US2373795A - Specific gravity indicator for drilling mud - Google Patents

Description

J. WAR EN; JR 2,373,795

April 11, 1945.,

SPECIFIC GRAVITY INDICATOR FOR DRILLING MUD 4 Sheets-Sheet l N Filed May 6, .1938

I I IIIIIIIIIIIIIFJ Apl'il 1945- J. B. WARREN, JR 5.

SPECIFIC GRAVITY INDICATO RFOR DRILLING MUD v Filed May 6, 1958 4 Sh eets-She'et 2 A fil 17, 1945.

'J. B. WARREN, JR

SPECIFIC GRAVITY INDIGATOR FOR DRILLING MUD 4. Sheets-Sheet 3 Filed llay 6, 193a J. B.WARREN JR.

April 11945 J. B. WARREN, JR, 2,373,795

' SPECIFIC GRAVITY INDICATOR FOR DRILLIKG- IUD l iled llay 6, 1938 4 Sheets-Sheet 4' I Patented Apr- John B. Warren, In, Houston, Tex. Application May- 6. 1938, Serial No. 206,327 9 Claims." (01. 73-32) The invention relates to a means for determining the specific gravity of aliquid and is'particularly adapted for use in determining the specific gravity of drilling mud used in the rotary method of drilling wells.

In the rotary method of drilling wells a circulation of slush is pumped downwardly through the drill stem and discharged therefrom adjacent the cutting edges of the bit. This circulation of mud has many functions such as to carry the cuttings away from the bit and keep the bit cool a and in some instances to wall up the formations which have been penetrated and to maintain such formations against caving. It is usual, therefore, to have this slush. made up of clays suspended in water or other liquids and there are many ingredients which .are used to obtain drilla ing muds having various specific .characteristics.

In some instances it is desirable to have the mudof greater specific gravity in order to prevent caving of the formation and to create a high unit area pressure on theformation to overcome the natural pressures encountered in the formation. In other instances it is desirable to have 'a mud with a greater viscosity so that it will carry cut-'- tings from the well bore without permitting the cuttings to settle out of the mud. In other instances itis desirable that the mud have greater sliming qualities, so that it will not create an undue-frictional resistance during its circulation into and out of the well bore and, in still other instances, it is. desirable to have a mud from fwhichthe gas can be readily expelled so that there will be no gas cutting or reduction in spa-- cific gravity of the mud, due to the presence of gas therein, and while in still other instancesthe --point of inlet.

Another object of the invention is to provide an arrangement whereby the specific gravity of a body of liquid may be determined as a function of'the differential pressure required to inject two spaced streams of fluid into a body of the liquid.

Still another 'object of the invention is to provide a bubble glass for use with a device for in troducing a flow of fluid into a body of hquid. Still another object of the invention is to provide a device for lubricating the inflow of fluid into a ,body of liquid to offset evaporation at the Still another object of the invention is to provide an apparatus for determining specific-grav ities, which apparatus will receive the body of the liquid, record the specific gravity thereof and discharge the body .of the liquid inan automatic sequence of periodic operations.

Still another object of the invention is to provide a mechanism for introducing fluid under pressure in order to determine the specific grav-- ity of'a'body of liquid, which mechanism will operate continuously and automatically.

Still another object of the invention is to provide a' particular type of bubble glass for deter- --mining the rate of flow of a fluid so that such mud may become diluted by the inflow of water or other materials from the formation in the well bore. v

During the drilling operation as the drill bit penetrates various formations the characteristics of drilling mud being introduced into the well bore must be changed in order to cope with the. circumstances which arise and with this in mind it is desirable to determine the specific gravity of the mud which is being discharged from the well bore at quite frequent intervals because any change in the specific gravity may have disastrous results depending upon the conditions which are being encountered.

With the foregoing-in-nfind it is one of the objects of the present invention to' provide a means for periodically determining the specific gravity-ofthe flow of mud as it emerges or enters the well bore.

glass may be tilted or turned without discharging the indicating liquid therefrom.

Still another object is to provide a tained compact device which may be readily connected to determine the specific gravity of a well drilling fluid.

Other and further objects of the invention will be readily apparent when the following description is considered in connection with the accompanying drawings wherein;

Fig. 1 is a side elevation of the upper portion'of the mechanism which may be used in practicing the invention. I

Fig. 2 is a vertical sectional view through the plunger apparatus for controlling the inflow and outflow of the liquid the specific gravity of which is being measured.

