US2690226A - Equalizing and control valve - Google Patents

Description

Sept. 28, 1954 l.. H. coMs'rocK EQUALIZING AND CONTROL VALVE 3 Sheets-Sheet l Filed Dec. 22, 1950 IN VEN TOR. 3a 82km# Mm@ l eJ//e H. i Comsoc/f A TTOR/VFY Sept' 28, 1954 l.. H. coMs-rocK EQUALIZING AND CNTROL VALVE 3 Sheets-Sheet 2 Filed Dec. 22, 1950 INVENTOR.

ATTORNEY Sept 28, 1954 H. coMsTocK 2,690,226

EQUALIZING AND CONTROL VALVE Filed Dec. 22, 1950 3 Sheets-Sheet 3 l eJ//e H. Coma oc/f INVENTOR.

BY MALA- /4 7' TORNE Y Patented Sept. 28, 1954 UNITED STATES PATENT OFFICE aquanrzm v.mn CONTROL AL'VE Leslie H. Comstock, Houston, Iex,

Application December 22, 195o, serial no. znazso (Cl. Uwe-145) Claims.

This invention relates to equalizing ,and 4con-.- trol valves and more particularly to a valve are rangement suitable for use in drill pipe or the like in oil Wells.

In the drilling of oil wells and the like it is customary to seal off a potential producing for mation in order to obtain a sample of the fluid of the formation ,and to obtain a shut-in or closed-in pressure reading of the formation. conventionally, a packer or packing means is set above the potential producing formation to pack oil' the upper end of the bore hole to prevent hydrostatic iiuid from above entering 11? formation or `the testing means employed.

In the testing of such formations it is often diicult to equalize the pressure above and below the packer in order to free the packer and t9 provide valve means which assure the operator of obtaining the closed pressure of the formation being tested.

It is an vobject of the present invention to provide a suitable valve arrangement which may be operated by manipulation of the drill stem or conduit to which it is connected and which is capable of performing various functions, such as, relieving the pressure beneath the packer when `it is being placed in position, enabling a test sample of the particular formation being tested to be obtained and providing a valve closure in order that the closed in pressure of the formation may be obtained prior to equaiizing the pressure above and below the packer.

It is a particular object of the present inven tion to provide a valve assembly which will equalize the pressure above and below the Dackel' but yet will provide a closure `prior to equazlizins the Ypressure after the sample has been obtained in order that a closed Vformation pressure may be obtained.

It is yet a further object and ,feature o1 the present invention to provide a valve assembly which has a. time lag between the closing o! the valve adapted vto permit formation iiuid to flow into the sample receiving chamber or conduit and the opening of the equalizlng valve whereby a shut-in pressure of the formation being tested is automatically obtained.

It is yet a further object of the present invention to provide a control and -equalizins valve assembly which is simple and rugged in use ,and which omits many of the elements of convene Etional valves now infuse.

A feature of the invention is the provision@ ,a control valve which opens only reiter the teal ifa 2 entering the sam-ple conduit or chamber and thereby cumming the usual disc valve for this purpose.

,A `faltbar ica/ture is the provision of automatic jarring moons to aid in .unseatins packing cloments used ,in oil well testing and the like.

Other and fiiilhtr objects and advantages re- Side incertain ooi/e1 features of thc arrangement and construction of parts as will be apparent from the tollowing description taken in connection with the accompanying drawing. 1n which Fig. 1 is .c view ,in Sido elevatori of apparatus illustrating the principles of the invention. tho arrangement illustrating equalizing and control valves in connection with a typical formation tester ,assembly 2 is c ticle View. partially in section. illustranne .the coualizing and control valves as trie device is lowered .into a .well bore.

Fis. 3 is `similiar to Fis- 2 `but illustrates the valve esscmhlyin position Lor taking sample 111.11@ from the formation being tested.

Fiss. Y4.. 5 and .6 .are enlarged sido elevations ,in section better illustrating the embodiment or Fig. 2 and Fiss. 'l-.ID inclusive .are .cross-.sectional views taken along .corresponding section lines of Figs. 4 and 6. and

Fis.. 1.1 illustratcsornodmcotion of valve means which may be utilized in the valve assembly.

