Liquid counter-balanced pumping system

Application filed June 2,

This invention relates to liquid counterbalanced pumping systems or, in other words, to pumps in which a liquid column is employed against a shoulder on the plunger to ⁸ counter-balance the column of liquid being raised by the plunger.

The commonly employed deep well pump in the oil fields has its plunger connected with a string of sucker rods which extends ¹⁰ downwardly from the top of the well. It will be obvious that the well may attain such depth that the strain on the sucker rods may reach a value in excess of the tensile strength of the rods, thereby entailing parting or rup¹⁸ ture of the rods.

In the pumping cycle of the commonly employed type of deep well pump, the sucker rods and pump plunger are started from a position of rest and moved upwardly by the ⁸⁰ power equipment at the surface of the earth. To accomplish this, it is necessary that the weight of the entire column of oil in the pump tubing above the plunger, plus the weight of the string of sucker rods, be started ²⁸ from a state of rest and moved upwardly a distance equivalent to the stroke of the pump. The amount of energy required to accomplish this is approximately 50% of the entire power consumption necessary to operate the ³⁰ plunger on its fluid lifting stroke. On the down stroke of the plunger the liquid in the tubing rests on the standing valve and the weight of the sucker rods aids the prime _a mover and, accordingly? on the down stroke ⁸⁸ very little power is required. This difference in power requirements on the two strokes of the pump is due to the unbalanced load.

In order to overcome the unbalanced load condition, it is common to employ at the ⁰ earth’s surface some form of counterweight that is connected with the prime mover in such manner that the weight is. raised when the plunger is on its down stroke and the weight descends when the plunger is on its up stroke. While counter-balancing is achieved by this arrangement, it does not relieve the sucker rods from that very severe stress which they undergo on the up stroke of the pump.

Accordingly, the expense involved in re1930. Serial No. 458,973.

placing broken sucker rods and the monetary loss due to the stopping of production, are not materially affected by the counter-balancing done at the surface of the earth.

At the present time oil wells are being ⁸⁸drilled, on an average, to much’ greater depths than was formerly the case. Production now is often obtained from depths ranging between 6,000 to 8,500 feet and it is impossible with pumps commonly used at the present ⁶⁰time to pump such deep wells after they cease flowing. The usually employed type of pump can only be used in wells below no greater depth than approximately 5,500 feet.

A very important object of this invention ⁰⁸is to reduce the strain on the string of sucker rods so as to minimize breakage thereof.

Another important object is to pump wells of greater depths than those which can be pumped with the pumps commonly in use in 70 the oil fields.

I achieve the foregoing objects by applying the pressure of a counter-balancing liquid column near the base of the string of sucker rods so as to not stress the rods beyond their ⁷⁸ultimate breaking strain. In an installation of this character, a reservoir must be provided outside of the pump tubing reaching from the surface of the earth down to the level where the pressure of the counter-balance ⁸⁰fluid is to be applied to the moving parts of the pump. This reservoir may be formed by a portion of the well casing, which portion is separated from another portion by a suitable packer. In other words, the upper por- ⁸⁸tion of the well casing constitutes the reservoir while the lower portion serves to convey the oil to the working barrel of the pump in the usual manner. The packer serves to seal off the producing zone of the ⁸⁰well from the upper portion of the casing. Since gas present in the well, when the ordinary pump is employed, is permitted to escape through the casing, it is necessary, because of the presence of the packer, to make ⁰⁸provision for the gas to escape from beneath the packer out of the well, and a very important object of the invention is to utilize such gas to aid in lifting the column of liquid above the pump plunger. 100

1,900,688 mitting liquid to flow from the chamber 14 into the working barrel below the ascending plunger. On the down stroke of the plunger head 17, the valve 19 closes and the valve 21 opens, thus permitting the fluid in the work- 70 ing barrel beneath the plunger to flow into the plunger head 17 and upwardly through a reduced tubu’ar portion 22 of · the plunger, said portion 22 being screwed or otherwise secured to the upper end of the head 17. The 75 upper end of the plunger portion 22 is provided with a port or ports 23 through which the fluid flows from the plunger portion 22 into a tubular member 24, the bore of which is sealed by a tubular member 25 from the 80 bore of the working barrel 16. The plunger portion 22 has a sliding fit in the member 25.

