US2941783A

US2941783A - Hydraulic earth boring and cyclone separation system

Info

Publication number: US2941783A
Application number: US671855A
Authority: US
Inventors: Donald L Stinson
Original assignee: Phillips Petroleum Co
Current assignee: Phillips Petroleum Co
Priority date: 1957-07-15
Filing date: 1957-07-15
Publication date: 1960-06-21
Anticipated expiration: 1977-06-21

Description

June 21, 1960 D. L. STINSON 2,941,783

HYDRAULIC EARTH BORING AND CYCLONE SEPARATION SYSTEM Filed July 15, 1957 2 Sheets-Sheet 1 I 24 a I 56 64 62 57 54 r INVENTOR. D. L. STINSON 4r TORNEVS June 21, 1960 D. L. STINSON 2,941,783

HYDRAULIC EARTH'BORING AND cycmm: SEPARATION SYSTEM Filed July 15, 1957 2 Sheets-Sheet 2 INVENTOR. D. L. STINSON Donald L. Stinson, Bartlesville, Okla, assignor to Phillips Petroleum Company, a corporation of Delaware Filed July 15, 1957, Ser. No. 671,855

8 Claims. (Cl. 2551) This invention relates to hydraulic earth boring and j d States Patfl cyclone separation systems. In one-aspect it relates to hydraulic cyclone separation systems in which the power to operate the system is applied from the mud pump of a hydraulic earth boring system. In another aspect it relates to combining hydraulic cyclone separation with a hydraulic earth boring system by the use of jet pumps 7 powered from the mud pump of said earth boring system. In the prior art a number of systems have been shown .in which there is some form of separation, or concentration of the drilling mud, in a hydraulic earth boring system, but in each instance a separate power system is required for the separation system, and a separate drilling mud pump is required for the earth boring system. 'I have found that it is possible to drive the hydraulic cyclone separation system with power from the mud pump of the conventional hydraulic earth boring system,

and thus both improve the operation of the combined systems and avoid the additional expense of a separate pump or power unit for the separation portionof the system.

One object of the invention is to provide a combined hydraulic earth boring and hydraulic drilling mud separating system.

Another object is to provide an improved'means for utilizing the pressure from a conventional mud pump to drive a hydraulic cyclone separator for the recovery of weighting materials, or for desanding the well drilling mud.

Another object is to provide improvements in the art of earth boring.

Numerous other objects and advantages will be apparcut to those skilled in the art upon reading the accompanying specification, claims; and drawing, in which:

Figure 1 is an elevational view with parts in cross section showing on specific embodiment of .the invention applied to the hydraulic drilling of a well.

Figure 2 is an enlarged elevational cross-sectional view of a hydraulic cyclone separator similar to the one shown in Figure 1.

Figure 3 is a cross-sectional elevational view of one of the jet pumps shown in Figure l.

Figure 4 is a view similar to Figure 1, showing a I second embodiment of the invention applied to a hydraulic earth boring system employing reverse circulation of the drilling mud in the well. 7

In Figure la well 4 is being drilled by anyconventional drilling process, such as the conventional rotary drilling process illustrated, in-which a rotary-drill'bit 6 having conventional cutting surfaces is attached to and rotated by drill string 7, which is rotated by rotary table 8 driven by motor-'9. The drill string 7 .is fed into'well 4 by gravity, by paying out the-usual supporting cable 11 connected todrill string 7 by rotary hydraulic swivel 12. Cable 11 is hoisted, or paidout, by the usual'draw 7 works (not shown).