Beierring now ,to the drawings. where like charactor references designate like parts throughout the several views.. and particularly to Fis. 1. the assembly time sbowmcludos theequauzing and control Avalve assembly i0. secured ot its .oppor end to the failing 91 .lf2 extending up $0 12.1110 surface met shown), and .connected at its lower end to o transient-hole .pocker I4, which in turn is secured to a conventional Ypnessure recording device il and .a perforated section of pipe il by which sample fluid trom Vthe form-ation being tested may Lbe obtained.

`The assembly indicated -is typical and is illustrated for the purpose oi disclosure. Any `type of conventionalpaeker or packing means may be utilized, such as a hook-wall" packer and any conventional pressure 4recording moons may be utilized For cemiile. .s ,pressure recording gie.- vioc illlllrated .in Patent No 2.915.623- issued April 21. 1&3?. .to li D. Wilde Jr.. .may be used and vthe ,formation tester ,may be such as that disclosed v.in the U. iS. patent to Moore, No. 2,189,919, dated February 13, 1940, entitled has :been ect viilfiereby preventing drill luid from .to Method ,and Apparatus for Formatonyressore 3 Testing." Manifestly. the formation tester and packing assembly may be of any known type.

Referring now more particularly to my novel equalizing and control valve assembly, and with particular reference to Figs. 2. 4, 5 and 6 the valve assembly is made up of two major elements, an upper valve element 20 and a lower valve element 22. The upper 20 and lower 22 valve elements each include tubular piston chambers 24 and 2t respectively, which are closed at their upper ends by the submembers 28 and 30, respectively, and are closed at their lower ends by the closure members 32 and 34, respectively. As illustrated, these elements may be threadedly secured together in the usual and customary manner.

Threadedly secured to the lower ends of the closure members 32 and 34 of the piston chambers 24 and lle are the tubular runout chambers 36 and 38, respectively. The function of these runout chambers will be apparent later.

In order that the valve assembly might be ma nipulated from the surface by means of the string of pipe l2, a mandrel 40 is threadedly secured at its upper end to the couplingr 42, which in turn is threadedly secured to the string of pipe l2 in the customary manner. At the lower end of the mandrel 40 the keys 44 are provided to move in the keyways 4B ol the upper tubular element 28 of the upper valve element 20. The keys 44 are defined by the flattened sides of the enlargement 43 which stops against the inwardly projecting circumferential ange 45 of the upper submember 28. Immediately below the keys or splines 44 the mandrel 4B is turned down, as indicated by the numeral 43 and has secured thereto the piston 5i), the mandrel extending therebelow through the upper piston chamber 24 and into the closure member 32. As better seen in Figs. 4 and 5, the mandrel 4U and its turned down portion 48 are provided with a central passage 52 therethrough which is in communication with the passage 54 of the coupling 42 which in turn is in communication with the interior passage 56 of the string of pipe I2. The lower end 0f the turned down portion 48 of the mandrel 40 is closed by the threaded plug 58 and disposed proximate the lower end thereof are the lateral ports 60 which are in communication with the central passage 52 of the turned down portion 48 of the mandrel 45.

The lower valve element 22 is similar to the upper valve element 20 and has the upper end of the mandrel 10, which extends from the upper end of lower valve element 22, threadedly secured to the lower portion of the runout chamber 36. The mandrel 'lil is substantially identical to the mandrel 4D and has the keys 14 slidable in the keyways 16 of the upper submember 30 of the lower valve element 22 and has the turned down portion 18 immediately therebelow extending substantially through the lower valve element 22. The keys 'I4 are defined by the flattened sides of the enlargement 13 which stops against the inwardly projecting circumferential flange of the lower sub 3U. A piston 8B is secured to the turned down portion 'I8 of the mandrel 10 and the turned-down portion 18 continues and is adapted to move into the runout chamber 3B. Thus the mandrel Hl and its continuation 18 is slidable through the lower valve element; however, the lateral ports 82 provided in the inandrel 1D are open to the well bore when the tool is being lowered into or raised from testing position.

