US2231425A - Oil well testing device - Google Patents

Description

Feb. 1941- M. 1.- JOHNSTON OIL WELL TESTING DEVICE Filed July 14; 1939 InvenrorzMax L. Johnsfon mean Feb. 11, 1941 4 UNITED STATES PAIENT OFFICE on. WELL TESTING DEVICE ltlax L. Johnston, Qrange, Tex., assignor to Shell Development Company, San Francisco, Calif., a corporation of Delaware A lication my 14, 1,939, Serjal No.;- 284,499

4 oiai sfi ioi. 16 6 1 Thisinvention relates to improvements well testing devices and especially to those well testing devices commonly known as formation testers;

Although many formation testers have been developed for commercial use, these have several common disadvantages. The most important is that in the event of the wells becoming lively when tested, circulation of drilling mud to-kill ing or sticking of the tool or drill string in. the

borehole while taking the sample. Further, in

115 soft formations a leak frequently develops atfthe seat of the packer which spoils the test.

Therefore, it is an object of this inventiontov provide an improved formation tester comprising a device containing a valve mechanism to, define 20 a chamber for storing a formation sample and to permit circulation of mud fluid without dis-,

carding the sample.

It is another object of this invention to provide.

,a formation tester with an auxiliary inflatable 25 packer capable of utilizing well pressures to, prevent leaks between the tester and the walls of .the hole.

Other objects or this-invention will be apparent from the following description taken in reference 30 to the drawing, wherein:

Figure 1 is a vertical cross section view of the lower portion, wherein the right hand side of the center line in the drawing shows the control L center line shows the valves in position for cir culating drilling mud while the left hand side of the drawing shows the compound valve mechanism in position for testing. p

The present device may be applied to either a rotative or a stationary testingtool and is also applicable whether the tester valve mechanism or control valve is operated by vertical or rotary movement. However, the device is preferably applied to a rotative formation test having 1 a controlvalve operated hy vertical movement, as there is less possibility of a rotating tester becoming jammed in the borehole.v

Briefly, a preferred form of the present in- 'vention, as applied to and including a formation tester of the above-preferred type, consists of a choke and telescopic valve-operating mechanism and drilling mud discharge ports. The

upper portion of the device comprises-a co'mpound valve mechanism by which the axial pas-f sagewithin the device and tubing may be opened to allow fluid flow upward or. closed to trap a. formation sample below the mechanism and by which circulating passages in the wall of the device may be opened to allow egress of mud fluid to kill the well, preventsticking of the drill string V ii'nthe borehole, or for any other purpose. l the' well necessitates discarding the test sarnple' In some cases it would be very desirable to circulate drilling fluid in the hole to prevent freez- The construction of an apparatus forming a preferred. embodiment of the present invention will be readily understood from the following deing a packing element 5 and a clamp 6, fitted to the exterior of the hollow cylindrical body I. The clamp contains drilling mud discharge ports I in its lower portion, and holds in place an outer casing or tubing 8, which with the hollow cylindrical body I forms 'an annular space for passage of drilling mud to the discharge ports 1. The

bore through the body I is enlarged above the -bottom internal thread to permit of the installation of the control valve assembly, which consists of a valve seat 9 threaded into the body I,

a valvedll, a spring I l acting to hold the valve i0 in'contact with the valve seat 9 and provided with a retainer collar 12 and a lock pin l3. This control valve assemblydefines the lower end of the sample-trapping chamber.

Into the bottom female thread- 3 is threaded the rotating thrust member [4, which consists of a cylindrical member having an axial bore and a flange 15 on itslower end.

The rotative member I4 fits within a stationary member consisting of a hollow cylindrical housing it, with an external thread ll at; its upper end and at the lower end a seat or shoulder l8 having an axial opening. Into the internal thread IQ of thisopening, is threaded the hollow adaptor nipple 20. To the upper end of stationary member I6 is threaded the retaining collarZi, this latter also being threaded at its upper end to take'the gland nut 22.

