CA2011972A1 - Device for steering a drill bit - Google Patents

Abstract

ABSTRACT
In a device for steering a drill bit the flushing fluid is caused to move pistons radially by a control device which is actuated by signals from a sensor which senses deviations of the drill bit. The control means is powered by an electric generator which is turned by turning the drill string.

Description

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B~CXGROllN~ g~ ~ I21V~T~O~
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THIS ir~v~n'clon r~lata~ to a d3vic~ ~or steorin~ a drill bit. ~ ~ .

A comnon probl~m eneount~r~d in the ~re o~ ~eep d~lling 15 ~he tendency of ~ dr~ill bit to w~n~er of cour~a. Thl~
c~u~ed ~y ~cto~Y ~uch ~5 the inh~ren~ f lexibility of th~
~xtended drill ~ing, and by the drill blt cros~ing tran~ition zo~ betw~en h~$der ~nd sof~r rock layer~
e~ ci~lly ~ an acutQ angl~

The p~sen~ vention ~ks lto p~ovide ~ de~ric~ er maint~inin~ q:h- ~lrill bi~ on ~t~ pr~d~t~rmin~d COUrSR. ` `.
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The inven~ion provide~ a device ~or ~eering in a d~ill hole a drill hit carried at ~he le~ding end of a drlll strln~
elemcnt h~ving an ~xlally ori*nted pas~a~e for conv~ying flu~hing fluid to th~ drill ~it du~ing drilling, ~ompri~in~
a body lo~a~e~ t~t~bly on the element, a ser ie~ oi~ pis'~ons ~dially nso~abl~ on she .bc: dy and adap~ed to ~ uat~d by the flushing fl~ n~lng means to s~n~ when ~ha drill bi~ wand~r~ o~f a pr~det~rmin~d course, ~r~d ~ontrol means responsive to th~ ~en~ g ~nean~ ope~able ~o control ~he f low of f luid to one or more of th~ pi 15tOfl~, th~r~y u~gin~ the pi~on c~r piston~ towards the w~ll of d~illed hole being ~rilled.

Prefe~a~ly, th~ cont~ol mear~ fllrther op~rabla to allow c~ne o~ mora of th~ pl~l:ons whlch ha~ b~Qn llrg~d ~owards the w~ll o~ tha drilto~ hole to r~ra~t af~er having radireet~d ~h~ d~ b$~

Th~ t nvBntion ~uEther ~rovide~ ~n elec~cric generatDr whi~h i~ p~w~e~ by th~ rotatlon of th~ ~lem~nt r~lative to th~
body, th~ gen~ra~or in ~urn p~riny ~he con~ol me~ns .

~n a p~e~r~e~ fo~m c~ invention, ~h~ ~ontrol means compr~s a motor wh~h drives v~lYe means .

Pr~erably, ~h~ pi~n~ are u~g~d again~ r~s~lient shoe~
whieh in 1:urn be,~a~ agains~ the w~ll of ~he d~illed hc~le, ær~v~ntins~ ms:~v~men~ o~ th~ bo~y r~lative to th~ elemen~

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Figur~ 1 3how~ a lorlgi~udin~l sec~on ~hrough the drill ~t~ing d~vice of the invention, Figur~ 2 show~ ro~s-sec~ioYl a~ the line A-A on Fi~ure l;

~gur~ 3 ~how~ a ~ro~ ec~ion at th~ line ~-~ on Figure 1.
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Dl:~RXPq!ICSN OF ~WDI~ ~ ~
: -Th~ lllustra~ed drill ~t~oer~ ng devlce 10 featur~ a hol low :
d~ill Yt~ing el4m~nt 12 havin~ a tube-sh~ped body 14 lo~ d ro~tably on ~ch2 el~m~nt, an~ an erd c~p 16 fixe~ to the l~a~ing end ci~ ~he elem~nt 12, An sxially o~ien~ed passag~
22 ~Un5 ~hro~lgh ~oth ~h~ elem2n~ ~n~ th~ ~nd cap 16 for eon~eying f lushin~ f luid in t~ direction of ~rrow 23 to ~he :
drl~l bi~ du~ing ~illing . ~hl3 fluid r~u~n~ back from th~
cuttlng ~ce~ in the annulus 25 between the w~11 o~ ~he h~le 27 ~nd th~ ~t~r1r~g devic~ 1OJ

