Note: Descriptions are shown in the official language in which they were submitted.
~L~5~6~i7
ME~OD OF SEPA~ TG SO~ID PHAS~ IN DRI~ G
~D A~D LPPARA~US FOR P~FORMING ~IS ~HOD
The present invention relates -to well-drilling technolo-
gy, and more particularly it rela-tes to methods of separatlng
the solid phase in a drilling mud and -to apparat-us adapted
for performing such me-thods,
~ he herein disclosed method and apparatus can be utill-
zed to utmost effectiveness in -the drilling o~ boreholes *or
oil-producing wells~ natural gas producing wells a~d survey
wells.
Howaver, the method and apparatus can be also used in
general chemistr~, pharmaceu~ical and other industries where
a solid phase has to be separated ~rom a suspension.
It is known that a drilling mud is a heteregene OU3 ~luid
s~stem where colloid particles of the solid phase are always
present. ~he presence of such particles in a drilling mud
provides, ~ro~ the borehole-drilling point o~ view, a number
o~ maaor rheological characteristics o~ the drilling mud. ~he
latter is expected to retain these characteristics which are
essential for promotion of the drilling process. However9
stable maintenance o~ the required properties of the drilling
mud throughout the drilling c~cle presen~ts a complicated
problem.
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~L15~667
The majori-ty of borehole-drilling jobs -takes place in
clayey rock ancl soil. ~he clayey rock being~ drilled is
partly disintegrated, and colloid particles thus produced
become resident in the drilling mud.
Inadequately efficient purifica-tio~ of the drilling mud
~ollowing several pum~ing cycles in the course of the boreho-
le-drilling operation significantly alters -the composi-tion
of the drilling mud, which necessita-tes the adop-tion of
various methods of enhancing the quality of the drilling mud,
which me-thods, howeverj are more o~en than not ins~fficiently
efIective. Thereforel quali-ty puri~ication o~ -the d~illing
~ud ~rom disintegrated rock particles, or sludge is of funda-
mental importa~ce ~or the success of a borehole-drilling
operation~
Poor quality of purification of -the drilling mud is a
major cause o~ various emergencies and complications involving
drilling mud losses t sticking or freezing of drill pipes an~
casings, caving-in of rock from the borehole walls~
The technical and economic ratings of a b~ehole-drilli~g
operation are considerably dependent on -the quality of the
drilling mud used and the degree of its purification from rock
cuttings~
Quali-ty purification of the drilling mud enhc~nces the
drilling rate and improves the oparating conditions of the
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~5~6367
drilling bits and other equipment. Aside rom the enhcmced
drilling ra-te, quality purification of the drilling mud
brings down the consump~ion of materials used for preserving
the properties of the drilling mud, prolongs th~ service life
thereof, helps avoiding complications and emergencies encoun-
tered in a borehole-drilling operation.
~ hus, quality puri~ication of -the drilling mud ~rom rock
cuttings is of major impoxta~ce in the borehole-drilling
technology, essentially influencing as it does the ~echnical
and economic ratings of -the drilling operation.
All the hitherto known apparatus -~or purification of
~he drilling mud provide ~or removing some o~ solid particles
~rom the circulating drilling mud a~ a certai~ rate and with
certain quality. However, all of them are not free from a se-
ries o~ disadvantages inherent in -the very principle o~ separa-
tion on which they are based. hus, the minimum particle size
o~ fines that can be separa-ted from -the drilling ~ud in vibra-
ted screens is determined by the mesh size. I~ the meah ~ize
is made ~lner ~o impr~v~ ~he purification quali-ty, the -through-
put becomes affected, and -the was-te of the mud wi-th the sludge
is stepped up.
When hydrocyclones are employed ~or -the puri~ica-tion,
coarser particles are removed from the drilling mud, whereas
particles with a lower density caused by dispersion o~ fi~er
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;67
-- 4 --
rock cuttings in the drilling mud are not removable in
hydrocyclones and like devices used for the purification.
