U.S. patent application number 10/423126 was filed with the patent office on 2004-10-28 for methods and apparatus for completing unconsolidated lateral well bores.
Invention is credited to Dusterhoft, Ronald G., Gibson, Ron, Lord, David L., McMechan, David E., Nguyen, Philip D., Sanders, Michael.
Application Number | 20040211559 10/423126 |
Document ID | / |
Family ID | 33299036 |
Filed Date | 2004-10-28 |
United States Patent
Application |
20040211559 |
Kind Code |
A1 |
Nguyen, Philip D. ; et
al. |
October 28, 2004 |
Methods and apparatus for completing unconsolidated lateral well
bores
Abstract
Improved methods and apparatus for completing unconsolidated
subterranean zones penetrated by well bores are provided. The
methods basically comprise the steps of placing a slotted pipe
having openings formed therein which vary in size or in the number
of openings along the length of the slotted pipe or both in the
subterranean zone, isolating the annulus between the slotted pipe
and the well bore and injecting particulate material into the
annulus whereby the particulate material is uniformly packed
therein.
Inventors: |
Nguyen, Philip D.; (Duncan,
OK) ; Sanders, Michael; (Duncan, OK) ; Gibson,
Ron; (Duncan, OK) ; Lord, David L.; (Marlow,
OK) ; McMechan, David E.; (Duncan, OK) ;
Dusterhoft, Ronald G.; (Katy, TX) |
Correspondence
Address: |
Robert A. Kent
Halliburton Energy Services
2600 S. 2nd Street
Duncan
OK
73536
US
|
Family ID: |
33299036 |
Appl. No.: |
10/423126 |
Filed: |
April 25, 2003 |
Current U.S.
Class: |
166/276 ;
166/242.1; 166/278; 166/387; 166/50; 166/51 |
Current CPC
Class: |
E21B 43/045 20130101;
E21B 43/086 20130101; E21B 43/12 20130101 |
Class at
Publication: |
166/276 ;
166/278; 166/050; 166/051; 166/242.1; 166/387 |
International
Class: |
E21B 043/04; E21B
043/08 |
Claims
What is claimed is:
1. An improved method of completing an unconsolidated subterranean
zone subject to migration of formation fines and sand with produced
formation fluids penetrated by a lateral well bore comprising the
steps of: (a) placing a slotted pipe in said lateral well bore
having openings formed therein through which said produced
formation fluids flow, said openings varying in size or varying in
the number of said openings along the length of said slotted pipe
or both so that said produced formation fluids flow into said
slotted pipe at substantially equal flow rates over the length of
said slotted pipe; (b) isolating the annulus between said slotted
pipe and said well bore; and (c) injecting particulate material
into said annulus between said slotted pipe and said well bore
whereby said particulate material is uniformly packed in said
annulus and in the interior of said slotted pipe whereby the
migration of formation fines and sand with produced formation
fluids is prevented.
2. The method of claim 1 wherein said well bore in said
subterranean zone is open-hole.
3. The method of claim 1 wherein said particulate material is
graded sand.
4. The method of claim 1 wherein said particulate material is
coated with a hardenable resin composition which hardens and
consolidates said particulate material into a hard permeable
uniform mass.
5. The method of claim 4 which further comprises the step of
drilling at least a portion of said hard permeable mass of
particulate material out of the interior of said slotted pipe.
6. The method of claim 1 wherein said annulus between said slotted
pipe and said lateral well bore is isolated in accordance with step
(b) by setting a packer in said well bore.
7. The method of claim 3 which further comprises an internal sand
screen disposed within said slotted pipe which forms an annulus
between said sand screen and said slotted pipe which is also
isolated.
8. The method of claim 7 wherein said particulate material is also
injected into said annulus between said sand screen and said
slotted pipe.
9. The method of claim 8 wherein said particulate material is
coated with a hardenable resin composition which hardens and
consolidates said particulate material into a hard permeable
uniform mass.
10. The method of claim 3 wherein said graded sand has a particle
size in the range of from about 10 to about 70 mesh, U.S. Sieve
Series.