- Fig. 3 is a side elevation taken at right angles to the view of Fig. 1 v

Fig. 4 is a top plan view looking down on the apparatus of Figs. 1 and 3.

Fig. 5 is a section taken on the line 5-5 of Fig. 3. p 7

Fig.6 is a sectional view of thecontrol valve.

Fig. 7 is a section of the valve taken on the line I 1- 1 of Fig. 6.

Fig. 8 is a vertical sectional view through one of the bubble gauges taken on the line 8-4 of self con- Fig. 11 with certain of the portions broken away to illustrate the arrangement of the parts.

The device is particularly adapted for use at a drilling rig to measure the specific gravity of the drilling mud, oil or water.

The invention contemplates that a charge of the drilling fluid used in the rotary method of drilling wells will be trapped. A flow of the fluid under pressure will be introduced into this trapped body of liquid at predetermined spaced elevations and the pressure required to so introduce the flow of fluid under pressure will be different for the two difierent elevations. If the specific gravity of the liquid varies the differential pressure required to introduce the fluid under pressure at the spaced elevations will vary in direct proportion thereto so that the entire mechanism herein disclosed is for the purpose of automatically introducing and determining this differential pressure In the several figures a return or flow line 2 has been illustrated and this pipe may be either the usual return line from the well to the slush pit in which the mud is retained, "or it may be abypass therefrom, as circumstances may require. In either instance, however, it isintended that there will be a flow of drilling fluid from the well passing through this pipe 2.

.The apparatus for determining specific gravity is indicated generally at 3 and is arranged about the pipe 2 so that a specimen of the liquid in the pipe may be deposited in the apparatus. The mechanism for obtaining such sample is best seen in Figs. 2 and 12. In Fig. 12 a container 5 of any desired size may be positioned about the pipe 2 in such a manner that a flow of liquid discharging from the opening 6 will flow into the container 5.

The container 5 is of suflicient height so that a predetermined volume of drilling mud will be trapped therein. In order to open the pipe 2 andv admit a flow of drilling mud into the container a top valve 8 has been provided. This valve is arranged tomove upwardly into the opening 6 to close the opening and to movedownwardly out of the opening to admit a flow of mud into the container. This valve 8 is carried by a valve rod 9, which is guided through a support H! exranged to close the discharge outlet I2 in the base of the tank. As seen in Fig. 12, the bottom valve is closed and the top valve is open.

It seems obvious that with the valves in the position of Fig. 12 a flow of liquid will pass into the container 5 and be trapped therein, whereas In this liquid to be measured shall be controlled auto- 'matically and that the. determination of the specific gravity of the charge or specimen of liquid will also be automatically determined. With this in mind a float l3 has been provided near the base of the tank and another float l4 near the top of the tank. The bottom float I3 is connected by means of spaced rods 5, best seen in Figs. 11 and 3, to a link portion l6, which link is slidable relative to a bolt 11 carried by the valve arm I8, which arm serves to actuate the control valve 19. It seems obvious that as the float [3 moves upwardly there will be a tendency to lift the link l6 and slide it upwardly relative to the bolt H from the position shown in Fig. 3.

The float I3 is guided by the valve rod 9 and will be stopped in-its upward movement by the guide arm l0 and this arm is so spaced relative to the float that the link 16 will not quite reach its upward limit of movement when the arm I8 is in the position shown in Fig. 3, so that while the float I3 may move upwardly on an accumulation of liquid in the container it will not move upward a sufficient distance to affect the arm l8 when it is in the position shown in Fig. 3.

The float M on the other hand is slidably mounted in a cage 20 and is arranged to' rest upon a stop 2| when it is in the position shown in Fig. 3. This float M has a member 22'which has a slot 23 therein arranged to slide relative to the pin'24, which projects from the arm l8. In the position shown in Fig. 3 any upward movement of the float M will tendto carry the arm 18 up ward with it by virtue of the pin 24 contacting the bottom of the slot 23.

and simultaneously the valve I I opens and allows the liquid from the chamber to discharge. As the liquid settles away'from the float l4 it will move downwardly. As the elevation of the liquid in the container continues to fall it will pass the float l3 and allow the float andthe rods D5 to move downwardly. In order to move the lever 18 down and reverse the movement of the piston 31 as hereinafter described, the link I6 will engage the bolt I1 and bring the lever I8 down when the container is substantially empty. It is of advantage to flow the sample into the container from the top as it has been found in practice that a more uniform sample is thus obtained. The container 5 will thus be either filling or emptying I in a continuous but periodic manner.