In order to cool bit 6, remove cuttings from well 4, seal the walls of the well from passage of fluid into the .With valve 21 closed and valve 2,941,783 Patented June 21, 1960 formation, and maintain sulficient hydrostatic pressure in the well to prevent conate fluids in formation 13 from blowing out of the well, it is conventional to employ a well drilling mud 14, a suitable supplyof which is stored in a mud container 16, which could (if desired) merely be a pit dug in the ground (not shown). The well drilling mud 14 may be of any composition known to the prior art, and often comprises water, and quite expensive amounts of a powdered mineral weighting agent suspended therein to increase the hydrostatic head in well 4, and may also contain suitable clay, bentonite, water-loss reducing agents and dispersing agents such as alkali metal carboxyrnethylcellulose, or otheringredients conventionally employed in the prior art. In some in stances, especially in shallow wells, or in drilling low pressure formations, it is unnecessary to use weighting material, and in such cases the greatest problem becomes 'the removal of sand and drilling cuttings. The well drilling mud 14 as it returns from well 4 unavoidably also contains drilling cuttings, sand, and possibly excessive amounts of clay, salt, and/or fluids coming from the formation 13 which are undesirable and tend to build up in the well drilling mud until it becomes difiicult to use. a

In the. prior art, when the well drilling mud becomes diflicult to use by such undesired additions from formation'13, it has been customary to discharge large quantities of the same and replace them with fresh desired ingredients. The most expensive ingredient is the powdered mineral weighting agent, if the same is used. If no weighting agent is used, then the clay and special treating agents, such as sodium hydroxide, quebracho, tannin, alkali metal earboxymethylcellulose, become the most expensive ingredients. Instead of throwing large amounts of the complete drilling mud away, as in the prior art, the present invention concentrates'and conserves the more expensive ingredients, as the case may be, and discards mainly the less expensive and undesirable ingredients which have been added to the mud from formation 13, thus eflecting substantial savings in the cost of new drilling mud in the course of drilling. -By powdered mineral weighting agent it is intended to include all such known to the prior art as well drilling mud weighting agents, such as barium sulfate (barite or barytes) B2180 the various lead oxides, chiefly litharge PbO and red lead Pb O the iron oxides, chiefly magnetite Fe 0 and hematite Fe O and powdered iron,

rosion of, and abrasiveness to, the well equipment, that.

it is vastly preferred over the others.

The well drilling mud is drawn from mud container 16 through intake pipe 17 of mud pump 18 and is forced into manifold 19 at a suitable high pressure, which may be several hundred p.s.i.g., or even over 1,000 p.s.i.g. 22 open, the drilling mud passes through stand pipe 23, and flexible hose connection 24 into hydraulic swivel 12 from which it proceeds down the hollow drill string 7 and out the usual openings in bit 6 into well 4, Where it agitates and picks up the cuttings produced by bit 6 and carries the same up the'annular space between drill string 7 and well -,casing 26, from which it may be returned to mud pit 16 through the usual well casing head 27. Although not essential, it is customary to provide a stutfing box 28 with an adjustable packing gland around 7 to. prevent uncontrolledflow of drilling mud out of the top of 28 around drillstring 7.

. While the most usual direction of mud circulation employed in drilling has been shown in Figure 1, it should be realized that it is common in the prior art to (7 use reverse circulation as shown in Figure 4, forcing the drilling mud down well 4 and up through drill string 7 with pipe 24 discharging into mud container 16, and obviously the present inventionv applies equally well to both regular and reverse circulation through well 4 and drill string 7.

In Figure I the drilling mud. returning from well 4 through casing head 27 is discharged through pipe 31 into mud container 16. This discharge may be direct without rendering the present invention inoperative, as bydraulic cyclone separators are quite rugged and can operate even with large cuttings suspended in the drilling mud. Furthermore, in the prior art, drilling operations have been carried out in which the larger cuttings were allowed to settle to the bottom of mud container 16, from which. accumulations of'the same were removed from. time 'to time with a shovel (not shown). The better, and almost universal and present practice, however, is to di rect the returning drilling mud through a metal screen 32, preferably reciprocated or vibrated in some manner, such as by motor 33, crank 34, and pitman 36. Such screens 32 are known as"sha'le shakers and commonly have sieve openings varying in the range of about 0.01 to 0.08 inch so that all solid particles having a diameter larger than the sieve opening will move by inerita and gravity over into pile 37 in a substantially'de'watered state and thus be removed from the mud circulation system. The essential components of the inud,v especially including the powdered solid weighting agent, such as barium sulfate, and the liner sands, clays, andd'rill cuttings, are of much smaller diameter and togetherwith the liquid in the drilling mud pass through 'screen'3 2 intothe body of mud 14 in container 16.