11. An improved method of completing an unconsolidated subterranean
zone subject to migration of formation fines and sand with produced
formation fluids penetrated by a lateral well bore comprising the
steps of: (a) placing a slotted pipe in said lateral well bore
having openings formed therein through which said produced
formation fluids flow and having an internal sand screen disposed
therein, said openings in said slotted pipe varying in size or
varying in the number of said openings along the length of said
slotted pipe or both so that said produced formation fluids flow
into said slotted pipe at substantially equal flow rates over the
length of said slotted pipe; (b) isolating the annulus between said
slotted pipe and said well bore and the annulus between said sand
screen and said slotted pipe; and (c) injecting particulate
material into said annulus between said slotted pipe and said well
bore and said annulus between said slotted pipe and said sand
screen whereby said particulate material is uniformly packed in
said annuluses and the migration of formation fines and sand with
produced fluids is prevented.
12. The method of claim 11 wherein said well bore in said
subterranean zone is open-hole.
13. The method of claim 11 wherein said particulate material is
graded sand.
14. The method of claim 11 wherein said particulate material is
coated with a hardenable resin composition which hardens and
consolidates said particulate material into a hard permeable
uniform mass.
15. The method of claim 11 wherein said annulus between said
slotted pipe and said well bore and said annulus between said sand
screen and said slotted pipe are isolated in accordance with step
(b) by setting a packer in said well bore.
16. The method of claim 13 wherein said graded sand has a particle
size in the range of from about 10 to about 70 mesh, U.S. Sieve
Series.
17. An apparatus for completing an unconsolidated well bore
comprising: a slotted pipe having openings formed therein through
which produced formation fluids flow, said openings varying in size
or varying in the number of said openings along the length of said
slotted pipe or both so that said produced formation fluids flow
into said slotted pipe at substantially equal flow rates over the
length of said slotted pipe; a removable cross-over adapted to be
attached to a production or work string attached to said slotted
pipe; and a production packer attached to said slotted pipe.
18. The apparatus of claim 17 which further comprises a sand screen
disposed within said slotted pipe and attached thereto.
19. The apparatus of claim 17 wherein said production packer is
selectively operable from the surface when located in said well
bore.
20. The apparatus of claim 17 wherein said cross-over is
selectively operable from the surface when located in said well
bore to change from a first flow pattern to a second flow pattern.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to improved methods and
apparatus for completing unconsolidated lateral well bores.
[0003] 2. Description of the Prior Art
[0004] Lateral well bores, i.e., well bores that are drilled
horizontally or substantially in a horizontal direction from a
vertical or substantially vertical primary well bore are often
completed in unconsolidated formations containing loose and
incompetent fines and sand which migrate with fluids produced from
the formations. The presence of formation fines and sand in the
produced fluids is undesirable in that the particles abrade tubular
goods, producing equipment, pumps and the like and reduce the fluid
production capabilities of the formations.
[0005] In order to terminate or reduce the presence of formation
fines and sand in produced fluids, completions utilizing gravel
packs are often utilized. In a typical gravel pack completion, a
screen is placed in the well bore and positioned within the
unconsolidated subterranean zone which is to be completed. The
screen is connected to a tool which includes a production packer
and a crossover and the tool is in turn connected to a work or
production pipe string. A particulate material which is usually
graded sand, often referred to in the art as gravel, is pumped in a
slurry down the work or production pipe string and through the
crossover whereby it flows into the annulus between the screen and
the well bore. The liquid forming the slurry leaks off into the
subterranean zone and/or through the screen which is sized to
prevent the gravel in the slurry from flowing therethrough. As a
result, the gravel is deposited in the annulus around the screen
whereby it forms a gravel pack. The size of the gravel in the
gravel pack is selected such that it prevents formation fines and
sand from flowing into the well bore with produced fluids.
[0006] Gravel packs have also been formed in well bores using
slotted pipes. The gravel is placed in the annulus between a
slotted pipe and the walls of the well bore as well as within the
pipe. The gravel is usually coated with a hardenable resin
composition which consolidates the gravel into a hard permeable
pack. Thereafter, the gravel deposited within the slotted pipe can
be drilled out of the slotted pipe or left in the slotted pipe as
desired.