There is known a method of regeneration of the
stable clayey suspension of the drilling mud, according
to which the sludge-carrying drilling mud emerging from
the borehole is prediluted and processed to remove coarse
particles In the thus dilutecl and purificed drilling
mud there remain fine unchargecl particles of rock cuttings
and negatively charged colloid clayey particles. Then the
negatively charged clayey particles are separated from the
drilling mud by deposition on a rotating anode, and sub-
sequently removed therefrom with a scraper-like tool. The
- negatively charged clayey particles being deposited entrainsome of the uncharged particles which also become deposited
on the rotating anode~
The above-described known method purifies but
- part of the drilling mud, while the substantially greater
remaining part is fed into the borehole unpurified.
The puri~ication of but a part of the drilling
mud, involving removing, first, coarser particles, and,
I then, finer ones is complex, and hence costly.
It is an object of the present invention to create
- a method of separation of the solid phase in a drilling mud,
which should provide for purifying the entire volume of the
drilling mud emerging from the borehole in a technologically
simple manner.
It is another object of the present invention to
reduce the drilling mud purification costs. I
It is still another object of the present inven- j
tion to enhance the drilling rate by improving the quality
of purification of the drilling mud. I
With these and other objects in view, there is
hereby disclosed a method of separating the solid
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phase in a drilling ~ud, including, in accordance with the
present invention, forming an adhesion layer ~rom the dril-
ling mud on a rota-ting curvilinear closed surface partlJ in-
troduced into tke drilling mud, ~nd sirnulta~eousl-g trea-ting
the drilling mud and the adhesion la~er formed therefrom in
a~ electric field produced by a direct current, to reduce the
surface tension value of -the adhesion layer, and regulating
the angular speed of the rotatio~ of the curvilinear closed
surface to attain the re~uired value o~ centrifugal a ~orces
ithin the adhesion layer.
It is expedient to treat the drilling mud being purified
with a low-voltage DC current-produced fi~ld.
This treatment enables to adjust the surface -tension in
the adhesion layer, and~ conse~uently, to regulate the process
o~ separation ~rom the adhesion layer of solid particles of a
density hlgher than that of the drilling mud from which the
adhesion layer is formed.
It ma~ be also expedient to treat -the adhesion layer in
a high-voltage produced electric ~ield~
~ he action o~ a high-vol-tage electric field upon the
adhesion layer reduces the latter's surface tension and
results in electrically charged par-ticles of the solid phase
being withrawn from this la~er.
I-t is expedient that -the electrosta-tic intensity of the
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~5~6~7
electric field produced by low voltage in the drilling mud
should be varied in accordance with the value of the concen-
tration o~ the solid phase in -the purieied drilling mud.
~ his kind o~ regulaGing enables to a-ttain an adequately
high degree Oe puri~ication of drilling muds containing prac-
tically any amount Oe rock cuttings.
It may also be expedient to var~ the direction of the
high-voltage electric eield in the adhesion layer, depending
on the mineralogical composition of the solid phase of the
drilling mud. ra
~ his enables to sepate from the adhesion layer ei-ther
the positively charged particles of -the solid phase, or the
negatively charged ones, a-t will. ~hus 7 to separa-te barite
particles charged positively, the adhesion la~er is acted upon
by a high-voltage field of a negative polarity, without a low-
voltage field being used. On the other hand, to separate ne-
gatively charged colloidal particles, there is pre~`erably
used a high-voltage field o~ a positive polari-ty~ with simul-
taneously acting upon the drilling mud with a low-voltage
~ield.
It may also be advantageous -that the intensity O:e ~the
high-vol-tage electric field should be varied depending on the
size of the particles o~ the solid phase in -the drilling mud.