. tending from the-side of the container 5. 'This valve rod carries a bottom valve II, which is ar- I and the valves 8 and \H is best seen in Figs. 2

when the valverod 8 and the valves 8 and H The mechanism for operating the valve rod 9 and 3 and comprises a cylinder 26 which may be mounted upon a suitable section of the pip 2, or may be otherwise mounted so that it is in alignment with the frame 21 about the pipe 2.

This frame 21, as best seen in Fig. 3, constitutes a cross piece 28 and the spaced rod members 29. These rods straddle the pipe 2 and the cylinder 26 and extend down into the container 5 where the cross piece 30 surrounds the valve rod 9. When this framework is moved to its upper position itwill raise the valve rod 9 and the valves 8 and H, but when it is moved downwardly, as seen in the drawings, it allows the valve II to seat and close the container. A piston 3|is connected to the rod 32 which is slidable within the cylinder 25 and is connected to the cross bar 28.

through the tour-way cross 53. In this manner A pipe 34 enters the cylinder 25 to introduce and allow the escape of fluid under pressure to move the piston 3| and a similar pipe 35 is connected to the base of the cylinder. It seems obvious that when pressure is introduced below the .piston it will rise and carry with it the frame 21 to raise the valve rod and open the container by 2 opening the valve whereas when the piston m'oves downwardly the frame 21 will move downwardly and the valve H will close and the valve 3 will open.

In order to control the flow of fluid under pressure in the pipes 34 and 35, the control valve I9 is arranged for operation by means of the lever It. The detailed construction of .this valve is' best seen in Figs. 6 and 7 wherein the valve body '40 has a plurality of passages 4| therein which lead to a central chamber-42. A pipe 43 furnishes a supply of fluid under pressure tothe control valve l9 and this pressure is introduced into the chamber 42. A valve member 44 is movable in the chamber by means of the lever I8 previously dein Fig. 7 and has the outstanding wings 45 therein which form a seal with the periphery of the chamber 42. In the position shown .inFig. '7 fluid is entering thepipe 43 and flowing out of the valve from the pipe 34; Fluid is also entering" through the pipe 35 on the opposite side of .the valve and discharging from the pipe 48. The pipes 34 and 35, as previously pointed out, are connected to the top and bottom, respectively, of the cylinder 25 so that with the valve in the position shown in' Fig. 7 pressure isbeing applied on top of the piston to force it downwardly and that fluid which was in the cylinder 25 below the piston is being allowed to discharge through the the atmosphere, as seen in Fig. 2. a

It seems obvious that as the lever l8 moves to its upper position the'valve member 44 will turn a suflicient amount 'so that the wings will pass over the openings to which the pipes 34 and 35 are connected. If this valve member moves approximately from the position shown in Fig.7,

then the pressure pipe 43 will be connected to 'the pipe 35 and pressure will be introduced under 5 the piston 3| in the cylinder and at the same time any pressure which was above the piston will escape through the pipe 34 and the pipe 43 into the atmosphere.

' The flow of gas from the pipe 43 thus provides the pressure can be directed into the pipe 43, into the gauge 52, or into the extension 55, which is pipe 53 and" into the bubble glass 60. This sight or bubble gauge is provided for the purpose of determining the rate of flow or thepressure fluid into the column of mud and the gauge is best seen-insection in Fig.8. The pipe 53 is connected to the inlet on the backside of the gauge scribed. This valve member is seen insection may be observed by the bubbles passing through and the pressure fluid thus enteringthe device will discharge from the open pipe 5| into the upper chamber 62 of the gauge. A .passage 53 through the central body 64 of the gauge in turn discharges the fluid from the lower pipe 65 into a body 56 of suitable liquid so that any pressure fluid discharging through the device will bubble up. through the liquid 65 and the rate of flow this liquid.

