US3483827A

US3483827A - Well producing apparatus

Info

Publication number: US3483827A
Application number: US689753A
Authority: US
Inventors: John Hooper
Original assignee: Sun Oil Co
Current assignee: Sunoco Inc
Priority date: 1967-12-08
Filing date: 1967-12-08
Publication date: 1969-12-16
Anticipated expiration: 1986-12-16

Description

Dec. 16, 1969 J. HooPER WELL PRODUCING APPARATUS Filed Deo. 8, 1967 FIG. 2 FIG. 3

INVENTOR JHN HOOPER ATTORNEY FIG. l

United States Patent O 3,483,827 WELL PRODUClNG APPARATUS .lohn Hooper, Baytown, TeX., assignor to Sun ii Company, Philadelphia, Fa., a corporation of New `lersey Filed Dec. 8, 1967, Ser. No. 639,753 int. Ci. F0413 21/06 US. Cl. 193-203 3 Claims ABSTRACT 0F THE DISCLGSURE The particular embodiments described herein as illustrative of the invention utilize a gas anchor or separator in a tubing string of a pumping well to reduce the volume of gas produced through the pump and thereby alleviate pump elhciency problems associated with producing high gas liquid ratio uids. At least a portion of the separator is constructed so that it is removable from the tubing string in the well bore to provide a full opening in the tubing and thereby facilitate remedial work in the well without pulling the tubing.

Background of the invention The present invention pertains to well producing apparatus and more particularly to an apparatus in a tubing string for separating liquid and gas prior to entry into a downhole pump with certain components of the separating apparatus being removable from the well to provide a full opening through the tubing.

When utilizing pumping apparatus to lift formation fluids from the well bore to the surface, a particular problem is encountered where the formation fluid has a high gas liquid ratio. Such pumping devices are commonly comprised of upper and lower valves having a plunger operable between the valves to draw fluids into the pump through the lower valve and expel the fluids through the upper valve. If the gas liquid ratio is high, the gas entering the pump with the oil or liquid causes serious loss of efficiency and may, at times, even prevent operation of the valves. Free gas and liquids enter the pump through the lower valve during the upstroke of the plunger, with gas being released from solution in the liquid by reduction in pressure, due to the suction effect of the rising plunger in the pump. These uids are compressed of the valves. Any free gas that may thus be trapped between the valves must be compressed on the downstroke of the plunger to the pressure of the superimposed column of fluid in the tubing ybefore the upper valve may open and permit upward displacement of fluid into the tubing.

lf a large amount of gas accumulates in the pump, the

valves may remain closed, the plunger merely expanding and compressing gas between the two valves with each up and down stroke. This situation is commonly termed gas lock.

Difficulties due to the presence of free gas between the valves of a pump, may be minimized by installing a suitable gas anchor or separator to exclude free gas from entering the pump. There are many types of gas anchor designs, all of which attempt to direct fluid ow in a manner that achieves gravitational separation of gas from liquid by the arrangement of the tubing and pump components. One type of anchor, in its simplest form, consists of a joint or two of tubing suspended from the shoe of the Working barrel of a pump, with the tubing capped at its lower end and provided with one or more holes near its upper end through which fluids may enter. Fluid entering this tubing is permitted to enter the pump "ice only through a smaller tubing, concentrically positioned within the outer tubing, the upper end of which is screwed to the standing valve in the pump, whereas its lower end is well submerged beneath the surface of the fluid in the outer tubing. Separation of gas from the oil is accomplished by causing the fluid to ow down through the annular space between the two tubes, one concentric within the other. During this downward movement of the fluid, the gas separates and moves upward by reason of its lower density, escaping to apertures above the fluid inlet and into the space between the casing and tubing from which it may be permitted to escape at the side outlets of the casing head. Such an arrangement of a gas anchor is shown and described in Petroleum Production Engineering by Uren, McGraw Hill, 1953, page 281.

It is often desirable to perform remedial operations on a producing well which require the removal of the pump from the well tubing in order that remedial workover equipment may be lowered into the well bore through the tubing string. Gas anchors, such as those described above, close the lower end of the tubing string so that even when the pump section is removed, the gas anchor obstructs the lower end of the tubing. Therefore, in such situations where gas anchors are used, it is necessary to pull the tubing string from the well in order to perform workover operations.

It is therefore an object of the present invention to provide a new and improved fluid separator and producing apparatus which may be removed from the well bore to provide a full open tubing string for subsequent remedial operations in the well.

