Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
~9~76
APPARAI~US FOR EI,ECTROKINETICALLY S~PARA~ING DRILLIN&
MUD
Th~ present invention relates to the drilling techniques,
and more particularly, to apparatus for electrokinetically
separating drilling mud into liquid and solid p~ase~.
Th~ apparatus according to tbe invenbion may be most
advantageously used fox drilling oil and gas production
wcllY, and geological prospecting boreboles. The apparatus
may als~ be used in tho chemical industry, for tho manufac-
ture of construction materials, and in othor industries
here colloidal clayog phase of a slurry i~ tD be utilized.
drilling mud
Known in the art is that represonts a hcterogeneous
liquid ~ystem inevitably containing colloidal solid phasc
particles. ~he presont of tbose particlos in drilling
mud dcbermines a numbsr of rhoological proparties of
drilling mud which are important from the vi~wpoint of
well drilli~g quality. ~herefore, the proc~ss for preparing
drillin~ mud i~ ossontially the ~rocoss for prcparing
clayoy slurrios with the conbent o~ aolloidal solid
phaso particlos at a le~el at which neces~ary rheological
proporties of drilling mud are obtained. ~he degree of
dispersion or comminution of clayey solid pba~o particles
detormine the qu~lit~ of drilling mud being prepared. Reduc-
tion of the total quantity of solid pbaso in drilling mud
*
97~6
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with the samo rh~DlDgical properties of drilli~g mud contri-
butos to an increas0 in tho mechanical speod of drilling.
~his r~quir~s an improved d~gree of dispersion.
Drilling mud i~ pr~parod from high-grado dry mud, and
exp~nsive cbomical roagents ar~ addod thoroto for control-
li~g and stabilizing prc-set proportios Df drilli~g mud.
A~tor the drilling is ov~r, all drilling mud i~ disposod
i~to a pile sinco its transportation to another drilling
~ite i9 too expensive owing to bigh tra5port co~t a5
drilling mud consists at 85-90% of wator. A prDbl~m, thsra-
fore, aris~s to soparato tbc most valuabla fraction ofdrilling mud - finost colloidal fraction - whicb constitutos
tho ba~is o~ tho structur~ of drilling mud, t~o moro
80 as it i8 rich in cb~mical reagents addad to drilling
mud.
At prasant drilling mud i9 only cleanod durinB drilling.
~haro flr~ various apparatus ~or cloaning drilling mud
during drilling.
Such k~own apparatu~ as vibratDry acroo~, bydrocyclonas
and contrlfug~l apparatu~ ~oparato cor~- lump~ o~ drilling~
fxom drilling mud, wharoa~ finost colloidal particlo~
romai~ tbu~ impairing tba propcrtios o~ drilling mud. ~bu~
a portion of drilling mud is to bo disposod, tho romai~
porbion i~ dilutod with wat~r and troatod with cbemical
~ 7~ ~
reagents for malntaining desired rheological parameters
of drilli~g mud which are importa~t for well drilll~g.
After the drilling is over, the drilliDg mud is generally
disposed.
a
It will be apprent that separation of colloidal par-
ticle 5 of solid phase from drilling mud is of a substantial
importance for the economi¢al performance of well drilling.
Enown in the art i9 an apparatu~ ~or separating
stable colloidal clayey phase ~rom drilling mud, wherein
drilling mud leaving the well and aontainin~ drilllng~
i8 preliminarlly dilut~d with water, and coar~e drillings
are separated therefrom. Fine non-aharged drilli~gs and
negatively charged colloidal clayey particles are present
in ~uah diluted and cleaned drilli~ mud. ~hen negatively
charged alayey particles are separated from the drilling
mud by depositing them on a rotary anode, with subsequent
removal by means o~ a saraper. ~he deposlted ne~atively
char~ed clayeg partiale~ entrain with them a portion
o~ non-charged partioles whioh are also deposited on
the rotary anode.
The above-desaribed ap~aratus aan only treat a por-
tion o~ drilling mud, whereas the remaining and much
~reater portion thereof is fed back to the well without
treatment.
