Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
APPARA~US FOR THE PREPARAq'ION OF DRILLING
MUD
~ be present invention relates to the well drilling
technolDgy, and mor~ particularl~, to apparatus for the
preparation of drilling mud.
The inven~ion may be mo~t advantageously used in the
~il and gas production.
The invention may also be used in the construction
and chemical industries for the preparation of ~arious slur-
ries and suspensions.
The production cycle for the preparation of drilling
mud comprises batching starting solid materials into a mix-
ing liquid, their stirring and subsequent dispersion of so-
lid phas~ in the liquid phase. Quality of mixin~ o~ the
phases, their bomogeneity and uniformity of distribution of
solid phase particles over the ontire volume of the liquid
phase ef~ect the quality o~` drilling mud being prepared.
Special r~quirements are imposed on apparatus for the prepa-
ration o~` drilling mud which en~ure the homogeneity of the
wat~r and clay su~pensiorl bein~ prepared 90 as to eliminate
th~ possibility of the presence of lumps and ag~reeates of
solid phase particles in drilling mud.
I~nown in the art are various apparatua for the prepa-
ration of drilling mud ensurin~ mixing of solid and liquidphases to~;ether, sueh as blade clay stirrers, hydraulic mo-
--2--
nitors, hydraulic jet mixers~ and the like.
Blade clay stirrer~ are in a widespread use at drill-
i~g ~ites owing to their ~imple structure. However, ver~ low
throughput capacity a~d large ~ize m~ke them outmoded.
Hydraulic monitors ensure high throughput capacity
in the preparation o~ water and clay suspension, but the re-
sultant mix is not homogeueous and contains a large quanti-
ty o~ lumps and extraneous matter.
The mo~t rational apparatus ~or the preparation of
drilling mud i9 a hydraulic jet mi~er (c~. US pate~t No.~867195,
Cl. BQl F, i~sued on ~ecember 18, 1975), having a loadin~ hop-
per communicating with a chamber of a jet mixer which ac-
com~odat~ a pipe communicating with a jet pump and having
jet nozzle. ~he loadin~ hopper i5 provided with noæzles ~or
~eeding liquid for creatinK a head and ior increasin~ the va-
cuum components in the chamber of the jet mixer to whic~o-
lid and liquid phase~ to be mixed are admitted. ~he hydrau-
lic ~et mi~er eifect~ batching of the starting materials to
the mi~ing liquid and the preparation of drilling mud, but
the resultant drilling mud i~ of rather poor quality ~o that
auxiliary equipment for en~urln~ high quality Or mi~ing oi
the component~ Or drilling mud i~ required. ~hi~ i8 e~plained
by a stron~ non-uniformity o~ the income o~ pulverule~t ma-
terial to the mi~ing zone thu~ re~ulting in large batches
o~ pulverule~t material having no time ior being wetted and
mi~ed with the liquid and formi~ a thick suspension which
results i~ clo~ing the cha~ber of the jet mixer~ Owing to
reduced pre~sure3 in the jet mixer provided by the nozzle
o~ the jet pipe under the action of a liquid jet, a large
quantit~ of air ~ets to the apParatus together with the powd-
er, the air hamperin~ the wetting o~ the powder with liquid
and imparting hydrophoboic properties to the powder which,
in turn, eifects the stability of density and homo~eneity
of drilling mud and operation of pumps, and also impairs
t~e quali ~ of chemical treatment and otner types of sub-
se~uent treatment.
~ he chamber of the jet mixer is rapid ~ cloKged with
lumps oi undispersed pulverulent material thus lowering the
reliability of the apparatus. To eliminate the resultant
clay plugs, high liquid pressure is required, that is piston
pumps ensurinK hi~h pressur~3 are to be used.