Summary of the invention With this and other objects in view the present invention contemplates a downhole well pump having a gas anchor with at least portions thereof lbeing removable from the well bore to provide a full opening in the tubing string after removal of the device. The gas anchor accomplishes iluid separation by flow pattern and gravitational forces which allow gas to move up and out of the liquids to the surface through a first flow channel and permit the liquids to settle out to the pump section where they are produced by a second flow channel to the surface. The gas anchor is constructed so that it is conveniently removable from the tubing string in the Well by means of a cable or the like suspended from the surface so that after the removal of the gas anchor, tools may be run through the tubing, into the producing zone of the well.

A complete understanding of this invention may be had by reference to the following detailed description when read in conjunction with the accompanying drawings.

Brief description of the drawings FIGURE l is a cross sectional schematic view of a rod actuated pumping device utilizing principles of the present invention;

FTGURE 2 is an alternative arrangement of the apparatus sh Wn in FIGURE l; and

FIGURE 3 is a cross sectional schematic view of a hydraulically actuated pumping device utilizing features of the present invention.

Description of the preferred embodiments Referring first to FGURE l, a well bore is shown traversing earth formations with casing 12 positioned in the well bore. A string of pipe or tubing 14 is suspended in the cased well bore from the surface of the well. Perforations 16 in the casing permit the entry of formation fluids into the well. A casing plug or the like 18 is shown positioned below the perforations to isolate the perforated section of the well bore from adjacent sections. A seating nipple 20 is positioned in the tubing string to provide an obstruction in the interior of the tubing upon which to seat a pump. A polished seal nipple 22 is shown located at the lower end of the tubing string. The seal nipple has a polished interior bore. The pump seating nipple 2G and polished seal nipple 22 are both arranged as integral parts of the tubing string for running into the well on the tubing string. A slotted pipe or tubing section 24 is included in the pipe string between the pump seating nipple and the seal nipple. In the arrangement shown in FIGURE 1 slots 26 are positioned in the upper end of pipe section 24 near the pump seating nipple 20 for reasons to be explained hereafter.

The type of pump schematically shown in FIGURE 1 is known as a rod or insert pump in which the complete unit is lowered into the well on the lower end of a column of sucker rods 28. The pump includes a working barrel 36 which forms a housing for the pumping apparatus. A

plunger 32 is movably mounted within the working barrel and is attached at its upper end to the rod 28 which extends through a rod guide 36 at the upper end of the working barrel. A ball and seat valve arrangement 38 in the plunger is commonly called a traveling valve. The upper end of the plunger has ports 40 to provide lfor the passage of iiuids from the plunger into the upper portion of the barrel. In a similar manner, ports 42 in the upper end of the 'barrel provide for the flow of fluids from the barrel into the tubing string thereabove. A lower ball and seat arrangement 44 is shown at the lower end of the working barrel and is commonly termed a. standing valve. Seating cups (not shown) are provided about the lower end of the working barrel for engaging the pump seating nipple 20 in the tubing. A spacer pipe 46 is shown connected t the lower end of the working barrel and extending downwardly concentrically into the tubing below the slots 26 in tubing section 24 thereof. A plugged seal nipple or blocking means 48 is positioned on the lower end of the spacer pipe 46 and is landed within the polished interior bore of nipple 22 at the end of the tubing string. The plugged seal nipple 48 has ports 50 on its top side. The ports 50 permit the flow of fluids Ifrom the pipe tubing annular space 51 into the seal nipple and from there upwardly into the spacer pipe connecting with the barrel of the pump.

In the operation of the apparatus described above, the plugged seal nipple, spacer pipe, pump, and -rods are run into the tubing and landed in place. The column of sucker rods which actuates the plunger in the pump, extends up through the tubing to the surface where it is suspended from the end of a walking beam or the like for reciprocally moving the sucker rods up and down. Liquid enters the lower end of the pump through the gas anchor and is lifted to the surface through the working barrel and tubing and then is discharged through a flow line connected to the tubing at the surface. Gas, which is depicted by the bubbles in FIGURE 1, rises through the annular space between the tubing and casing to a surface lead line connecting with the annular space through side outlets in the casing head. Some gas, of course, also nds its way with the oil into the working barrel of the pump and is pumped with it through the tubing to the surface, Where the two iluids may be separated by a tra-p of suitable design.

The gas anchor works as follows: fluids entering the casing from the producing formation move upwardly in the column of liuid in the casing. When the producing uids reach the height of the slots 26 in the tubing, most of the gas constituents continue to lbubble upwardly out of the liquid through the casingtubing annulus. The liquid and some gas constituents of the formation uids enter the slots 26 of the tubing and flow down in the space 51 hetween the interior wall of the tubing and the spacer pipe. Gas within the space 51 between the interior wall of the tubing and outer wall of the spacer pipe can gravitate upwardly through slots 26 and into the casing if the upward displacement of gas is faster than the downward ilow of liquids, Fluids that flow downwardly through the space 51, flow through the ports 50 in the top of the plugged seal nipple 48 and then upwardly through the spacer pipe 46 and standing valve 44 into the pump barrel.