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~IL5~6~7
'~his enables to control the volume of -the withdrawal
o~ soli~ phase particles from -the drilling ~ud~
The present invention further resides in an apparatus
Por separating the solid phase in a drilling mud, compris-
ing, in accordance with the invention, a receptacle adap-ted
to contain the drilling mud to be purifi-ed ana a receptacle
adapted to contain ~he pu~ified drilling ~ud, and a driven
drum acnommodated above the receptacle with -the drilling mud
to be purified so that a part of the cylindrical periphery
thereof projects into the drilling mud to be puri~ d9 Por an
adhesion layer to be formed thereon in the course o~ rotation
of the drum, and electrodes connectable -to a direct-current
voltage source, adapted to generate an electric field in -the
drilling mud to be purified and in the adhesion la~er formed
on the surface o~ the drum from the drilling mud to be purified.
While being of a rela-tivel~ simple struc-ture, the herein
disclosed appara-tus enables to conduct puriPication of the
entire volume o~ the drilling mud emerging from the borehole,
and provides for a high degree o-f the purification.
In one embodiment of the inventionl one of the elect-
rodes is mounted within the receptacle for the drilling mud
to be puriPied, while another electrode is moun-ted within -the
vessel for the purified drilling mud, both electrodes being
connected to a low voltage direct-current source.
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I-t is further ad~isable that the apparatus should also
include at least one electrode accommodated adjacen-t to the
cylindrical surface of the drum,adapted to carry the adhesion
layer, and at least one high voltage direct-current source
having one output terminal thereof connected to the electrode
accommodated in one of the two said receptacles ~or the dril-
ling mud, and -the opposi-te-polarit~ other output terminAl there-
of connected to the electrode accommoda-ted aajacent to the
cylindrical surface of the drum, adapted to carr~ the adhesion
layer, at a spacing in excess of -the high~volta~e break-through or
punc-ture air gap.
~ he abovedescribed design enables to step up the rate
and the degree of purification of the drilling mud.
I-t ma~ be expedient -that the electrode accommodated
adaacent to the drum should be shaped as a portion of a
hollow cylinder having its concave side facing the drum.
~ his shape of the electrode has been found to ensure
that the electric ~ield exer-ts a uniform ac-tion upon tha ad-
hesion layer.
It is ~urther expedient that the apparatus should incl-
ude a responsive member or sensor adap-ted to produce a signal
represen-tative of -the concentra-tion of the solid phase in -the
puri~ied drilling mud, accommodated in ~the receptacle for
collecting the purified ~rilling mud, and having i-ts output
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~151~66
_ 9 _
connected through a regulating device to the input of -the
low-vol-tage c~irec-t-curreIrt SouI ce .
It may be also practicable that ~he responsive member
adapted to produce a signal represen-tative o~ -the concentration
of the solid phase in the purified drilling mud should have
i~s outpu-t connected to the input OI the high-voltage direc-t-
current source~
~ he provision of said repsonsive member or sensor provides
~or automatic regulating of the value of the sur-face tension
o~ the adhesive layer, and, hence, ~or maintaining the pre-
determined content of the solid phase particles in the purifi~
ed drilling mud.
Thus, the herein discloseà method of separating the
s~lid phase in a drilling mud and the apparatus capable o~
performing this method provide for attaining a high degree
o~ puri~ication o~ the entire volume of the drilling mud, for
regulating the degree o~ withdxawal of ~he ~o~~id phase wit~in
a broad range, and ~r having selectivit~ o~ the withdrawal of
~olid particles, depending on -the mineralogical composition
o, the solid phase. The substantial technical advantages to be
gained by the herein disclosed me-thod are at-tained in a simple
technology involving economic operations~ ~he apparatu~ capab-
le of performing the disclosed method is relatively simple and
compact, its ~-iving arra~gement being uncomplicated~ ~he uti- :
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l:~S06~7
- 10
lization of ~he ~resent inventiorL offers subs-tarl-tial economy
over the hitherto known practice of employing appara-tus of
the prior art for purifiyin~ the drilling mud used in a bore-
hole drilling operation.
~ iven hereinbelow is a description of an embodiment of
the presen-t invention~ with reference being made to the
accompanying drawings, wherein:
Fig.l schematically illustrates in a cross-sectional
view P~n apparatus for separating the solid phase of a drill-
ing mud, embodying the invention, wi-th the drive system o~
the drum not shou~;
Fig.2 shows a plan view of the apparatus illu~trated
ln Fig.l, with the high-voltage electrodes and sludge rec~p-
tacles removed for clari-ty sake.
