ADJUSTABLE BENT SUB

RACCORD CINTRE REGLABLE

English Abstract

ABSTRACT OF THE DISCLOSURE
An adjustable bent sub for use in earth drilling. The
bent sub has a tubular mandrel with an offset axis which is
telescopically received in a tubular housing with an offset
axis. By rotation of the mandrel in relation to the housing
an adjustment may be made in a bend created by the cumulative
effect of the offset axis of the mandrel and the offset axis
of the housing. A longitudinal stop limits longitudinal
displacement of the mandrel within the housing. The mandrel
is longitudinally slidable within the housing between a first
position wherein further displacement toward the second end
of the housing is limited by the longitudinal stop and a
second position wherein the mandrel is displaced toward the
first end of the housing. A rotational stop prevents
relative rotation between the mandrel and the housing when
the mandrel is in the first position and allows such relative
rotation when the mandrel is in the second position.
rotator acts between the mandrel and the housing, reacting to
longitudinal displacement between the mandrel and the housing
to cause a predetermined amount of relative rotation between
the mandrel and the housing when the mandrel is displaced
from the first position to the second position and returned
to the first position. A split ring locks the mandrel in the
first position.

Claims

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. An adjustable bent sub for use in earth drilling,
comprising:
a. a tubular housing having a first end, a second end,
and a primary axis, means being provided to offset the second
end of the tubular housing at an angle to the primary axis
thereby creating an offset axis;
b. a tubular mandrel having a first end, a second end,
and a primary axis, means being provided to offset the first
end of the mandrel at an angle to the primary axis thereby
creating an offset axis, the first end of the mandrel being
telescopically received in the second end of the tubular
housing such that by rotation of the mandrel in relation to
the housing an adjustment may be made in a bend created by
the cumulative effect of the offset axis of the mandrel and
the offset axis of the housing;
c. a longitudinal stop to limit longitudinal
displacement of the mandrel within the housing, the mandrel
being longitudinally slidable within the housing between a
first position wherein further displacement toward the second
end of the housing is limited by the longitudinal stop and a
second position wherein the mandrel is displaced toward the
first end of the housing;
d. a rotational stop preventing relative rotation
between the mandrel and the housing when the mandrel is in
the first position and allowing such relative rotation when
the mandrel is in the second position;
e. a rotator acting between the mandrel and the
housing, the rotator reacting to longitudinal displacement
between the mandrel and the housing to cause a predetermined
amount of relative rotation between the mandrel and the
housing when the mandrel displaced from the first position
to the second position and returned to the first position;



and
f. means for locking the mandrel in the first position.

2. The adjustable bent sub as defined in Claim 1, the means
for locking the mandrel in the first position being a split
ring which clampingly engage the mandrel, the split ring
having one peripheral edge which engages the second end of
the housing and and opposed peripheral edge which engages a
shoulder on the mandrel to prevent relative movement of the
mandrel in relation to the housing.

3. The adjustable bent sub as defined in Claim 1, the
rotator being comprised of:
a. a plurality of generally parallel sided depressions
on the mandrel defining at least two adjacent longitudinal
channels and at least one crossover channel, the longitudinal
channels being generally parallel to each other, the
longitudinal channels having a front end and a back end, the
crossover channel connecting adjacent longitudinal channels
having an upper end opening the front end of one of the
longitudinal channels and a lower end opening into the back
end of an adjacent one of the longitudinal channels; and
b. at least one slider affixed to the housing, the
slider engaging and being slidable along the channels on the
mandrel.

4. An adjustable bent sub as defined in Claim 1, the
rotational stop being engaging spline on the housing and the
mandrel which non-rotatably couple the mandrel to the
housing.