When the pump is operated, a decrease in pressure is applied to the standing valve 44 at the input side of the pump. The pressure decrease is transmitted through the spacer pipe and plugged seal nipple to the longitudinal portion of the tubing between the pump and plugged seal nipple. This reduction in pressure along with gravitational. forces permits the liquid constituents of the Huid to pass downwardly through the slots 26 in the tubing while the gas constituents tend to continue moving upwardly through the liquid level and to the surface through the tubing-casing annular space. In the operation of the pump schematically shown in FIGURE 1, an upward movement of the plunger within the barrel causes a reduced pressure on the up side of the standing valve. This in turn causes the ball to unseat in the standing valve and causes fluids in the spacer pipe to move upwardly into the barrel below the plunger. Upon subsequent downward movement of the plunger within the barrel the standing valve is closed and the traveling valve in the plunger is opened to admit uids from the barrel into the plunger. The iluids in the plunger are displaced through the ports 40 in the upper end or" the plunger to the upper end of the barrel and from there upwardly through the ports 42 in the upper end of the barrel into the tubing string above the pump. A repetition or' the operation just described causes the fluids to he moved upwardly through the tubing to the surface for recovery into sur-face vessels.

When it becomes necessary to perform remedial operations in the well bore below the pump, the sucker rods are pulled from the well which in turn lift the plunger, barrel, spacer pipe, and plugged seal nipple, all of which are connected with the sucker rod, upwardly through the tubing to the surface. When these parts are removed, a full vertical opening is left in the tubing string which permits the entry of workover tools into the well by means of a wire line or the like.

Referring next to FIGURE 2 of the drawing, a pump device 52 similar to that shown in FIGURE 1 is positioned in the tubing with an alternative gas anchor system 54 `suspended from its lower end. A packer 56 is schematically shown positioned about the tubing section 24 between the tubing and casing 12 to form a seal therebetween. Formation fluids entering the well bore through perforations 16 move upwardly into the lower end of the tubing section 24. Although the lower end of the tubing is shown but a short distance below the gas anchor 54. it is readily appreciated that the lower tubing section 24 may be comprised of many pipe sections, depending upon the particular characteristics of the well involved. The gas anchor 54 includes a concentric crossover 58. A tubular member extends upwardly from the crossover for connection with the lower end of the pump below the standing valve. The crossover includes a ow path tube 62 (represented by dotted lines) centrally located within the crossover. Tube 62, which opens to the lower end of the crossover, extends upwardly concentrically within the crossover and curves at its upper end to an upper opening or port 64 in the side of the crossover tool in communication with the interior of the tubing string. A lower opening or port 66 in the side of the crossover tool communicates with an annular chamber 68 about the tube 62. The chamber 63, in turn, communicates with the tubular member 60 extending upwardly from the upward end of the crossover. Upper and lower annular sealing surfaces 70, 72 are provided on the crossover housing above and below the lower opening 66 to provide a sealing engagement between the crossover housing and the interior surface of the tubing wall. One or more upper openings 76 in the tubing wall are arranged to communicate with the annular space 78 between the tubular member 60 and the tubing which in turn is in communication with the flow path tube 62 through the crossover.

In the operation of the apparatus described in FIGURE Z the pump 52 and gas anchor 54 are assembled and lowered into the tubing on sucker rods in a manner similar to that described with respect to FIGURE l. Care must be taken, of course, to seat the assembled apparatus in the tubing so that the ports 64, 66 in the crossover are aligned and sealed with the corresponding upper and lower ports 76, 74 formed in the tubing wall. Fluids entering the well bore through the perforations 16 in the casing move upwardly into the tubing section 24 in communication with the lower end of the gas anchor. These fluids, including both liquid and the gaseous constituents, travel through the flow path tube 62 into the annular space 78 between the tubular member 60 and tubing wall and out through the upper slots or ports 76 in the tubing. The gaseous constituens of the uid tend to rise upwardly from this point through the uids thereabove and into the tubing-casing annulus above the liquid level. The liquid constituents, on the other hand, due to gravitational and pump forces tend to move downwardly and thereby be placed in communication with the lower ports or slots 74 in the tubing wall. These liquid constituents enter the lower ports 74 in the tubing and the lower port 66 in the crossover which in turn is in communication with the annular chamber 68, tubular member 60, and the lower end of the standing valve in the pump. The pump is operated as described with respect to FIGURE l to lift iiuids through the pumping device to the surface through the tubing. Again, when it is necessary to do remedial work in the well below the pump, the pump and gas anchor are conveniently removable in a single operation `by pulling the sucker rods which in turn leaves a full opening through the tubing string.