From the bore of the member 24, the fluid flows through a port or ports 26 into another reduced tubular portion 27 of the plunger, 86 said portion 27 being connected with the portion 22 by a rod 28. The fluid flows upwardly through the tubular portion 27 into the lower end of the upper hollow head 29 of the plunger 18, said head 29 being provided 80 at its upper end with an outlet valve 30 of any approved type. In this instance the upper end of the tubular portion 27 is screwed into the lower end of the plunger head 29. The cage of the valve 30 is indicated at 31 and 05 to it is connected, in the usual manner, a string 32 of sucker rods which extend to the surface of the earth for connection with suitable pump operating mechanism, not shown.

The plunger head 29 operates in a cylinder 100 33 and the upper end of said cylinder connects with pump tubing 34 which extends to the surface of the earth as is customary in this art. Accordingly, the fluid discharges from the plunger head 29 through the valve 105 30 into the cylinder 33 above said valve and thence into the pump tubing through which it flows to the surface of the earth in a manner well understood in this art.

It will be readily understood that recipro- 110 cation of the pump plunger is effected by operation of the string of sucker rods, in a manner well understood in this art and the construction for counter-balancing the liquid being raised by the pump plunger will now be H⁵described: The underface 35 of the lower end of the plunger head 29 constitutes an annular shoulder on the plunger and against this annular shoulder comes the pressure of the liquid column that occupies the reservoir 13. For 120 example, if oil is the liquid being pumped; the reservoir 13 will be filled with oil to the surface of the earth. This oil in the reservoir has access to the cylinder 33 beneath the plunger head 29 through ports 36 in a mem- 125 her 37 that, in this instance, constitutes a coupling that connects a tubular jacket section 38 with another jacket section 39. The section 38 surrounds the cylinder 33 and the section 39 constitutes a packing expanding mem-. 130

Another very important object of the invention is the prevention of a “gas lock”, a condition often present in the commonly employed pumps and resulting when an accu5 mulation of gas occurs between the pump plunger and the standing valve, said gas slipping downwardly by the plunger on the up stroke of the plunger.

Another very important object is to pre10 vent sanding up of the pump. In the ordinary type of deep well pump, the lower end of the pump barrel screws into a seat member in which the standing valve seats and the sand accumulates around the barrel, 15 making it very difficult to pull the pump.

I avoid this difficulty by placing the seat member above the level of the standing valve so that at least that portion of the working barrel is suspended from the seat member.

Other objects and advantages will appear in the subjoined detailed description.

The accompanying drawings illustrate the invention: :

Figure 1 is a broken elevation, partly in 25 section, of a liquid counter-balanced pumping system constructed in accordance with the provisions of this invention.

Fig. 2 is an enlarged broken longitudinal section of the upper portion of the pumping 30 system.

Fig. 3 is an enlarged broken longitudinal section of the lower portion of the pumping system.

Fig. 4 is an enlarged sectional detail of 35 some of the parts illustrated in Fig. 3, constituting the lock for the working barrel.

Fig· 5 is a horizontal section on the line indicated by 5—5, Fig. 4.

Fig. 6 is an enlarged sectional detail of 40 those parts of Fig. 3 that constitute the means for releasing gas from beneath the packer into the column of liquid being pumped.

Referring to the drawings, a well casing is indicated at 11 and is divided by a packer 45 12 into an upper chamber or reservoir .13 and a lower chamber 14. The casing 11 is provided with the usual perforations 15, through which fluid from the producing area may flow into the pump. It is to be particularly 60 noted that the perforations 15 communicate only with the chamber 14 that is below the packer 12.

