US 2263144 A
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C. N. SCOTT PUMP 2 Sheets-Sheet 1 Filed April 18, 1959 z w B 5 5 o s A up 0 8 Z Z 3 3 2 L .N T 2 3 WI N n w 2 Q 0/ 8 5 Z Z N. 3 Z 3 Al. W Z m 8 D H m 3 5 -I i. \W J A a A l Nov. 18, 1941. c. N. SCOTT- PUMP 5 mm s INVENTOR.
Filed April 18, 1939 Patented Nov. 18, 19%!) PUMP Clarence N. Scott, deceased, late of Houston,
Tex., by Bertha Britto Houston, Tex.
11 Scott, administratrix,
Application April 18, 1939, Serial No. 268,483
'1 Claims. 01. 103-203) The invention relates to theoperation of bored wells equipped with pumping apparatus,
for raising the fluid from the pumping depth in the well to the surface of the ground.
In such pumping apparatus and well pumping methods at present in general'use, the liquid and more or less associated gas are drawn into' the same common working-chamber of the pump together; the gas is compressed by the pump to full discharge pressure and thus heated correspondingly and the liquid and this compressed hot gas are then discharged together into the discharge tubing which connects the pump with the lead lines at the surface of the ground.
In many oil wells now operated, the wells are of considerable depth and the oil to be pumped contains considerable quantities of gas in suspension, saturation, solution and entrainment. A
, considerable part of this associated gas for various reasons is not discharged from the pump working-chamber on the discharge stroke and accordingly on the suction stroke following, it reexpands in the working-chamber to several hundreds of times its fully compressed volume and seriously diminishes the fluid-handling capacity of the pump. This often takes place to the ex tent of causing the pump to become gas-locked and idle without pumping any fluid during long, frequently recurring idling periods. During these periods, bottom-hole pressure in the well builds up materially until gas-lock in the pump has been terminated by increased bottom-hole pressure opening the pump standing-valve and permitting the pump to resume its intake and discharging functions. v v
Gas-locking and idling and impairment of the fiuid-handling'efliciency of the pump are also caused by:
(a) Uncovering of the pump suction inlet openings by lowered liquid-level in the well bore causing the pump to lose liquid suction and become gas-docked and idle, at more or less regular intervals. s I
(b)' The heat of compression of the gas compi'essed in the working-chamber of the pump, as
at present operated and constructed, vaporizing or gasifying a portion of the oil in contact with said heated gas and reexpanding in said working-chamber on the suction stroke following.-
(c) Gas pockets in the working-chamber of the pump.
'(d) Unnecessary excessive clearance volume in the working-chamber of the pump.
An object of the invention is to provide a's'yspump adapted to the system, in which all or a material part of the associated gas entering the pump from the producing formation and well bore with the liquid, or gasor air from whatsoever other source, will be separated and segregated from the liquid on the suction stroke and initial portion of the discharge stroke and will be separately discharged by the pump against little or no pressure into the casing space surrounding the pump and discharge tubing and out of the casing at the surface of the ground. The segregated liquid which remains 'in the pump working-chamber after the discharge of the gas into the casing space, will then be discharged with any vagrant gas into the discharge tubing against the high pressure in same to the surface of the ground. This will increase pump efficiency and as a result of minimizing, if not entirely preventing, the gas-locking and idling of the pump, will reducethe average bottomhole pressure in the well and increase'the production of fluid flowing from the producing formation into the well here and hence the oil production of the well. I
I have illustrated the invention as applied to a pumping wellequipped with my improved pump and operated by my improved system, discharging the gas content from the working chamber of the pump into the casing space outside the pump and oil tubing, against little or no pressure and then consecutively and separately discharging the oil from said working chamber into the dischargetubing of the pump against the full pressure of the column of liquid in same to the surface of e ground.
In th drawings herewith, g. 1 is a-central longitudinal section through a lower portion of a preferred form of my improved deep well pump.