5. An adjustable bent sub for use in earth drilling,
comprising:
a. a tubular housing having a first end, a second end,
and a primary axis, means being provided to offset the second
end of the tubular housing at an angle to the primary axis
thereby creating an offset axis;
b. a tubular mandrel having a first end, a second end,
and a primary axis, means being provided to offset the first
end of the mandrel at an angle to the primary axis thereby
creating an offset axis, the first end of the mandrel being
telescopically received in the second end of the tubular
housing such that by rotation of the mandrel in relation to
the housing an adjustment may be made in a bend created by
the cumulative effect of the offset axis of the mandrel and
the offset axis of the housing;
c. a longitudinal stop to limit longitudinal
displacement of the mandrel within the housing, the mandrel
being longitudinally slidable within the housing between a
first position wherein further displacement toward the second
end of the housing is limited by the longitudinal stop and a
second position wherein the mandrel is displaced toward the
first end of the housing;
d. biasing means disposed between the first end of the
mandrel and the first end of the housing thereby urging the
mandrel into the first position;
e. a rotational stop comprising engaging spline on the
housing and the mandrel which non-rotatably couple the
mandrel to the housing when the mandrel is in the first
position, thereby preventing relative rotation between the
mandrel and the housing when the mandrel is in the first
position and allowing such relative rotation when the mandrel
is in the second position;
f. a rotator acting between the mandrel and the
housing, the rotator reacting to longitudinal displacement


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between the mandrel and the housing to cause a predetermined
amount of relative rotation between the mandrel and the
housing when the mandrel is displaced from the first position
to the second position and returned to the first position,
the rotator being comprised of:
i. a plurality of generally parallel sided
depressions on the mandrel defining at least two adjacent
longitudinal channels and at least one crossover channel, the
longitudinal channels being generally parallel to each other,
the longitudinal channels having a front end and a back end,
the crossover channel connecting adjacent longitudinal
channels having an upper end opening the front end of one of
the longitudinal channels and a lower end opening into the
back end of an adjacent one of the longitudinal channels; and
ii. at least one slider affixed to the housing,
the slider engaging and being slidable along the channels on
the mandrel; and
g. a split ring which clampingly engages the mandrel,
the split ring having one peripheral edge which engages the
second end of the housing and an opposed peripheral edge
which engages a shoulder on the mandrel to prevent relative
movement of the mandrel in relation to the housing, thereby
locking the mandrel in the first position.

Description

T~ preC;erlt invelltiorl relates k~ arl adillcjtable ben-t
sub .

BP~C~CCiROUN13 OF THE INVENTIO~
"Berl-t subs" are commorlly used in ear-th drilling in
order to deviate the borehole from vertical to a de~ired
ang.le. "Subs" are short threaded sections of drill
pipe. They are "bent" ei-ther by physical bending or
machined -to crea-te an angular offset be-tweerl the
lOrespective ends of the sub. Wherl the b~nt sub i~ plac;ed
iIl the drill ~trillg, -the bend in the sub causes -the
drill string ~o devia-te from vertical as drilling
progresses. One drawbac,k in the use of bent subs is
that the angle is fixed. This means tha-t numerous bent
15subs must be kept a-t -the drill site -to provide a
selection of a range of angles which may be required as
drilling progresses. The trend in the indus-try ha~,
therefore, been to develop a single bent sub on which
the angle can be ad jU5 ted.
SUMMARY OF THE INVENTION
The present invention represents an alternate
structure for an adjustable bent sub.

According to the present invention there is
provided an adjustable bent sub for use in earth
drilliny which is comprised of a tubular housing having
a first end, a second end, and a primary axis. Means
are provided to offset the second end of the -tubular
30 housing at an angle to the primary a~is -thereby creatiIlg
an offset axis. A tubular mandrel is provided having a
fir~t end, a second end, and a primary axis. Means are
provided to offse-t the first end of the mandrel at an
35 angle to the primary axis thereby creating an offset
axis. The first erld of -the mandrel is telescopically