As better illustrated in Fig. 6, the lower end of the turned down portion 18 of the mandrel l0, here illustrated as an additional threaded member to the lower end of the mandrel 1D, is not plugged. but is open and fluid may circulate through the lateral ports 82 out through the apertures in the section of pipe l in order that drill fluid may circulate past the packer and formation testing means. Thus, a swabbing action is avoided and the pressure above and below the packer is equalized.

The upper ends of submembers 2li and 30, and the lower ends of the closure members 32 and 34 are counterbored, all as indicated by the numeral 84 and conventional packing 86 and a gland ring 88 are utilized to provide an effective seal for these members, which comprise in effect stuffing boxes. The stuffing boxes illustrated are all substantially the same except that the stufling box in the lower end of the closure member 32 is extended with respect to the others. This is best seen in Fig. 5 and the extended stuiiing box is provided in connection with the lateral ports 6G for a purpose which will be apparent later. Packing is provided at the lower ends of the piston chambers 24 and 26, the packing here illustrated as C-cups 90. It is noted that the C-cup 98 disposed at the lower end of the piston chamber 24 extends upwardly and the C-cup 9i! disposed at the upper end of the lower piston chamber 2B extends downwardly. These C-cups are positioned in this manner inasmuch as the valve action in the upper and lower chamber is reversed. A junk ring 9| may be provided in connection with the lower C-cup to provide the required support for the cup.

Referring now more particularly to the pistons 5B and 80 positioned in the piston chambers 24 and 25, these pistons are formed of resilient material or rubber and the piston 50 is downwardly and outwardly diverging and terminates in a substantially circumferential head 92. The lower piston is upwardly and outwardly diverging and terminates in the upwardly facing circumferential head 94. Each piston is drilled and tapped and has the removable orifices or chokes 96 threaded in their heads. Each piston chamber is drilled and tapped, as at 98 in order that the chambers may be provided with hydraulic oil or fluid, the threaded openings 98 normally being closed by the threaded plugs Illu. Thus, as the upper piston 5U moves downwardly its downward movement will be relatively slow inasmuch as the rubber piston is expanded against the piston chamber walls; whereas, when it moves upwardly its upward movement will be fast in relation to its downward movement inasmuch as the rubber piston is compressed because it diverges downwardly and outwardly. In order to insure a fast initial upward movement, the compression spring l02 is disposed in the lower end of the upper piston chamber 24. The movement of the lower piston is the reverse of the movement of the upper piston 5l). Thus the downward movement of the lower piston 8e will be fast with respect to the upward movement of this piston. For reasons which will be apparent later, a plurality of vertical grooves or recesses ll to permit the bypassing of hydraulic fluid is disposed near the upper end of the lower piston chamber 26.

l As illustrated in Fig. 1l, as an alternative embodiment, a piston |04 may be employed in lieu of the tapered pistons illustrated. The piston |54 is illustrated with the check valve asiembly lill and, in the event such a valve is used, the upper valve would have the check vaivo as illustrated in Fig. il and. the 'lower valve would have the check valve in an inverted posltion to that oi' the piston illustrated in Fig. il. In other words, -any suitable valve means may be utilized which will provide a relatively slow downward movement with respect to the upward movement of the upper valve 5I), and a relatively fast downwar-d movement with respect to the upward movement of the lower valve Ml. It is essential. in order to obtain a closed in pressure reading of a formation, to close the control valve and thereafter open the equalizing valve.

To seat and remove a packer and obtain a sample of the formation fluid and the shut-in or closed-in pressure of the formation with the apparatus just described. the operation may be as follows:

The assembly may be lowered into the well bore H as illustrated in Fig. 1. In lowering the apparatus into the well bore the elements of the valve assembly will be in the position indicated in Figs. 2, 4, and 6. That is, upper and lower valve elements 20 and 22, respectively, will be hanging or suspended from the mandrels 48 and 10 by means of the enlargements 43 and 13 engaging the flanges 45 and 15 at the upper ends of the sub members 2B and 30. Thus, the ports B0 will be in the upper end of the packing 86 and the ports B2 will be in communication with the hydrostatic pressure of the w-ell fluid in the well bore lI I0. Thus as the apparatus is lowered into the well bore, the drill iluid may circulate through the apertures in the section of pipe I8 through a passa-ge in the tester and packer on up through the central passage in the turned-down portion 18 and the lower mandrel 10, out through the apertures B2 in the formation. Thus a swabbing action is prevented and the apparatus may be lowered readily into a well bore having drill uid therein.