The rriud'pump 18 draws drilling mud out of tank 1 6 through pipe 1 and discharges the same into manifold '19 as previously described. By opening valves '38 and 21 some of the drilling mud at high pressure in manitold 19 passes into hydraulic jet pump 39 through jet nozzle 41 as shown in Figure 3, entraining'and inducing well drilling mud 14 to pass into conduit 43 through jet pump outlet 44 from jet pump inlet 46.

The well drilling mud in conduit 43 at relatively high pressure is passed tangentially through tangential inlet '47 i'nto'a hydraulic cyclone separator generally designated as 48,, which is substantially identical to hydraulic cyclone separator 48Ashown' in Figure 2, the only difierence being that whenviewed from above the vortex of fluids inside separator 48 is moving clockwise, whereas in 'sepa ra'tor 48A it is moving counter-clockwise. The process and degree, of separation is the same in separator 48 and 48A, and they areillustrated merely to point out thatthe rotation can be-in either direction, and also be'cause it"is possible to illustrate more in the drawing in elevationwith the tangential inlet 47 on the front in Figure l, and to show more in cross section with the tangential {inlet 47A in the back as in Figure 2.

Either hydraulic cyclone separator 48 and 48A comprises a generally conical chamber 4i with a tangential lighter and less expensive components pass through overflow outlet 51, elbow 57, valve 54 and discharge pipe 58 to a suitable place of discard, such as pit 59 dug in the ground 61.

While not essential to the operation of the hydraulic cy- -clone separators 48 or 48A, I have found that separation is improved by installingzafiseeond jet pump in elbow 57 as shownirLFigure 2,, employing, ajet nozzle 62 similar, to 4I of Figure Sandpowering the same with well "drilling mud under pressure from manifold 19 taken through a conduit. 65, valve 56,. conduit 64 and said nozzle '62..

l' have-also found that. the separation of the weighting material, or sand, in. hydraulic cyclone separators 48 and 48A may be improved by adding water to the mud indischarged by pipe 31 take pipe 65 from-any available source of water at a higher pressure than exists in pipe 65, such as pump 70, through valve 66, and when this is done it reduces the amount of make-up water which needs to be added through 'va'lve 67". While the pressure in line 43 is preferably "great enough to cause a pressure drop of 80 to 200 p.s.i'.g. in passing through cyclone 48 to line 58 and through valve '53 (as discussed six paragraphs below), the pressure in mud intake pipe 65 is in actual operation much less than the hydrostatic head up to surface '14 due to the aspiratin'g' eifect of let pump 39, so that often pump 70is'urinecessary, and may be omitted entirely.

While the more expensive weighting material is being concentrated and returned through valve 53, and a large in Figure4. Issuer instances in which the pressure in inlet 47 'or 47A, respectively, an axial overflow outlet 51 adiacent the base end of the cone and an axial under-flow outlet 52 adjacent the apex end of the cone 49. By the term generally conical it is intended to include frustroconical, or irregularly tapered chambers having the efffe'ct of a cone, such as belled, semi-ellipsoidal, paraboloidal, or hy'perbol'oidal chambers (not shown). 'While not essential in a balanced system, it is preferred tocontrol and balance the flow through the hydraulic cyclone separator by means of conventional valves 53. 54 and 56, as this allows more freedom in designing the proportions and sizes of the parts employed. When the system 'is being employed to concentrate a'nd'preserve a powdered mineralweighting agent suspended in the well drilling mud, this heavy agent concentrates and passes out in the underfiowdischarge 'out1et'52 and valve 53 and is directed 'back into mud container 16, "while the 'portion'is preserved by returning the discharge from pipe portion of the undesirable cuttings, sand and excessive amounts of clay, salt, and other fluids coming from the formation 13 are being discarded'through pipe 53 to discard 59, i't may also be true that some of the ingredients being lost in the discard need replacing, such as water, alkali metal carboxymethyl cellulose, sodium hydroxide, tannin, and other chemicals. However, I have found it cheaper to "get rid of the unwanted materials added by "drilling through pipe 58, even though losing some chemicals'wit'h them, by conserving most of the expensive weighting material and returning the same through pipe 52, and -then "adding any necessary chemicals and water 'directly'to the drilling mud in container 16, rather than follow the. prior art practice of throwing away large quantities of the complete drilling mud 1-4 containing all these ingredients, and then have to replace them all with 'fres h supplies thereof.