It is an object o~ the invorltion to provide an appa-
ratus ~or the preparation o~ drillinK mud h~ving means ~or
ensurin~ high-~rade and intensive mi~inK Or solid and li-
quid phases, their homo~eneity and unirormity of distribu-
tion of solid phase particles over the entire volume of the
liquid phase, eliminatin~ ~ormation of lumps of solid ph~se
and ag~reg~ates of solid partioles.
Another object of the invention is to reduce the con-
sumption of clay materials and chemical reagents and improve
~ ~ ~9'7~75
the t~rou~hput capaci-ty.
The present inve~tion resides i~ that an appar~tus
~or the preparation of drilling mud, comprising a loading
hopper having nozzles which are co~nected to a source of
mi~ing liquid and communicates with a chamber Or a jet
mixer accommodating a pipe communicating with a jet pump
and having a jet nozzle, accordin~ to the i~vention, the
apparatu~ is provided with a diaphragm electrolyzer insert-
ed in a line ~or feediog a mi~in~ liquid, the interior o~
the ne~ative ~lectrode o~ the electrolyzer communicating
with the nozzles o~ the loading hopper and with the pipe
oi the ~et mi~er.
This arranKement improves the adsorption and chemical
activity o~ solid phase particles thus improvin~ the hydro-
philization of their surface and the condition~ for mixing
of ~olid particles with the liquid.
Th~ pipe o~ the jet mixer is pre~erably mounted ~or
rotation an~ is provided on it~ surface with a helical blade
formin~ a conveyor screw.
The provision o~ the jet pipe in the ~orm oi a con-
veyor screw ensures uni~orm feedin~ of the thick ~raction
o~ the suspension to the chamber Or the jet mixer.
~ he end turns of the screw blade are preferably ri~id-
ly secured to the screw, and intermediate turns of the screw
~9 7 7 5
~re a~ially movable. ~hi~ f acility eliminates clogging oi
the chamber oi the jet mixer and interturn space o~ the
screw with solid pha~s lumps and thick fracbion OI sus-
pension ~o ~g to eliminate clogging in the cha~ber o~ the
jet mixer.
The invention will now be described with reference to
the ~pecific embodiment shown in the accompauying drawing
illu~tratin~ an apparatus ~or the preparation of drilli~g
mud.
An Apparatus ~or the preparation o~ drilling mud ac-
cording to the invention comprises a chamber 1 o~ a jet mi~-
er, which communicates with a loading hopper 2. The chamber 1
of the j~t mixer accommodate~ a rot~table pipe having a jet
nozzle a~d provided oa it~ surface with a helical blade for-
ming a conveyor sorew 3 which ensure~ uni~orm ~eeding of t~e
thick fraction o~ the suspension to the chamber 1 of the
jet mixer. ~nd turns 4 o~ the blade o~ the ~crew 3 are ri-
gidly ~ecured to the screw. Intermediate turns 5 of the ~crew3 are axially movable with a play 6 thus eliminating clogg-
in~ of the chamber 1 o~ the jet mi~er and interturn ~pace of
the screw 3 with lumps of solid phase and thick fraction of
~uspension. The loading hopper 2 has nozzle~ 7 conne¢ted to
a source o~ a mixic~ liquid (not shown) to ensure ~eedlng
o~ ~n additional batch Or a mixing liquid at an increased
~9~;'75
~6--
pH ~incrqa~ed alkalinity) ~or pre-wetting solid phese ied
through a net iilter 9 from bags which are out open by mean~
0~ a mill 8. The ~c~ew 3 is rot~ted by a drive 10. A pump 11
ieeds working liquid to the screw ~. The prep~red drilli~g
mud is delivered through a pipe 12 of the chamber 1 of the
~et mixer.