In the event an obstruction is encountered in lowering the assembly into the well bore, the upper valve element 20 will not be prematurely opened in view of the slow downward movement of the piston 50 in the upper piston chamber 24. This prevents contaminating fluid from entering the sampling string of pipe i2. I have found that a time lag of about i'our or live minutes between the closing or the lower valve element and the opening of the upper valve element is satisfactory, although other periods of lag may be provided as desired. By this construction the ordinary disc valve is omitted.

Assuming now that the arrangement is lowered to the desired position at which a test is to be taken and, as illustrated in Fig. l, the rat-hole packer I4 has entered and is seating on the upper portion oi the rat-hole H2, the downward movement of the assembly will be stopped. In pressing the packer into position in the rat-hole, downward force will be transmitted by means of the string of pipe I2 downwardly through the mandrel 40 and the mandrel 10.

As indicated heretofore, the downward travel of the piston 5u will be relatively slow and its downward travel will be metered by the hydraulic duid passing through the removable orifice or choke B6. The downward travel of the mandrel 'I0 will be relatively fast and the ports 82 will rapidly move into the packing 86 thereby closing the assembly .Hl with respect to hydrostatic pressure above the packer it. Thus there is a time lag between the movemmts of the mandrel: VIll and 10 thereby permitting the pocker to be set in sealing engagement with the walls of the rathole before the ports 80 move into the rimout chamber 86.

When the valve assembly is in formation testing position, the elements will be in the position illustrated in Fig. 3. Thus, both pistons 50 and 80 will have moved downwardly through their stroke and the apertures `8l will have moved quickly into the packing 86. Subsequently, the apertures 6U will move down out oi the packing 86 into the runout chamber 3B at the lower end of the upper lvalve element .20 oi the valve assembly. Thus a. sample of the formation fluid is permitted to enter the apertures of the perforated section IB and flow up through the pressure recording means and packer into the oentral passage 19 in the turned-down portion Il and the mandrel 111, thence into the Hamont chamber 36, through the apertures and into the central passage B2 of the upper mandrel 4l), through the passage 54 in the coupling 42 and on up into the interior passage 58 oi the .string of manipulating pipe l2.

After the desired sample oi the formation fluid has been obtained and it is desired to release the packer, a simple upward pull on the manipulating string of pipe I2 will raise the mandrels 41| and 10 and the pistons 5U and 80 connected thereto. Due to the upwardly and inwardly tapering piston head 5l), the upper piston will move upwardly rapidly thereby rapidly moving the ports 60 into the packing or packed oil anca 8B of the closure member 32 ci the piston chamber 24. To assure a fast initial upward movement of piston t0, the compression spring U12 has been provided. The upward movement of the lower piston will be much slower than the upward movement of the upper piston E, and the upward movement of the lower piston B0 will be metered by the removable orifice or choke It positioned therein. Thus the ports 8'! will he delayed from moving out or the packing M in the upper portion of the upper sub member 3.0 of the lower piston chamber 2i and, inasmuch as the lower end of the turneddiown portion 48 ci' the mandrel 40 is plused. as indicated at 5B, the lower valve element 22 remains closed and a shut-in or closed in pressure oi the formation may be obtained by the pressure recorder i6. inasmuch as the upward movement of the piston B0 is measured by the rate of ilow of hydraulic fluid through the removable orice or choke 96, any desired time lag may be obtained by utilizing any desired size of choke. Several minutes time lag has been found to be satisfactory in use. however, in order to obtain a shut-in pressure. Thus, the travel of the lower piston B0 is metered by the mcasurai escape of hydraulic oil from the top oi' the piston chamber 26 to the bottom through the orifice 9B and, when the piston 80 reaches the by-pass grooves il, the upward movement of the piston is greatly accelerated. and provides a jarring action to aid in releasing the packer. Preterably, the jarring takes place after the pressure is equalized below and above the packer. and. manifestly, more pull on the manipulating string will result in a greater jarring action. When the ports 82 have moved upwardly out of the packing 8B. the pressure above and below the packer M is equaliaed and further upward movement of the manipulating string of pipe il in combination with the jarring action o the lower valve will 7 unseat the packer I4 and the device may be removed from the well bore.

