U.S. patent application number 11/410225 was filed with the patent office on 2007-10-25 for offset valve system for downhole drillable equipment.
Invention is credited to Christiaan Krauss, Steve Rosenblatt.
Application Number | 20070246224 11/410225 |
Document ID | / |
Family ID | 38618385 |
Filed Date | 2007-10-25 |
United States Patent
Application |
20070246224 |
Kind Code |
A1 |
Krauss; Christiaan ; et
al. |
October 25, 2007 |
Offset valve system for downhole drillable equipment
Abstract
Float equipment is constructed to have the check valve in an
offset and/or skewed position with respect to the centerline of the
tubular housing that is part of a string. The design is applicable
to poppet type check valves as well as flapper type valves that are
actuated with a flow tube. The off center and/or skewed position of
the valve components allows the cutting structure on a drill bit,
rather than the nozzle area on the bit bottom to make intimate
contact with the valve components to accelerate the milling one of
the assembly and the making of additional hole beyond the recently
cemented string.
Inventors: |
Krauss; Christiaan; (Spring,
TX) ; Rosenblatt; Steve; (Houston, TX) |
Correspondence
Address: |
DUANE MORRIS LLP
3200 SOUTHWEST FREEWAY
SUITE 3150
HOUSTON
TX
77027
US
|
Family ID: |
38618385 |
Appl. No.: |
11/410225 |
Filed: |
April 24, 2006 |
Current U.S.
Class: |
166/376 ;
166/177.4; 166/242.8; 166/285; 166/327 |
Current CPC
Class: |
E21B 33/1204 20130101;
E21B 33/14 20130101; E21B 21/10 20130101 |
Class at
Publication: |
166/376 ;
166/177.4; 166/285; 166/242.8; 166/327 |
International
Class: |
E21B 33/14 20060101
E21B033/14; E21B 17/14 20060101 E21B017/14; E21B 29/00 20060101
E21B029/00 |
Claims
1. A completion assembly, comprising: a tubular housing having a
longitudinal axis; a valve member having a valve longitudinal axis
in a flow path therethrough, wherein said axes are not aligned.
2. The assembly of claim 1, wherein: said axes are parallel.
3. The assembly of claim 1, wherein: said valve longitudinal axis
is skewed with respect to the housing longitudinal axis.
4. The assembly of claim 3, wherein: said axes intersect.
5. The assembly of claim 1, wherein: said axes do not
intersect.
6. The assembly of claim 1, wherein: said valve member comprises at
least one spring loaded poppet.
7. The assembly of claim 1, wherein: said valve member comprises a
flapper actuated by a flow tube.
8. The assembly of claim 1, further comprising: a bit having
cutters surrounding circulation nozzles on a bottom face thereof,
said cutters being in alignment with more of said valve member as a
result of said non alignment of said axes as compared to said axes
being aligned.
9. The assembly of claim 8, wherein: said valve member comprises at
least one poppet or flapper.
10. The assembly of claim 8, wherein: said valve member comprises a
flapper actuated by a flow tube.
11. A method of inserting and removing a downhole tool, comprising:
running a tool to a desired position downhole; supporting the tool
so that its longitudinal axis is not aligned with the longitudinal
axis of the surrounding tubular or the wellbore; running a bit to
the tool; drilling up the tool.
12. The method of claim 11, comprising: making said axes
parallel.
13. The method of claim 11, comprising: making said axes
skewed.
14. The method of claim 13, comprising: making said axes
intersect.
15. The method of claim 11, comprising: making the longitudinal
axis in said tool coincide with a selectively closeable passage in
said tool.
16. The method of claim 15, comprising: using a valve in a float
shoe or collar as said tool.
17. The method of claim 15, comprising: using a flapper valve
actuated by a flow tube in a float shoe or collar as said tool.
18. The method of claim 11, comprising: drilling more hole after
drilling up the tool.
19. The method of claim 11, comprising: supporting said tool in
cement.
20. The method of claim 11, comprising: using a packer as said
tool.
Description
FIELD OF THE INVENTION
[0001] The field of this invention is downhole equipment destined
to be milled out after use and more particularly the positioning of
the movable components within a surrounding tubular to speed up
milling and even more specifically in a cementing application to
obtain improved cement distribution while minimizing drilling fluid
entrainment which can adversely affect the quality of the cement
seal in the surrounding annulus.
BACKGROUND OF THE INVENTION
[0002] Float Equipment or an Auto-fill Collar is normally run at
the bottom of a casing or tubing string to halt cement
displacement. The short tubular section between the shoe and float
collar is called the shoe track and is provided as a buffer within
the casing to retain contamination that may build up ahead of the
displacement plugs. The length of the shoe track is adjusted
accommodating to well conditions.