Referring next to FGURE 3 an alternative arrangement of the full open gas anchor is shown in use with a sub-surface hydraulic pump. The system utilizes a dual tubing string which includes an input tubing 80 and an output tubing 82, which tubings extend parallel to one another into the well bore and are connected at their lower ends by means of a flow passage 84. One such hydraulic pump system utilizes a portion of the crude oil produced by the Well, which is subjected to high pressure by a surface pump (not shown) and transmitted through the input tubing 80 to operate a pump 86 submerged in the well duid. The working portions of the downhole hydraulic pump are not shown on FIGURE 3 but include a pump plunger reciprocated in a vertical cylinder 'by a direct connected piston of a double acting engine actuated by the power fluid trnasmitted through tubing 80. The spent power uid is returned to the surface with the wells production through tubing 82. On delivery at the surface, the crude petroleum is passed through a gas separator and receiving tank (not shown) where suspended solids and water are allowed to settle. From the uid near the top of the settling tank, clean oil for power use is drained by the surface power pump. Different arrangements of tubing may be used, of course, to provide a ow path for the descending power fluid and another flow path for the ascending well production and returning power uid. For example, two separate columns of tubing may be used side by side as shown in FIGURE 3, two concentric tubes may be used with power fluid flowing down through the inner tube and returning with the wells production through the annulus between the two tubes, and a single column of tubing may be used for suspending the pump at its lower end with a packer to close the annular space between the pump and well casing. In the latter case the power iiuid is transmitted down to the annular space between the tubing and casing. The power uid used in such a system need not be oil but, of course, may be any suitable fiuid which is readily available. The hydraulic pro duction unit itself normally consists of two principal parts: a hydraulic engine 88 and a reciprocating displacement pump 90. The arrangement and operation of such a hydraulic pump is illustrated and described in Petroleum Production Engineering by Uren, McGraw Hill, 1953, page 388. Such a pump, as with the mechanically actuated pump, is subject to decreases in eiciency due to high oil gas ratio.

A gas anchor for use `with such a hydraulic pump is shown in FIGURE 3. A seating shoe 92 is shown connected to the lower end of the tubing below the hydraulic pump, and is arranged to join the dual tubing string. The seating shoe has a landing surface 93 for a standing valve 94, and hold the tubing section 24 which forms a part of the gas anchor. The standing valve 94 is shown positioned within the seating shoe and having a pipe 96 extending downwardly from its lower end. The pipe 96 is concentrically arranged within the tubing section 24 below the seating shoe 92. A polished nipple 95 is located at the lower end of the tubing section 24 and is sized to receive a plugged seal nipple 97 which is joined to the lower end of the pipe 96. The reception of the plugged seal nipple 97 within the polished nipple 95 provides a seal at the lower end of the tubing to prevent the direct flow of formation fluids to the lower end of the tubing. The tubing section 24 below the seating shoe is slotted at 98 while the upper end of the plugged `seal nipple has ports 99 in the plugged seal nipple to permit entry of the liquid constituents of formation uids into the lower end of the pipe 96. As with the operation of the gas anchors of FIGURES l and 2, separation of the gas from the formation uid is accomplished by allowing uid to How in through the slots 98 in the tubing down through the annular space between the pipe 96 and tubing. During this downward movement of the uid, any gas which still remains in the fluid separates and moves upward by reason of its lower density, escaping through the slots 98 to the space between the tubing and casing where it is permitted to escape upwardly through the casing annulus to the side outlets of the casing head.

In the event that it is necessary to perform remedial operation in the well bore below the pump, the pump is removed from the tubing by reverse circulation of the power oil through the output tubing S2. The standing valve and associated gas anchor system are then removed from the tubing by means of a wire line which may be lowered into the tubing and connected with the upper end of the standing valve. With the standing valve 94, pipe 96 and plugged nipple 97 removed from the tubing, the opened tubing string will permit wire line work through the tubing.

It is appreciated, of course, that the arrangements of pumping devices shown and described are Ibut a few of the many various arrangements which are commonly used for removing fluids from a well bore. In addition, while particular embodiments of the present invention have been shown and described it is apparent that changes and modifications may be made without departing from the invention in its broader aspects and therefore, the aim in the appended claims is to cover all such changes and modifications as fall within the true spirit and scope of this invention.