Fig. 2 is a centrallongitudinal section through the upper portion of said pump.
, Figs. 1 and 2 adjoin each other on the line AA. I
Fig. 3 is a fragmentary larger scale longitudinal section of that portion of the same pump adjacent the blind cage shown in Fig. 1, illustrating more clearly the construction of the low pressure gas control valve.
Fig. 4 is a fragmentary larger scale longitudinal section of that portionof said pump adjacent and between the upper end of the free plunger I3 and the lower end of the main plunger 29, both in their lowest operating po sitions and showing a modification of' the Fig. 1 embodiment.
tem .of operating such wells and an improved as 5 is a central longitudinal section of that a suction opening 4.
3 is a string of discharge tubing which usually extends from the pump to the surface of the ground and from and by which the pump is suspended or supported. I have shown this tubing 3 in Figures 1 and 2 extended on down to enmediate elevation depending upon the gas/oil compass the pump barrel 2 and preferably closed.
at its lower end 5. As shown in Fig. 2, it forms an upper compartment 6 extending to the surface of the ground in which is full discharge pressure. It also forms in Figs. 1, 2, 4 and 5 an intermediate compartment 1 in which is casing gaspressure usually only-slightly above atmosphere. It also forms in Fig. 1 a lower compartment 8 into and through which the fluid to be pumped may pass from the well bore or casing space to.
the suction opening 4, Compartment 6 is separated from compartment I by a pressure tight hold-down or packing means 9, which is so located as to be free from sand-packing troubles. The compartment 1 is separted from compartment 9 byan obstructing but not necessarily pressureetight flange III on the inner surface of p pe 3. y
In the embodiment of the invention shown in Figs. 1 and 2 the sucker rod 28 is reciprocable through the pump barrel 2. Said barrel is formed atits upper end to engage closely about the sucker -rod-28 through a bushing 21. The lower end of said bushing is screwed within a cage having fluid openings 26 therein for the fluid being pumped. Below the opening 26 the cage has a fluid tight fit within the discharge tubing 3, as shown at 9. At the'lower end of the pump barrel is a standing valve I2 of ordinary construction.
The sucker rod extends through the bushing 21 and 'is secured to the upper end of the upper plunger 29 through engagement with the valve cage 24 secured to said plunger. Within the cage a ball valve 23 seats within the passage 22 ough-.theyplunger. T e body 29 of the plunger 11 may serveas a-coupl'ing p n er sections. v I
*lowerrend! of th plunger body is the cage II having a seat ring therein for the ball valve l9. The outer periphery of the cage l8 has. longitudinal flutes to allow passage of fluid. The lower end of the cage is squared off to fit upon a bufier or valve seat l6 which acts also to cushion the impact of the pump plunger and cage with the upper end of the free or floating plunger or piston l3. Said piston [3 may form a seal with the pump barrel in any preferred manner and I have shown a close metal to metal .fit. Said free piston has an axial passage M with a pressure reducing orifice tube l5 therein at its upper end.
Fluid to be pumped enters compartment 8 in Fig. 1 through openings II in tubing 3. These openings may be located near the lower end of space 3 or near the upper end or at some interllthereon supported upon; an.
and correlated length, that gas will pass from below to above the plunger l3 at normal pump speeds without creating. by friction, or otherwise, sufflcient difference in pressure above and below plunger l3 to move the said free piston or plunger I3 upwards. The construction is such,
however, that a combination of static pressure and friction of liquid in its endeavor to pass through I4 and [5 at normal speeds of the pump, with liquid below I3 and before or after the gas has passed through and is above l3, will create suflicient preponderance of pressure below [3 to cause it to move upwardly and follow the gas piston I 1 and the main plunger or piston 29.
Fluid will continue to be drawn into the pump 1 these n- 1 free-plunger propelling surface 2'].