[0003] The float shoe can prevent reverse flow, or U-tubing, of
cement slurry from the annulus into the casing. The float shoe also
reduces hook weight, because the check valve increases the buoyancy
of the casing string by preventing backflow of fluid as the casing
is lowered into the well.
[0004] Float equipment is basically delivered in two versions. The
first version in based upon a check valve mechanism (Float shoe and
Float Collar) and starts functioning, the moment is it run in the
well bore. The second version in normally referred to as Auto-fill
float equipment. This version allows the check valves to be
by-passed while the tubular string is run in the wellbore. At a
predetermined depth, the by-pass mechanism is de-activated (by
means of flow, or a ball or plug) and converted to a check valve as
described in the first version.
[0005] These valve mechanisms are normally placed in the center of
the well and can create great problems when they are milled or
drilled up at a later stage to deepen the wellbore.
[0006] In the present invention, placing the valve mechanism off
center, on an angle (or skewed) will prevent excessive spinning of
the valve mechanism when milled/drilled operations are performed.
An increase decrease in drill-up time can greatly increase cost
savings.
[0007] In another aspect of the present invention, a combination of
the off-setting and skewing the valves will aid in the cement
displacement and greatly improve the contamination possibility with
conventional placed equipment.
[0008] Casing is normally run in the hole with a float shoe. This
is basically a check valve that allows flow out of the casing
string being run as it is delivered into position in the wellbore.
Flow through the casing allows it to advance. When flow is cut off,
circulation stops but well fluids are prevented from entering the
casing string and it essentially floats, hence the name float shoe
because the check valve assembly is at the leading end of the
casing string. The excess cement is displaced with wiper plugs.
After the particular string of casing is cemented additional hole
will often need to be drilled beyond its lower end. To do this the
float shoe assembly must be drilled out as the bit advances into
the formation beyond the recently cemented casing.
[0009] Float shoes have been made in several ways. The most common
is to centrally support the check valve assembly in cement that
finds support in the inner wall of the casing string. Another way
is to centrally mount the check valve assembly in a soft metallic
material that is readily drillable.
[0010] Since time is money in drilling a well the speed with which
the mill out occurs is important. Operators also want to continue
the hole after mill out as quickly as possible. This has meant that
bits ideally suited for making more hole have been used to do the
mill out. Of late, these bits have been the polycrystalline diamond
type or roller cone bits or flat bottom mills. The bottom view of a
typical bit is shown in FIG. 1. The bit 10 has centrally located
nozzles 12 while the cutting inserts 16 are disposed closer to the
periphery on the bottom face. What happens when such bits are
employed to mill out a check valve 18 (or the valve mechanism #46
in the Auto-fill equipment) that is suspended in cement (or
composite material) 20 near the lower end of a casing string 22 is
that the check valve encounters the nozzle area 12 rather than
cutting inserts 14 and it starts to spin. The milling rate through
the valve 18 is considerably slower than the rate that the cutters
14 go through the cement 20. Also, since the valve mechanism is in
the center of the borehole, it makes it difficult to prevent the
valve mechanisms from spinning. As a result, operators either put
up with the slower mill rate or actually trip out of the hole to
change the bit for a mill just to mill out the float shoe and then
trip out again to install the polycrystalline diamond bit to make
more whole. Either option is not ideal. Despite this problem, the
design of float shoes has been virtually unchanged for years.
[0011] The present invention addresses the problem by moving the
position of the check valve relative to the longitudinal axis of
the assembly off center or/and skewed. It places the check valve in
greater alignment with the cutting structures on the bit to
accelerate the milling process. Those skilled in the art will
appreciate the various aspects of the present invention from the
description of the preferred embodiment and the associated drawings
as well as the claims that define the full scope of the
invention.
[0012] The following U.S. patents relate generally to design of
float equipment: U.S. Pat. Nos. 2,467,835; 4,133,378; 4,823,890;
6,296,059; 6,854,534 and 6,286,597.