[0007] Another more recent gravel pack procedure which prevents the
formation of gravel bridges in the annulus between the walls of a
well bore and a screen or slotted pipe has been developed and
utilized successfully. Gravel bridges occur as the result of
non-uniform gravel packing in the annulus due to the loss of
carrier liquid from the gravel slurry into high permeability
portions of the subterranean zone. The gravel bridges occur before
all of the gravel has been placed and they block further flow of
the slurry and gravel through the annulus which leaves voids in the
annulus. When the well is placed on production, the flow of
produced fluids is concentrated through the voids in the gravel
pack which soon causes the migration of fines and sand with the
produced fluids.
[0008] Gravel bridges have heretofore been prevented by utilizing a
slotted pipe, i.e., a pipe with openings formed therein, with a
sand screen disposed within the slotted pipe. The gravel slurry is
injected into the annulus between the slotted pipe and the walls of
the well bore and between the slotted pipe and the sand screen.
This arrangement allows the gravel slurry to flow around gravel
bridges and deposit gravel in voids produced.
[0009] Another problem very often encountered in the completion of
lateral well bores involves unequal production of formation fluids
along the length of the lateral well bore. Lateral well bores are
utilized in subterranean formation producing zones to increase the
area of well bore penetration in the subterranean zones to thereby
increase hydrocarbon production. However, the portion of a
subterranean formation penetrated by the heel of a lateral well
bore often experiences higher draw-down pressure than the portion
of the well bore closest to the toe. The term "heel" refers to the
portion of the lateral well bore where the well bore begins its
curvature to horizontal and the term "toe" refers to the end
portion of the lateral well bore. As a result of the higher
draw-down pressure, higher hydrocarbon production rates result from
the heel than from the toe. The higher hydrocarbon production rates
from the heel can bring about early water break through or early
gas break through. This in turn can cause the full production
potential of the toe section to never be realized.
[0010] Thus, there are needs for improved methods and apparatus for
completing lateral wells bores in unconsolidated subterranean zones
using gravel packs whereby gravel bridges are prevented and
produced formation fluids are caused to flow into the slotted pipe
at substantially equal rates over the length of the slotted
pipe.
SUMMARY OF THE INVENTION
[0011] The present invention provides improved methods and
apparatus for completing unconsolidated subterranean zones subject
to migration of formation fines and sand with produced formation
fluids penetrated by lateral well bores which meet the needs
described above and overcome the deficiencies of the prior art. The
improved methods basically comprise the steps of placing a slotted
pipe in the lateral well bore having openings formed therein
through which produced formation fluids flow. The openings vary in
size or vary in the number of the openings along the length of the
slotted pipe or both so that the produced formation fluids flow
into the slotted pipe at substantially equal flow rates over the
length of the slotted pipe. The annulus between the slotted pipe
and the well bore is isolated and particulate material is injected
into the annulus whereby the particulate material is uniformly
packed in the annulus and in the interior of the slotted pipe so
that the migration of formation fines and sand with produced
formation fluids is prevented.
[0012] The lateral well bore can be cased with perforations formed
therein or completed open-hole and the particulate material is
preferably graded sand. The particulate material utilized is
preferably coated with a hardenable resin composition which hardens
and consolidates the particulate material into a hard permeable
uniform mass. Once the hardenable resin has hardened whereby the
particulate material is consolidated into a hard permeable pack in
the annulus between the slotted pipe and the well bore as well as
in the interior of the slotted pipe, at least a portion of the hard
permeable mass within the interior of the slotted pipe can be
drilled out if desired.
[0013] Another method of the present invention is comprised of the
following steps. A slotted pipe is placed in the lateral well bore
having openings formed therein through which the produced formation
fluids flow and having an internal sand screen disposed therein.
The slotted pipe includes openings that vary in size or vary in the
number of openings along the length of the slotted pipe or both so
that the produced formation fluids flow into the slotted pipe at
substantially equal flow rates over the length of the slotted pipe.
The annulus between the slotted pipe and the well bore and the
annulus between the sand screen and the slotted pipe are isolated.