An unpurified drilling mud receptacle 1 (Fig.l) has the
unpurified drilling mud 2 being supplied thereinto. ~he rota-
-table curvilinear closed surface is in the form o~ a drum 3~
~he drum 3 has its periphery partly submerged into the dril-
ling mud 2, to form thereon an adhesion layer 4 upon rotation
of the drum 3. ~he unpuri~ied drilling mud 2 and -the adhe-
sion layer 4 evolved therefrom are treated in an electric
~ield crea-ted by a direct current, to reduce the value of -the
surface ten3ion of the drllling mud 2 ln the adhesion layer 4.
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~L~l5~667
~he angular speed of the drum 3 is regulated -to create -the prede-
termined level o~ the cen-tril`ugal forces within the adhesion
layer 4, depending on the mineralogical co~position of the
drilling mud 2 being purified. ~hus, the centrifugal forces de-
veloping in the adhesion layer 4 upon rotation of the drum 3
provide for separation o~ the solid phase particles from this
ayer, depending on the mineralo~ical co~position of the dril-
ling mud 2. ~he drilling mud 2 being purified is treated in a
lo~w-vol~age electric field of which the intensity is varied,
depending on the value of the concentration of the solid phase
in the purified drilling mud. ~he adhesion layer 4 produced
from the drilling mud 2 being purified is -treated in a high-
voltage electric ~ield. ~he direction or sense o~ the high-
voltage electric ~ield can be varied, depending o~ the mineralogi-
cal composition of -the solid phase of -the drilling mud 2 being
pu~i~ied, while the value o~ the intensity o~ -this elec-tr1c
field is varied, depending on the size o~ the solid phase
particlas in the drilling mud 2 being puri~ied.
~ he essence o~ -the method in accorda~ce with the preseNt
invention will be described hereinbelow in greater detail,
in connection with the description o~ the apparatus capable of
per~orming this ~ethod, to be described bo-th in a statlc state
and in operation.
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~5V667
~ he apparatus for separa~ing the ~olid phase in a dril-
li~g ~lud comprises a receptacle 1 (Figs l and 2) adapted to
receive and con-tain therein a dr:illing mud -to be purified,
partly accommodating therein a drum 3 operatively connected to
a drive 5 (~ig.2) through an r.p,m. regula-tor 6. A scraper 7
is provided ~or stripping the layer of the puri~ied drilling
mud 8 o~ -the periphery of the drum 3. A receptacle 9 is moun-
ted adjacent to the receptaGle 1, adapted to receive and con-
tain therein the puri~ied drilling mud 8. An electrode 10 is
mounted within the receptacle 1, and an elec-trode 11 is moun-
ted within the receptacle 9. The electrodes 10 and 11 are con-
nected to a lo~-vol-tage direct-current source 12, with the
electrode lQ being connected to the negative terminal o~ the
source 12, and the ele~,trode 11 being connected to the posi-
tive terminal thereo~.
The receptacles 1 and 9 are made o~ a dielectric ma-teri-
al.
To act upon the adhesion la~er 4 with a high-voltage
field, the apparatus includes high-vol-tage direct-curren-t
sources 13 and 14, and high-voltage electrodes 15 and 16
mounted above the drum 3 adjacent thereto. ~he negative -ter-
minal of the high-voltage DC source 13 is connected to the
hi~h-voltage electrode 15, and its positi~e ter~inal is con-
nected to the electrode 10.
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~S~667
The positve terminal of the high-vol-tage directcurrent
source 14 is connected to the high-voltage elec-trod& 16; and
its negative ter~inal is connectea to the electrode 11.
~ he high-voltage ~ectrodes 15 and 16 are spaced f.rom
the drum 3 by a dis-tance in excess o~ the breakthrough or
puncture voltage gap, to avoid the high voltage o~ the sources
13 and 14 breaking through this gap.
