US3148629A

US3148629A - Deep well pump for viscous oil

Info

Publication number: US3148629A
Application number: US279197A
Authority: US
Inventors: Wayne N Sutliff
Original assignee: Individual
Current assignee: Individual
Priority date: 1963-05-09
Filing date: 1963-05-09
Publication date: 1964-09-15
Anticipated expiration: 1981-09-15

Description

Sept. 15, 1964 w. N. SUTLIFF DEEP WELL PUMP FOR VISCOUS OIL Filed May 9, 1963 l I l E a, .2. i g 35 2 Sheets-Sheet 1 INVENTOR. W? [M SUTL/FF Sept. 15, 1964 w. N. SUTLIFF DEEP WELL PUMP FOR vxscous on 2 Sheets-Sheet 2 Filed May 9, 1963 United States Patent 3,148,629 DEEP WELL PUMP FOR VISCOUS 01L Wayne N. Sutlitf, 2931 Pierce Road, Bakersfieid, Calif. Filed May 9, 1963, Ser. No. 279,197 2 Claims. (Cl. 103-179) This invention relates to the art of oil well production and particularly to production from wells in which the oil has a relatively high viscosity.

Discovery of new and important compounds derivable from natural petroleum with a high viscosity has recently awakened interest in improving the techniques of re moving this type of oil from the ground. Thinning viscous oil by the addition of a solvent or by heating it have been extensively tried to expedite pumping this oil to the surface. These expedients have proved either too cum bersome and expensive or have introduced intolerable fire hazards.

It is accordingly an object of the present invention to provide an improved pump which is particularly adapted to pump relatively viscous oil from a deep well without the aid of these expedients.

One of the chief problems met with in pumping viscous petroleum from a well is the retarding of the return movement of the plunger in the pump barrel by the resist ance set up in all portions of the pump by the viscous character of the production fluid. To solve this problem, heavy weights have been applied to the plunger but the effect of these weights greatly decreases where the bottom portion of a well inclines as much as 45 from vertical, and such an angle of inclination is not at all uncommon. Another expedient widely tried has been to apply a coiled spring to the plunger which is stretched or compressed on the upstroke of the plunger, the tensioned spring thus speeding up the downstroke of the plunger. This func tions regardless of the angle at which the well is slanted but the spring can be made etfective for only a relatively short stroke and the power applied varies radically from one end of the stroke to the other.

Another object of the present invention is to provide an improved deep well plunger pump incorporating means for increasing the speed of the downstroke of the plunger which is operative regardless of the slant of the well bore where the pump is located, and which is equally effective throughout the stroke, without limit as to the length of the stroke.

Still another object of the invention is to provide a deep well pump in which the pump barrel and standing valve are mounted on the lower end of the pump tubing string and installed in the well with said string and in which the pump plunger is suspended on a sucker rod string and may be run into the well after the tubing string is installed and may be pulled from the well separate from the tubing string and in which withdrawal of the plunger from the barrel automatically drains the production fluid column from the tubing string.

A still further object of the present invention is to provide such a deep well pump in which a substantial downward assist is given the pump plunger by the hydrostatic pressure in the lower end of the production fluid column so as to make this especially well adapted to operate in viscous oil having the tendency to retard the downstroke of the plunger.

The manner of accomplishing the foregoing objects as well as further objects and advantages will be made manifest in the following description taken in connection with the accompanying drawings in which FIG. 1 is a diagrammatic vertical sectional view of a preferred embodiment of the deep well pump of the invention and illustrates the downstroke of the pump just as the plunger approaches its lowermost limit.

FIG. 2 is a horizontal cross sectional view taken on the line 22 of FIG. 1.

FIG. 3 is a horizontal cross sectional view taken on the line 33 of FIG. 1.

FIG. 4 is a horizontal cross sectional view taken on the line 44 of FIG. 1.

FIG. 5 is a View similar to FIG. 1 and illustrates the upward stroke of the pump with the pump plunger closely approaching the upward limit of said stroke.

FIG. 6 is a fragmentary view similar to FIG. 5 showing the plunger further withdrawn from the pump barrel so as to be out of sliding contact with the latter and barrel 13 of smaller diameter, which barrels are connected together by a tapering tubular adapter 14 which has threaded engagement with adjacent ends of said barrels. Provided vertically in the adapter 14 is a series of drain ports 15.