What is claimed is:

1. An apparatus for lifting fluids from producing formations traversed by a well bore to the surface through a tubing string, comprising; fluid lifting means positioned in the tubing string, intake port means in the apparatus for communicating fluids with the fluid lifting means, said apparatus and tubing string forming first and second flow channels in said apparatus, separator means positioned in the tubing string below the fluid lifting means for directing gaseous constituents of the uid upwardly through a first flow channel to the surface and for directing primarily liquid constituents of the Huid downwardly to said intake port means for lifting of said liquid constituents to the surface by means of said fluid lifting means through a second ow channel, and blocking means positioned within the tubing string for preventing unseparated liuids from directly entering the fluid lifting means, said blocking means being removable while the tubing string is in the well bore to provide a full opening through the tubing string.

2. An apparatus for removing fluids through a pipe string in a well bore, comprising; uid pumping means positioned in the pipe string, said fluid pumping means being removable from said position in the pipe string by means passing through said pipe string from the surface;

rst port means in said apparatus for communicating well bore iluids between the interior and exterior of the pipe string;

second port means in said apparatus for passing well fluids from the well bore into communication with said fluid pumping means, said second port means being spaced downwardly from said rst port means for passing liquid constituents of the well fluid, the gas constituents of the lwell fluid tending to rise upwardly from said first port means; and means plugging the pipe string below said second port means,

said plugging means also being removable from within the pipe string by means passing through the pipe string from the surface.

3. An apparatus for removing fluids from a well bore having a tubing string extending from the surface to a position in the well bore occupied by fluids, comprising; fluid lifting means in said tubing string for moving uids from said position to the surface through the tubing string, said fluid lifting means being removable from the tubing string lby means passing through the tubing string from the surface, -flrst port means in the apparatus for communicating fluids at said position with the interior of said tubing string below said uid lifting means, second port means in said apparatus spaced downwardly from said first port means for communicating the interior of said tubing string with the uid lifting means, and plugging means closing the lower end of said tubing string at a point below said second port means, said plugging means being retrievable from the tubing string by means suspendable in the tubing string from the surface.

4. The apparatus of claim 3 and further including a tubular member extending downwardly from said fluid lifting means and having said second port means at its lower end, said plugging means also being attached to said lower end of said tubular member.

5. An apparatus for passing fluids from an earth formation traversed Iby a well bore to the surface of the well and arranged for operation with a tubing string having upper and lower ports positioned in the well bore, said apparatus comprising; fluid lifting means positioned in the tubing string -above the ports in the tubing; first ow passage means communicating the well bore with the interior of the tubing and the upper port inthe tubing string below said liuid lifting means, second flow passage means communicating the lower port in the tubing string with the -fluid lifting means, means for preventing direct uid ow -between the formation uids in the interior ot the tubing string and said second flow passage means. and means on said apparatus for plugging the lower end of the tubing string to prevent the direct flow of formation fluids into the fluid lifting means, said apparatus being removable from within the tubing string by means passing through the tubing string from the surface.

6. The apparatus of claim 5 wherein packer means are providede on said tubing string below the lower port for providing a fluid ow seal between the tubing string and the well bore.

7. An apparatus for removing uids through a pipe system in a well bore, comprising: a rst pipe string in the well bore; a second parallel pipe string in the well bore, passage means connecting the lower end of said second pipe string with said first pipe string, at least one of said pipe strings having a vertical bore which opens at its lower end into said well bore; valve means in said one of said pipe strings below said passage means and arranged to permit the upward ow of fluid through said valve while preventing low in the opposite direction; uid lifting means positioned in said one of said pipe strings and operable by the movement of fluid through at least one of said pipe strings; means for communicating one side of said valve means with said fluid lifting means; and fluid separator means formed by the lower end of said one of said pipe strings and means extending downwardly in said one of said pipe strings from said valve means, said iluid lifting means, valve means, and downwardly extending means being removable from said one of said pipe strings in said well bore.

8. The apparatus of claim 7 wherein said fluid separator means includes a tubular member extending downwardly from said valve means, means on the end of said tubular member for plugging the lower end of said bore in said one of said pipe strings, and port means in said one or' said pipe strings and said tubular member for causing a partial downward flow path for fluids flowing from said `well bore into said valve means.

References Cited UNlTED STATES PATENTS 993,520 5/ 1911 Hahn. 1,603,675 10/19216 Folsom et al. 1,877,112 9/1932 Yerkes et al. 2,363,343 11/ 1944 Lindgren.

ROBERT M. WALKER, Primary Examiner