The high-voltage electrodes 15 and 16 are shaped as
portions of a hollow cylinder and have their concave sides
facing the drum 3. This design of the high-voltage electro-
des 15 and 16 provides for producing a substantially unifor~
high-voltage electric field acting upon -the a~esion layer 4.
~ o collec-t the sludge separated ~rom -the drilling mud 2,
the apparatus includes sludge receptacles 17 and 18 mounted
to underlie the high-voltage electrodes 15 and 16, respective-
ly.
The receptacle 9 accommodates a sensor 19 adapted to
produce a signal representative of the concentration of the
solid phase in the purified drilling mud 8. The sensor 19
has its output connected via a regulating device 20 to the
inputs of the sources 14 and 12 of high~voltage and low-vol~
~ tage, respectively.
:~ The apparatus operates, as follows.
The drill:;ng mud 2 to be purified i~ supplied into the
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receptacle l. 'rhe drum 3 is ~o-tated by the drive 5 through
the r.p.m~ regulator 59 and forms on the peripheral surface
thereof an adhesion layer 4.
The adhesion layer 4 col~tains therein all th~ fractions
of -the solid phase con-tained in t;he drilli~g mud 2, ~nder
the actio~ of centrifugal forces and surface tension, -the
solid particles become redistributed in the adhesion la-~er 4
in accordance with their size or volume and mass. The heavier
and larger particles of -the solid phase migra-te -toward the
external sur~`ace of the adhesion layer 4, whereas ~he finer
- part~cles, and, particularly, the colloid or colloid-size
o~es become concentrated at the internal surface Gf the adhe-
sion layer 4, next to the peripheral cylindrical surface of the
drum 3. As the drum 3 rotates, depending on -the speed of the
adhesion layer 4~ the larger or coarser particles of sludge
leave the surface of the adhesion layer 4, while the remaining
layer of the fluid containing the colloid clayey particles is
directed into the receptacle 9 for further use. A solid phase
particle in the adhesion layer 4 has acting upon it, on the one
hand, centrifugal ~orces:
F = m V , (1)
where 7'm7' is the ~ass of a particle; "R" is the radius of its
rotation, and "V" is the linear velocity of the rotation
of the peripheral surface of the drum 3,
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and on -the other hand, it has acting upon it its weight 9 the
viscous ~riction forces and forces Fl o~ -the sur~ace tension
of the adhesion layer 4-,
~ 1 = 2~r ~, (2)
where "r" is the radius of the particle, and "~" is the sur-
~ace ~riction ~actor o~ the drilling mud 2.
~he evalua-tion o~ the relative significance of the
~orces taking part in -the distribution of the solid particles
through the adhesion layer ca~ be done by applying the Foude
cr~terion showing the ratio o~ the centrifugal ~orces -to gravity
~orces in a ~iven unit.
Fr = R (3)
g
~here "~" is the angular speed of rotation o~ the drum 3;
"R" is the radius of rotation o~ the particle;
"g" is the gravity aGceleration.
~ he maximum and minimum values of ~roude numbers for
real~ e structures are within 20 to 2000.
It Gan be see~ from the abovesaid that wh~en the ~orces
acting upon solid particles in the adhesion la~er ~ are calc-
ulated5 it is unnecessar~ to make provisions ~or their weight,
. since the centr:i~ugal or inertia ~orces are 20 to 2000 times
greater. Since th2 ~ric-tion ~orce between the sur~ace o~ the
solid phase part-icles and the ~luid en-training -them ~or rotat-
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ion 1~ diracted ta~entiall,y kc th~ ~urf~cs of th~ drum 3
and perpendicularly to tbe radius th~reD~, khe peculiariti~
D e tbe radi~l m~tio~ of t,he par~icle~ e. ~he ba~lc
lo~ ~ the proce~ o~ paration D~ the pba~e~ and
fraction~. (i.e. of t~e p~rificat~on proce3~3-may be G~n8
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dered wit~out prDeisio~s for t~e ~i~cou~ ~rie~ion Iorce~.
