Note: Descriptions are shown in the official language in which they were submitted.
:~~
The present invention relates to borehole survey/core
orientation instrumellts ~or use with wireline drilling
equipment ~o survey boreholes ~nd ob~ain the orientation of
core samples.
The disadvan~ages of known exi.sting e~uipment for
these purposes were outlined on page 2 of Australian Patent
No. 420553, and its corresponding U.S.A. Patent 3rsla~22
Canadian Patent g01974 and South ~frican Patent 69/0260.
The device disclosed in these paten~s attempted ~o overcome
~hese defieiencies. I~ relied on an injection mechanism ~o
ir.ject a catalyst into a gel tube holding a gellable
liquid. When the lig~id gelled it secured into place a
magnetic compass ball, from which the orien~a~ion of the
bore and the core sample c~uld be ob~ained.
Operation of the ins~rument depended on the generation
of a fluid impulse or ne~ative pressu~e wave which
momentarily destressed drilling fluid circula~ing in ~he
drill string and borehole~ The sudden reduc~ion in pressure
allowed air entrapped wi.thin the instrument and compressed
by the combined pressure of ~he static head and the
circulating fluid pumped ~hrough the drill string to expand
~nd thereby activate the injection mechanism. Generation of
~he negative pres~ur2 w~ve was aceomplished by ~apidly
collapsing ~he pressure in the drilling fluid pumped through
the drill string by opening a fast-ac~ing by-pass valve
fitted in the pump delivery circuit.
The prior art device suffered from ~he disadvan~age
that in deep bores where the static head pressure was high
the entrapped air pocket leng~h was small and a~ter
generation of the negative pressure wave ~he expansion of
the air pocket was insufficien~ to acti~ate ~he injection
mechanism. This deficiency wa~ compounded by the need for-
additional seals in ~he in~rument a~ greater depths which
in ~urn increased ~he friction on sliding par~s and crea~ed
the need for extra force to operate the injector~
one further di&advantage o this pri.or ar~ device is
that it can not be used in horizontal or near ~orizontal
bores ~s Lhe entrapped air, vital to its operatiorl, could
esca~e.
It is an object of the present invention to provide a
.3~
bore~lole ~,urvey/core o~ielltaLlon înstrurnent whic3~ ~vercuTrles
or subs~:antially ameliorates the abo~re mentioneà
disadvantages. This applies particularly ~o ~he harrlPssirlg
of an adequate force to ensure operat;sn of the ins~rurnents
at depth.
~ rherefore, acc:ording to one broa~ asp2c~ t-E ~he
present invention there ;s provided a borehole surveyJcore
orien~ation ins~rument suitable for use with wireline
dr;lli~g eguipmen~, ~aid instrument comprisin~ a co~DpGsite
cylinder having ~ fir~t member telescoplcally lin};ed ~o a
second member, said flrs~ member being biased away flom sa;d
~econd member ~ said second member includlny a ~ransparen~
~ressel co~taining a plumbed ma~netlc compass ball ~ubmerged
in a gellable first liguid, a leservoir containinq a
catalyst for gelling ~aid first liguid a~d an injection
~nechanism fs: r in jec~ g ~ai~ catalyst in~o said ~res~el V1~ a
normally closed communication mearls l~etween s~id reservoi~
and saia vessel, said communication means being su~h ~ha~
compress;ve movement of said first member relati~e ~o ~iaid
~e~ond member allows said injecti.on mecllanlsm ~to be
activated causing ~aid communioation means ~o i~pen and ~aid
ca~alys~ to en~er said vessel.
One emb~diment of the present irlventlon ~ill n~w be
descr;bed with reference to the drawlngs in whic2~
Fig~ 1 is a sect;onal view of an upper p~rt30n o an
embodimen~ of th~ ~resent invention;
E'ig. 2 i~ a ~ectional view of a lo~er porti.on o~ ~he
apparatus of Fig. 1 and
The de~ignation~ ~upper" and Wlower~ refer go ~e
posi~ion the components would assume in a ~elt.lcal or near
vertical bore All components, ~;th the except;on o~ ~he
compass, ar~ made from non-magnetic material
As illustrated in Fig~ nd 2~ the ins~rumen~ 1,
~ornprises the tubes 2 and 3 ~hich are ~elescopically llrl,ced
together. The upper tube 2 is bia~ed ay~ins~ cornpression
r~lative to t~e lower tube ~, by mearls of ~he oompr~ss-L~n
sprin~ he sprln(J ~ is located w;t~;n ~he ~ube 3 by
means of the rela.iv~ly stationary spring sea~ nd
movable seat ~b.
The tube 2 is fitted with a w~sh~r or pump packiny 44
for the pumping of the instrument 1 through ~he wlreline
drill string and for increasing the effectiverless o~ the
force which can be applied to tube 2 to telescope it
relative ~o tube ~ when the instrument 1 engages with the
core barrel spearhead 42.