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received in t~le ~ecorld end of tne -tubular housirl~. By
rotation of the mandrel in relation to the housiny an
adjustmen-t may be made in ~ berld created by -the
cumulative efect of the off~et axis of the ma~ldrel and
5-the offset axis of the housing. A lvngitudiIlal stop
limit~ longitudirlal displacemen-t of the mandrel within
-the housirlg. T~le mandrel is lorlgitud.inally slidable
withirl the housing between a first position whereir
fur-ther di~placemerlt -toward the second end of -the
lOhousirlg is limited by the longitudirlal atop and a second
position wherein the mandrel is displaced toward -the
first end of the housirlg. A rotatiorlal s-top prevents
relative ro-tation betweerl the mandre:l and the housiny
when the mandrel is in the first position and allows
15~uch relative ro-tation wherl the mandrel is in the second
position. A rotator acts between -the mandrel and the
housing. The rotator reac-ts -to longitudinal
displacemerlt between the mandrel and the housing to
cause a predetermirled amo-unt of relative rota-tion
20between -the mandrel and the housing when the mandrel is
: displaced from -the ~ir~t po~i-tion to the second positior
and returned -to the first position. Means is provided
for locking the mandrel in the :Eirst posi-tiorl.
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BRIEF DESCRIPTION OF THE DRAWINGS
.
These and other features of the invention will
become more apparent from the following description in
which reference is made to the appended drawings,
30 wherein: -
FIGVRE 1 is a longitudinal section view of a
preferred embodimen-t of the invention.
FIGURE 2 .is a detailed view of a portion of the
35 Adjustable Bent Sub i.llustrated in FIGURE 1.


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DETAILED DESCRIPTION OF T~E~ ~R~U ~0 IM~A~
The preferred elslbodimerlt will now be desc~ibed with
reference to FIG~R~S 1 and 2. T~le ~referred embodi~nent,
generaily de~igna-ted by reference nu~leral 10, is an
5 adjustable berl-t sub for u~e in ear-th drillirly. The
primary componen-t~ of adjus-table bent sub 10 are a
tubular ho-usirlg l2 alld a tubulal marldrel 1~.

Housing 12 has a fir~t end 16, a second erld 18, and
a primary axis (no-t shown). For ease of assembly
ho~sing 12 is constructed of two comporlerlts; a sprir1g
housing 20 and a ro-ta-tor hou~ing 22. First end 16 of
housirlg 12 is equivalerl-t to firs-t end of spring housing
20. Second end 18 of ho-ll~irlg 12 is equivalen-t -to second
end of rotator housir1g 22. Sprirlg housing 20 has a
second end 24 which -telescopically receives a first end
26 of rotator housing 22 at a threaded connection 28.
Threaded connec-tiorl 28 i~ ~;ealed by an 0 ring seal 30.
Hou~ing 12 has an interior bure 32 which is machined at
20second end 18 a-t an angle -to offset second end 18 of
tubular housing 12 at an angle to the primary axis (not
shown) creating an off3et axis 34. A -threaded
connection 36 is positioned at firs-t end 16 of holl~ing
12. Threaded connection 36 permits hou~ing 12 to be
2s~ecured in the drill string.

Mandrel 14 has a fir~-t end 33, a secorid end 40, and
a primary a~is (not shown). A threaded connection 42 is
po~itioned at secolld end 40 of mandrel 14. Threaded
30connectiorl 42 permits mandrel 14 to be ~ecured in -the
drill string. Mandrel 14 has an armular sho~lder 44,
the sîgnificance of which will be hereinafter further
described. Fir~-t end 38 of mandrel 14 is machined a-t an
3sangle in ~rder -to offset firs-t end 38 of mandrel 14 at
an angle to the primary axi~ (rlot ~howrl) creatirlg an




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offset axis 46. Fir~-~ end 38 of marldrel 14 i5
telescopicall~ received in secorld end 18 of housirlg 12.
By ro-ta-tion of mand:rel 14 in r~lation -to ho-using 12 arl
adjustmerlt may be made in a berld created by a cumulative
5 effect o.C offse-t axi~ 46 of marldrel 14 and off~et axis
34 of housirly 12.