~g776
Separation oP solid phase particles only from a por-
tion oP drilling mud and the two-stage character o~ the
process: first, separation of coar~e particles, and then
separation of finer particles, make the proce~s complica-
ted and e~pe~sive.
Kno~n in the art is an apparatus for electrokinetical-
ly separating drilling mud into liquid and solid phase~,
wherein a casing has an inlet for drilling mud a~d out-
lets for separated phases of drilling mud and ao~ommodates
electrodes which ar~ conneoted to terminals o~ a d-c
souroe~
~ he electrode conne¢ted to the positive terminal o~
the d-c source comprises a cbamber having a per~orated
wall which ~s connected to a closed circuit for a cir~ula-
tion of an electrically conducting liquid. The casing
comprises the other elec~rode and i~ connected to the ne~a-
tive termlnal o~ the d-c source. ln operation airculating
throush the chamber is enriched with solid phase, and
drilliD~ mud which is wi~hin the casin~ and around the
chamber is depleted therefrom. After several cycles of
pumpi~ o~ the eleotricallg conducting liquid through
the ohamber the process o~ cleaning of the drilling mud
i~ completed.
~1~9~;'76
After that the electrically conducting liquid enri¢hed
wit~ solid pha~e i drain~d and replaced by rresh liquid.
~a~ batch o~ drill~g mud i8 poured in the casing of t~e
~pparatus, and the cleaning process continu~s.
The need for circulatin~ the electrically conducting
liquid limits the amount of solid phase taken i~ thereb~.
It is an ob~ect of the invention to provide an appara-
tus for eleotrokinetically separating drilli~g mud into
liquid and ~olid phases, wherein the electrode conn~cted
to the negative terminal of a d-c source and the Gasing
are so oonstru¢ted as to substantially completel~ separate
solid phase rioh in chemioal rea~ents ~o as to enable
it~ utilization.
~ nother ob~ect of t~e invention is to redu¢e the cost
of separation of solid phase ~rom drilling mud.
Further ob~eot of the invention i8 to increase the
drilllng speed o~in~ to an improvement o~ quality of
proce~sed drilling mud.
With thes0 and other ob~eots in view, there is provided
an apparatus ~or separating drilling mud into ~olid a~d
liquid pha~es comprising R casing having a~ inlet for
drilling mud and outlets ~or separated phases thereo~ and
accommodating electrodes connected to the negative term~nal
~9776
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and to the po~itive terminal, respectively, o~ a d-c sourse,
wherein, according to the invention, the eleatrode which
is con~ected to the negative terminal compri~es a conveyor
screw and has a cylindrical portion and an adjacent conioal
portio~ and the casi~g ~orms the electrode co~nRcted to
the positive terminal and has respective cyli~drical and
oonical portions, the outlet ~or solid phase of drilling
mud being provided at the end of the conical portion o~
the casi~g, a~d wherein there is provided Q receptacle ~or
collecting solid phase of drilling mud communicating with
the outlet ~or solid phase of drilliDg mud provided
in the oasing.
The receptacle for collecting solid phase pre~erably
aompris~s two coaxiall~ arranged containers made of a
flexible oorrugated material, the inner contalner being
made of a reticulate electrically conducting material,
¢o~nected to the ~egative terminal o~ the d-c source and
communioati~3 with the casing outlet ~or solid pha~e,
and the outer container being made of a non-aonducting
material having openings ~or draining separated liquid
pha~e~
Flcxible ¢orrugated ~tructure of the receptacle
for oollecting solid phase whiah exhibit~ var~i~g inter-
nal volume eliminates the ~ormation of air pockets hampering
the flow of electric current.
~7--
The provi6ion of the inner container in the ~orm of a
reticulate cathode al~o pre~e~ts clayey particles from
sticking to the walls of the inner container and contribu-
tes to an additional ~eparation of liquid phase (flltrate),
tha~ is to ~urther thickeniDg of solid phase of the
drilling mud.
~ be outlet ~or liquid p~ase of drilli~g mud i~ pre-
ferably arra~ged within the conical portion of the
ca~ing and i8 provided through a reticulate partition
w~ll .