"through 4 and will follow the rising free plunger so long as liquid is below same until the end of the suction stroke. Thus, when the gas piston I! or the combined gas valve and gas piston 39, of the Fig. 3 embodiment and the main plunger 29 reach the end of their up-stroke, the free plunger l3 will have reached a position in its upstroke-or movement flxed by the relative quantities of gas, with perhaps some vagrant oil, above,
and of liquid, with perhaps some vagrant gas, below the same. a
The lower end of the cage I8 forms a buffer contact surface and valve 2|, which on its down stroke after contact with N5, pushes the free plunger I3 downwards and also functions as a .valve, seating on 5, to confine full discharge liquid and fluid pressure within duct 20 and duct l4 while the free plunger [3 is being pushed down by the descending main plunger 29, or while liquid is being discharged through the free plunger l3 under full discharge pressure by way of ducts I4 and 20, past open valve l9, through duct 22, past open traveling valve 23, through open cage 24, into the space 25 within barrel 2, thence through openings 26 in t e upper end of barrel 2 into tubing compartmen 6 to the surface of the ground.
It will be noted that the tubular member or hollow'piston rod 32 forms the liquid discharge duct 22 and connects together the main plunger the blind cage 18 and the 33-is a low-pressure gas-discharge valve,
opening and closing gas discharge port 34. It
permits the discharge of gas and/or vagrant liquid from the working-chamber space above the free plunger l3 and below the gas piston I! as the contact surface or valve 2| approaches, and before it contacts thevalve seat IS on the down stroke of the pump. It, as well as the combined .valve and piston 29, when closed also prevents the discharged gas from re-entering the workingchamber of the pump on its suction stroke. The lowpressure gas so'discharged passes 'between blind cage I8 and pump-barrel 2, into annular gas passage 36 in Fig. l or 40 in Fig. 3 through gas port 34 or passage 4i into passage 35 and thence through perforations or ports 31 in barrel 2 and tubing 3, into the casing space. It then passes on out between the periphery of the tubing 3 and the inside diameter of the casing I to the surface of the ground, against only slightly .tion 46 to the main plunger 23' is provided. This more than atmospheric pressure. Those of the perforations 31, which are in barrel 2, must be below the lowest position of the main plunger coupling and guide 38; but those of the perforations 31 which are in 3 may, if desired, be located atthe upper end of compartment. I, below' hold-down or packer means 9. Thus the gas entering with the oil, or passing out of solution therein, cannot accumulate below the piston 30 to gas lock its action. If gas entersthe tubing in appreciable volume, it will pass through the free plunger 13 without causing said plunger to rise and follow the blind cage l8. Said gas will therefore accumulate above the plunger l3 until liquid following the gas into the well causes said plunger l3 to follow the pump piston upwardly. n the down stroke of the pump piston and fluid cage l3,-the gas above the oil will escape extension or elongation, by its covering and uncovering of the gas discharge ports 43 in barrel 2, functions as a valve dividing the downstroke of the pumpinto two periods; the primary period during which the segregated gas in the working-chamber of the pump is discharged through the uncovered ports 43 into space I and from it through openings 31 into the casing space 8 against no pressure; and the secondary period during which gas discharge to the casing space past valve 33 with.little opposition. When the blind cage encounters the surface l2 of the free plunger l3, it forms a seal therewith and the liquid in and below the free plunger l3 will be forced upwardly through'passages I4 and past the valve l9 and from thence upwardly from the well. Thus most of the gas will escape before the blind cage [8 seals against the upper endof the free plunger and starts said free plunger to move downwardly as a part of the main pump plunger.
When propelling surface and valve 2| contact with buffer or valve seat It, the free plunger I3 is moved down and there being no other avenue of escape for the liquid under it, it exerts sufllcient pressure in l4 and 20 and 22, to open valves I! and 23' and permit the liquid and any vagrant gas to be. discharged through duct 22, open cage 24, barrel space 25, openings 26 and tubing space 5, to the surface of the ground.