The tube 2 is provided with a spear head 5 for
ret.rieval of ~he instrument 1 and core sampling barrel once
the downhole orientation p.rocedure has been completed. The
combination guide/stops 6 are a~tac~ed to the tube 2 and are
adapted to slide within ~he groove 7 in tube 3. The surface
8 at ~he bottom of the groove 7 prevents over compression o
th~ telescopically linked barrels 2 and 3.
Extending downwardly from the base 3 of the tube 2, is
a cylindrical hollow spigot 10, which engages a sliding
valve member 11 within sliding ~alve subassembly llb. The
slidinq valve member 11 i5 biased to keep por~ 12 closed by
means of the compression spring 13. Seals lla within the
sliding valve member 11 prevent fluid ingress to ~he port 12
when the valve member 11 is in its elosed position. The
spigot 10 is located over the centre of the valve member 11
by sitting over and around a circular stop 14 which al~o
prevents the valve member 11 from disengaging the valve
guide rod 15. There is furthef provided in the spigot 10 a
series of hole6 16 which allow the pas~age of water or fluid
(not illustrated) under pressure.
As illustrat.ed in Fig. 2, ~he port 12 (Fig. 1) in the
valve guide rod 15 communicates, by means of passage 17 and
outlet 18. with an inner chamber 19 of an injector
sub-assemhly 20. Within the chamber 19 i~ an injec~or pin
21 which s ~ealably slidable ~hrough it~ guide bore 21a by
mean~ of the s~al 22 and gland nut 23. A~ the ba~e of ~he
~uide bore 21a i~ an injection chamber 24 ~orin~ the
gelliny cataly6t 25.
The cataly~t 25 remain~ in the chamber 24 by mean~ of
~he normally closed non return valve 26. The non-re~urn
valve 26 i~ bia~ed closed again~ valve ~ea~ 27 by means of
spring 28. The injec~ion chamber 24 communicate~ wi~h a
tran~paren~ ve~sel or gel tube 29 a gel tube subas~embly 29a
via annular spring re~ainer 30.
The transparent gel tube 29 comprises a hemispherical
base 31 and is filled with a gellable liquid 32. It i~
sealably mounted on a spigot 43 on the lower end of the
injec~or subas~embly 20 and is covered by a wa~ertight gel
tube cover 29b. Beneath ~he surface of the liguid 32 is a
magnetic compass ball 33 having a meridianal line 34 to
indicate direc~ion i.e. magnetic north, and a di~inguished
upper hemisphere 35 to indicate the horizontal plane. The
compass ball 33 also h~s a weighted pivot 36 which allows
the compass ball 33 to ~pin freely in a plumbed position.
The plumbing effect of ~he pivo~ 36 allows the compass ball
33 ~o indicate the horizon~al plane by mean~ of the junction
line of the lower hemisphere of the ~ompass ball 33 and the
distinguished upper hemisphere 35, due to ~he influence of
gravity on the weighted pivot 36. Wh~n ~he gel ~ube 29 i5
fitted to the instrument 1 a longitudinally ~cribed mark
(not illus~rated) on the ex~erior of the gel tube ~ is
plac~d in regi~er with a Da~um line lnot illus~ra~ed) on
the exterior of the injector sub-assembly 20.
The tube 3 is al~o provided with hole~ 39 which allow
fluid under preszure to surround the whole instrument
The lower portion of the tu~e 3 has a thread end 37
which connect~ wi~h ~he threaded upper end of the injector
sub-assembly 20. The lower end 37a of the injector
sub-assembly 20 is al~o threaded and connect~ with a tube 38
which allows the connection of the instrument 1 to the core
barrel (containing the core ~ample to be orientated) by
m~ans of jaws 40 and spearhead 42 on the core barrel. This
connection, by m~an~ of toothed portions 41 on both ~he jaws
40 a~d ~pearhead 42, pre~ents rota~ion o~ the core barrel
relative to the in~trument 1. Retrieval o~ the core barrel
together with the coupled ins~rument 1 i8 achiQved by means
of the spear head 5 and a grappling device on a wire line
~not illustrated) which i~ lowered through the drill ~tring.
PREPARING INSTRUMENT FOR OPERATION IN A V~RTICAL OR NEAR
VERTICAL BORE.
The ~liding valve ~ub~a~embly llb. in~ection ~ub-assembly
20, ~nd gel ~u~e ~ub-assembly 29a are removed as a ~ingle
unit from the i~trument 1. The g~l tube cover 29b, the gel
-
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tube ~9. and ~he non return valve 26 are detached and a rod
in~erted into ~.he injection chamber 2~ to push the injector
pin 21 back to the top of its strcke pOSitiOII. The
injection chamber 2~ i5 filled with a solution of ammonium
persulpha~e or other suitable initiator catalyst ~hrough ~he
counterbore in the bot~om of ~he injec~ion sub assembly 20
where the non return valve 26 fits. When the injection
chamber 2~ i~ full the non return valve ~6 i~ refitted and
~he out~ide of ~he injection ~ub assembly 20 wiped clean.
