US2964942A

US2964942A - Bottom-hole pressure testing apparatus

Info

Publication number: US2964942A
Application number: US759589A
Authority: US
Inventors: Davis W Reed
Original assignee: Shell Oil Co
Current assignee: Shell USA Inc
Priority date: 1958-09-08
Filing date: 1958-09-08
Publication date: 1960-12-20
Anticipated expiration: 1977-12-20

Description

Dec. 20, 1960 D. w. REED BOTTOM-HOLE PRESSURE TESTING APPARATUS Filed Sept 8, 195a FIG.

FIG.

INVENTORI DAVIS W. REED BY: CMZZUI HIS AGENT United States Patent BOTTOM-HOLE PRESSURE TESTING APPARATUS Davis W. Reed, Ventura, Califi, assignor to Shell Oil Company, a corporation of Delaware Filed Sept. 8, 1958, Ser. No. 759,589-

4 Claims. (Cl. 73-155) The present invention relates to well testing apparatus and pertains more particularly to apparatus adapted to be positioned within an oil well for obtaining bottom hole pressures thereof while the well is being pumped.

This invention finds particular utility in oil well pumping systems wherein downhole fluid-operated pumps of the reciprocating type are employed for pumping oil and other fluids from the well. In fluid-operated pumping systems of this character, an operating fluid, such as oil, is delivered to the fluid operated pump near the bottom of the well under pressure by way of a power-fluid supply line which extends from a source of pressurized operating fluid at the surface of the group downwardly in the well to the pump. Such a fluid-operated pump includes a motor piston which is reciprocated in its cylinder by an alternating fluid pressure differential applied thereto, and includes a valve for so regulating the delivery of the operating fluid to the motor cylinder and the exhaust of the spent operating fluid therefrom as to reverse the fluid pressure differential each time the motor, In such a fluid piston reaches the end of its stroke. operated pump, the delivery of the operating fluid to the motor cylinder from the power fluid supply line is interrupted momentarily each time the motor piston reaches the ends of its stroke with the result that the fluid pressure in the power-fluid supply line increases momentarily, assuming that the rate of delivery of the operating fluid under pressure to the supply line is substantially constant, which is usually the case.

In the conventional type of hydraulic pumping equipment, the fluid operated pump is run into the production tubing within the well while being secured to the lower end of the power-fluid supply line. If it is desired to obtain pressures within the well, say at a level opposite the oil-producing Zone, it is necessary with the present equipment to withdraw the pump and inner power supply tubing string from the well prior to lowering a pressure sensing and recording instrument down the production tubing while being attached to the well pump. With the pump and power tubing string reinstalled in the well, the well is produced for a predetermined time while borehole pressures are recorded by the pressure device adjacent to the pump, and thereafter the pump and power tubing string are again withdrawn from the well so that the pressure recording instrument can be recovered from the well. The pressure recording device is normally run into the well at the bottom of the pump.

It is, therefore, a primary object of the present invention to provide an apparatus whereby bottom-hole operating pressures may be obtained in a well being pumped by a fluid-operated pump.

A further object of this invention is to provide apparatus whereby a pressure-sensing and recording instrument may be positioned within the power supply line to a fluid-operated pump in a manner such that the pressuresensing device is isolated from the pressure of the fluid supply line while being exposed to. thewell pressures in;

2,964,942 Patented Dec. 20, 1960 the vicinity of an oil-producing formation while the pump is operating.

Another object of the present invention is to provide apparatus adapted to be positioned in a well being pumped by means of a downhole fluid-operated pump whereby a pressure-sensing instrument may be run down to the bottom of the well, record bottomhole pressures for a predetermined time, and then readily withdrawn from the well without shutting the well down.

These and other objects of this invention will be understood from the following description taken with reference to the drawing, wherein:

Figure l is a diagrammatic view, taken in partial longitudinal cross-section, of well testing apparatus of the present invention illustrated in the position within the production tubing string of an oil well being produced by the fluid-operated pump.