While the equalizing control valve assembly has been illustrated for the purpose of disclosure in connection with a rat-hole packer, it is manlfest that such assembly may be utilized in connection with a hook-wall packer such as shown in Figs. 4 and 5 of Patent No. 2,073,107, issued March 9, 1937, to M. O. Johnston; that is, the type of packing assembly that is manipulated by J-slot arrangement. Inasmuch as the elements M and 'I4 are splined and intert with the keyways 46 and lli, relative rotation between the mandrels and the bodies of the valve assembly is prevented. Of course, if desired, in using a rat-hole packer as illustrated here, the splines may be omitted. However, it is preferable to have a valve assembly which may be utilized either with a bottom hole packer or a packer which may be s-et at any desired location in a wall bore.

Many changes may be made in the details of the assembly illustrated and, if desired. the pistons may be covered with a suitable sheath, such as rubber and the like and may be of any conventional configuration in whi-ch rapid movement is permissible in one direction and measured movement is obtained in the opposite direction. Moreover, the splines may be advantageously placed in other parts of the tool and the tool may be changed considerably in its details. It should be noted that the mandrels have been described as continuous elements; however, for ease of assembly, the mandrels may be made up of several threaded elements, as illustrated in the drawings.

It seems manifest that this testing tool eliminates many valves of conventional tools, such as the disk valve, main valve seats and springs on the main valves and the conventional shut-in valves. This permits of compactness of construction which is not otherwise permissible in conventional testing tools. Moreover, the operation of the tool insures against fouling of the tool and resultant misleading indications to the operators, erroneous conclusions or loss of the test altogether.

While only one embodiment of the invention is shown and described herein, it is obvious that various changes and uses may be made Without departing from the spirit of the invention or the scope of the annexed claims.

I claim:

1. A valve assembly1r adapted for use with a formation tester and adapted to be secured to a string of pipe for lowering into a well bore comprising, in combination, a first valve including a first piston chamber, a first mandrel having an internal passage closed at its lower end slidably extending into the piston chamber and adapted to be secured to and in uid communication with the interior of the string of pipe, a first piston on the mandrel slidably disposed in the first piston chamber, a closed run-out chamber connected to the piston chamber, a first stufiing box between the run-out chamber and the first piston chamber, the lower portion of the first mandrel being slidably disposed in the stufllng box when the first mandrel is in elevated position, ports on the lower portion of the first mandrel establishing fluid communication of the run-out chamber with the internal passage of the first mandrel, said ports being disposed in the stuffing box when the first mandrel is elevated whereby the first valve is closed when the first mandrel is elevated, and a second valve including a second mandrel provided with an internal passage throughout its length and in uid communication with and extending from the run-out chamber, a second piston chamber, said second mandrel slidably extending into said second piston chamber, a second piston on the second mandrel slidably disposed in the second piston chamber, a second stuing box in the upper end of the second piston chamber, ports in the second mandrel permitting fluid circulation through the second mandrel and said lastmentioned ports, said last-mentioned ports disposed above the second stufng box when the second mandrel is in elevated position whereby the second valve is open when the second mandrel is elevated, hydraulic fluid in each piston chamber, said first and second valves including means operable in each of said piston chambers for providing relatively slow downward movement of said first mandrel and fast downward movement of said second mandrel and relatively fast upward movement of the first mandrel and slow upward movement of the second mandrel whereby downward movement of the rst and second mandrels moves the ports of the second mandrel into the second stuffing box before moving the ports of the first mandrel out of the first stuiiing box thereby closing the second valve before opening the first valve, and whereby upward movement of the mandrels moves the ports of the first mandrel into the first stuffing box before moving the ports of the second mandrel out of the second stufling box thereby closing the first valve for a predetermined time interval before opening the second valve.