The gel tube 29 is partially fille~d with a ~ui~able gellable
xolution. One such solution i~ AM~, a chemic~l ~rout which
has been marketed by Cyanamid Aust Pty Ltd. It i~ a mixrure
of two organic monomers, acrylamide and ~,N7 --
methylenebisacrylamide ln propor~ions which produce ~ f
gels ~rom dilute aqueous solu~ion~ when properly cata1ysed.
An activator catalyst is needed in addition ~o the initiator
cataly~t which is injected from the injec~ion chamber ~9. A
~uitable activator cataly~t is B-dimethylaminopropionitrile
whieh is included with ~he ~M9 ~olu~ion in the gel tube 29.
The gel tube 29 is focced o~er a seal on the 8pigo~ 4
at the bottom of the injection ~ub-as~embly 20 and is held
in place by the pressure of the seal on ~he in~ide wall of
the ~el tube 29. When :Eitting the gel tube 29 the datum
line scribed on ~he tube (not illustrated) i~ placed in
register with ~he datum line (not illustra~ed) on ~he
injection ~ub a~embly 20. The gel tube co~rer 29b is
replaced on the injectioll ~ub a~sembly 20 to maintain the
posi~ion of the gel tube 29 and 62al it in a waterl:ight
compar~.ment . The combined slidirlg valve sub-~s~embly 1~ b~
injection sub-a~sembly 20 and gel ~cube ~ub-as~embly ~9a are
mounted in the lower tube 3 and the tube 38 is then
connected to the injec~ion ~ub-assem~ly 20.
Before the in~trument 1 can be used wi~h standard
wireline drilling equipment, non magnei:ic drill rod~ ~hould
be insert.ed behind ~he core barrel to isola~e the rnagne~ic
compas6 ~all 33 from the inf luence of the s~eel core barre:l
and drill rod~. A non magnetio drill rod section of
approxima~ely 6 metres leny~h is normally adequate and the
length of the tube 38 is arranged so th~at the compass ball
33 i~ po6ition~d in the approxima~:e centre of ~he ~on
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magnetic drill rod section. F~rther reguirements are:
(a) the ~pearhead on the core barrel ~hould ~e replaced by
the toothed ~pearhead 42 which prevents rotation of
the core bar~el relative to the i~strument 1 when the
said core barrel and instrument are in engagement.
(b~ the swivel bearings in ~he core barrel, which allow
the ccre tube to remain relatively stationary when the
core barrel rot~tes during drilliny, ~hould be loc~ed
by insertion of a grub sc.rew or similar device through
the bearing housing of the core barrel to prevent
relative movement bstween the core barrel and ~he core
tube.
OPL~A.I-f~5~Ur~ INSTRU~ENT.
When an orientation of a core sample is .requirea,
approximately 15cm of core are drilled, the instrument 1 is
then fed into the hollow sec~ion of ~he drill string, which
include~ a non-magnetic ~ection immediately above ~he core
barrel. By means of ~he circulating luid being pumped
through ~he drill ~ring ~he ins~rument is forced down until
it locks on the core barrel, which con~ains the core sample,
by means of spearhead 42 and jaw~ 40. Circulating fluid
whicb may be water. water with additives. or air, i~ used in
drilling to cool the drill bit and remove cu~ings which
could jam the drilling equipment i~ ~he hole.
When the instrument 1 reaches the core barrel the
lower tube 3 becomes stationary and the drilling fluid under
the high pres~ure produced by it~ pump will. force the upper
tubc 2 to move through the tube 3 as it overcomes the
oppoing force due tv ~he spring 4. The ~ube 2 moves
relative to ~he tube 3, and as the injector ~ub-a~embly 20
is fixed relative to ~he tube 3, the ~pigo~ 10 ~ends ~o moYe
the sliding valve member 11 along the valve guide rod 15
again~t the 6pri~g 13. The action uncovers the por~ 12. A8
the drilling fluid under pressure i~ acting upon ~he
ex~ernal componen~s of the in~rument~ the ~xpo~ition of ~he
port 12 allows fluid under pressure ~o enter the inn~r
chamber 19.
Conseguently~ a pres~ure i5 applied to ~he surface o
~he injector pin 21~ thus sealably ~liding ~he pin ~1
through ~he gland nu~ 23 and seal ~. Thl~ cre~es a
.- .
pressure on the fluid 25 in t~e injection chamber 2g, which
is sufficien~ to overcome ~he spring 28 and open ~he
non--re~urn ball Yalve 26D The catalyst 25 thus enters the
gel tube 29 and begin$ ~he gelling of the gellable fluid
32. In this way the compass ball 33 is ~e~ in t~e position
it has freely assumed relative to the earth's magnetic field
p~ior to gela~ion.