Figure 2 is a diagrammatic view, taken in partial longitudinal cross-section, of another arrangement of the present well testing equipment, illustrated as being positioned in the production tubing of a well with a closure sleeve or plug substituted for a pressure-indicating and recording device.

Figure 3 is a diagrammatic view, taken in partial longitudinal cross-section, of another arrangement of the present well testing equipment, shown as being positioned in a well tubing and having an inner power fluid tubing which is provided with an offset portion.

Referring to Figure 1 of the drawing, duction tubing string an oil well prois illustrated as surrounding a power-fluid supply tubing string 11 with a fluid-operated pump 12 of the reciprocating type being disposed in the lower end of the production tubing 11 and being operable by a fluid under pressure in the supply tubing 11 to pump oil from a well into the production tubing 10 which conveys the oil upwardly to the surface. The intake of the pump may be at 13 while fluid from the top is discharged into the annular space 14 within the production tubing 10, when the pump is operating in an oil well which normally has a perforated casing (not shown).

The production tubing 10 extends upwardly to a well head assembly (not shown) at the top of the well while the power supply tubing extends to the top of the well where it is connected to a source of operating fluid under pressure, suchas a conventional pump (not shown) adapted to deliver the operating fluid under pressure at a substantially constant rate. Thus the power-fluid supply tubing 11 forms a supply line for delivering the operating fluid under pressure to the fluid-operated pump 12 in the well to operate it, the rate of delivery of the operating fluid to the pump '12 being controlled by any suitable valve arrangement (not shown) at the surface. The pump 12 is positioned in a fluidtight manner within the bottom of the production tubing 10, being removably secured therein to permit it being readily withdrawn from the well.

Just above the pump 12, the power-fluid supply tubing 11 is provided with the portion 15 having an enlarged cross-sectional area in which portion 15 and instrument holder '16 may be fixedly positioned. The instrument holder 16 may take any form, but is preferably a tubular member which is fixedly secured, as by welding, to the inner wall of the power fluid tubing 11. One or

more fluid ports

17 and 18 are provided in the power tubing 11 and the production tubing 10, respectively, at a point opposite the instrument holder 16 so that the interior of the instrument holder 16 is in communication with the space outside the production tubing 10.

The instrument'holder '16 is provided with a suitable seat, preferably at the top thereof, forseating an instrument 20 therein in afluidtight manner. The instru.-.-,

ment 20 is diagrammatically illustrated as having a cylindrical housing "having a seat 21 near the upper end thereof, with a fishing head 22 secured to the top thereof for withdrawing the instrument from the instrument holder 16 in a manner well' known to theart. The instrument 20 may be of any suitable designor construction of the type employed to measurepressures, temperatures, etc. at the bottom of a well. Since the design, construction or operating principle of the instrument 20 forms no part of this invention, the instrument will not be further described'here.

border to prevent power fluid from draining from the supplytubing 11 when an instrument is being lowered 'into'or withdrawn from the well, a suitable valve, "such as a spring-loaded sleeve valve 23 is slidably mounted within the instrument holder 16 to close port 17 when the instrument 20 is withdrawn from the holder 16. A valve stop 24 may be provided within the instrument holder 16 for limiting the upward travel of the springloaded sleeve valve 23. Additionally, a shoulder 25 may be formed on the outer surface of the instrument 20 for contacting the top of the sleeve valve 23 and opening it when the instrument 20 is dropped into its holder 16. The shoulder 25 and the stop means 24 of suitable dimension or arrangement so that the shoulder 25 can pass through the stops 24.

Instead of employing a sleeve valve 23 to close port 17 when the instrument 20 is withdrawn from service, the port 17 may be closed in a manner illustrated in Figure 2 wherein a dummy instrument or a closure plug 26 is dropped down the power supply tubing 11 andinto the instrument holder 16 to top of the holder 16 in a fluidtight manner. In this arrangement the bottom 27 of the instrument holder 16 is normally closed.