In Fig. 4 is shown a modification of ,my device, in'which gaspiston l1 and gas discharge valve 33 in .Fig. l and the combined gas valve and gas piston 33 in Fig. 8 are omitted and tubular member 32 which connects the main plunger 29 with the blind cage l8 and contact buffer surface and valve 2l, is decreased in outside diameter to form between. its perimeter and the inside diameter of the barrel 2 an annular gas passageway 42 slightly longer than the maximum through ports 43, now covered by the plunger extension, is discontinued and during which the liquid is discharged through the ducts 20 and 22' into the oil tubing against full discharge pressure to the surface of the ground. In using this construction it would be necessary to primarily determine the approximate relative quantities of liquid and associated free or other gas or air to be handled for each well individually so that the proper length of the plunger extension 46 and the proper corresponding length of the standing valve blind cage 48, can'be selected and applied. Also that the totallength of the pump stroke, to provide the proper length of the gas discharging primary period, can be determined and arranged for. In those other constructions in which the free plunger is used these predeterminations and fixed adjustments are not required as the free plunger automatically fixes these periods to suit the relative quantities of liquidand gas. In the construction shown in Fig. 5, gas discharge valves 44 are necessary to prevent the re-entry of the discharged gas back into the working-chamber of the pump in the port-uncovered period of thesuction stroke.
Fig. 6 shows how the structure of lower end of "the pump barrel may be further modified. By
' pump barrel is otherwise like that of Fig. 5.
stroke of the pump and of the minimum annular 7 cross sectional area permissible to pass the segregated gas primarily and separately discharged from the working-chamber of the pump into the casing space outside the perimeter of the pump barrel 2 and discharge tubing 3. This arrangement may be preferred in cases where the large volume of passageway 42, in percentage of the volume of the pump displacement, is not objectionable.
'In-Figs. 4 and 5, 43 is a gas discharge port or ports, formed in pump barrel 2' and connecting gas-pamageway 42 with the space or compartment 1', from which the discharged gas passes 'through perforations 31 in tubing 3' to the easing space outside the tubing. 44 is a gas-valve mounted on a spring arm secured to theinnei" surface of tubing 3'. It opens and closes gas It will be noted that in each hi my embodiments of the invention, the gas passing out of solution from the -oil or otherwise liberated at the lower end of the well cannot lock" the pump or materially impair its continual eflicient operation.
What is claimed as new is: 2 1. In a deep well pump,a pumpbarrel, a main plunger reciprocate'd from the surface, a fluid indischarge port 43 and prevents the re-entry of gas from passageway 'I' and casing space 8 into gas-passage 42 and the working chamber of the pump on its suction stroke. Also, as will be obvious the port 43 may open directly into the casing space 8 instead of into space I.
In Fig. 5. is shown another construction which may be used in which-the free plunger I3 is take valve at the lower end of'the barrel, and a liquid discharge port and valve in said plunger, forming an elongated pump working chamber; in combination with a free plunger or piston in saidwhamber 'reciprocated on the suction stroke bya preponderance of liquid intake pressure below the same and on the'discharge stroke by contact with said main plunger, said free plunger having a passage therethrough.
2. In a deep well pump, a pump barrel, a main plunger or piston recipropatedfrom the surface, a fluid intake valve at the lower end of the barrel, and a liquid discharge port and valve in f said plunger, forming an elongated pump working chamber, in combination with a free plunger or piston' in said chamber, a fluid. duct connecting the space at one end of the free plunger with the space at the other end, and adapted to pass gas at normal pump speeds without moving said free plunger but also adapted to offer sufilcient resistance to the passage of liquid to.
cause said free plunger to follow the main plunger on its liquid intake stroke. I
3. In a deep well pump having a pump barrel,
. I a main plunger reciprocated from the surface, a fluid intake valve at the lower end of said barrel, and a liquiddischarge port and valve in said plunger, forming an elongated pump working chamber, in combination with a free plunger or piston in said chamber moved upwardly by a preponderance of intake pressure below same and moved downwardly by contact with said main plunger or an extension-of same, there being a fluid duct between the ends of said free plunger and a gas discharge port and valve adapted to discharge gas from the interior to the'exterior of said working chamber separately from the discharge of liquid from said working chamber to the discharge tubing.