The upper end of upper barrel 12 is connected by a tapering adapter 16 to the lower end of a production tubing string 17 which extends from the pump 10 to the top of the well. The inside diameter of upper barrel 12 is materially less than that of the tubing string 17 and is substantially larger than the inside diameter of the lower barrel 13.

Secured as by threads 18 in the lower end of lower barrel 13 is a standing valve 19 including a centrally apertured valve base 20 providing a seat 25, and an open cage 26 which confines a ball valve 27 in seating relation with said seat.

Suspended on the lower end of a sucker rod string 28, disposed within the pump tubing string 17, by a ported rod-plunger adapter 29 is a pump plunger means 30 including a tubular upper plunger 31, a tubular lower plunger 32 and a tapering imperforate tubular adapter 33 which makes a fluid-tight connection through

threads

34 and 35 respectively with the lower end of upper plunger 31 and the upper end of lower plunger 32.

Mounted by threads in the lower end of lower plunger 32 is a travelling valve 41 which includes a centrally apertured valve base 42 which provides a valve seat 43 which is adapted to be closed by a valve ball 44, the latter being enclosed by an open cage 45 provided on said base.

As shown in FIG. 1 the upper plunger 31 has an outer diameter which slidably fits Within the upper barrel 12 and the lower plunger 32 has an outer diameter which slidably fits in the lower barrel 13. These fits are close enough so that there is little leakage longitudinally between each of the upper and lower plungers and the respective upper and lower barrels in which they reciprocate during the operation of the pump 10. The pump 10 is built so that the clearance between the plunger means and pump barrel means varies with the degree of The installation of the pump 10 in a well begins with running the tubing string into the well with the pump barrel means 11 assembled on the lower end thereof and, after this step has been completed, running in the pump plunger means 30 suspended on the lower end of the rod string 28. The travelling valve 41 opens of course as the lower plunger 32 slidably extends downwardly into the lower barrel 13 of the pump until the travelling valve has reached a position substantially as shown in FIG. 1 which represents the downward limit of the downstroke of the plunger means 30 of the pump. The upper end of the sucker rod string 28 is now connected to a suitable reciprocator so that through the reciprocation of the sucker rod string the pump plunger 30 is reciprocated through a stroke the lower limit of which is shown in FIG. 1 and the upper limit of which is shown in FIG. 5. Each upstroke produces a suction in chamber 46 of the lower bartel 13 and this causes the travelling valve 41 to close and the standing valve 19 to open as shown in FIG. so that a fresh charge of oil is drawn in from the well surrounding the pump into said chamber. The upstroke also forms a suction in chamber 47 of upper barrel 12 which sucks a charge of oil into said chamber through the drain ports 15.

At the start of each downstroke standing valve 19 closes thereby causing the travelling valve 41 to open so that during the downstroke then commencing, the charge of oil occupying the pump chamber 46 is transferred upwardly through the travelling valve 41 into the lower plunger 32. In fact, during each downstroke, the plunger means 30 sinks in the oil in the two

pump chambers

46 and 47 but the oil in the latter does not resist this sinking but is idly expelled through the drain ports 15 into the low pressure oil in the well surrounding the pump whereas the oil charge in chamber 46 is trapped therein by the standing valve 19 so that the latter charge of oil is added to the production fluid column 48 which, during the normal operation of the pump 10, occupies the pump tubing string 17 and fills the space between this and the sucker rod string 28 throughout the length of the tubing string, or in other words to the top of the well.

The differential between the horizontal cross sectional area of the upper plunger 31 and that of the lower plunger 32 is what causes the suction of liquid inwardly through the drain ports 15 and the expulsion of said liquid out of said ports by the reciprocation of the pump plunger means 30. This differential in horizontal cross sectional areas of the two plungers also results in a net downward application of the hydrostatic fiuid pressure existing at the lower end of the production fluid column 48 against the pump plunger means 30 which is equal to the application of this pressure downwardly onto a horizontal area equal to the ditference between the horizontal cross sectional areas of the two plungers, less the horizontal cross sectional area of the sucker rod string 28 as shown in FIG. 2. This feature of pump gives it a tremendous advantage in operating on highly viscous oil in that the downward power assist given the plunger 30 on its downstroke by the hydrostatic pressure thus applied downwardly against said plunger operates over the full downward stroke of the plunger; operates regardless of the angle at which the pump is positioned at the bottom of the well; and operates uniformly throughout the stroke.