~ he provi~ion o~ the outlet for liquid phase within
the coni¢al portion of the oAsin~ ensures mo~t e~ficient
separation of filtrate and thickenin~ of solid phase
of the drilliD~ mud in the casing of the apparatus.
~ he oylindrioal portion of the casing preferably ¢on-
8i~t9 of three part~ of which the intermediate part is
electri¢allg insulated from the end parts and functione
as an ~ode.
~ hl~ aon~truction ensures the provi~ion of anode and
cathode ~ones in the intermediate part of the casin~ and,
a~ fin~t colloidal negati~ely oharged partieles are depo~i-
ted on th~ anode, the deposition of the thickened part
of drillins mud on the intermediate portion of the ca~ing
i~ most effi¢ient.
7 6
-8-
~ he screw blades and the conical portion of the screw
are preferabl~ made of an insulating material and the
screw shaft is made of an electri¢ally conducting material.
Thi~ arrangement is needed to provide a uni~orm eleo-tric
field within the apparatuQ.
~ collector for separated liquid phase is preferably
provided under the outer container.
~ his fa¢ility makes it possible to re-use the ~iltrate.
~ here~ore, the apparatus for separating solid phas~
of drilling mud from liquid phase (~iltrate) provides
for an eificient thickeni~g of solid phase of drilling mud.
Substantial technioal advantages of the apparatus ac-
oording to the invention are aohieved by USiDg simple
techniques and e¢onomic~l operations. ~ simple kinematic
chain ensures a reliable operation of thQ apparatus ac-
oording to the invention ~or separatin~ solid phass of
drilllng mud from ~iltrate. mO use of the invention makes
it possible to obtain substantial ~avings of dry mud and
ohemioal reagents.
A ~peoi~ic embodiment o~ the invention will now be
d~soribed with rererenco to the aocompanyin~ drawing, ~howing
a diagrammatio view o~ an apparatu~ ~or eleotrokinetally
separating dri.lling mud i~to solid and liquid phases,
acoording to the invention, in longitudinal section (the
screw drive not shown).
~977~;
_g_
An app~ratus ~or eleotrokinetically separating drilling
mud i~to solid and liquld phaso~ comprises a casing 1
having a pipe 2 oonnected thereto for an inlet of drilling
m~d, a~d a pipe ~ ~or an outlet of separated liquld pha~e
o~ drilli~g mud. The ca~ing 1 accommodates a conveyor
scrow 4 ha~iDg a cylindrical portion 5 and an adjaoent
conical portion 6. A ~aft 7 of the screw 4 i9 made
o~ an electricallg conducting material a~d i~ connected
by mea~s of a slip ring 7a to the negative terminal of a d-c
source 8. Blades 9 of the screw 4 and the oonical portion
6 oi the ~arew are made of an ins~llating material. ~he
¢asing 1 has a respeative cylindrioal portion consisting
of inter~o~nected parts 10a, 1~b and 10c5 and a respectivo
conical portion 11. The intermediate part 10b is insulated
~rom the end parts 10a and 10c by mean~ of ~pacers 12 oi
an in~ulatiD~ material. The intermediate part 10b i~ ¢on-
neoted to tho positi~e terminal of the d-c source 8.
An ouklet 13 ~or aeparated ~olid pha~e of drillin~
mud is provided at the end o~ the conical portion 11 of
the casing ~. ~o thi~ end ad~olns a receptaole 14 ~or ool-
le¢ting oolid phaso of drilling mud which oommunicates with
the outlet 1~.
~ he receptacle 14 comprise~ two coaxially arranged
3L~49~76
conta-iners - an inner container 15 a~d an outer contalner 16 -
made of a flexible corrugated material a~d having a common
base 17. Th~ containers 15 and 16 are installed in such
a ma~ner that a~ annular space i8 de~ined therebetween.
The ~nner container 15 iæ made of a reticulate ele¢trical-
ly conducting material a~d is con~e¢ted to the negative
termiDal oi the d-c source 80 that it ~orms a cathode. The
container 15 communicates with the outlet 13 o~ the ¢asing 1.