Tbu3, b,~ ~s~un~g the equalit~ of the a4ntri~u~al
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rces "1?'l a~d th0 ~urface te~slD~ *orc~ tb~re
can be ~ormul~t~d the CD~ditiD~I D:e equ:ilib~i um oi par~lale~
in the adbesion la,ye~ 4 o~ t~e c,yli~drical p~ripheral
surface ~f the r~-Abing dr~lm 3:
~d 3 ( JJ _ p ) cl,2f~ - r~, (4)
or el~s, relabive t~ the diameber of ~ par~icle (~h~c~
latter i~ conditio~ll,y tske~ b~ be ~pherlcal~"
d = \~¦f~ ;" 2~ -
~heres "d'~ he dismeter c~ a p~rb$cla (d = 2r);
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",P1" a~d "J~2 " ~re, re~pectiv~l,y9 the den~ity
of the sol~d phass a~d ~f t~e liSIuid?
"~ s r~diu~ of rotatio~ ~ bhe part;icle~
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tha ~ac~ ~rlcb~on ~actor ~ the liqui~
tbe a~heslo~ er 4.
I1; ca~ be ~een ~rom expression~ (4~ and (5) b~ali tb~
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movement o~ a particle of a diameter "d" within the adhesion
layer 4 a~d its expulsion from -this layer depend on -the den_
sity of -the dispersio~ medium, the radius 'IR" of -the circular
path of ro-tation of the paxticle, the speed of its ro-tation
and the value o~ the sur~ace tension o~ the adhesion layer 4.
~he radius o~ the circular path of rotation of the particle
is de~ined by the diameter of the drum 3.
Increasing the diameter of the drulll 3 is limi~ed by bhe
~tructu~al consldera~ions and the Illanu~c-~uring ~omp7ex~t~.
~here~or~ bhe major par~me~r~ of the process o~ ~parR~io~
o~ tne solid phase in t~ drilling mud 2 on the rotating cy-
lindrical surface of the drum 3 are the angular speed of its
rotation and the value o~ the surface -tension o~ the adhesion
la~er 4~
By varying the r.p.m. of the drum 3 and the value of
the surface tension of the adhesion layer 4, it is possible to
regulate within a broad range the process of separation o~ the
solid phase in the drilling mud 2, so as to remove the surplus
solid phase and -to retain the fine clayey particles which are
the major colloid componen-t of a cla~ey drilling ~ud~ :
To remove the weighting material from -the drilling mud ~ -
by its cen-trifugal separation, the solid rock cuttings are
disin-tegrated, prior to the separation, -to -the particle size ~-
of the weighting material. In this case the weighting material
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par-ticles of the speci~ic mass of 4 2 g/cm3 are separated
f`rom the surface of the adhesion layer under an~ given condi-tions
generally faster than the particles of sludge,which have -the
same size but a lower specific mass (2.6 g/cm3). ~he purified ad-
hesion layer 4 of the drilling ~ud 2 is scraped off b~ the scraper
7 ~nd directed in-to the receptacle 9
~ o reduce the ~alue of the surface -tension and -to regu-
late this value, low-voltage direct electric curren-t is made
to flow through the drilling mud and the adhesion layer 4 from
the direct-current low-volta~e source 12 via the ~ollowing
circuit: negative terminal of the direct~current source 12 -
electrode 10 - drilling mud 2 being purified - adhesion la-
yer 4 - purified drilling mud 8 - electrode 11 - positive -ter-
minal of the low-voltage direct-current source 12. The electro-
de 10 thus acting as the cathode9 the electrolysis of salts
contained in the purified drilling mud 2 within the receptacle
1 results in -the increasing pH value of the medium. As it is
nown from drilling practice, this increase of the pE value
reduces the surface tension. ~herefore, by varying the value
o~ the low-~ol~age electric current flowing through the drillin~
mud, the value of the surface tension can be regulated.