Positioned within the chamber 14 is a working barrel 16 in which operates the hollow 55 head 17 of a plunger which is indicated in general by the character 18, and the lower end of the working barrel is provided with a suitable standing valve 19. In this instance, the standing valve 19 is of the poppet type. The 60 valve body 20 is threaded into the lower end of the working barrel 16. The plunger head 17 is hollow and is provided at its lower end with an inlet valve 21. Thus, upon up stroke of the plunger head 17, the valve 19 opens, ¢5 while the valve 21 remains closed, thus per1,900,588 ber. The outer face of the member 39 is of conical form to fit the tapered inner face 41 of a resilient tubular packing member 12. The tapered faces taper inwardly and down5 wardly so that the weight of the pump expands the packer member 12 against the inner face of the well casing 11. The members 39, 12 together constitute the packer hereinbefore referred to as dividing the casing into 10 the chambers 13,14.

The member 39 is unseated from the member 12 by pulling the pump tubing and the member 39 is provided beneath the member 12 with an annular shoulder 42 that, when the 15 member 12 is expanded, is spaced from the lower end of the member 12. Thus, when the member 39 is raised to release it from the member 41, said member 12 is engaged by the shoulder 42 and is withdrawn from the 20 well when the pump is pulled.

When the pump is installed in a well producing gas, as is the case in an oil well, gas that separates from the oil within the chamber 14 cannot flow to the surface of the earth 25 through the casing because of the presence of the packer 12, but it is necessary to relieve the gas pressure within the casing for, otherwise, the pressure would increase to such an extent as to hold back the fluids in the nroduc30 ing stratum. In this instance, not only is the gas pressure relieved in the chamber 14, but provision is made for utilizing said gas to aid in lifting the column of oil in the pump tubing. Accordingly, there is provided a ported 35 means to permit of the flow of gas from the chamber 14 into the tubular member 24 and, in this instance, said ported means is constructed as follows: A tubular member 43 is screwed into a reducing coupling 44 that in 40 turn is screwed into the lower end of the jacket section 39, and said member 43 is screwed into the upper end of the tubular member 24.

The member 43 is provided with a port 45 45 that communicates at one end with the chamber 14 and at its other end with the bore of the member 43. Within the port 45 is a valve seat 46 for a ball check valve 47 that opens when the pressure within the chamber 14 ex50 ceeds that in the tubular member 24. This difference in pressure is caused by reason of the plunger portion 22, tubular portion 27 and rod 28 together constituting one form of lost motion connection between the plunger 55 heads 17,29. In this instance, the lost motion is due to the fact that the combined lengths of the plunger portion 22, tubular portion 27 and rod 28 are sufficient so that there is a material stretching thereof, thus insuring that the upper plunger head will move upwardly a material distance before the lower plunger head begins its up stroke.

When, as above explained, the upper plunger head moves upwardly while the lower C⁰ plunger head remains stationary, a lowered pressure is produced within the tubular portion 27, and, accordingly, the fluid flows from within the tubular member 24 through the ports .26 into the tubular portion 27, thereby lowering the pressure within the tubular ⁷⁸member 24 and bore of the member 43. Accordingly, the valve 47 will open and gas from within the chamber 14 will pass through the port 45 into the bore of the member 43, thence through the ports 26 into the tubular 75 portion 27, thence into the upper plunger head.

On the next succeeding down stroke of the plunger head 29, when the valve 30 opens, the gas that has flowed into the plunger head 80 29 will pass said valve and flow up through the pump tubing, expanding as it ascends and thus aiding in raising of the liquid column in the pump tubing in the manner of the, sotermed, “gas lift”. It is noted that the gas 85 that passes through the port 45 cannot pass upwardly through the jacket section 39 because in said jacket section is a plug 48.