While the chief value of the present invention is when -it is employed as shown in Figure 1 to conserve the more expensive weighting materials, I have found the invention still has considerable value when used in drilling mud's whichdjo'not contain Weighting material, as shown forfmation ;13' is less than the hydrostatic head of unweighted drilling mud in well 4, it would be an unwarranted'expense to employ'weighting material, and when there no weighting material the character of the discharge fromv hydraulic cyclone separator 48 changes, because now'the "sand and drilling cuttings are the heaviest materials in the cyclone and therefore come out the underflow outlet 52'and are directed into the discard 59, On the other hand, the overhead through the overflow outlet 57fco'ntains 'tlr'e'chemicals such as sodium carboxymethyicenalose, sodium hydroxide, tannin, and all the usual 'wafersoluble chemicals employed in drilling mud,

which in the absence of weighting material are then the most'expensiv'e jp'ortion of'the mud; and therefore, this S3 an1d valve '54'to the drillingmud 14 in the container 15. While. it is obvious that the system of returning the "weightin'g jrnaterial 'to container 16 of Figure l and the 's'y'stem'ofdiscardingfthels'and from the unweighted mud of. Figure 4 can both he used with either direct or freverse circulation ofthe, drilling mud in the well, it has been considered unnecessary to show all four possible species, but instead direct circulationwith one is shown in Figured and reverse circulation with the other is keep,

shown in Figure 4. This could as wellhave been shown vice versa.

As many of the same parts as possible in Figure 4 have been given the same numbers as in Figure 1, although possibly even more could have been so numbered. However, there are differences in the piping arrangement of a minor nature which will now be explained. Mud pump 18 is drawing mud from container 16 through pipe 17 and passing the same into a manifold 68 (which is somewhat like manifold 19 in Figure 1) and drilling mud under pressure in manifold 68 can pass through valve 6? into well casing head 27, down the annular space around drill string 7, in through the openings in drill bit 6, and up through drill string 7, hydraulic swivel 12, and rotary hose 24 into the mud 32. At the same time, mud under high pressure can pass through valve 71 into manifold 72 from which it may pass through valve 56 (when open) and pipe 73 into jet pump 57, and/or through valve 74 (when open) and pipe 76 into nozzle 41 of jet pump 39. Whenconsidered desirable, water can be added through valve 77 into the mud passing through pipe 76. Obviously, the water passing through valve 77 into pipe 76 must come from a source of water at a higher pressure than exists in pipe 76, which higher pressure can be produced by any conventional pump or pressure creating means, such as pump 70. However, this point of entry from valve 77 into pipe 76 is alternative, as it can preferably be shifted to the mud intake pipe 65 as valve 66 is connected in Figure 1, where the pressure in pipe 65 is much lower. In fact, as shown in Figure 4 the pressure in pipe 65 is negative due to the aspirating effect of jet 41 drawing mud up the intake pipe 65, so that when valve '77 is connected to intake pipe 65, pump 7 is unnecessary and may be omitted entirely. As considered desirable, water can be added to container 16 through valve 67 and other necessary drilling mud ad: ditives can be thrown or poured into the drilling mud 14 in container 16 as required.

While the financial savings is not as great as when saving weighting material in Figure 1, nevertheless the system employed in Figure 4 with unweighted drilling mud results in a considerable financial savings, making either system very desirable to install, and the original cost, up-

and operating cost of the systems shown in Figures 1 and 4 is greatly reducedbecause of the fact that they .operate with power from the conventional drilling mud pump 18 acting through jet pumps 39 and 57, which completely eliminates the expense and upkeep which .would be necessary if pumps 39 and. 57 were special independent mud pumps requiring an independent motor for each of them. w

it is preferred that the pressure drop through the hydraulic cyclone separation zone of separator 48 be at least about 50 and preferably 80 to 200 p.s.i.g., there being no upper limit except that wear on the body of the cone 49 may become excessive at still greater pressure drops.