Another important feature of the pump 10 is its capacity to automatically drain the production tubing string 17 of the fluid column 48 at the beginning of the operation of pulling the sucker rod string 28 and the plunger 30 from the well. This pulling operation is illustrated in FIG. 6 which shows the lifting of the pump plunger 30 upward beyond the upper limits of its ordinary upstroke (shown in FIG. 5) so as to connect the drain ports with the lower end of production fluid column 48 in the production tubing string 17. When the plunger 30 is thus lifted, the ball travelling valve 41 is closed so that the liquid cannot pass downwardly through the plunger but the clearance between the inside diameter of the tubing string 17 and the outside diameter of the upper plunger 31 gives plenty of room for the oil in the production fluid column to flow past the plunger 30 and downwardly and out through the drain ports 15 into the Well outside the pump. This feature of the pump 10 permits a quick and clean job to be made of pulling the sucker rod string from the well and permits this to be pulled separately from the production tubing string 17. It also makes a clean job of pulling the production tubing string after the rod string has been pulled.

While the pump 10 is particularly adapted for use with highly viscous oils, it is also possible to use this with oils of normal viscosity, in which case a much smaller differential in cross sectional diameter might be used between the upper and

lower plungers

31 and 32. As a matter of fact the outside diameters of these plungers might be made equal or just a single continuous pump plunger might be used of uniform diameter but equal in length to the two

plungers

31 and 32 and the adapter 33. In such a case the upper and

lower pump barrels

12 and 13 would have to have a uniform inside diameter throughout the length of pump barrel means 11 and the tapering tubular adapter 14 would be cylindrical in character but would still have drain ports 15 which would perform the function of automatically draining the production fluid column 48 from the pump when the pump plunger had been lifted entirely clear of the upper end of the pump barrel means 11.

It is appreciated of course that the smaller the cross sectional diameter given the lower plunger 32 and the lower barrel 13 in which this slides, the smaller the amount of oil pumped for a stroke of a given length by the pump 10.

Having provided a suflicient downward assist force which will speed up the downstroke of the pump throughout the length of this stroke by a suitable differential in the cross sectional areas of the upper and lower plungers, the pump 10 may be designed for a stroke of any desired length and the downward assist provided in this pump overcomes the obstacles heretofore met with in employing a relatively long stroke in a deep well pump. Thus the speeding up of the downstroke and the increasing the length of this stroke which may be accomplished by the peculiar characteristics of pump 10, will greatly increase the productivity of wells the oil in which is highly viscous.

The embodiment of the invention herein disclosed is diagrammatic and for illustrative purposes only and it is to be understood that various changes and modifications may be made in this without departing from the spirit of the invention or the scope of the appended claims.

The claims are:

1. A deep well pump associated, when in use, with a production tubing string and a sucker rod string, said pump comprising: pump barrel means having means for connecting the upper end of said barrel means to the lower end of said tubing string, the maximum ID of said barrel means being substantially less than the ID of said tubing string; a standing valve provided at the lower end of said barrel means and checking downward flow therefrom; pump plunger means slidable within said barrel means and having means to connect the same to the lower end of said sucker rod string for lowering said plunger means through said tubing string into said barrel means and reciprocating said plunger means in said barrel means; and a travelling valve provided on said plunger means for checking downward flow through said plunger means, there being port means at an intermediate location in said barrel means, said port means communicating between the interior of said barrel and the exterior thereof, upper and lower portions of said plunger means making a sliding fit with corresponding portions of said barrel means disposed respectively above and below said port means throughout the vertical pumping strokes of said plunger thereby preventing communication between said port means and said standing valve and communication between said port means and the lower end of said tubing string during the normal operation of said pump but effecting the automatic draining of said tubing string through said port means when said plunger means is withdrawn upwardly from said barrel means.

2. A combination as recited in claim 1 wherein the lower portion of said pump barrel means has a substantially smaller inside diameter than that of the upper portion thereof and wherein the outside diameters of 10 upper and lower portions of said pump plunger means correspondingly differ so as to slidingly fit their counterparts in said barrel means, the differential in horizontal cross sectional area between said upper and lower portions of said barrel means nad plunger means effecting the application downwardly to said plunger means of a sub stantial force assisting the downstroke of the latter said force being derived from the hydrostatic head of the production fluid column occupying said tubing string.

No references cited.