To improve tha adsorption a~d chemical activity of
solid phase particle~, hence, to enhance their hydrophilic
capacity so as to improve the conditions for m$2in~ solid
pha~e particles with a mixing liquid, the apparatus is pro-
vided with a diaphragm electrolyzer 13 inserted in a line
ior ieeding a mixing li~uid. The diaphragm electrolyzer
13 comprises an anode 14 and a cathode 15 which are separat-
ed by a semipermeable diaphragm 16. An interior 17 oi the
ne~ative electrode (cathode 15) in which the major volume
o~ the mi~in~ liquid is treated to increase its alkalinity
communicatQs with the nozzle~ 7 and with th~ inlet oi the
s¢rew 3, and an interior 18 of the po~itively charged élect-
rode (anode 14) where products oL oxidizing reaction~ areformed communicate~ wi~h a drain pipe 19 ~or removing ~uch
produot~,
The apparatus for t~le preparation of drilling mud func-
tions i~ the ~ollowing manner.
~1~9~75
Solid pulverulent phase is fed to the loading hopper 2
through the net iilter 9 on which extraneous matter remains
(9uch as re~idues o~ bag material or too coarse lumps of ~o-
lid pha3e) Yrom bags which are cut open by means o~ the mill
8. At the same time, a mixi~g liquid is fed through the noz-
zles 7 to the loading hopper 2, the liquid being pretreated
in the interior 17 of the cathode 15 of the diaphragm elect-
rolyzer 13. The mixing liquid passing tbrough the zone o~ the
negatively charged electrode(cathode 15) is enriched with
negatively charged hydroxyl groups oi the OH type as a re-
sult of redox reactions occurring in the diaphragm electro-
lyzer 13. An excess o~ hydroxyl groups in the mixing liquid
increa~es it~ alkalinity which i~ characterized by a grow-
inK pH o~ mixing liquid and contributes to an active reac-
tion thereof with the sur~ace o~ solid phase particles. Hy-
dration o~ solid pha~e particles oontribute~ to an increase
in the adsorption and chemical activity of the particles 80
that lumps and aggreg~te~ o~ tha particles are dispersed
into individual particles thue improving the conditions ~or
prewetting of particles and their mixin~ with the mixing li-
quid. ~hi~ i9 al~o ~aoilitAted by the mixing liquid leaving
the nozzles 7 under a head~ which iill8 the loading hopper 2
to create a chaotic motion o~ ~ù~pension in the hopper ~o
a~ to improve the conditions ~or pre-wetting and mixing.
However, the water and clay ~uspension is a sedimentary un-
--8--stable ~ystem so that ~ portion of SoLid ph~se settles down
to th~ bottom of the loading hopper 2, that is into the
chamber 1 of the jet mixer. Upon providing a hea~ o~ the
working liquid fed along the acrew 3 pressure reduction oc-
cur~ in the chamber 1 of the jet mi~er which contributes
to the intake o~ the pretreated water and ~l~y suspension
from the loading hopper 2 to the chamber 1 o~ the jet mi~-
er where it i9 mixed with working liquid and admitted under
the head to thc pipe7~o be delivered for use. ~he working
liquid ma~ compri~e water, water containing dissolved che-
mical reagents, or drilling mud which is to be enriched with
clayey phase or a weighting agent.
Thickened suspension settling down to the bottom of
the chamber 1 of the ~et mi~er can ~orm an obstacle in the
form o~ lumps or plugs ~or a ~ree passa~e of premixed solid
phase and mi~ing liguid to the zone o~ mixing with the work-
inK liquid. ~lo avoid this, the screw 3 in the form of the
jet pipe is driven ~or rotation 90 as to expell the thickened
part of ~uspension by its turn~ 4,5 to the zone of mixing
with working liquid. Jaulming o~ the screw 3 is eliminated
owing to the axial play 6 o~ it~ i~termediate turns 5. When
too thick suqpension or large lump o~ qolid phase accumulates
between the turns 4,5, the intermediate turns 5 more apart
without stopping rotation of the screw 3 until the thick
part of suspen~ion i8 e~pelled to the zone of its mi~ing with
775
_g_
~rorking li~uid, wherea~ter the intermediate turn~ 5 again
return back to t~e initial positio~ under the action of their
i~herent elasticity.