As an example of the operation with weighted drilling mud in Figure 1, a well drilling mud consisting of 90% water, 2.2% clay and 7.8% barium sulfate is run through the system shown in Figure 1 with a pressure drop of about 100 p.s.i.g. across hydraulic cyclone separation zone 48. The composition of the various streams, given in parts, and not percentages, are substantially as follows in Table I: 3 TABLE I Composition of streams (in parts) Stream Involved i l Mater a S Feed in 43 Underflow Overflow in 52 in 58 container. 16 through shale shaker Composition of streams Stream Involved Materials Feed in 43 Underflow Overflowin 52- in 58 Percent Percent Percent H1O 183. 2 63. 4 86. 5 Solids 16.8 36. 6 13. 5

While a specific combination of parts have been shown in the drawing in order to illustrate certain preferred specific embodiments of the invention, obviously the invention is not limited to these specific embodiments chosen only for illustrative purposes.

Having described my invention, I claim:

1. A hydraulic earth boring system comprising in combination a drill string, a drilling mud container, a mud pump, a first conduit connecting the intake of said pump with said container disposed to draw drilling 'mud therefrom a second conduit connecting the outlet of said pump to one end of said drill string .to circulate said drilling vmud therethrough under pressure, a third conduit connecting the annular space around said drill string with said container for discharging said drilling mud back into saidcontainer, a hydraulic cyclone having a general- 1y conical chamber with a tangential inlet, an axial overflow outlet at the base end of the cone, and an axial underflow outlet at the apex end of the cone, a first jet pump having a jet inlet for fluid under pressure, a feed inlet for fluid being pumped, and an outlet, a fourth conduit connecting said feed inlet of said first jet pump to said container disposed to 'draw said drilling mud therefrom,

will force drilling mud from said fourth conduit into said cyclone, a seventh conduit connecting a supply of water to said fourth conduit, a second jet pump havinga jet inlet for fluid under pressure, a feed inlet for fluid being pumped, and an outlet, a discard pit, an eighth conduit connecting said second conduit to the jet inlet of said second jet pump, a ninth conduit connecting the overflow outlet of the cyclone with the feed inlet of said second jet pump, and a tenth conduit connected to the outlet of the second jet pump, one of said axial underflow outlet and said tenth conduit being disposed to discharge liquid into said container, the other being disposed to discharge liquid into said pit.

2. A hydraulic earth boring system comprising in combination a drill string, a drilling mud container, a mud pump, a first conduit connecting the intake of said pump with said container disposed to draw drilling mud therefrom, a second conduit connecting the outlet of said pump to one end of said drill string to circulate said drilling mud therethrough under pressure, a third conduit connecting the annular space around said drill string with said containers for discharging said drilling mud back into said container, a hydraulic cyclone having a generally conical chamber with a tangential inlet, an axial overflow outlet at the base end of the cone, and an axial underflow outlet at the apex end of the cone, a first jet pump having a jet inlet for fluid under pressure, a feed inlet for fluid being pumped, and an outlet, a fourth cogfrom,

duit connecting said feed inlet of said first jet pump to said container disposed to draw said drilling mud therefrom, afifth conduit connecting the outlet of said first jet pump tothe inlet of the cyclone, a sixth conduit connecting said second conduit to the jet inlet of said jet pump so that, drilling mud under pressure from said second conduit will force drilling mud from said fourth-conduit into said cyclone, a second jet pump having a jet inlet for fluid under pressure, a feed, inlet for fluid being pumped, and an outlet, a discard pit, a seventh conduit connecting said second conduit to the jet inlet of said second jet pump, an eighth conduit connecting the overflow outlet of the cyclone with the feed inlet of said second jet pump, and a ninth conduit connected to the outlet of the second jet pump, one of said axial underflow outlet and said ninth conduit being disposed to discharge liquid into said container, the other being disposed to discharge liquid into said pit.