The pressure fluid passing through the liquid 66 will enter the pipe 61v and discharge into the low pressure pipe 58', which extends from the bubble gauge 60 downwardly to the elevation of the lower end thereof at 59 in the tank 5.

this manner pressure fluid will be forced from pipe and through the-valve to exhaust into the lower end 63 of the pipe and the pressure re-. .quired to eflect such a continuous discharge will be either indicated or recorded. upon the gauge 10 shown generally in Fig. 12. This pressure is conveyed from the glass 50 by means-of aconduit or-coupling 1|, whichis connected to the body 64 of the gauge, as seen in Fig. 8.

Particular attention is directed to the fact that the pipes SI, 65 and 51 are all curved so that the ends thereof are approximately in a vertical plane v which is midway b'etweemthe sides of the gauge. In this manner if-the gauge is laid on its side the liquid 85 will beretained-therein and will not flow through any one of these pipes. The upper chamber 52 is provided so that if there is a back pressure on the pipe 68 sufllcient to force 4 the liquid upwardly through the pipe 65 it will the power for actuating the valves to control the trapping and discharging of the body of liquid in the container!) whose speciflcgravity is to be determined. This supply of gas'is-directed into the valve l3 from a'pressure reducer 50, which receives its supply of gas from the inlet pipe line 5|. :While gas has been used as the term to describe the fluid under pressure which is used to, actuate ,the device it is to be understood that compressed air or any other suitable fluid maybe used for this purpose.

The pressure reducer 53 may be of any desired type'so as to reduce the pressure from the source in the pipe 5| to the. pipe 43. In actual practice it has been Ioundthat a pressure of approximately twenty pounds per square inch in the pipe 43 is suflicient for operation of the mechanism, whereas if gas pressure to be found in the oil flelds is utilized it is not uncommon to have a pressure in excess of onehundred pounds per square inch in the pipe 5|'.- 'A gauge 52 in Fig. 1

indicates the pressure which is present beyond the pressure reducer 5| andwhich is flowing not escape through the pipe 5| but will merely accumulate in the'top chamber until such pressureis reduced. As seen-in Fig. 1,. the gauge is uspended on a shelf 13, which is carried by the device. It seems obvious that by adjusting the valve 53 any desired rate offlow may be introduced into the low pressure pipe.

. A valve-30 is similar to thevalve "and controls the-rate of flow of the fluid through a second sight gauge 5|, which will be known as the high pressure gauge because it controls the rate of flow through the high pressure line 82 by which the flow of fiuidis introduced into the lower portion of. the container 5 where thefluid pressure discharges from the'lower end 33 of the line 32. By manipulation or arrangement ofthe valve 3|! any desired rate of flow may be provided through this pipe.

'It seems obvious that, inasmuch as the distance between the lower end of the low pressure pipe at II and thelower end of the high pressure pipe at is a fixed distance,'/th,ere will be a diflerential pressure which isthe diiierence betweernthe pressure required to force the flow of fluid through the high pressure pipe 82 and the pressure required' to force the fluid through the low pressure pipe 68. This difierential pressure can be measured and will, of course, vary with the specific gravity of the liquid which is in the container 5. If the liquidis heavier a greater differential pressure will be required. If the liquid is fighter a lesser diiierential pressure will be required. In Fig. 12 the gauge line 84 extends from the sight gauge 8| the same as explained in connection with the line 1|. The recording meter 10 in Fig. 12 will record the diflerential pressure and as seen by the recording line 85 the pressure drops down materially when the container is emptied and builds up to a maximum point when the container is filled. Therefore, the maximum radial distance which the recording line reaches, as at 86, when the tank is fllled will indicate the specific gravity of the liquid which fills the container. The gauge 10 may be so calibrated that this recording will be either in pounds per gallon or may be otherwise suitably calibrated.

In actual practice it has been found that the discharge of a fluid under pressure from the pipes 68 and 82 causes an evaporation at the point of discharge such as 69 and 83. This evaporation dries the drilling mud and forms a cake or nozzle about the ends of the pipe and it has therefore been found to be desirable to lubricate the fluid 'under pressure which is being introduced into the device and to this end a tank 90 carries a body of 7 water or other liquid 9 I, which can be fed through the pipe 92 into a lubricator injector 94, which in turn discharges through the pipe 95' into a connection 96' so that there is a. small flow of liquid downwardly through thepipe 82, as best seen in Fig. 3.