Thereafter, particulate material is injected into the annulus
between the slotted pipe and the well bore and the annulus between
the slotted pipe and the sand screen whereby the particulate
material is uniformly packed in the annuluses and the migration of
formation fines and sand with produced fluids is prevented.
[0014] The objects, features and advantages of the present
invention will be readily apparent to those skilled in the art upon
a reading of the description of preferred embodiments which follows
when taken in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] FIG. 1 is a side cross-sectional view of a lateral open-hole
well bore penetrating an unconsolidated subterranean producing zone
having a slotted pipe, a production packer and a crossover
connected to a production string disposed therein. The drawing
illustrates the placement of gravel between the well bore and the
slotted pipe and between the slotted pipe and the sand screen.
[0016] FIG. 2 is a side cross-sectional view of the lateral well
bore, the slotted pipe with an internal sand screen, the production
packer and the cross-over of FIG. 1 after the gravel has been
placed and produced fluids are flowing to the surface.
DESCRIPTION OF PREFERRED EMBODIMENTS
[0017] The present invention provides improved methods and
apparatus for completing an unconsolidated subterranean zone
subject to the migration of formation fines and sand penetrated by
a lateral well bore having unequal produced formation fluid flow
rates over the length of the well bore. The term "lateral well
bore" is used herein to mean the portion of a well bore in an
unconsolidated subterranean producing zone to be completed which is
substantially horizontal or at an angle from vertical in the range
of from about 65.degree. to about 105.degree.. The term "slotted
pipe" is used herein to mean pipe which includes slots, holes or
other shaped openings therein.
[0018] Referring now to the drawings, the improved apparatus of the
present invention is illustrated disposed in an open hole lateral
well bore 2. The lateral well bore 2 is illustrated extending into
an unconsolidated subterranean zone 4 from a cased and cemented
well bore 6 which extends to the surface. A slotted pipe 8 having a
plurality of openings 24 therein is disposed in the lateral well
bore 2 whereby an annulus 22 is formed between the walls of the
well bore 2 and the slotted pipe 8. A sand screen 10 is disposed
within the slotted pipe 8 in a manner whereby an annulus 12 is
formed between the slotted pipe 8 and the sand screen 10. The
slotted pipe 8 and sand screen 10 are connected to a removable
cross-over 14 which is in turn connected to a production or work
string 16. A production packer 18 is connected to the slotted pipe
8 which is set within the casing 20 in the well bore 6. As will be
described further hereinbelow, FIG. 1 illustrates the operation of
the apparatus of this invention when a slurry of particulate
material is pumped into the annulus 12 between the slotted pipe 8
and the sand screen 10 and into the annulus 22 between the slotted
pipe 8 and the walls of the well bore 2. FIG. 2 illustrates the
apparatus of the invention after the particulate material 26 has
been packed into the annuluses 12 and 22 and the well is returned
to production. The pack of particulate material 26 within the
annuluses 12 and 22 filters out and prevents the migration of
formation fines and sand with produced formation fluids that enter
the well bore 2 from the unconsolidated subterranean zone 4.
[0019] As is understood by those skilled in the art, the removable
cross-over 14 is a sub-assembly which allows fluids to follow a
first flow pattern whereby particulate material suspended in a
slurry can be packed in the annuluses 12 and 22 between the sand
screen 10 and the slotted pipe 8 and between the slotted pipe 8 and
the well bore 2. That is, as shown by the arrows in FIG. 1, the
particulate material suspension flows from inside the production or
work string 16 into the annulus between the sand screen 10 and the
slotted pipe 8 and into the annulus between the slotted pipe 8 and
the well bore 2 by way of ports in the cross-over 14.
Simultaneously, fluid is allowed to flow from inside the sand
screen 10 through the cross-over 14 to the other side of the packer
18 outside the production string. By pipe movement or other
procedure, flow through the cross-over 14 can be changed to a
second flow pattern whereby fluid from inside the sand screen 10
flows directly into the production string.