The upper end of the jacket section 38 is connected by a reducing coupling 49 to the 90 lower end of the pump tubing 34.

The working barrel 16 is screwed on, or otherwise connected with the sealing member 25 which is provided with an external tapered face 50 removably fitting a tapered seat 51 in 95 a seat member 52. The member 25 is releasably held against upward movement by a spring arm or arms 53 which are riveted or otherwise secured at 54 in the seat member 52. The arms 53 normally spring inwardly so that 100 their lower ends overhang the upper end of the member 25 and recesses 55 are provided in the seat member 52 to accommodate the arms 53 when said arms are retracted outwardly to permit the member 25 passing up- 105 wardly.

To effect retraction of the spring arms 53, the upper end of the member 25, as clearly shown in Fig. 5, is provided with radially extending shoulders or projections 56 which 110 may be caused to engage and retract the spring arms 53 by rotation of the member 25 into a position where the projections 56 are in alinement with the spring arms 53.

It is to be noted that sanding-up of this pump 115 cannot occur because the pump barrel 16 is suspended from the seat member 52. In the ordinary pump, the seat member is at the lower end of the working barrel.

The construction and operation of the in- 120 yention will be understood from the foregoing description and, briefly stated, the operation is as follows : The pump having been installed in a producing well, with the packer 12 in place, the reservoir 13 will be filled 125 with oil and the operating mechanism at the the surface of the earth will be connected with the string of sucker rods in a manner well understood in this art. As the lower plunger head moves upwardly, the fluid flows 139

1,800.688 into the working barrel below the plunger through the standing valve. Any slippage of gas past the plunger from the base of the liquid column above the plunger, will travel ⁵ downwardly under high velocity, but instead of said gas flowing into the suction chamber of the working barrel and thus retarding inflow of liquid from the well, the gas that has passed along the plunger and that enters the ¹⁰ working barrel above the lower plunger head 17, flows outwardly through a port or ports 57 in the upper portion of the working barrel into the chamber 14. The same thing occurs on the down stroke of the plunger.

¹⁵ As the ordinary rod operated pump is so designed that the seal of the pump plunger is at all times subjected to the hydrostatic pressure of the column of liquid in the pump tubing, there is no way to avoid “gas lock” ²⁰ resulting from gas released by agitation of .’the fluid, for it is impossible to design a practical pump with a working clearance sufficiently small to avoid slippage of the gas past the plunger. Therefore, in order to ²⁵ minimize and practically prevent slippage of gas past the plunger into the suction chamber of the working barrel, I provide a differential releasing chamber between the suction chamber and the fluid column in the pump ³⁰ tubing. It will be seen that the gas that passes out of the working barrel through the ports 57 passes with other gas in the chamber 14 through the port 45 when there is a pressure differential favorable to the pas- ³⁵ sage of gases from the chamber 14 into the tubular member 24, and this is when the upper plunger head 29 has moved upwardly, before upward movement of the lower plunger head 17 occurs. As soon as the pressure ⁴⁰ of gas within the chamber 14 falls below the pressure within the tubular member 24, the icheck valve 47 closes, thus preventing backflow of oil from the pump tubing into the casing.

⁴⁵ The up stroke of the pump plunger is assisted by pressure of the oil in the reservoir against the shoulder 35, the head of oil in the reservoir being the same as that in the pump tubing,-provided the discharge of the oil in ⁵⁰ the pump tubing is at the surface of the earth or, in other words, at approximately the level of the upper end of the reservoir 13. If the effective area of the shoulder 35 is the same as the effective areas of the valve 30 and the ⁵⁵ upper end of the plunger, the counter-balancing column will exactly counter-balance the fluid column above the plunger when the plunger is at the lower end of its stroke. These areas may, of course; be different and, ⁶³ also, if desired, the upper end of the casing may be carried to any desired height above the surface of the earth to increase the head of the counter-balancing liquid in the reservoir.