US1926030A - Automatic stage lift flowing apparatus for wells - Google Patents

Description

A. BOYNTON Sept. 12, 1933.

AUTOMATIC STAGE LIFT FLOWING APPARATUS FOR WELLS 2 Sheets-Sheet led April 5, 1927 Sept. l2, 1933. A. BoYNToN l926,030'

AUTOMATIC STAGE LIFT FLOWING APPARATUS FOR WELLS Filed April 5, 1927 l2 Sheets-Sheet 2 nu f1/Eu.- l 51 3l mons/Na l n/LL 4.9

CIS/V TUB/IIE ATTORNEY struct an adjacent flui -teristics of the fluid in a ing the installation of vaiented Sept. 12, 1933 Alexander Boynton,

lto Chas. A. Beatty, San

PATENT OFFICE AUTOMATIC STAGE LIFT FLOWING APPARATUS FOR WELLS San Antonio, Tex., assignor Antonio, Tex.

Application April 5, 1927. Serial No. 181,144 1 Claim. (Cl. 137-111) An object of the invention is to provide a valve for well flowing apparatus,

said valve including a relatively large and heavy plunger which substantially fills the uid passageway but is so pro- 5 portioned as to leave a circumferential oy-pass and to be capable of a limited end-movement,

said plunger having a central cone-formation at one end which, when seated on a solid portion at one end of theY posely off-centered. 'Another object of passageway, will not obd passage which `is purthe invention is to provide a valve in which the plunger is judiciously proportioned in size and weight after'the charac'- particular well have ybeen investigated, said proportion being in such accordance with the load characteristic of the fluid that said plunger will perform certain pick- .up and drop-back actions at determined pres- .20 sure periods.

lOther objects and advantages will appear in the following specification,

to the accompanying drawings,

diagram of an oil well illustratthe apparatus according hereinafter described,

Figure 1 is a to the tubing 'method reference being had Figure 2 is a detail section of one of the valves,

Figure 3 is -i of Fig. 2,

Figure 5 is a diagram of on the .line

a well illustrating an installation of the apparatus according to the casing method hereinafter described,

Figure 6 is a detail sectional view or one of the valves employed in the apparatus, this being a substantial inversion oi shown in Fig. 2,

the arrangement Figure 7 is an end view of the valve in Fig.

6,'the tubing being shown in section,

Figure 8 is a cross section taken on the line 16-16 Of Fig. 6.

The invention involved herein accomplishes the purpose of elevating or lifting liquids froin flow of desired a well which cannot does not flow at the its own accord"`or rate, and although the following description is applied to oil wells it must be understood made to 'apply to other wells.

oi' the invention is known as that the principle can be One adaptation` the tubing method,

so called because fluid pressure is applied in the outer casing thereby tubing suspended therein. of the invention is known as forcing the oil` out of the A second adaptation the casing method,

namely, wherein the fluid pressure is applied to the o`l in the tubing causing the oil to now up and out of the casing. The first to be considered is The tubing method Reference is first had to Figs. 1 to 4 inclusive. The tubing string 1 is composed of tubing sections of suitable length that are joined by the bodies 2 of the valves which constitute the invention and make possible the improved method of elevating the oil, or, in other words, flowing the well. well casing 3 which casing is suspended from the casing head 4 to which a gas pipe 5 is attached. An appropriate gland (not shown) makes a gas-tight joint around the tubing string 1 where the latter emerges from the casing head. The tubing string has a valve 'l by which the flow of oil is regulated. The tubing string is known as the flow line. The string 1 terminates at the bottom in what is known as an intake nipple 8 having a plurality of openings 9 at which oil from the casing is admitted to the tubing. A joint 10 connected with the bottom of the nipple 8 serves as a tubing support to properly space the intake openings 9 from the bottom of, the well and vto prevent the intake openings from being fouled with mud or other sediment. The joint 10 is closed by a plug 11 and serves as a trap for heavy settlings which are withdrawn with the tubing whenever the latter is pulled.

Numerous valves are connected in the string of tubing but inasmuch as they are all alike in construction the description of one will sufiice. The complete valve in Fig. 2 has only three parts, namely, the body 2 previously mentioned, the differential plunger 12, and the chamber plug 13. The cored out conduit 14 is smooth and the same in internal diameter as the tubing string, thus making the alinement perfect. The valve. chamber 15 communicates with a counter` bore 1 6 with which it merges at an annularr bevel 17 providing a seat for the valve end 18 ofthe differential plunger.