The ~rill st~i~g e1ement 1~ i~ provid~d ~ a femal~
~chread~ ~o~ t 1~ at it~ l~adiny ~nd whi~h i~ coupled with . `
'che ~orre~pondlng m~le ~h~ded ~nd 19 o~ a d~ill bit. The en~ ~p ~16 i~ ~qu~!p~Qd with ~ m~le th~ead~d erld ~'0 ~or couplin~ wi~h a corre~ponding f~mals thraaded 80cl~et ~ llot ~h~dn) o a furth1!r ~imllar ~rill ~ ing elemen~. In thi~
m~nn~sr, the ~ill ~t~ering d~i~tice 10 ~ 1n~rt~ b~atwe~n two rod ~i~oi~ a ~illing ~tring in which torc~u~ and f l~i~h~ng ~ .
~lu~d ~ co~ o~d ~o ~ lt.
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A ~e~3 of pi~ton~ 2~ a to f ~re arranged in cylinders 26 ~pa~d equ~lly ir~ rows abou~ the ou~er surf~e of the body 14. The pi~tons 24 a to ~ b~ar agains~ r~ nt ~hoe~ in the ~orm o~ le~ ~pring ~trip~ 28 moun~ed in ~r~oves 30 lo~a~ed on the auter suL ~ace o~ the body 14 ~ E~ch group o~
cylind~ 26, ~hich sr~ disp~ radially outwardly r~la~ive ~o the body 14, cQ~n~Yni~ate wi~h the pas~ge 22 via f i~st ~nd s~cond supply ~a~iti@s 32 and 33. Th~a s~ond cavity ~ntrance i~ lo~a~ed on a gho~lld~r 34 whe~e ~h~ p~age 22 broadons is~éo the socket 18. An annula~ pla~e v~lve 36 ha~ving an ~E~er~u~ 3~ be~ween th~ ~lrs~ and s~cond supply cavi~les 37 and 33 ~ s loca~ed rota~ably on th~ man~ 12 .

Th~ plate valve 36 i5 sanClwlch~d b~twe~n an ~nd ~ac~ 40 o~
the ~ody 14 and an oppv~in~ ~holllder face on ~che drill ~tring ~l~m~n~ 1~. Fa~ load on th~ valve plat~ 3~ i3 m~ nt2~ined ~y a ~pring ele~nent 44 ~eated on a f~ce 46 a~ th~
traillng ~nd of th~ eap 16 whioh bear~ aqainst a thrust plate 48, locæted a'l: the oppo~te end o~ body 1~
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An el~ct~i¢ ~n~rator S0 i~ mounted ad~a~ent the ~hrust platQ 48. The ge~nera~r SO h~ a ~o~cor 52 mount~ on the ~entral ~ha~t o~ the st~ing alement 12, and ~ st~to~ 54 partly ~slrrcsundin~ the rotor 52 ~d mounted ol~ the body 14.
~lectric~ pow~r i9 ~nera~0d by r~tation of the ~rill ~trin~ al~menk 12 rela~iv~ ~o the body 14~ ~h~ body i~
prevented fro30 rot~ion ; ln th~ dr~ll hole ~y ~he le~f sprin~: 28, which b~a~ ag~in~ the ~ 7 o~ th~ drill hole, and ~l~o ~rv~ ~o prot~t ~ho plston~ 24 by co~rering th~m, ~he~e~by pr~ nlting ~he~ ~rom ~oulinq again~t. ~h~ wall~
of th~ hol~
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The ~n~ærator S0 pow~ A ~er~o-mo~cor 513 hou~ in an o~ od pEe~s~u~ comp~n~s~t~d moltor cavi~y ~o. l~h~3 motor ' ':' - ~;

';.::' ' ' , , drl~te~ a pinion 6~ which turn~ the ~alve pl~te 36 . S~n3ing ~ean~ in ~he form of in~trumentation 64 fo~ ~he d~tQctlon o~
devia~ion of th~ drill ~eEir~g device ~ro~ ~ prQdetermined pa~h. is hou~ in a ~eries of in~rum~n1;~tion caviti2s 66 lo~ed i~ the body 14 . ~aeh ~at ity ha$ a ~luq ~B 'c~
pro~ect ~he in~t~ument~tion agairlst d~ ing ~lui~ and high pr~ur~s.

In oper~clon, ~he ~teering d~vice wor~ in th~ following manne~, ~he in~ entation ~4 d~t~ct~ wh~n the drill ~eering d~vic~ 10 wande:~ o~ a predetermined path, and 3~nds a signal to the servovmotor S8 via a c~ble glarld 70.
~he ~rvo motor 58 r~spon~ by turning the pla~ valve 3 6 an amoun~ de~c~rmined by th~ ~ign~l 90 that th~ ap~r~c~r~ 38 in ~he valve ~egi~'se~ with th~ f ir~t arld ~cond ~avi~ie~ 32 and 3~. If th~ ~e~r~ing devicR is devia~ing in th~
~irection indica ed by ~h~ arrow 72 in ~iqure ~, ~he ape~ture 38 will r~glster with ~he fir~t ~nd a~cos~d cavi~les which conununicate with ~he ~ylinder~ 2 6a .