~ nder the action of the flowing elec-tric current, charged
particles are produced wi-thin the adhesion layer. ~o amplify
-the inlDluence of the charge of the charged particle~ upon the
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~L5~7
- 19 --
sur~ace tension o~ the drilling mud in the adhesion la~er 4~
and to enhance the conditions o~ separation of -the solid phase
particles of a certain mineralogical composi-tion in -the aahesion
layer 4 ~ there are produced in the latter -the areas o~ high-
voltage electric fields. ~he portion o~ the adhesion layer
which is the area opposing the negatively charged electrode 15
is always charged positlvely ~rom the high-voltage source 13
along the circuit: positive terminal o~ the high-voltage
direct-current source 13 - electrode 10 - drilling mud 2 to
be purified - adhesion layer 4, ~he positive charge o~ the
particles moving toward the e~ternal surface o~ the adhesion
layer 4 provides for separation in this area~ to the greater
degree, of neutral and positively charged particles (io e.
mainly OL the weighting material).
~ he other piortion of the adhesion layer 4, i,e. the area
facing the positvely charged electrode 16 ls al~a~s charg~d
negatively ~rol~ tne high-volta~e ~ource 14 via the eircuit:
nega~ve ~erminai of ~he ~lgh-~o~tage ~irec~-current source 14
- electroae 17 - puriYied ari~ n~ mud ~ - adhesion layer 4.
In this zone negatively charged particles o~ clay move toward
the surface of the adhesion layer 4.
Under the action of the centri~ugal forces, the reduced
surface tension and the high-voltage electric field, the
charged par-ticles contained in the adhesion layer are expelled
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- 20 -
from this layer 4 into the respective sludge receptacles
17 and 18 arranged to underlie the respective electrodes
15 and 16. Some of the chargecl particles as far as the
respective high-voltage electrodes 15 and 16 where they
lose their charge and flow down the planes of the high-
voltage electrodes 15 and 16 into the respective sludge
collectors 17 and 18.
Therefore, the herein disclosed apparatus is
operable to separate the drilling mud in a single process
into three parts, Within the first area or zone, it is
the weighting material that is predominantly separated.
Clayey rock particles are removed in the second area.
The third part is the drilling mud purified from the
extra solid phase.
The sensor 19 of concentration of the solid
phase, accommodated in the flow of the purified drilling
mud 8 is used to maintain the optimum duty of the purifi-
cation of the drilling mud 2,
An example of implementation of the disclosed
method can be provided by data obtained by a series of
tests aimed at determining the optimum parameters of the
operation of purifying the drilling mud 2. There were
tested various drums 3 of diameters ranging from 100 to
500 mm, rotatable from 10 to 10,000 r.p.m. It has been
found that with the drum 3 rotated at speeds from 1000
to 2000 r.p.m. the thickness of the formed adhesion
layer 4 of the drilling mud of a viscosity from 10
:
~ ~'
~ -- - ' ' '
,
. ' ~ .
.
,
1~5~616~
- 21 -
to lQO cen-tipoise is from 15 to 30 mm. Under the action of the
low and high voltage supplied by the sources 12, 13, 14 o~
direct current there has been a-ttained satis~ac-tory puri~i-
cation oL the drilling mud from sludge and removal o-f the
weighting material.
~ hus, the herein disclosed method of separa-ting the
solid phase in a drilling mud and the apparatus performing
this method offer considerable technical advantages over
purifying devices currently in use in the drillin~ operation.
By regulating the speed of rotation of the drum 39 by ~arying
the values of the high and low direct-current voltage
supplied, there is attained a high degree of the purification
o~ the drilling mud at relatively low investment a~d operat-
ing costs. ~he absence o~ complicated driving arrangements
facilitates reliable per~ormance of the apparatus in an au-to-
matic mode.
~ he economic e~iciency o~ implemen-ta-tion o~ -the present
inv~n-tion is defined by the reduced cost o~ purif~ing -the dril-
ling mud, reduced consumption o~ chemical agents and higher
mech~lical drilling rates, owing to the enhanced quality
of the purifica-tion of -the drilling mu.d.
.
'