A spiral 19 causes the differential plunger 12 to rotate as it is lifted by the by-passing gas inthe valve chamber l5 thereby keeping the cylindrical valve end 18 constantly ground to a perfect sealing fit upon the seat 1'7. The counter bore 16 enters a cross bore 20 by which communication of` the chamber 15 is established with the valve conduit 14. The bottom end 21 of the plunger l2 is tapered to a cone shape in order to permit the plunger to land upon the The tubing string is supported in the chamber plug 13 without closing or obstructing the twin intake passages 22, which in the instance of Fig. 2 are inclined inrespect to each other so as to diverge inwardly and provide a medial landing for the cone end of the plunger. This fact also explains'the reason for these passages. 'Ihe sloping walls 23 and 24 at the bottom and top of the lateral enlargement in which the valve chamber 15 is formed provide against catching upon obstructions as the valve is lowered into or removed from the well.

The casing method is considered next, reference being had to Figs. 5 to 8. This method is distinguished by the fact that the oil or other liquid is lifted through the casing rather than through the tubing and although the valves of the casing method are identical in principle and similar in construction to the valves of the tubing method, enough difference is involved in the casing method to require a separate explanation. Valves 25 are connected in and join the sections of the tubing string 26 which is suspended from the casing head 27 and at the bottom end terminates in a pipe joint 28 serving the double purpose of a bottom spacer and settling trap. The flow of gas into the tubing 26 is controlled by a valve 29. Discharge ports 30 in the bottom joint 28 afford the gas outlet below the valves through which outlet the gas passes after the well has been staged down to a point where the gas pressure in the tubing more than equals the weight of liquid in the casing.

It is observed by comparison of Figs. 2 and 6, that the latter valve involves but little more than the inversion of the structure in Fig. 2. The valve body 25 has a longitudinal conduit 31 which is the same in diameter as the interior of the tubing 26. The valve body has a lateral enlargement with a co-axial valve chamber 32 in which the so-cal1ed differential plunger 33 is lifted and operated. A spiral groove 34 Lrunning either full length of the plunger is shown in' Fig 6 or only part way thereof as in Fig. 2, causes turning of the plunger upon lifting thereof by the by-passing gas so that the grinding of the valve end'25 upon the seat 36 of the closure plug 37 becomes an automatic operation. When permitted to recede the conical bottom end 38 of the plunger 33 rests upon a landing 39 at one side of a counter bore 40 through which and through a cross bore 41 communication lis established between the conduit 31 and valve chamber 32. As before, the upper and lower extremities of the lateral enlargement containing the valve member 33 are beveled as at 42 and 4,3 to avoid hanging of the valve body upon ob- :tructions during passage of the lstring in and out of the casing.

'Ihe plungers 12 and 33 are large and heavy relatively to the passageways 15 and 32 in which they work. Although each plunger substantially lls its respective passageway it is sufcient- 1y undersized to leave a restricted circumferential by-pass clearance and room for only a limited end-movement. The extent of this endmovement is less than the length of the plunger.

Operation of the tubing method take nipple 8 to a point within three hundred feet of the top, the usual Working pressure being -both inside and outside of the tubing stands at 44 as -a result. The oil enters the tubing 1 through the perforations 9 of the intake nipple 8.

Gas at say 250 pounds pressure, is admitted into the casing head 4 by way ofthe'pipe 5. The valve 7, in the tubing 1 is then opened and the ilowing operation takes place. The differential plungers 12 (Fig. 2) of all of the valves 2 are assumed to have gravitated to the seating position upon the respective closure plugs 13 thus leaving the top of the valve chambers 15 open for the escape of gas from the casing 3 into the tubing string 1.

As inrushing gas proceeds downwardly in the casing 3 and nds an exit of least resistance at the first and uppermost valve 2 it rushes into the twin intake passages 22 and valve chamber 15 of said rst valve through the counter bore 16 and cross bore 20 into the tubing 1. 'I'he particular plungers 12 now under consideration are designed to seat and close oi the counter bore 16 at a pressure of approximately 22 pounds, and therefore as soon as a difference (in other words a differential) of 22 pounds pressure between the inside of the tubing 1 and inside of the casing 3 is established, the socalled differential plunger A12 of the aforesaid uppermost valve 2 will form a tight closure at the valve end 18 and seat 17 so that no more gas can escape into the tubing 1 at this particular point.

The inrushing gas progresses downwardly until the next valve 2 is reached whereat a repetition of the foregoing operation occurs. The required 22 pounds diierential pressure is thus established at the second valve, and thus in quick and rhythmic succession each of the succeedingly lower valves above the uid level 44 is closed by the rapid progression of gas under pressure in the casing 3. It must be stated here that in the actual installation there will be numerous valves 2 before the oil level 44 is reached, the drawing in Fig. 1 being made on a relatively large scale because it would be diflicult to depict actual proportions.

