US1811101A - Oil well pump - Google Patents

Description

- H. F. WATKINS June 23, 1931 gall/IA OIL WELL PUMP Filed April 17, 1929 2000000 ognggog TTORNEYS.

Patented June 23, 1931 UNITED STATES PATENT Fl-ice HAROLD IF. WATKINS, OF OAKLAND, CALIFORNIA ASSIGNOR TO WATKINS INTER- HITTING PUMP COMPANY, OF SAN FRANCISCO, CALIFORNIA, A CORPORATION OF CALIFORNIA on. WELL rum? Application filed April 17, 1929. Serial No. 355,702.

that it pumps the oil with a minimum amount of emulsification, and therefore it is of particular value when used in connection with wells having a considerable flow of water. As is well known, emulsification of oil is commonly experienced in gas lift pumps of the ejector type, and makes necessary additional equipment and treating processes to effect de-emulsification' Furthermore such apparatus may cause an accumulation of gas within the well, thus decreasing the flow of oil. WVhi le the apparatus disclosed in said copendlng application No. 27 8,090 is successful and operable, I have found that under certain operating conditions or when operating in wells of a certain character, emulsification may still take place to a certain degree and gas may accumulate within the Well.

It is a general object of this invention to devise a pumping apparatus which will prevent emulsification of the oil irrespective of the operating conditions.

It is a further object of this invention to devise a pumping apparatus which will give uniform results when'used in different wells or under different operating conditions.

It is a further object of this invention to devise a pumping apparatus of the above character, which will have means for precluding the possibility of gas or air under pressure accumulating within the well.

Further objects of the invention will appear from the following description in which I have set forth the preferred embodiment of my invention. It is to be understood that the appended claims are to be accorded a range of. equivalents consistent with thestate of the prior art.

Referring to the drawings:

Figure 1 isa side elevational view illustrating my apparatus assembled in a typical oil well.

Fig. 2 is a cross sectional detail illustrat- 1ng my valve apparatus in one operating positlon.

Fig. 3 is a view similar to Fig. 2 illustrating the valve apparatus in a different operating position.

My invention can be outlined briefly as comprising a pair of pipe strings which extend down into an oil well below the normal level of oil. Located within the well-and associated with these pipes, there is a valve mechanism which is recurrently operated.

This mechanism serves to control communication between the pipe strings and to control flow of oil from the well into one of the pipes. In addition to this valve mechanism, other means is provided to preclude the possibility of gas under pressure being introduced into the well proper from the pipe strings, and to prevent such inflow of oil as would cause formation of oil emulsion.

Referring to the drawings for a detailed description of my invention, in Fig. l I have shown a well 10 within which is extended a pair of pipe strings 11 and 12. These pipe strings are preferably arranged concentrically, and one, for example string 11., serves to convey gas under pressure down into the well and can therefore be termed the gas pipe string, while the other may be termed the oil pipe-string and serves to convey oil to the surface of the well. Associated with the lower portions'of pipe strings'll and 12 and located a substantial. distance below the normal oil level within the well, I

provide valve mechanism 13, the details of which will. be presently described. At the mon. The construction shown is practical and effective, and consists of a valve barrel 19 within which is arranged a movable valve member 21. For example the barrel 19 can consist of a tubular casing 22 within which is arranged a suitable liner 23. Valve member 21 is in the form of a hollow tube having a lower closed 'end, and being machined or ground to have a fluid tight fit .with the liner 23. Valve member 21 and liner 23 are made of suitable wear resisting material so as to permit operation over long periods without appreciable 'wear or leakage. Upper and lower pipe couplings 26 and 27 serve to retain casing 22 and liner 23 assembled, and the upper coupling 26 connects with the lower end of pipe string 11.

Extending below the barrel 22 and communicating with the same, I provide one or more pipe sections 29 forming a fluid chamber. These pipe sections may be considered as a continuation of the oil pipe string 11. Adjacent the upper end of barrel 19, valve member 21 is provided with one or more gas flow ports 31, and likewise adjacent the lower end of barrel 19, valve member 21 is provided with one or more oil flow ports 32 In practice, for effecting operation of valves 17, 18, I provide mechanical motion applying mechanism at the surface of the well, and this mechanism preferably serves to effect relative reciprocating movements between pipe strings 11 and 12. Thus in Fig. 1 I have shown the gas pipe string 11 stationary, while the upper end of pipe string 12 is connected to an actuating mechanism 34 thru a convenient cable 36. I prefer in this connection to utilize hydraulic actuating mechanism of the type described in my copending application No. 316,163 filed Oct. 31, 1928. Such actuating mechanism can be conveniently adjusted so as to vary the stroke of pipe string 12, and to adjust the rate of its up and down movement.

Assuming that actuating mechanism 34. properly reciprocates the pipe string 12, as valve member 21 approaches the upper limit of its stroke, ports 31 are exposeda ove the barrel 17, to establish communication between pipe strings 11 and 12. On its downward stroke, communication between the two pipe strings is first interrupted and .then after a given time interval ports 32 are exposed below the lower end of barrel 19, to establish communication between pipe 29 and pipe string 12, thru valve member 21.