3. A hydraulic earth "boring system comprising in combination a drill string, a drilling mud container, a mud pump, a first conduit connecting the intake of said pump with said container disposed to draw drilling mud therefrom, a second conduit connecting the outlet of said pump to one end of said drill string to circulate said drilling mud therethrough under pressure, a third conduit connecting the annular space around said drill string with said container for disc-barging said drilling mud back into said container, a hydraulic cyclone having a generally conical chamber with'a tangential inlet, an axial overflow outlet at the base end of the cone, and an axial underflow outlet at the apex end of the cone, a jet pump having a jet inlet for fluid under pressure, a feed inlet for fluid being pumped, and an outlet, a fourth conduit connecting said feed inlet of said jet pump to said container disposed to draw said drilling mud therefrom, a fifth conduit connecting the outlet of said jet pump to the inlet of, the cyclone, a sixth conduit connecting said second conduit to the jet inlet of said jet pump so that drilling mud under pressure from said second conduit will force drilling mud from said fourth conduit into said cyclone, a seventh conduit connecting a supply of water to said fourth conduit, and a discard pit, one of said axial underflow outlet and said axial overflow outletbeing disposed to discharge liquid into said container, the other being disposed to discharge liquid into said pit.

-4. Ahydrau'lic earth. boring systemcomprising in cornhination a drill string, a drilling mud container, a mud pump, a first conduit connecting the intake of said pump with said container disposed to draw drilling mud therea second conduit connecting the outlet of said pump to one end of said drill string to circulate said drilling mud-therethrough under pressure, a third conduit connecting the annular space around said drill string with said, container for discharging said drilling mud back into said container, a, hydraulic cyclone having a gen- 'erally conical chamber with a tangential inlet, an axial base end of the cone, and an axial underflow outlet at the apex end of the. cone, a jet pump having a jet inlet for fluid under pressure, a feed inlet for fluid being pumped, and an outlet, a fourth conduit connecting said feed inlet of said jet pump to said container disposed to draw said drilling mud therefrom, a. fifth conduit connecting the outlet of said jet pump to the inlet of the-cyclone, asixth conduit connecting said second conduit to the jet inlet of said jet pump so that drilling mud under pressure from said second conduit will force drilling mud from said fourth conduit into said cyclone,,'and a discard pit, one of said axial underflow out-let and said axialoverflow outlet being disposed to discharge liquid into said container, the other being disposed to discharge liquid into saidpit.

5. A drilling mud solids separation system comprising in combination a mud pump, aafirst conduit connecting the intake of said pump-with a container of drilling mud and overflow outlet at the "a sccondconduit connected. to the outlet of said pump, a

a, hydraulic cyclone having a generally conical chamber with a tangential inlet, an axial overflow outlet at the base end of the cone, and an axial underflow outlet at the apex end of the cone, a first jet pump having a jet inlet for fluid under pressure, a feedv inlet for fluid being pumped, and an outlet, a third conduit connecting said feed inlet of said first jet pump to said container disposed to draw said. drilling; mud therefrom, a fourth conduit connecting the outlet of said first jet pump to the inlet 'ofthe cyclone, a fifth conduit connecting said second conduit to the jet inlet of said first jet pump so that drilling mud. under pressure from said second conduit will force drilling mud from said third conduit into said cyclone, a sixth conduit connecting a supply of water to said third conduit, a second jet pump having a jet inlet for fluid under pressure, a feed inlet for. fluid being pumped, and an outlet,.a discard pit, a seventh conduit connecting said second conduit to the jet inlet of said second jet pump, an eighth conduit connecting the overflow outlet of the cyclone with the feed inlet of said second jet pump, and a ninth conduit connected to the outlet of the second jet pump, one of said axial underflow outlet and said ninth conduit being disposed to discharge liquid into said container, the other beingdisposed to discharge liquid into said 6. A drilling mud solids separation system comprising in combination a mud pump, a first conduit connecting the intake of said pump with a container of drilling mud and a second conduit connected to the outlet of said pump, a hydraulic cyclone having a generally conical chamber with atangential inlet, an axial overflow outlet at the base end of the cone, and an axial underflow outlet at the apex end of the cone, a first jet pump having a jet inlet for fluid under pressure, a feed inlet for fluid being pumped, and an outlet, a third conduit connecting said feed inlet of said first jet pump to said container disposed to draw said drilling mud therefrom, a fourth conduit connecting the outlet of said first jet pump to the inlet of the cyclone, a fifth conduit connecting said sec ond conduit to the jet .inlet of said first jet pump so that drilling mud under pressure from said second conduit will force drilling mud from said third conduit into said cyclone, a second jet pump having a jet inlet for fluid under pressure, a feed inlet for fluid being pumped, and an outlet, a discard pit, a sixth conduit connecting said second conduit to the jet inlet of said second jet pump, a seventh conduit connecting the overflow outlet of the cyclone with the feed inlet of said'second jet pump, and an eighth conduit connected to the outlet of the second jet pump, one of said axial underflow outlet and said eighth conduit being disposed to discharge liquid into said container, the other being disposed to discharge liquid into said pit.