It will have become apparent to the reader that all avenues ofescape for the gas are now closed, and thatv the pressure of 250 pounds is imposed upon the oil at 44. The result is that the level of oil in the casing 3 is lowered to a level approximately atN 45 while the oil in the tubing 1 is elevated to a level approximately at 46. It is assumed that each'100 pounds of gas pressure will support a column of oil approximately 300 feethigh and that the oil level 46 in the tubing 1 is approximately 750 feet above the oil level 45 in the casing 3. 'Ihe 'ow of oil from the tubing 1 begins as soon as a valve 2 above the oil level 45 opens.` The oil level 45 is supposedly just above the valve 47 (Fig. 1) so that this valve is regarded as being dead or ooded.

It is supposedly a fraction less than 60 feet to the next valve above, this being the last valve through which the gas can be admitted from the casing 3 to lift the oil from the tubing. The reader will at once understand the tendency toward the establishment of a balance Within the tubing 3 and casing but just before the weight of the oil in the tubing string 1 comes to a bal- Cal ifi)

Inf'

ance against the 250 pounds gas pressure in the casing 3, the valve 48 just mentioned, automatically opens, thus admitting gas from the casing into the tubing.

The valve 48 (differential plunger 12, Fig. 2) must open just at the time stated because the oil in the tubing 1 between valve 48 and the level 46 in said tubing, by virtue of its weight, exerts a back pressure of 230 pounds, urging the plunger 12 away from its seat 17 while the outside gas pressure of 250 pounds is urging the plunger 12 upon the seat 17.

Except for the weight of the differential plunger 12the latter would remain seated by virtue of the predominating outside pressure tending to establish this condition and thus keep the gas passage into the valve 48 closed Aby a margin of twenty pounds, but the plunger 12 and plunger seat 17 are so proportioned that the plunger drops away from its seat 17 ata differential pressure of twenty-two pounds, consequently the plunger 12 must drop from its seat and-the valve 48 must open by two pounds or in other words a 10% factor of assurance. Stated in another way, the plunger 12 is so designed and proportioned for the particular installation now under discussion that it will gravitate from its seat 17 as soon as the pressure of oil upon the upper end of the plunger is twenty two pounds less than the external gas pressure upon the lower end of the plunger.

It is a purpose of the plunger or plungers to perform an automatic action in admitting the proper amount of gas through the wide open valve or valves when the load is greatest and throttling down the discharge openings through the valves to admit less gas as less gas is needed to ow the well ,from the level of any valve; The foregoing automatic action is explained thus: Plunger 12 (Fig. 2) rises fromits lower seat to within close proximity of its upper seat 17 at'say, a differential of ten pounds, but does not form a complete closure or seal-off until the differential pressure reaches twenty-two pounds as already assumed. On account of the unobstructed opening through twin passages 22, the full volume of gas that the valve is designed to handle'is discharged into the oil column in the tubing 1 until the lifting force of the bypassing gas picks up the plunger 12 and holds it in close proximity of its upper seat 17.

This picking up or lifting of the plunger 12 occurs in this set of valves at the approximate differential pressure of ten pounds. The assumption of a ten pound differential means that at 250 pounds gas pressure in the casing upon one end of the plunger there is a back pressure of 240 pounds of oil in the tubing upon the other end of the plunger. This small differential indicates that the oil column is moving upwardly slowly in the tubing.

The largest amount of gas is therefore required and consequently is admitted until the differential pressure exceeds ten pounds, it being clear that the plunger l2 as yet remains down at this particular differential pressure. As the oil column becomes lighter (moves faster) and the differential pressure decreases, the need for less gas to lift the oil column becomes evident until the difference of pressure within and without the tubing reaches such a point where the.

matic action of the differential plunger 12 becomes apparent. The action may be described as oscillatory or vibratory; first,v there is a tendency of the plunger 12 to seatby virtue of the predominating outside gas pressure, and second, there is lthe tendency of the plunger 12 to unseat by virtue of the approximate balancing of pressure inside and outside of the tubing. It

is thus apparent thatas often as the oil column slows its upward movement suiciently to allow the differential pressure to drop below 22 pounds, every valve within the range of such pressure drop opens sufficiently wdeto admit a little more gas and thus keep the oil column moving with not less than ten pounds nor more than twenty two pounds of applied lifting energy per square inch.