A s-topper 48 is secured to .Eirs-t end 38 of mandrel
14. The connection between stopper 43 arld fir~t end 38
lOof mandrel 14 is sealed by an O ring seal 49. S-topper
48 serves as a longi-tudinal stop -to limit lorlyitudinal
displacement of marl~rel 14 within housiIly 12. Mandrel
14 i9 longitudinally slidable within housing 12 between
a f.irst p~sition wherein further displacement toward
15second end 18 of housirlg 12 is limited by stopper 48
striking first end 26 of rv-tator ho-us.irlg 22, and a
second position whereirl mandrel ls is displaced toward
first end 16 of housirly 12. The movemer~t of mandrel 14
in the second position is limi-ted by annular shoulder 44
200f mandrel 14 striking second end 18 of housing 12. A
coil spring 50 is disposed within spring housing 20. A
firs-t end 52 of sp-.ring 50 acts ayainst a shoulder 54
within interior bore 32 at firs-t end 16 of housing 12.
A second end 56 of spring 50 acts against a sealing riny
~558 having an annular seal 60. Sealing ring 58 in turn
acts against stopper 48. 0 ring seal~ 62 are positioned
where sealing ring 5~ meets stopper 48. The effect of
spriny 50 .i5 to apply a bia~ing force be-tween first erld
38 of mandrel 14 and firs-t end 16 of hou~ing 12 which
30uryes mandrel 14 in-to the first po~i-tion.

A rotatiorlal stop in the form of engaying splirle 64
and 66 on housiny 12 and mandrel 14, respectf-ully.
355pline 64 and 66 no~-rotatably couple mandrel 14 -to
housiny 1~ when mandrel 14 i5 in -the fir~-t po~ition.




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This has -the e:Efe~t of preverltinc3 relative rotatiorl
: between mandrel 1~ and hou~irlg 12 wherl mandrel 14 is in
-the firs-t po6i-tiorl and allowi.rly such rela-tive :rotatio
wherl mandrel 14 i5 in the SeCOrld poYi tion. Splirle 64
5 and 66 are be~-t ill-ustra-ted in FIGURE 2.

A ~v-tator 68 ac-ts between mandrel 14 and housing
12. Rota-tor 68 react~ to longitudinal displacement
be-tween marldrel 14 and housirlg 12 to cause a
lOpredetermiIled aMour--t of relative rotation be-tweerl
mandrel 14 and housing 12 when mandrel 14 is displaced
from -the -first posi-tion to -the second position and
returned ta the first position. Referrirlg to ~IG~RE 2,
rotator 68 consists of a plurali-ty of generally parallel
15sided depressions on mandrel 1~ defiIling adjacent
longitudinal channels 70 and crossover channels ~2.
I,ongi-tudinal charlnels 70 are geIIerally parallel to each
other and have a front end 74 and a back end ~6.
Crossover charmels 72 connec-t adjacerl-t longitucliTlal
20channels 70. Crossover chanrlels 72 have an upper end 78
opening into front end ~4 of OTle of lOTlgi tUdirlal
channels 70 and a lower end 80 opening into back end ~5
of an adjacen-t one of longi-tudinal cha}lIlels 70. Sl:iders
82 are affixed to housing 12. Sliders 82 erlgage and are
25slidable along channels 70 and 72 on mandrel 14.