2. An equalizing and control valve assembly adapted for use with a formation tester for testing oil wells and the vlike and adapted to be secured to a string of pipe for lowering into an oil well comprising, in combination, a first valve including a first piston chamber, a first mandrel having an internal passage closed at its lower end slidably extending into the piston chamber and adapted to be secured to and in fluid communication with the interior of the string of pipe, a first piston on the mandrel slidably disposed in the first piston chamber, a closed runout chamber connected to the piston chamber, a first stuffing box between the run-out chamber and the first piston chamber, the lower portion of the first mandrel being slidably disposed in the stufling box when the rst mandrel is in elevated position, ports on the lower portion of the first mandrel establishing fluid communication of the run-out chamber with the internal passage of the first mandrel, said ports being disposed in the stuffing box when the first mandrel is elevated whereby the first valve is closed when the first mandrel is elevated, and a second valve including a second mandrel having an internal passage throughout its length and in fluid communication with and extending from the runout chamber, a second piston chamber, said second mandrel slidably extending into said second piston chamber, a second piston secured to and slidably disposed in the second piston chamber, a second stuffing box in the upper end of the second piston chamber, ports in the second mandrel permitting circulation of fluid through the second mandrel and the last-mentioned ports, said last-mentioned ports disposed above the second stuffing box when the second mandrel is in elevated position whereby the second valve is open when the second mandrel is elevated, hydraulic fluid in each piston chamber, and means mounted on the rst and second mandrels and operable in the rst and second piston chambers for providing relatively slow downward movement of said rst mandrel and fast downward movement of said second mandrel and relatively fast upward movement of the first mandrel and slow upward movement of the second mandrel whereby downward movement of the rst and second mandrelsmoves the ports in the second mandrel into the second stufllng box before moving the ports of the first mandrel out of the first stufiing box thereby closing the second valve before opening the first valve, and whereby upward movement of the mandrels moves the ports in the first mandrel into the rst stuffing box before moving the ports of the second mandrel out of the second stufling box thereby closing the first valve for a predetermined time interval before opening the second valve.

3. An equalizing and control valve assembly adapted for use with a formation tester for testing oil Wells and the like and adapted to be secured to a string of pipe for lowering into an oil well comprising, in combination, an upper valve including an upper piston chamber, an upper mandrel having an internal passage closed at its lower end slidably extending into the upper piston chamber and adapted to be secured to and in fluid communication with the interior of the string of pipe, an upper piston on the mandrel slidably disposed in the upper piston chamber, a closed run-out chamber, an upper stun-lng box connecting the closed run-out chamber to the lower portion of the upper piston chamber, the lower portion of the upper mandrel being slidably disposed in the upper stufling box when the upper mandrel is in elevated position, ports on the lower portion of the upper mandrel establishing fluid communication of the run-out chamber with the passage in the upper mandrel, said ports being disposed in the upper stuffing box when the upper mandrel is elevated whereby the upper valve is closed when the upper mandrel is elevated, and a lower valve including a lower mandrel provided with a passage throughout its length and in fluid communication with and extending from the run-out chamber, a lower piston chamber, said lower mandrel slidably extending into said lower piston chamber, a lower piston secured to the mandrel and slidably disposed in the lower piston chamber, a lower stuffing box in the upper end of the lower piston chamber, ports in the lower mandrel permitting circulation of fluid through the lower mandrel and the last-mentioned ports, said last-mentioned ports disposed above the lower stuing box when the lower mandrel is in elevated position whereby the lower valve is open when the lower mandrel is in elevated position, hydraulic fluid in each piston chamber, choke means in each piston for permitting hydraulic fluid to pass therethrough, and by-pass means associated with each of said pistons and piston chambers whereby hydraulic fluid bypasses the lower piston when moving downwardly thereby providing faster downward movement of said lower mandrel than that of said upper mandrel and hydraulic fluid bypasses the upper piston when moving upwardly thereby providing more rapid upward movement of the upper mandrel than that of said lower mandrel whereby said lower valve closes before said upper valve opens on downward movement of said mandrels and said upper valve closes for a predetermined time interval before said lower valve opens on upward movement of said mandrels.