4. In a deep well pump having a pump barrel, a fluid intake valve, a main plunger or piston, and a liquid discharge port and valve in said plunger, in combination with a free plunger or piston reciprocating in said barrel between said intake valve and said discharge port or main plunger and forming a liquid space below, and a gas space above said free plunger, a'fluid duct connecting the space below said free plunger with the space above and adapted to pass gas at normal pump speeds without moving said free plungerbut also adapted to offer suf flcient resistance to the passage'of liquid from the space below to the space above to cause said from the pump to the surface of the ground, a
pump barrel or cylinder, a fluid intake or suction valve, a main plunger or piston within said barrel or cylinder, 2, free plunger or piston reciprocating within said barrel and located between said fluid intake valve and said main plunger, a liquid duct extending from below said main plunger to the discharge tubing above, a
' liquid discharge valve in said duct, a fluid duct gas port connecting the space below the gas piston with the space above, and a gas discharge valve in said gas duct adapted to discharge gas from the interior to the exterior of the working chamber within the barrel separately from the discharge of liquid into the liquid discharge pipe. 5. In a deep well pump having discharge tubing extending within the well bore or casing from the pump to the surface of the ground, a pump barrel or cylinder, a fluid intake valve in said barrel, a main plunger or piston reciprocated within said barrel or cylinder from the surface of the ground, a gas piston spaced apart below said main plunger, a free plunger or piston reciprocating within said barrel between the said intake valve and the said main plunger, a' gas piston below and moi-able with the main piston, a gas discharge valve releasing gas from the pump space above the free plunger below the gas piston to the exterior of the pump barrel and discharge tubing and preventing its reentry, a liquid discharge port and valve in the main plunger releasing liquid from within the pump space into the discharge tubing, and a fluid duct connecting the pump spaces below and above the free plunger, and so adapted that gas will pass upwardly through'same without causing sumextending from below said free plunger to above it and so adapted that gas will pass upwardly through same without causing suflicient preponderance of pressure below said'free plunger to move it upwards but that liquid in passing said duct will by friction or otherwise cause suflic ient preponderance to move said free plunger upwards and follow the main phns ger on its up stroke, whereby said free plunger functions as a variable extension of the main plunger, said liquid duct at the lower end of the main plunger and the said fluid duct at the upper end of the free plunger registering, a valve and its seat between said main and free plungers and around said liquid and fluid ducts so adapted as to confine liquid discharge pressure within said ducts when said main and free plungers are in contact, a gas discharge port connecting the pump barrel space contiguous and between the said plunger ends when not in contact, with the casing space, and a discharge valve closing said gas port to prevent the reentry of said discharge gas from the casing space to the pump barrel space on the suction stroke of the pump.
7. In a deep well pumping installation including a well casing, a reciprocating pump having a cylinder with a working chamber within which cient preponderance in pressure below said free plunger to move it upwards but that 'liquid in passing through same will by friction or otherthe pump piston operates, and a discharge tubing within the casing extending from the pump to the surface of the ground, the combination comprising, means for separating andv segregating the liquid and associated gas and for introducing the separated liquid and gas to the working chamber on the downstroke of the pump, means for separately discharging the segregated gas from the interior of the'working chamber to the space between such chamber and the wall of the well bore or casing during the initial por, tion of the upstroke of the p, and for thereafter discharging the segre ted liquid through the discharge tubing to the surface of the ground. BERTHA BRITTON SCOTT.
Administratrix of the Estate of Clarence N.