[0020] As shown in the drawings, the slotted pipe 8 includes a
plurality of circular openings 24 formed therein through which the
produced formation fluids flow. The openings 24 are of varying
sizes extending over the length of the slotted pipe 8. That is, the
openings 24 are small at the inlet end of the slotted pipe 8
adjacent to the heel portion of the well bore 2 (identified in the
drawings by the numeral 30) and increase in size over the length of
the slotted pipe to the toe portion of the well bore (identified in
the drawings by the numeral 32). The openings 24 can be of varying
size over the length of the slotted pipe 8 as shown in the drawings
or the openings 24 can be of the same size over the length of the
slotted pipe 8 with the number of openings increasing or otherwise
varying over the length of the slotted pipe 8.
[0021] As is well known and generally the case, the production of
produced hydrocarbon fluids near the heel portion of a lateral well
bore have a high flow rate while the production of hydrocarbons
near the toe of the well bore are much lower. This unequal
production of hydrocarbons from the heel to the toe often leads to
premature gas or water coning at the heel portion of the well bore,
i.e., the area of high flow rate, which reduces the total volume of
hydrocarbons that can be produced from the well bore. In accordance
with the present invention, this problem is prevented by varying
the size or the number of openings 24 over the length of the
slotted pipe 8 whereby the flow rate of produced fluids into the
slotted pipe 8 from the lateral well bore is distributed
substantially equally over the length of the slotted pipe 8. The
required sizes of the openings 24 or the number of the same size
openings 24 allocated over the length of the slotted pipe 8 is
determined by production tests conducted in the lateral well bore
prior to the placement of the slotted pipe 8 and related apparatus
in the well bore or by estimation of the pressure drop from the
heel of the well bore to the toe of the well bore. Depending on the
particular lateral well bore involved and the particular areas of
high or low formation fluid production, the sizes and/or number of
openings required in the slotted pipe 8 to produce substantially
equal flow rates of produced fluids into the slotted pipe 8 over
its length are determined. A slotted pipe 8 with those openings is
then placed in the lateral well bore along with the other apparatus
required.
[0022] Referring again to FIGS. 1 and 2, the methods of the present
invention for completing the well bore 2 in the unconsolidated
subterranean zone 4 are as follows. The slotted pipe 8 containing
the openings 24 required to produce equal produced fluid flow over
the length of the slotted pipe 8 with the sand screen 10 therein is
placed in the well bore 2. As will be understood, the sand screen
can be omitted if the procedure described above is utilized whereby
the particulate material placed in the well bore is consolidated
into a permeable pack or is otherwise prevented from flowing out of
the well bore with produced formation fluids. The annulus 22
between the slotted pipe 8 and the walls of the well bore 2 as well
as the annulus between the sand screen 10 and the slotted pipe 8
are isolated by setting the packer 18. Thereafter, a slurry of
particulate material is injected into the annulus 12 between the
sand screen 10 and the slotted pipe 8 and into the annulus 22
between the walls of the well bore 2 and the slotted pipe 8.
Because the particulate material slurry is free to flow through the
openings 24 as well as the open end of the slotted pipe 8, the
particulate material is uniformly packed into the annulus 22
between the well bore 2 and slotted pipe 8 and into the annulus 12
between the sand screen 10 and the slotted pipe 8. The pack of
particulate material 26 formed filters out and prevents the
migration of formation fines and sand with fluids produced into the
well bore 2 from the subterranean zone 4. The methods and apparatus
of this invention are particularly suitable and beneficial in
forming gravel packs in long-interval lateral wells without the
formation of sand bridges.
[0023] The particulate gravel material utilized in accordance with
the present invention is generally of a size such that formation
fines and sand that migrate with produced fluids are prevented from
being produced. Various kinds of particulate gravel materials can
be utilized including graded sand, bauxite, ceramic materials,
glass materials, polymer beads and the like. Generally the gravel
particles have a size in the range of from about 2 to about 400
mesh, U.S. Sieve Series. The preferred particulate gravel material
is graded sand having a particle size in the range of from about 10
to about 70 mesh, U.S. Sieve Series. Preferred sand particle size
distribution ranges are one or more of 10-20 mesh, 20-40 mesh,
40-60 mesh or 50-70 mesh, depending on a particular size and
distribution of formation solids to be screened out by the
particulate gravel material.