In combination with the above apparatus, I prefer to provide valve means associated with pipe 29, to control flow between this pi e and the well. This valve is preferably 0 the fluid operated check type and can conwithin the well at this point, ball 39 is re-.

tained upon its seat, but when pressure in the well adjacent this valve is greater than the pressure within pipe 29, the ball is forced away from its seat and inflow of oil occurs.

Generally the oil in pipe 29 contains sufficient gas to allow member 21 to reciprocate. However to insure proper elasticity I can provide a gas chamber 41 having a lower open end, and within which gas from the. oil can accumulate, thus providing a pneumatic cushion.

The operation of my apparatus can be explained as follows: Assuming that valve member 21 is being properly reciprocated by the actuating mechanism 34 at the surface of the well, when this member is at or near the bottom of its stroke as shown in Fig. 3, oil from the well will flow past check valve 35, thru ipe 29, thru valve member 21 and up into t e oil pipe string 12. After such flow has occurredfor an appreciable period and a substantial column of oil exists in pipe string 11 about the ports 31, further flow of oil into pipe string 11 is arrested by upward movement of valve member 21. As valve member 21 approaches the limit of its upward stroke, gas under pressure which exists between pipe strings 11 and 12, blows thru ports 31 and forms a pneumatic iston tending to expand upwardly and to orce upwardly the column of oil above it in pipe string 12. After this introduction of a charge of gas has been continued for an appreciable period, downward movement of valve-member21 interrupts communication thru ports 31, and further introduction of gas is interrupted. By the time ports 32 are againexposed, condltions may be such that due to the presence of gas in pipe string 12, the pressure within the lower portion of this pipe string and valve member 21 may be considerab greater than the pressure of oil in the we 1 adjacent the oint of its inflow into pipe 29. If this con ition exists upon opening ports 32, back flow of gas into the well proper is prevented by,

check valve 35. Therefore in such event check valve 35 automatically remains closed after opening valve 18, until the pressure in the lower portion of ipe string 12 is reduced sufiiciently, to e ect opening of check valve 35, after which inflow of oil from the well a ain commences to fill the lower portion 0 pipe string 12. It is therefore evidenced that if it were not for the check valve 35, a certain amount of gas under pressure might escape from the valve mechanism and accumulate within the well proper. It has been found that such accumulation of gas within the well may seriously interfere with the quantity of flow.

In connection with the above apparatus it is to be noted that it operates more satisfactorily and gives better results than an apparatus utilizing a single positively operated valve 17 in conjunction with a single check valve 35. The presence of valve 18 positively prevents flow of oil past ports 31, while gas is being blown thru these ports to form a pneumatic piston. If such flow of oil were permitted, as might be the case under certain circumstances by omitting valve 18, emulsification of the oil would occur.

My apparatus has given unusually satisfactory results and can be installed in wells of different depths and capacities with equally good results. The reciprocation of pipe string is at a relatively slow rate compared to oil pumps of the past. For example I employ a time period for a complete stroke varying from one minute to four hours, compared to 18 to 28 strokes per minute used in standard sucker rod pumps. The timing period should be adjusted to a value which will give optimum operation for any one installation and set of operating conditions. For example it is dependent upon the depth of the well, the pressure of gas employed, the natural well flow, the height of the natural oil column, the sizes of casing and pipe employed, the resistance ofiered to the flow of oil being discharged, and other such factors. The apparatus is highly economical and utilizes a minimum amount of gas and power, for pumping a given quantity of oil.

I claim:

1. In an oil well pump, oil and gas pipe strings extending down into the well for a substantial distance below the normal level of oil in the same, said gas pipe string being adapted for connection with a source of gas underpressure at the surface of the well, a. valve for establishing and interrupting com-' munication between said pipes at a point substantially below said level, means actuated from the surface of the well for directly applying motion to said valve whereby it is recurrently opened and closed, a second oil valve adapted to control flow of oil into said oil pipe from the well, said second valve being located below the first and being adapted to be recurrently operated responsive to operation of the first valve, and a third valve associated with the oil pipe and serving to control flow between the second valve and the well.

2. In an oilwell pump, oil and gas pipe strings extending down into the well, for a substantial distance below the normal level of oil in the same, said gas pipe string being adapted for connection with a source of gas under pressure at the surface of the well, a valve for establishing and interrupting communication between said pipes at a point substantially below said level, a second valve serving to permit or interrupt flow of oil from the well into said oil pipe above said first valve, common means for positively oppositely actuating said valves whereby for one period the second valve is open and the first valve is closed and for another period the first valve is closed and the second valve is open, and a check valve interposed between said second valve and communication of the oil pipe with the well, said check valve serving to prevent outflow from said oil pipe into the well.

3. In an oil well pump, oil and gas pipe strings extending down into the well for a substantial distance below the normal level ofoil in the same, said gas pipe string being adapted for connection with a source of 1gas under pressure at the surface of the wel valve for establishing and interrupting communication between said pipes at a point substantially below said level, a second valve serving to permit or interrupt flow of oil from the well into said oil pipe above said first valve, means actuated from the surface of the well for applying motion to said valves whereby they are recurrently and oppositel operated, and a check valve associated wit said oil pipe string a substantial'distance below said second valve, said check valve permitting inflow of oil from the well to said second valve but preventing outflow of oil or gas into the well.

In testimony whereof, I have hereunto set my hand.

HAROLD F. WATKINS.

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