 21 of the target
formation or reservoir 16 is depicted showing an adjacent portion
22a of a casing 22 having an extendable member 23 aligned adjacent
a site 21a of the section 21 of the target reservoir 16. Although
FIG. 4 shows only a single member 23, a plurality of members 23 can
be associated with sections of the casing in a spaced apart
configuration to provide a plurality of production conduits within
the target reservoir 16 depending on the production requirements of
the reservoir 16. In one preferred arrangement, four extendable
members per foot of formation are used to provide an adequate
number of production conduits for most formations within producing
hydrocarbon reservoirs. However, lesser and greater number of
extendable members can be used as well depending on the desired
production level. Generally, the number of extendable members will
be between 1 per foot of formation to about 20 per foot, with
between 2 and 10 being preferred and between 3 and 8 being
particularly preferred.
[0040] Referring back to FIG. 4, an extendable member 23 is shown
in its run position or retracted state. The extendable member 23
includes an inner sleeve 30 having an inner sleeve lip 31, an
interior 32, a sand control medium 33 disposed in a distal end
portion 34 of the interior 32, an outer sleeve 35 having an inner
sleeve stop 36 and an outer sleeve lip 37 and a fitting 38 having
an outer sleeve stop 39, where the fitting 38 is adapted to attach
the member 23 to the casing 22. The annulus 13 may be filled at
this point with "Drill-In Fluid" or the "Drill-In Fluid" displaced
with a solids free fluid. A filter cake 20 protects a face 21b of
the formation section 21.
[0041] Referring now to FIG. 5, the expendable member 23 is shown
in its extended state, where hydraulic pressure has been used to
force a distal end 40 of the member 23 in contact with a portion 25
of the filter cake 20 associated with the site 21a of the section
21 of the formation 16. The well is now ready to be cemented.
[0042] Referring now to FIG. 6, the annulus 13 is shown filled with
a cement 24 isolating the section 21 of the formation 16, except
for flow control points associated with the extendable members 23.
At this point production tubing/equipment is run into the well and
the well made ready for production.
[0043] Referring now to FIG. 7, the formation section 21 is shown
producing through an interior 32 of the extendable member 23. It
should be noted that fluid 26 produced from formation section 21
has removed the portion 25 of the filter cake 20 in the area
constrained by the extendable member 23. The produce fluids 26
travel through the interior 32 of the extendable member 23 into an
interior 22b of the casing 22. The produced fluids 26 continue up
the casing 22 and eventually enter the production tubing. They
produced fluids 26 which may contain oil, gas, and/or water flow to
the surface via the production tubing for processing and/or sale.
Should production not reach expected levels quickly enough a
solvent may be used to facilitate filter cake removal.
[0044] All references cited herein are incorporated by reference.
The terms comprising, including and having are equivalent open
ended claim terms and are used interchangeable to make the claims
for understandable. While this invention has been described fully
and completely, it should be understood that, within the scope of
the appended claims, the invention may be practiced otherwise than
as specifically described. Although the invention has been
disclosed with reference to its preferred embodiments, from reading
this description those of skill in the art may appreciate changes
and modification that may be made which do not depart from the
scope and spirit of the invention as described above and claimed
hereafter.
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