The enlarged portion 15 of the tubing 11 may take any form of a by-pass line around the instrument holder 16 and its instrument 20 so that the power fluid can be readily pumped down through the supply tubing 11 and around the instrument holder 16 to the pump 12 while the instrument is positioned coaxially within the tubing 11. Alternatively, it is realized that the enlarged portion of a cross-sectional area may be formed by means of an ofiset portion 30 (Figure 3) in which the instrument 20 may be positioned or withdrawn therefrom. In this arrangement a portion 37 of the tubing wall .11 forms an instrument holder together with the offset portion 30. In this case the ports 1'7 and 18 in the tubings 11- and 10, respectively, are positioned below theseat formed on 'the top of the tubing wall section 37.

A pair of

packers

31 and 32 are provided within the production tubing above and below the enlarged portion of the power-supply tubing thereby closing the annular space between tubing string 10 and 11 in a fluidtight rnanner. Positioned in the annular space 34- and extending through the

packers

31 and 32 is a'by-pass pipe 35 through which production fluid from the pump 12 by-passes theportion of the :annulus 34 between tubing strings-10 and 11, which is located between

packers

31 and 32, and is in

communication throughports

17 and 18 with the instrument and the pressure outside the tubing string 10. This production by-pass pipe 35 is of a size sufiicient to handle the flow of fluid from the pump 12.

In operation, the present apparatus is employed to be used in conjunction with indicating and. recording devices to secure information such as borehole pressures by dropping, or lowering on a wire line, an instrument .20 through thepower supply tubing 11. so thatit seats in a fluidtight manner within the instrument holder 16. :In the illustrated apparatus, the seating portion21 of the instrument 20 is of a diameter so that it passes readily through the power supply tubing 11. The instrument may be a self-contained type having aclock-typerrecorder built .in itso that .a predeterminednumberof "pressure readingszmay -.bei:periodically :taken' within "the 'well with the instrument being later retrieved by a wire line. Alternatively the pressure recorder 20 may be lowered on an electric cable extending upwardly through the power supply tubing to the top of the well where it may be connected to a suitable recorder (not shown) or other equipment. Thus by using the present apparatus, pressure readings can be obtained at the bottom of the well being pumped with a fluid-operated pump of the reciprocating type while pumping operations are going on. In certain instances it is desirable to obtain static bottomhole pressures when the pump is not operating. At all times the pump is operating, the production fluid therefrom together with the exhaust power oil used to operate the pump is transmitted upwardly through the bypass pipe 35 and into the annulus 34 to the surface of the well.

When the instrument 20 of Figure l is withdrawn from the instrument holder 16, the spring-loaded sleeve valve 23 is forced upwardly to close port 17. In the arrangement of Figure 3, when the instrument 20 was withdrawn from its seat, a dummy instrument .or closure plug 26 (Figure 2) would be lowered into the offset portion 31 to close port 17.

I claim as my invention:

1. Apparatus for obtaining bottom-hole pressures in an oil well being pumped by a hydraulically-powered reciprocatingpurnping unit said apparatus comprising a pro duction tubing string positioned in a cased oil well and extendingfrom the surface to an oil-producing level therein, a hydraulically-powered reciprocating pump positioned within the lower end of said production tubing, said pump having a discharge being in communication with said production tubing, a power-fluid tubing string depending within said production tubing throughout the length thereof, the lower end of said power-fluid tubing being operatively'connected to the upper end of said pump, said power-fluid tubing having a portion of enlarged crosssectional area located above said pump, an instrument holder fixedly positioned within said power-fluid tubing in the enlarged portion thereof, said holder being formed to provide a chamber for a pressure-measuring instrument, the wall of said power-fluid tubing being formed with first port means in communication between the space outside the power-fluid tubing and the interior of said instrument holder chamber, means normally closing said first port'means when no instrument is within said instrument holder, the wall of said production tubing being formed with'second port means at substantially the same level, closure means in the annulus formed between said produ tion tubing and said power-fluid tubing, said closure means being positioned above and below said first and second ort means, and conduit means extending through said closure means in open communication between the annulus above the upper closure means and the annulus below the lower closure means.