[0024] As mentioned, the particulate gravel material can be coated
with a hardenable resin composition. After the hardenable resin
composition coated gravel is placed in the well bore, the
hardenable resin composition hardens and consolidates the gravel
into a hard permeable mass. A variety of resin compositions are
well known to those skilled in the art as is their use for
consolidating gravel material into hard permeable masses. Examples
of hardenable organic resins which are suitable for use in
accordance with this invention are novolac resins, polyepoxide
resins, polyester resins, phenol-aldehyde resins, urea-aldehyde
resins, furan resins, urethane resins, and mixtures of such resins.
These resins are available at various viscosities depending upon
the molecular weights of the resins. The resin or mixture of resins
utilized is generally diluted with a diluent. For example,
polyepoxide resins can be diluted with methanol, butanol,
dipropylene glycol methyl ether or dipropylene glycol dimethyl
ether; whereas furan or phenolic resins can be diluted with
phenols, formaldehydes, furfuryl alcohol, furfural or 2-butoxy
ethanol. Also, silane coupling agents are generally utilized in the
hardenable resin compositions to promote coupling or adhesion to
sand or other similar particulate gravel materials. Particularly
suitable coupling agents are aminosilane compounds or mixtures of
such compounds. A preferred coupling agent is
N-beta-(aminoethyl)-gamma-aminopropyltrimethoxysilane. The
hardenable resin composition used is caused to harden by allowing
it to be heated in the formation or by contacting it with a
hardening agent. When a hardening agent is utilized, it can be
included in the resin composition. Examples of suitable internal
hardening agents for polyepoxide resins include, but are not
limited to, amines and amides, preferably 2-ethyl 4-methyl
imidazole and 4,4'-diaminodiphenyl sulfone. The suitable internal
hardening agents for resin compositions containing furan resin,
phenol aldehyde resin or urea-aldehyde resin include, but are not
limited to, hexachloroacetone, 1,1,3-trichlorotrifluoroacetone,
benzotrichloride, benzylchloride and benzalchloride. The hardenable
resin compositions can also include other components such as
surfactants, dispersants, esters and other additives which are well
known to those skilled in the art.
[0025] When particulate gravel material coated with a hardenable
resin composition is utilized, the sand screen disposed within the
slotted-pipe can be eliminated. When the sand screen is not
utilized, resin composition coated particulate material is injected
into the annulus between the walls of the well bore and the slotted
pipe as well as into the interior of the slotted pipe. After the
hardenable resin composition coated proppant has hardened into a
strong permeable pack within the annulus and within the slotted
pipe, all or a portion of the consolidated proppant can be removed
from the interior of the slotted pipe if desired.
[0026] When a sand screen within the slotted pipe is utilized as
illustrated in the drawings, the sand screen prevents the proppant
material from flowing out of the well bore with produced fluids. In
addition to the sand screen, the particulate material can also be
coated with a hardenable resin composition whereby the particulate
material is consolidated into a strong permeable pack.
[0027] The particulate gravel material carrier liquid utilized can
be any of the various viscous carrier liquids utilized heretofore
including gelled water, oil based liquids, foams or emulsions. The
most common carrier liquid utilized heretofore which is also
preferred for use in accordance with this invention is comprised of
an aqueous liquid such as fresh water or salt water combined with a
gelling agent for increasing the viscosity of the carrier liquid.
The increased viscosity reduces fluid loss and allows the carrier
liquid to transport significant concentrations of particulate
gravel material into the subterranean zone to be completed.
[0028] A variety of gelling agents have been utilized including
hydratable polymers which contain one or more functional groups
such as hydroxyl, cis-hydroxyl, carboxyl, sulfate, sulfonate, amino
or amide. Particularly useful such polymers are polysaccharides and
derivatives thereof which contain one or more of the monosaccharide
units galactose, mannose, glucoside, glucose, xylose, arabinose,
fructose glucuronic acid or pyranosyl sulfate. Various natural
hydratable polymers contain the foregoing functional groups and
units including guar gum and derivatives thereof, cellulose and
derivatives thereof and the like. Hydratable synthetic polymers and
copolymers which contain the above mentioned functional groups can
also be utilized including polyacrylate, polymethylacrylate,
polyacrylamide and the like.