7. A drilling mud solids separation system comprising in combination a mud pump, a container for drilling mud, a first conduit connecting the intake of said pump with said container, and a second conduit connected to the outlet of said pump, a hydraulic cyclone having a generally conical chamber with a tangential inlet, an axial overflow outlet at the base end of the cone, and an axial underflow outlet at the apex end of the cone, a jet pump having a jet inlet for fluid under pressure, a feed inlet for fluid being pumped, and an outlet, a third conduit connecting said feed inlet of said jet pump to said container disposed to draw said drilling mud therefrom, a fourth conduit connecting the outlet of said jet pump ,to the inlet of the cyclone, a fifth conduit connecting said second conduit to the jet inlet of said jet' pump so that drilling mud under pressure from said second conduit will force drilling mud from said third conduit into said cyclone, a sixth conduit connecting a supply of water to said third conduit, and a discard pit, one of said axial underflow outlet and said axial overflow outlet being disposed to discharge liquid into said container, the other being disposed. to discharge liquid into said pit.

8. A drilling mud solids separation system comprising in combination a mud pump, a container for drilling mud, a first conduit connecting the intake of said pump with said container, and a second conduit connected to the outlet of said pum a hydraulic cyclone having a generally conical chamber with a tangential inlet, an axial overflow outlet at the base end of the cone, and an axial nnderfiow outlet at the apex end of the cone, a jet pump having a jet inlet for fluid under pressure, a feed inlet for fluid being pumped, and an outlet, a third conduit connecting said feed inlet of said jet pump to said container disposed to draw said drilling mud therefrom, a fourth conduit connecting the outlet of said jet pump to the inlet of the cyclone, a fifth conduit connecting said second conduit to the jet inlet of said jet pump so that drilling mud under pressure from said second conduit will force drilling mud from said third conduit into said cyclone, and a discard pit, one of said axial underfiow outlet and said axial overflow outlet being disposed to discharge liquid into said container,

the other being disposed to discharge liquid into said pit.

Petroleum (New York),

Cross et a1 May 2, 1939 Corwin Nov. 10, 1942 Garrison Jan. 4, 1944 Buckley et a1 June 5, 1951 Eder Sept. 16, 1952 Gn'flin et a1. Mar. 24, 1953 Howe July 31, 1956 Failing Aug. 26, 1958 OTHER REFERENCES Production Engineering, Development, published by McGraw-Hill Book Co. 1956. (Page 255 relied on.)

UNlTED STATES PATENT OFFICE QERTIFICATE OF CORRECTION Patent No, 2,94l 783 June 21, 1960 v Donald L, Stinson s in the-printed specification It is hereby certified that error appear he said Letters of the above numbered patent requiring correction and that t Patent should read as corrected below.

line 32, after "from" insert a comma; line 69 Column 6, for "containers" read container Signed and sealed this 20th day of December 1960.,

(SEAL) Attest:

KARL H. AXLINE ROBERT C. WATSON Commissioner of Patents Attesting Ofiiccr