4. The equaliz'lng and control valve assembly of claim 3 where the by-pass means comprises a valve in each piston, the valve in the upper piston adapted to be closed on downward movement and open on. upward movement of said upper piston, and. the valve in the lower piston adapted to open on downward movement and. close on upward movement of said lower piston.

5. The equalizing and control valve assembly of claim 3 where the 'oy-pass means comprises upwardly-tapering sides on the upper piston and downwardly-tapering sides on the lower piston, each said piston formed of resilient material whereby downward movement of said first piston and upward movement ol' said second piston expands said pistons and thereby provides relatively slow downward and upward movement, respectively, and upward movement of the upper piston and downward movement of the lower piston compresses said pistons thereby permitting relatively fast upward movement of said upper piston and downward movement of said lower piston.

6. The equalizing and control valve assembly of claim 3 including additional bypass means disposed proximate the upper end of the lower piston chamber adapted to permit rapid passage of hydraulic fluid about the lower piston whereby said lower piston moves upwardly at a relatively slow rate until reaching said second by-pass means where it is rapidly accelerated thereby imparting a jarring action to the lower piston chamber.

7. rI'he equalizing and control valve assembly of claim 3 including spring means at the lower end of the upper `piston chamber to resiliently urge the upper piston upwardly.

8. The equalizing and control valve assembly of claim 3 including means to prevent relative rotation between each of said mandrels and said piston chambers.

9. A valve assembly adapted for use with a formation tester and adapted to be secured to a stringr of pipe for lowering into a well bore comprising, in combination, an upper control valve, said control valve including a first piston chamber, a rst mandrel provided with an internal passage closed at its lower end extending downwardly into the upper end of and suspending the piston chamber and adapted to be secured to and in fluid communication with the interior of the string of pipe, a first piston on the mandrel slidably disposed in the first piston chamber, a `closed run-out chamber, a first stuiiing box connecting the run-out chamber to the lower end of the rst piston chamber, the lower portion of the first mandrel being slidably disposed in the stuiiing box when the rst mandrel is in elevated position, ports on the lower portion of the first mandrel establishing fluid communication of the run-out chamber with the passage in the first mandrel, said ports disposed in the stufling box when the rst mandrel is elevated whereby the control valve normally is closed when lowering or raising the valve assembly, and a lower equalizing valve including a second mandrel provided with an internal passage in fluid communication with the interior of and extending from the lower portion of the run-out chamber, a second piston chamber, said second mandrel slidably extending through and suspending said second piston charnber, a second piston secured to and slidable in the second piston chamber, a second stuffing box in the upper end of the second piston chamber, and ports in the second mandrel above the second stumng box when the second mandrel is in elevated position but adapted to move into the stufing box when the second mandrel is in lowered position whereby the equalizing valve normally is open thereby permitting circulation of fluid through the second mandrel and said last-mentioned ports when lowering or raising the valve assembly into or from the Well bore, hydraulic iluid in each piston chamber, and means mounted on the first and second mandrels operable in each piston chamber whereby hydraulic fluid Hows past the lower piston faster than the upper piston on the downstroke o! the mandrels and ows by the upper piston faster than the lower piston on the upstroke of the mandrels thereby closing the circulating valve before opening the control valve on downward movement of said mandrels and closing the control valve for a predetermined time interval before opening the circulating valve on upward movement o! said mandrels.

10. The valve assembly of claim 9 including bypass means disposed proximate the upper end of the second piston chamber for bypassing hydraulic uid about said second piston whereby said second piston moves upwardly at a relatively slow rate until reaching said bypass means where it is accelerated rapidly thereby imparting a jarring action to the second piston chamber.

References Cited in the le o1 this patent UNITED STATES PATENTS Number Name Date 2,073,107 Johnston Mar. 9, 1937 2,189,103 Dripps et al Feb. 6, 1940 2,265,431 Kerr Dec. 9, 1941 2,288,780 Bradner July 7, 1942 2,499,695 Storm Mar. 7, 1950 2,567,321 Courter Sept. 11, 19-51

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