The outer container 16 i~ made of a non-conducting
material, aonn~cted to the base 17 and pro~ided w~th ope-
ning5 18 for draining the additionally separated liquid
phase. A collector 19 communicating via a pipeline 20
with a tank 21 ~or drill~ng mud i9 provided u~der the
outer container 16 for collectin~ this liquid phase.
~ he receptacle 14 and the casing 1 are interconneated
by mean~ of flanges 22 and 23, respeotively, with the
interposition o~ a gasket 24. The ~lange~ are tied-up
by means o~ a ¢lamp 25 made o~ a~ in~ulatin4 material.
~ he pipe 3 i8 aonn~ated to the casing 1 within the
aonical portion 11 thereof since it is within this portion
that mo~t e~icie~t s~paration of liquid phase throu~h a
reticulate partition wall 26 takes place.
The ~a~k 21 communicates, via a pipeline 27, with
the pipe 3 and, via a pipeline 28 and a pump 29, with the
~ ~977 6
pipe 2.
Th~ apparatus for ele¢trokinetically separati~g drilliDg
mud aocordin~ to the invention ~unctions in the following
maLDar.
When the apparatus is started, drives o~ the sarew 4
and pump 29 (not shown) are turned on. DrilliDg mud to be
treated i8 ~ed by the pump 29 throueh the pipeline 28
and tho pipe 2 to the interior o~ the aasi~g 1 where tho
drilling mud is electrically treated. As a rosult of th~
electrical treatment, colloidal clayey phase of the drilling
mud i8 deposited on the part 10b of the casi~s 1, and the
treated drilling mud passes through the reti~ulate par~ition
wall 26, pipe 3, and pipeline 27 back to the tank ~ he
drllling mud being treated repeatedly airoulates through
the electrio field of the apparatus 1 ~ivi~ up its clayey
phase to the part 1~b of the oa~ing 1. First, finest col-
loidal particles of the drillin~ mud are deposited i~ the
oasiLB 1, on it~ part 1~b, whioh are continuously removed
~rom the ~alls by the rotatin~ ~crow 4 and trans~erred
thereby bo the receptacle 14 and further through tho
outlet 13 into the interior of the container 15 colleoting
solid phase. Sinoe the aontainer 15 is made of a flexible
¢orrugated material, a back pressure develops causing a
aompaotion of olayey phase in the interior of the container.
~ 7'~6
U~der the action of the electric ~ield, additional separa-
tion of liquid phase oocurs within the compacted clayey
phase. ~he negatively charged container 15 repells negati-
vely charged colloidal clayey particles, while allowi~g
the ~iltrate to pass through unhampered. The separated
filtrate passes into the annular space between the containers
15 and 16 and through the openings 18, is drained into the
¢ollector 19 ~or collecting separated liquid phase and
is farther ~ed ba¢k to the tank 21.
By changing the number of cycles of circulation o~
drillin.g mud through the casin~ 1 and by varying the inten-
sity of current, colloidal phase of drilli~g mud having
of one and the same parti¢les size may be collected in the
recptacle 14. After the finest fraction is separated, the
receptacle ~or colleating solid phase i8 repla¢ed b~ an empty
receptacle, a~d the intensit~ o~ current is increased to
circulate the drilling mud through the casi~ 1 for a desired
number o~ ay¢les 80 as to colleot a coarser fraotion, and
so on.
~ e receptacle 14 ~or collecting solid phase maybe
then used for the storage and transportation o~ the
separated paste-like mud to another site for re-use. Connec-
ting the sorew 4 and container 15 to the negative terminal
of the d-c source 8 prevents clayey particles ~rom sticking
thereto.
-13-
Therefore, the apparatu~ for electrokinetically separa-
ting drllliDg mud into ~olid phas~ a~d liquid phase i~
highly efficient in separating finest colloidal phase rich
i~ che~ical reagents a~d makes it possible to obtain a paste
of drilling mud for subseque~t use.
Economical e~ficiency of the apparatus for separati~g
drilli~g mud into solid and liquid phases accordi~g to the
inventio~ is determined by reduced cost of chemical reagonts
used for the preparation of drilli~g mud and maintenance
of its parameters, i~creased drilling speed owing to a better
quality of drilling mud prepared from the pase and
prolonged life of drilling mud.