After allowance of the few minutes of ~ime reguired
for the settin~ of the gel, the instrument 1 and the core
barrel coupled in tandem are withdrawn from ~he drill s~ring
by means of a grappling device on a wire line which en~ages
with the spear head 5. When the in6trument coupled to the
core barrel is brought to the surface, ~he da~um line (not
illustrated) on the injector sub-assembly 20 projected to
the bottom of the drill barrel i~ marked on the piece of
core held by the core lifter. This mark is now in alignment
with the datum line ~cribed on the gel tube 29 and core
orientativn is established by reference to ~he compass ball
33 when the gel tube 29 i~ removed rom the instrumen~ 1.
In circumstance~ where orientation of a continuous run
of bore core is required scribing diamonds or knives are
fieted to the core barrel to mark all incoming core.
Individual pieces of core can ~hen be rela~ed to ~he las~
piece drilled for which orientation is determined.
As illustrat~d in ~ig. 2, the gel tube 29 is shown as
being only about three-quarters full with yellable fluid
32. Thi~ i5 enough ~o submerge the compa~s 33 in a vertical
or near vertical position. However if drilling o~her ~han
near the vertical is reguired, ~he ~ube 29 will have ~o be
filled completely, for if the compass ball 33 were to break
~he surface of the fluid, the surface tension ~ould prevent
free rotation of the compass. Injection of ~he catalyst
from the injection ch~mber into a compls~ely filled gel ~ube
neces~ita~e~ ~he employment of a means of di~placing
gellable fluid from the gel tube to accommodate the incoming
cataly~t or altsrna~ively a means of increasing the volume
of the gel ~ube as the catalyst i~ injected. Displacemen~
of gellable fluid from the gel tubs to accornmodate incoming
ca~alys~ fluid can be accomplished by fi~ing a ~mall
non-re~urn valve to ~he bot~om of ~he gel ~ube. Pre~ure
applied 9~o the catalyst fluid during in3ect:ïQrl and
transmi~ted ~hrollgh the gellable fluid in the s~el tube wou~ d
cause ~e non return ~alve ~o open and gellabl~ fluid to be~
released in~co the ~el tube s~over cap
Alternatively the gel tube can be biased by a ~;pring
in ~he cover cap ayainst ~ seal at the ba~e of the spigo~ ~n
the injector sub-assembl~ Pressure applied t:o the catalyst
fluia and ~n~imitted to the gellable fluid in lthe gel tube
would cause the gel tube to lift off it~; sealed ~eat thereby
aisplacin~ ~ellable fluid ~rom the gel tube~ A short
ext~nsion tube fit:ted to the no:n-return valsre in the
i~iection c~amber wollld ensure that the eat~lys~: was
înjec~ed at sufficieIIt depth in ~he gel tube ~o aYoid being
displaced with the gellabl e fluid
The tec~lniqlle used to activate the instr~ment whe~L it
is ~ein~ use~ only for ~orehole ~;urvey i~ simi lar ~Lo ~:hat
d~scribed îor co.re orienta~ 33 e~cept in ~wo reE;p~cts
~irstl~f the instrume}~t is purnped dow~ ~he drill ~cring
witholl~ a g~ppllng device to engage with the ~;pearheed on
the ~ore ~arrel. Secondl~ no attentlon need be paid to
datum lines. The inclina~io~ and asimuth of ~he ho.le are
deri~rea ~irectly from the compass ~all
The :oregolng describ~s only some ernbodiments o~ the
present invention and modîfica~:ions, obvious ~o ~hose
slcilled in t~e art, can be made there~o wi~hou~ depar~ir
f rom îhe scope of t~e present inverltion as def ined i n the
followin~ cl~ims.
~)
s~
SUPPLEMENTARY DISCL.OSURE
Figure 3 is a sec-tiona] view of -the gel tube
for use with another embodiment of the presen-t invention.
Increasin~ the volume of the ~el tube as -the
catalyst is injec-ted is the preferred me-thod to be usecl
with a completely full ~el -tube. As shown in Fi~. 3,
this involves replacing the ~el tube 29 wi-th a gel -tube
45 open a-t both ends and fitted wit~ a pis-ton 46 which
under light pressure can sealably slide within -the -tube.
lYhen pressure is applied -to -the injector pin 21 and
transmitted through the catalys-t fluid 25 to the
gellable fluid 32 in -the gel tube 45 and -thence to -the
piston, the pis-ton 46 moves increasing the volume of
the gel tube 45 and permitting the injection of the
catalyst fluid 25 into the gel -tube.
-- 1 1