Bearing in mind that. the weight of the oil in the tubing above the level (Fig. 1) plus resistance always exactly balances the gas pressure in the casing 3, it is clear that as soon as valve 47 is uncovered and as soon as the oil level 45 lowers sufficiently to establish a slight differential at that point between pressures outside and inside the tubing such valve 47 will begin to intake gas because the plunger 12 thereof previously assumed an open position because of the previous lack of differential'pressure at that point to raise the plunger. Thus, stage by stage, or valve by valve, the succeeding valves are uncovered until all of the oil is lifted from the well or such point is reached where inflow and outflow balance, which point then becomes the permanent working level during the remainder of that particular flowing operation and until the well is allowed to head up again.

The heaviest possible differential pressure against which any valve must ever open is always equal to the weight of the fluid between valves."If, as in the example given in Fig. 1, the valves are spaced sixty feet apart, the oil between the Valves will exert a pressure of approximately twenty pounds per square inch. The valve plungers 12 should therefore be designed to drop back from their upper seats 17 at twenty-two pounds the extra two pounds being the margin of safety to insure positive opening. It is possible to establish any desired action of the valves by the use of data involving three basic factors, first, differential pressure required to force up the plunger valve and hold it upon its upper seat 17, second, differential pressure at which the plunger l2 will fall back from proximity of the upper seat to the lower seat and third, the volume of compressed air or gas that the plunger 12 will allow to by-pass be fore such by-passing air will pick up the plunger and cause it to seal-olf upon its upper seat.

The proper combination of these three basic' the pick-up and drop-back of the plunger 12. The plunger can be made to rise from its lower seat at differential pressures varying anywhere from l to 50 pounds and fall back from its upper seat at differential pressures varying anywhere from 50 pounds to 1 pound. The result will be very different and it appears possible to meet any imaginable flowing requirement within these limits. The drop-back differential serves two purposes; first it determines the spacing of the valves, or what is the same, the spacing of the valves determines the drop-back; second, the drop-back governs the gas intake, allowing more or less as needed to overcome the increasing or decreasing back pressure (weight of oil in the tubing) at differential pressures ranging from 10 pounds to 22 pounds (still assuming a valve that picks up at 10 pounds and drops back at 22 pounds).

The operation of the casing method involves the principle already announced, and such differences as exist may be brought out with a brief description. The casing method eliminates most of the back pressure on the sand because the aerated column can weigh only as much as the unaerated column in the well at the beginning plus the displacement from the tubing. The aerated column becomes elongated to a point where its upper end will reach beyond the surface of the well. The pressure fluid is carried by the' tubing 26 (Fig. 5) and released through the stage lift valves 25 as needed to lengthen the column of fluid in the well casing. The relatively larger space between the casing and tubing makes possible the handling of larger quantities of liquid than by the tubing method.

The valves 25 (Fig. 5) may be regarded as being spaced feet apart beginning at the pipe joint 28 to a point within 300 feet of the top. Assuming the absence of gas pressure, the oil in both the tubing and casing stands at the level 49. Upon readiness to flow the well, the operator opens the valve 29 admitting gas into the tubing 26 -at a pressure of, say, 250 pounds, as before.

By virtue of a preponderance of pressure within the tubing all differential plungers 33 (Fig. 6) above the oil level 49 rise and seal-off upon their upper seats 36, the closure of the plungers occurring successively downward as the gas pressure progresses in the tubing thus preventing the waste of gas at the beginning of the flowing operation. The gas under pressure soon reaches the oil driving the oil in the tubing to the level 50 and elevating the oil in the casing to the level 51.

As each valve is uncoveredby the receding oil level in the tubing string 26, such succeeding valves begin discharging gas into the casing because the differential plungers 33 (Fig. 6) are already in the open position by virtue of the fact that there is no dierence in pressure to raise the plungers at su'ch points where the valves are submerged. The differential plungers rise from their bottom landings to close proximity of their upper seats whenever 'there 'is ten pounds less pressure in the casing than there is in the tubing at the level in question, and seal-off completely at 22 pounds differential. each valve below the oil level 49 discharges gas into the uid column in the casing until the differential pressure builds up the 22 pounds, whereupon that valve closes. The reader will recognize the similarity of operation with that already described in connection with the tubing method, and inasmuch as the operation has already been fully brought out, it is deemed unnecessary to engage in repetition.

The plungers are subject to some variation in construction, but in all cases are the vital elements which make possible the automatic operation of the valves. The reader will doubtless 'understand that the essentialelements in properly operable plunger construction involve Consequently,

the pick-up, seal-off, drop-back the size of the top seat and the check valve feature. 'Ihe latter feature that the plunger should act as a check valve upon its bottom seat, or lacking this function in the plunger itself, that a check valve should be associated with the plunger. is a most convenient feature in the practical operation of both the tubing and casing methods, and one which has been omitted from the foregoing discussion.