Flushin~ ~luid pas3in~ through the ~ssa~ 22 lr di~ecti on of th~ ~;rrow 23 ~ill therehy b~ rmitted to pa~
~h~ou~h th~ t ~nd sec~nd c~viti~ 32 and 33 ~nd into the ~ylin~ers ~6~. The ~reScure of th~ flushin~ ~lu~d in ~he cylind~r~ Z~ rqe~ ~h~ pi~ton~ 24~ ~ut~ardly r~lativ~ to the ~dly 14 ~oward~ ~h~ w~lls3 o~ ~he hol~, ag ~an b~ ~een in Figure 3, hereby forcing ;~l~e l~a spring 9~ip 28 a~ain~
~he hole wall~, and moving ~h~ ring d~ic~ 10 in th~
oppo3it~ dir~c~io~ ~o th@ d~r~ction of devlation 72. ~he tru~nta~iorl 64, on $en~ing tha~ the st~rlng de-rice 10 i~ b~ck on ~our~o, ~end~ a ~l~r.aL ~o the ~rvc~ mo~o~ 5 which ~n ~eU~FI roe~ta~ ~h~ pl~te ~ra1v~ 3~ ~o tha~ ~h~
~p~rtu~ 38 ~ov~ out o~ al~nmen wl~h ~h~ ~upply ~vi~o 32 ar~d 33, th~e~y blockinq off th~ flo~ of pr~Bflurlz~

2~1g72 ~ . .: ., ~lu hing ~luid to the ~ylind~r~ 25~!10 Exce~ pr~sllrl3ed fluid in th~ first ~upply cavity 3~ and ir. the cylind~r~ ~6 e~cape~ th~ough the v~nt hole 73, as the re~ n~ ac~ion of ~he leaf ~p~ing 28 eause~ the pis~on~ to rc~turn inwardly b~c}c to ~he~.r normal position in ~h~ cyl$nd2r~ ~6a, and pres~;u~e b~tw~n the ~luid in the ~upply cavity ~ and th~
2nnulula 25 i 8 e~alised. : -Each o~ ~h~ eyllrld~rs Z~ a to ~ h~e thQir own ~upply vent~
Devi~lon of ~h~ stee~in~ d~vice in another dire~tion, ~uch a~ ~h~t in~cated by the arrow 7~, will ~e~ult in th~
~per~ur~ 38 in th~ plats ~alv~ 36 being brou~ht into : .
~ommuni~ation with th~ v~nt supplying th~ ~ylin~r 2~c, th~reby ~u~ ng the pi~ton 24c 1:0 be urg~d outwards . ~he plate v~ may h~ve more than on~ ~perture, ~ wing ~ny ~wo o~ more o~ th~ pi~ton~ to b~ opexa~ed ~lmultaneou~ly.

The inv@n~iorl, in u~ln~ equal area pis~ons, makes use o~ the ph~no~non th3~ the~ ~xi~t~ a di~renc~ ~n pr~sure b~tw~en the f ll~hlng ~luid i~lowinq down through ~he pa~age ;~
22 towa~ the bit, a;~d ~h~ r~turning ~lu~d in the arlnulu~
25. Th~ devi~ o de~igned that th~ ~or~e exer~ed by the l~lushin~ flul~ i~ th~ cyl~n~rs on one sid~ of th~ pistons ..
24~ 9XCI~ th~ eount~r-~o~ce ex~r~e~ by the lea~ spring and the ræ~urn f luid on th~ oppoait~ side o~ the pi3ton5 24 . ` ~

Th~ ventis~n ~n~oy~ the advasl~ag~ that it malc~ u~ o - ~;
~xi~tlr~g su~ici-r~tly powe~ul hydra~ c force~ wh$ch ar~
rsadi ly ~allablo in ~itu to hold the ~t~ering deviee on ~ou~se~ atro-m~ch~nic~l m~an~3 are only u~d to regul~te th~ hy~r ~lic ~o~
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Claims (5)

1.
A device, for steering in a drill hole a drill bit carried at the leading end of a drill string element having an axially oriented passage for conveying flushing fluid to the drill bit during drilling, comprising a body located rotatably on the element, a series of pistons radially moveable on the body and adapted to be actuated by the flushing fluid, sensing means to sense when the drill bit wanders off a predetermined course, and control means responsive to the sensing means operable to control the flow of fluid to one or more of the pistons, thereby urging the piston or pistons towards the wall of the hole being drilled.

2.
The device claimed in claim 1 in which the control means is operable to allow one or more of the pistons which has been urged towards the wall of the hole to retract after having redirected the drill bit.

3.
The device claimed in claim 2 including an electric generator which is powered by rotation of the element relative to the body, the generator in turn powering the control means.

4.
The device claimed in claim 3 in which the control means comprises a motor and valve means driven by the motor.

5.
The device claimed in claim 4 in which the pistons are urged against resilient shoes which in turn bear against the wall of the hole, thus preventing movement of the body relative to the element.