SUMMARY OF THE INVENTION
[0013] Float equipment is constructed to have the check valve in an
offset and/or skewed position with respect to the centerline of the
tubular housing that is part of a string. The design is applicable
to poppet type check valves as well as flapper type valves that are
actuated with a flow tube. The off center and/or skewed position of
the valve components allows the cutting structure on a drill bit,
rather than the nozzle area on the bit bottom to make intimate
contact with the valve components to accelerate the milling out of
the assembly and the making of additional hole beyond the recently
cemented string.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] FIG. 1 is a bottom view of a known bit;
[0015] FIG. 2 is an elevation view of the float shoe assembly of
the prior art just before a bit mills it up;
[0016] FIG. 3 shows a float shoe of the present invention with a
poppet style valves off center from the longitudinal axis of the
housing;
[0017] FIG. 4 is an elevation view of a prior art flapper type
float shoe valve located on center in its housing;
[0018] FIG. 5 an elevation view of a flapper type float shoe valve
located off center in its housing for faster mill out;
[0019] FIG. 6 shows poppet style valves off center and skewed to
illustrate also the cement flow pattern between them.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0020] FIG. 3 shows a bit 24 just above a shoe track 26 which
comprises poppet type valves 28 in a float collar and 30 in a float
shoe of a typical shoe track 32 which is offset from centerline 34
of the shoe 26. Valves 28 and 30 can also be on different
centerlines from each other while both are offset radially from the
centerline 34 of the shoe 26. Cement (or any type of drillable
material) 36 and 38 respectively surrounds valves 28 and 30 for
support in the shoe track 26. As an alternate to cement, other
common drillable materials used in the oil industry can be
used.
[0021] The bit 24 has bottom details similar to those shown in FIG.
1. It can be a polycrystalline diamond bit, a rock bit or a tapered
or flat bottom mill.
[0022] Because the valves 28 and 30 are offset from centerline 34
the inserts 40 dig directly at the valve assemblies as opposed to
having the nozzles 42 that are generally in the center of the bit
align with valves 28 and 30 which makes them harder to mill out. In
the past with such alignment between nozzles 42 and the centerlines
of the valves 28 and 30 the bit simply started the valves rotating
on their own axes rather than tearing them up. This was because the
nozzles on the drill bit aligned with the valve centers rather than
the sharp cutters. Now with the orientation shown in FIG. 3 or
another orientation where each valve is offset from centerline 34
but is on a different center than the other valve, the inserts 40
can readily mill up the valve.
[0023] FIG. 4 illustrates in Auto-fill type Float equipment where
using flapper type valves for float equipment, the same difficulty
milling out with a bit that had nozzles in the middle of its lower
face happened.
[0024] The flow tube is pumped down hole and out of the Auto-fill
float collar. The assembly normally lays on a catcher plate/sub,
further down the well-bore. The parts that need to be drilled up,
are the Flapper and the Flapper body. By offsetting the center of
the flow tube holder 44' and the flapper 46' from the centerline of
the surrounding tubular, the bit (not shown) can more quickly mill
out the assembly as the inserts on the bit make more and initial
contact with the flow tube. This keeps it from rotating on its long
axis and results in faster mill out of it and the associated
flapper 46'.
[0025] While radial offset has been described, it is also within
the scope of the invention to skew the longitudinal axis of the
valve member in the float shoe such that the skewed axis still
intersects the longitudinal axis of the housing. Alternatively, the
longitudinal axis of the valve assembly in the shoe can be both
radially offset from the housing longitudinal axis and skewed as
shown in FIG. 6. The skew of the mechanism places the cement more
uniform in the shoe track, preventing possible leakage after curing
of the cement. Additionally, the larger casing sizes will more
likely accommodate a skew than smaller casing sizes. The skew also
allows the inserts from the bit to get a better bite on the valve
components to speed up the milling process. Again while the
selected valve materials may be soft, the prior designs aligned
them with the nozzles of bits making it easier for the mechanism to
spin, thus retarding the milling rate overall. The bits were
desired to be able to make more hole after the cementing of the
casing string and milling out the shoe track used to deliver the
string.
[0026] Those skilled in the art will appreciate that the offset
technique works well with valves of all types used in float
equipment as well as other tools. For example, when using bridge
plugs, anchors or packers, collectively referred to herein as
"packers" that later had to be drilled out prior designs tended to
use plastics, soft metals or composite materials that presented
reduced resistance to drilling out. However, past designs
positioned a mandrel of such packer or bridge plug on center in the
surrounding tubular as a result of the setting process. The present
invention contemplates a set packer or bridge plug or other tool
whose center is offset from the surrounding tubular center to also
take advantage of the faster milling afforded by such a
relationship. The seal and slips, in another embodiment, could be
asymmetrical with respect to the mandrel centerline plug so that
when set it could obtain the offset central axis position with
respect to the surrounding tubular centerline. The slip mechanism
needs to be secured into the surrounding tubular to prevent the
complete system from rotating during milling or drilling.
[0027] The above description is illustrative of the preferred
embodiment and many modifications may be made by those skilled in
the art without departing from the invention whose scope is to be
determined from the literal and equivalent scope of the claims
below.
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