A plunger will alwayspride close to its bottom seat on the cushion of by-passing gas until the pressure of the by-passing gas lifts the plunger either against or within close proximity of its upper seat. Whether the by-passing gas that raises the plunger will carry it all the way to its upper seat 0r only to within close proximity of its upper seat, depends upon whether or not the pick-up is greater than the drop-back. If the pick-up is greater than the drop-back, the plunger will go all the way to its upper seat and seal-olf against the upper seat as soon as it leaves proximity of the lower seat, but if the pick-up is less than the drop-back, the plunger will leave the proximity of its bottom seat at a given differential and seal-olf against the upper seat at a higher differential.

Much depends upon the proper proportioning of the plungers for experiments. have proved that plungers that recede from their upper seats at diierential's less than the weight of the fluid between valves, cause wells to flow intermittentlyor by heads. Much slippage results, and the fluid is needlessly agitated and churned, and if oil is so lifted much damage often results through emulscation. The best operation follows by providing a plunger that must open against the greatest differential that can possibly exist between adjacent valves. This diierential, as before stated, comprises the weight of fluids between such valves. Y A plunger having a drop-back slightly greater than the Weight of the fluid between adjacent valves will always impart a new lifting impulse to the rising column as soon as the upward movement of the column slows down enough to establish a differential of pressures equal to or slightly greater than the weight of the fluid between adjacent valves. Such action provides safe means for obtaining economy in applied energy, and the plungers designed according to this principle will perform a proper automatic operation at the proper time. The desirability of the foregoing check valve feature relates to the necessity of blowing out the well should it become fouled with mud, paraffine, sand, or the like; In such event, it is only necessary to reverse the pressure in either the tubing or casing methods Ithereby clearing either the perforations 9 in Fig. 1 or discharge ports 30 in Fig. 5, but such reversal of ,pressure will not have the desired effect unless a check valve is incorporated in the passages 22 and 40 (Figs. 2 and 6).

While on the subject of the plunger it is thought wise to state certain important dimensions which should be taken into account in the manufacture of the apparatus. The clearance all around the plunger 12 (Fig. 2) may vary from .020 to 115". The intake ports 22 may be of any size which maybe conveniently drilled in the plug 13. The vertical discharge port 16 may vary from 32" to 1A". The horizontal discharge port may be of any convenient size. Respecting Figure V6, the parts are shown 'in approximately correct scale, but there should be a clearance all around the plunger 33 varying from .010 to 312.

In conclusion', it may be stated that a law applicable to all plungers in both vmethods is that the horizontal cross sectional area of the counter bore or discharge port 16 in Fig. 2 or the discharge port in Fig. 6 should be less 'than the dierence between the horizontal cross sectional area of the plunger at its greatest diameter and the horizontal cross sectional area of the plunger chamber, and the latter diierence in areas'should, in turn, be les's than the horizontal cross sectional area of both intake passages 22 and 40 in Figs. 2 and 6, The meaning of the foregoing is that from the top downward there should be a diminution of the three areas involved, for unless the intake ports are larger than the by-passing area around the plungers there would be a slowing down of the gas current which could be obviated only by providing an unnecessary closeness of the plungers in the plunger chamber in order to develop the proper pick-up. For proper operation, it is necessary that the smallest of the three areas should be the discharge port or passage at the top for the reason that the drop-back of the plunger is governed by the area upon which the differential pressures can act after the sealing-01T occurs.

This area, of course, is the upper valve seat 17 or valve end 36 (Figs. 2 and 6) plus the vertical cross sectional area of the discharge port. The smaller this area, the lighter the plunger required for any desired drop-back.

While the construction and arrangement of the improved automatic stage lift is that of a generally preferred form, it is obvious that the principles of the invention may be carried out with any one of a number of modifications without departing from the spirit of the invention or the scope of the claim.

I claim:-

In a valve having a body with a passageway provided with a fluid opening at one end and having a plug in the opposite end; a plunger situated in the passageway, the major portion of the plunger being cylindrical, a conical for1nation at the end of the plunger confronting the plug, said plug having an off-centered passage providing a landing place by which said conical formation is supported upon gravitation of the plunger, the opposite end o the plunger having a short spiral portion terminating in a diametrically diminished' Valve end capable of sealing said opening upon rising of the plunger.

ALEXANDER BoYN'roN.

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