2. Apparatus for obtaining bottom-hole pressures in an oilwell being pumped by a hydraulically-powered reciprocating pumping unit said apparatus comprising a production tubing string positioned in a cased oil well and extending from the surface to an oil-producing level therein, a hydraulically-powered reciprocating pump positioned within the lower end of said production tubing, said pump having a discharge being in communication with said production tubing, a power-fluid tubing string depending within said production tubing throughout the length thereof, the lower end of said power-fluid tubing being operatively connected to the upper end of said pump, said power-fluid tubing having a portion of enlarged crosssectional area located above said pump, an instrument holder fixedly positioned on the inner wall of said powerfiuid tubing in the enlarged portion thereof, said holder being formed to provide a chamber for a pressure-measuring instrument, a seat formed on said instrument holderffor seating an instrument therein in afluidtight manner, the walltoti said instrument holder below the. seat .thereot and the wall of said power-fluid tubing being formed with common first port means in communication with the space outside the power-fluid tubing, means normally closing said first port means when no instrument is Within said instrument holder, the wall of said production tubing being formed with second port means at substantially the same level, closure means in the annulus formed between said production tubing and said power-fluid tubing, said closure means being positioned above and below first and second port means, and conduit means extending through said closure means in open communication between the annulus above the upper closure means and the annulus below the lower closure means.

3. Apparatus for obtaining bottom-hole pressures in an oil well being pumped by a hydraulically-powered reciprocating pumping unit said apparatus comprising a production tubing string positioned in a cased oil well and extending from the surface to an oil-producing level therein, a hydraulically-powered reciprocating pump positioned within the lower end of said production tubing, said pump discharge being in communication with said production tubing, a power-fluid tubing string depending within said production tubing throughout the length thereof, the lower end of said power-fluid tubing being operatively connected to the upper end of said pump, an instrument holder fixedly positioned on the inner wall of said power-fluid tubing near the lower end in a manner so as to form, conduit means around said instrument holder in communication with the power-fluid tubing above and below said instrument holder, said holder being formed to provide a chamber for a pressure-measuring instrument, the wall of said power-fluid tubing being formed with first port means therethrough in communication between the space outside the power-fluid tubing and the interior of said instrument holder chamber, means normally closing said first port means when no instrument is within said instrument holder, the wall of said production tubing being formed with second port means at substantially the same level, closure means in the annulus formed between said production tubing and said power-fluid tubing, said closure means being positioned above and below said first and second port means, and conduit means extending through said closure means in open communication between the annulus above the upper closure means and the annulus below the lower closure means.

4. Apparatus for obtaining bottom-hole pressures in an oil well being pumped by a hydraulically-powered recipro cating pumping unit said apparatus comprising a production tubing string positioned in a cased oil well and extending from the surface to an oil-producing level therein, a hydraulicallypowered reciprocating pump positioned within the lower end of said production tubing, said pump discharge being in communication with said pro duction tubing, a power-fluid tubing string depending within said production tubing throughout the length thereof, the lower end of said power-fluid tubing being operatively connected to the upper end of said pump, said power-fluid tubing having an axially offset portion forming an instrument holder within said power-fluid tubing, said holder being formed to provide a chamber for a pressure-measuring instrument, an instrument adapted to be seated therein in a fiuidtight manner, the wall of said power-fluid tubing being formed with first port means through the wall thereof in communication with the space outside thereof, means normally closing said first port means when no instrument is within said instrument holder, the wall of said production tubing being formed with second port means at substantially the same level, closure means in the annulus formed between said production tubing and said power-fluid tubing, said closure means being positioned above and below said first and second port means, and conduit means extending through said closure means in open communication between the annulus above the upper closure means and the annulus below the lower closure means.

References Cited in the file of this patent UNITED STATES PATENTS 2,703,585 Coberly Mar. 8, 1955 2,846,014 Dafiin et al. Aug. 5, 1958 2,846,876 Willingham Aug. 12, 1958 2,856,008 Spencer Oct. 14, 1959