Within the housing and seated against the bottom internal shoulder I8, is a ball thrust race 23 with a heavy spring 24 between the ball race and flange ii of the thrust member I. Retention of the lubricating medium and exclusion of a well fluid from the interior of the stationary housing is maintained by packings 25 and 26.

Threaded into the upper end of the adaptor 6 nipple 20 is the hollow guide mandrel 21, which is fitted at its upper end with a combination choke and valve thrust member consisting of nipple 28 and choke member 29 holding between the flanges thereon stop collar.3|| and packing 26.

10 At the outer end of choke member 29 is fitted the rotating thrust head 3| and thrust ball bearing 32.

Into the lower end of adaptor nipple 20 is threaded the packing elements consisting of the 15 central hollow mandrel 33, having both an internal thread 34 and an external thread 35 at its lower end. Onto the outer end thread 35 is screw locking collar 36, which retains in place the washers 31, 38, 39, and 40, rigid packing 20 rings 4| and a hollow-expansible auxiliary packer 43, provided with a dividing diaphragm 42, said auxiliary packer being made of rubber, canvas, or similar resilient material and having its lower end attached to lock collar 35 by a cap washer 25 M and screws 45, or by other suitable means.

Openings l6 and 41 to the top and bottom of the I 80 of the lower portion may be screwed the usual perforated closed end nipple 68. A bottom hole pressure recording bomb, temperature recorder,

or any other desired instrument may likewise be attached to the formation tester at this or any 35 other point below the packer in a manner understood by those familiar with the art.

, Refen'ing to Figure 2 of the drawing, the upper portion containing the upper half of the trapping formation tester comprises a hollow tubular body 40 48, which is attached to the hollow cylindrical body by means of tool joint pin 49 and tool joint box 50 joined directly together or joined by means of drill pipe or other suitable connecting tubes, depending on the amount of sample 45 desired.

Approximately midway of the bore of tubular body ll is-a restriction having a valve seat 52 on the lower side. A threaded valve seat member 53 is screwed in at some distance below valve 60 seat 52, andhas within it a valve 53, valve spring 55, and locking collar 5.8.

Above this valve assembly, is a hollow piston 51, 7

is preferable that the relative strengths of coilsprings be such that spring 83 is stronger than 65 spring 55, which in turn is stronger than spring 60. Y

Surrounding the tubular body 43 is the continuation of the outer casing 8, which extends above the ports 34 in said tubular body II and is 10 attached thereto by means of a threaded coupling .35 and threaded connections I and II on the casing 3 and tubular body ll, respectively.

In operation. the assembled tester is attached to the drill or tubing string by tool joint box 83 76 and is lowered into the well, until the expansible In the wall of the tubular body 48, are

rubber packer assembly enters the rat hole and the solid packer 4| comes to rest on the rat hole seat.

On placing further weight upon the drill stem, the rotative telescopic section IB moves down- 5 wards, compressing spring 24. The valve retaining collar l2 of the control valve assembly is forced into contact with the ball bearing thrust head 3|, which arrests the downward motion of valve l0. Continued downward motion forces 10 the valve seat 9 away from the valve 10, thus opening the lower end of the tool to the well pressure below the packer.

On the well starting to flow, the fluid passes up through the tubes 33 and 21, the choke 29, valve seat 3, and around valve l0, and mounts in the drill stem until it encounters valve 54 of the compound valve mechanism. The pressure of the fluid forces this oil its seat 53, passes through the hollow piston 51 and encounters the second valve 59, which, in turn, is forced open, allowing the fluid to enter the drill stem above the compound .valve mechanism.

, On relieving the weight on the drill stem, the above-described operations are reversed. The telescopic section I4 is moved upwards, aided by the heavy spring 24; the valve assembly (elements 9 to 13) is withdrawn from the thrust head 3|, and the valve In is permitted to close under the force of its spring thus trapp n the bottom hole sample within the drill pipe between the lower and the upper valve assemblies, the valves in the latter being automatically closed by their spring as soon as the control valve is shut.