A split ring 84 clampingly engages mandrel 14.
Split ring 84 has one peripheral edge 86 which engages
second end 18 of housing 12 and an opposed peripheral
30edge 88 which engages annular shoulder 44 on mandrel 14.
Split ring 84 is removably secured -to mandrel 14 by
bol-ts 90. When split ring 84 is placed in position as
described when mandrel 14 is in the first position
35relative movement of mandrel 14 iII relation to housirlg
12 is prevented, thereby locking mandrel 14 :irl the f.irst




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pO~i~iOII. Mandrel 1~ iS Ullable to move -tovJaId seco-nd
end 18 of housing 1~ due -to ~topper 48. Mandrel 14 is
: unable to move ~oward first end 16 of housing 12 du~ -to
the imposition of split rin~ ~4 between anrlular shoulder
5 44 of mandrel 14 and second end 18 of nous:irly 12.

An oil filled chamb~r 92 is created between ~andrel
14 and ~lousing 12. Ol:L filled chamber e~-tends from
second end 18 of housirlg 12 to anrlular seal 60 on seal
ring 58. Second end 18 of housing 12 has a seal 94 to
prevent the escape of oil from oll filled chamber 92.
Oil is placed in oil filled chamber 92 after assembly of
the tool through oil plug 96.

The use and op~ratioIl of adj-ustable bent sub 10
will now be described with reference to FIG~RES 1 and 2.
In order -to adjust adjustable bent ~ub 10 split ring 84
i5 removed. Once split r;ng 84 is removed mandrel 14 is
iongitudirlally slidable within housing 12 from the first
20position to the second position. As mandrel 14 is moved
toward the second po~ition coil ~pring 50 is compre~sed.
Wherl Illandrel 14 i5 moved into -the second position spline
64 on housirlg 12 are di~engag~d rom spline 66 on
mandrel 14, thereby allvwing relative rotation of
mandrel 14 in relation -to housing 12. This relative
rotation is control:Led by rotator ~8. ~ach of
longitudinal channels 70 represents one incremental
adjustmen-t. The displacemen-t of mandrel 14 from the
f.irst position to the secorld position, and then the
30return of mandrel 14 to the first posi-tion resul-ts in an
adjustment from one on longitudinal channels 70 to an
adjacent one of longitudinal chanrlel~ 70. Thi~ i9 due
to -the path followed by sliders 82. As mandrel 14 moves
3sfrom the first position tv the ~econd position sliders
82 move via crossover chanrlel~ '72 from frorl-t end '74 of

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one vf longi-t-udirlal cha}lrle:l~ 70 to back erld 76 of an
adjacent one of longitudirlal chant~ 700 As mandrel 14
moves from -the secorl~ position back to t~le fir~-t
position slider~ 82 move from back end 76 to front end
5 ~4 of the adjacen-t one of longi-tudirlal charlrlel~ 70.
. MandLel 14 is displaced betweerl the f irst and ~econd
: posi tions as many t:imes as may be required to achiave
the desired adjustment. This is due -to t:he ~ac-t -that
xot~tion of m~ndrel 14 in rela-tion -to hollsing 12 ad,jus-ts
: lOthe bend created by the cumulative offset of offset axis
: 46 of m~ndrel 14 and offse-t a~is 34 of housillg 12, and
rotator 68 controls the rotation of marldrel 14. Once
the desired adjustmen-t has been made ~plit ring 84 is
put back in positionO Split riny 84 occupies the space
15between anTIular shoulder 44 on mandrel 14 and Yecond end
18 of housing 12. This maintains stopper 48 against
fir~t end 26 of rotator housing 22. Marldrel 14 is
~ therefore maintained in a pos.ition where no longitudinal
: movement in relation to housing 12 i5 po~ible. With
20split ring 84 maintainirlg mandrel 14 in the first
position, spline 64 on housing 12 are kept enga~ed with
spline 66 on mandrel 14. Spline 64 and 66 norl-rota-tably
couple mandrel 14 and ho-using 12~

It will be apparent to one skilled in the art how
-the structure of -the presen-t invention permits an
adjustment to be made of adjustable bent ~ub 10. It
will al~o be apparent to one skilled in the art that
modifications may be made to the preferred embodiment
30withou-t departing from the spirit and scope of the
invention.




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Representative Drawing