The regulator or injector 94 may be so adjusted as to permit a predetermined flow. In order that .the liquid 9 will be forced into the pipe 82 with suificient pressure to overcome the back pres-- sure due to the head of liquid in the containerB a supply of pressure fluid is introduced into the tank 90 by means of the connection 95. This connection has a gauge 96 thereon and receives a flow of gas from the regulator 91, which in turn receives its flow of pressure fluid from the connection 55 through the cross 53. This regulator 51 may be set for a very low pressure, say five pounds per' square inch, if the regulator 50 is set and which will be a compact self-contained unit adapted to be readily connected for use at a drilling rig.

What is claimed is:

1. A specific gravity measuring device for drilling mu-ds including means to determine the differential pressurerequired to pass a flow of fluid into a body of mud, as an indication of the specific gravity of such mud, and additional means operable by the mud to effect the discharge and admission of the mud.

2. A device of the character described comprising a container, means to admit and discharge rotary drilling mud adjacent the top of and adjacent the bottom respectively of said container, means operable by the admission and discharge of mud to actuate said first means so that said device operates automatically to admit and discharge drilling mud, means to continuously effect a flow. of fluid into said container at spaced elevations, and additional means to indicate the differential pressure required to maintain such flow of fluid as an indication of the specific gravity of the drilling mud which is in the container.

3. A device of the character described comprising a container, means to admit and discharge rotary drilling mud adjacent the top of and adjacent the bottom respectively of said container, means operable by the admission and discharge. of mud to actuate said first means so that said device operates automatically to admit and discharge drilling mud, means to continuously efiect a flow of fluid into said container at spaced elevations, and additional means to indicate the differential pressure required to maintain such flow of fluid as an indication of the specific gravity of the drilling mud which at twenty pounds per square inch. A similar luity of the drilling fluid which is flowing through the pipe 2 and the operator need onlyobserve the gauge 10 in order to'determine that the Specific gravity of his mud as it returns from the well bore is within predetermined limits. In event the mud becomes gas-cut the specific gravity will be reduced and the operator will observe this change.' The same applies to other factors, which influence the'speciflc gravity of the mud.

Broadly the inventioncontemplates a device which will operate automatically to periodically determine the specific gravity of a drilling mud,

is in the container, said flow means including a bubble glass. 4

- 4. A device of the character described comprising a container, means to admit and discharge rotary drilling mud adjacent the top and adjacent the bottom respectively of said container, -means operable by the admission and discharge of mud to actuate said first means so that said device operates automatically to admit and dischargev drilling mud, means to continuously efiect a flow of fluid into said container at spaced elevations, and additional means 'to indicate the 'difierential pressure required to maintain such flow of fluid as an indication of the specific gravity of the drilling mud which is in the container, saidv additional means including a recording differential pressure gauge.

5. In a device for measuring specific gravity of a drilling mud, ameans to introduce fluid into the body of drilling mud so that the pressure required for suchintroduction may be determined as an indication of the specific gravity, said means including a bubble glass including a top and a bottom, and curved inlet and outlet pipes for the flow of fluid, the ends of said pipes being along the axis of said glass so thattilting thereof will not discharge I the liquid therefromr 6. A device for determining the specific gravity of a, drilling mud, means to connect the device toperiodically receive adjacent the top and discharge adjacent the bottom a quantity of drilling mud so that the mud may flow by gravity,

diflerential pressure between. two vertically spaced points in the drilling mud.

7. A device for determining the specific grav-" ity of a drilling mud, means to connect the device to periodically receive adjacent the top and discharge adjacent the bottom a quantity of drilling mud so that the mud may flow by gravity, and

means to periodically indicate the specific grav-.. ity of the mud when the device contains a predetermined volume of' mud, both of said means being operable from a source of fluid under pressure. a

8. In a specific gravity measuring device, a

container, means to admit and discharge liquid whose specific gravity is being determined to the top and from the bottom respectively of said container, float means in said container and .operable by the filling and emptying of such container, and fluid pressure power operated means connected to said float means to operate said first means, and additional means to continuously inject two streams of fluid under pressure into the varying head of liquid in the container at spaced elevations, and means to determine the presmre diflerential to effect such the difl'erential pressure required to efl'ect discharge is a function of the specific gravity of the mud in the container while the mud between the ends of the members is dormant, and

means to discharge the mud when the level in so the container reaches a predetermined position.

JOHN B. WARREN, JR.

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