Should it be found desirable to rotate the apparatus during the taking of themsample, this may be done whether the tool is in the open or closed position. In the open position (right half cross section) the thrust between the stationary 40 and rotative elements is taken up by thrust ball bearings 23 and 32, but in the closed position (left half cross section), the thrust is taken up only by thrust ball bearings 23,- locking co1lar|2 not being in contact with thrust head 3|, thus relieving the bearing 32 of all thrust. In either case the drill ortubingstring, together with parts I- I5, 23, 24, 3|, 32, 48-61 and 89 connected thereto isallowed to rotate, while the packer ll, together with parts |B22, 25-30, 3H0, 42-41 and .8 50' connected thereto, remains stationary.

Should the well become lively, or for any other reason it be found desirable to circulate mud fluid, this can be accomplished before, after, or during a test. On forcing mud fluid down the drill stem, it continues downward until it encounters the piston 51 and valve 59 in the tubular body 48. Should the valve 53 be open, the mud fluid pressure forces it shut, thus trapping the bottom hole sample, should there be fluid be-. on tween the upper and lower valve assemblies.

A further increase in pressure, sufllclent to overcome the resistance of spring 63 plus any pressure below the piston 51, forces this latter downward along with valve 53 and seat 53, thus 6,: uncovering ports 64 and permitting the pe of fluid from within thefdrill stem through the annular space or conduit between the outer casing 8 and bodies 48 and and outthrough the discharge ports I to the'well and thence to the surface. 4

Normally, the auxiliary expansible packer 43 is inoperative when the solid packing element ll makes a tight connection on the rat hole seat. Should, however, this seat leak, then the well fluid, passing upward from below the auxiliary packer, in atempting to pass out around the solid packer seat, enters within the lower section through the openings 41 and forces it to expand outward, thus making a tight connection with the walls of the rat hole. Likewise, a tight connection is maintained if the pressure diflerential is positive in the downward direction. For instance, when the mud pressure in the hole is higher than the formation pressure, fluid passing by the solid packer seat enters the openings 46 of the upper section of the expausible packer and forces it outward to make a seal.

Although the above description of our preferred embodiment shows the device of the present invention as co-operating with a rotative formation having a control valve operated by vertical movement, it is to be understood that this device may be employed with other types of formation testers, such as the stationary type having rotary-operated control valves, without departing from the spirit of the present invention.

I claim as my invention:

1. In a formation tester, a tubular string, a tubular stem member fitted for rotational and telescoping motion with regard to the lower end of the string, a packer rigidly mounted around said member, said member opening to the borehole below the packer, a choke member rigidly attached to the stem member within the upper end thereof, a normally closed valve structure rigidly attached to the string within the lower end thereof, spring controlled meansactuated by the pressure of said choke member for opening said valve when the string is telescoped with regard to the stem member, an annular conduit around the'tubular string, ports near the lower end of said conduit opening to the borehole above the packer, ports opening from said conduit to 40 the inside of the string above said first ports, a

piston mounted for a limited axial motion within the string masking said upper ports, a valved passage in said piston, and means for opening said upper ports and closing said valved passage by applying fluid pressure to said piston.

2. In a formation tester, a tubular string, a tubular stem member fitted for rotational and telescoping motion with regard to the lower end said valve structure .with regard to said choke member when the string is telescoped with regard to the stem member, an annular conduit around the tubular string, ports near the lower end of said conduit opening to the borehole above the packer, ports opening from said conduit to the inside of the string above said first ports, a piston mounted for a limited axial motion within the string masking said upper ports, a valved passage in said piston, and means for opening said upper ports and closing said valved passage by applying'fiuid pressure to said piston.

3. The device of claim 1,, having anti-friction means between the packer member and the lower end of the tubular string fitted for rotational motion with regard to said member.

4. The device of claim 1, having an auxiliary packermounted on the tubular member supporting the main packer, said auxiliary packer comprising a flexible annular envelope having periorations opening to the borehole space below the main packer.

MAX L. Jonns'roN.

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