[0029] Particularly preferred hydratable polymers which yield high
viscosities upon hydration at relatively low concentrations are
guar gum and guar derivatives such as hydroxypropylguar and
carboxymethylguar and cellulose derivatives such as
hydroxyethylcellulose, carboxymethylcellulose and the like.
[0030] The viscosities of aqueous polymer solutions of the types
described above can be increased by combining cross-linking agents
with the polymer solutions. Examples of cross-linking agents which
can be utilized are multivalent metal salts, alkali metal borates,
borax, boric acid and other boron compounds. The gelled or gelled
and cross-linked carrier liquids can also include gel breakers such
as those of the enzyme type, the oxidizing type or the acid buffer
type which are well known to those skilled in the art. The gel
breakers cause the viscous carrier liquids to revert to thin fluids
that can be produced back to the surface after they have been
utilized.
[0031] An improved method of the present invention for completing
an unconsolidated subterranean zone subject to migration of
formation fines and sand with produced formation fluids penetrated
by a lateral well bore comprises the steps of: (a) placing a
slotted pipe in the lateral well bore having openings formed
therein through which the produced formation fluids flow, the
openings varying in size or varying in the number of the openings
along the length of the slotted pipe or both so that the produced
formation fluids flow into the slotted pipe at substantially equal
flow rates over the length of the slotted pipe; (b) isolating the
annulus between the slotted pipe and the well bore; and (c)
injecting particulate material into the annulus between the slotted
pipe and the well bore whereby the particulate material is
uniformly packed in the annulus and in the interior of the slotted
pipe whereby the migration of formation fines and sand with
produced formation fluids is prevented.
[0032] Another preferred method of this invention for completing an
unconsolidated subterranean zone subject to migration of formation
fines and sand with produced formation fluids penetrated by a
lateral well bore comprises the steps of: (a) placing a slotted
pipe in the lateral well bore having openings formed therein
through which the produced formation fluids flow and having an
internal sand screen disposed therein, the openings in the slotted
pipe varying in size or varying in the number of the openings along
the length of the slotted pipe or both so that the produced
formation fluids flow into the slotted pipe at substantially equal
flow rates over the length of the slotted pipe; (b) isolating the
annulus between the slotted pipe and the well bore and the annulus
between the sand screen and the slotted pipe; and (c) injecting
particulate material into the annulus between the slotted pipe and
the well bore and the annulus between the slotted pipe and the sand
screen whereby the particulate material is uniformly packed in the
annuluses and the migration of formation fines and sand with
produced fluids is prevented.
[0033] A preferred apparatus of the present invention for
completing an unconsolidated well bore comprises: a slotted pipe
having openings formed therein through which produced formation
fluids flow, the openings varying in size or varying in the number
of the openings along the length of the slotted pipe or both so
that the produced formation fluids flow into the slotted pipe at
substantially equal flow rates over the length of the slotted pipe;
a removable cross-over adapted to be attached to a production or
work string attached to the slotted pipe; and a production packer
attached to the slotted pipe.
[0034] As mentioned above, the production packer and the cross-over
are selectively operable from the surface. When operated, the
packer is set and the cross-over changes from a first flow pattern
to a second flow pattern.
[0035] As will be understood by those skilled in the art, instead
of the single slotted pipe or single slotted pipe with a sand
screen disposed therein as described and claimed herein, other
arrangements of one or more slotted pipes of this invention having
openings varying in size or varying in the number of the openings
along the length thereof, or both, with or without sand screens can
be substituted therefore. Examples of such other arrangements that
can be utilized are described in detail in U.S. Pat. No.
6,516,881B2 issued to Hailey, Jr. on Feb. 11, 2003 and in U.S. Pat.
No. 6,516,882B2 issued to McGregor, et al. on Feb. 11, 2003, which
are incorporated in their entireties herein by reference
thereto.
[0036] Thus, the present invention is well adapted to carry out the
objects and attain the ends and advantages mentioned as well as
those which are inherent therein. While numerous changes can be
made by those skilled in the art, such changes are encompassed
within the spirit of this invention as defined by the appended
claims.
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