US2308387A - Tester - Google Patents

Description

Jan. 12, 1943. Y E. L; PoTTs TESTER Filed Nov. 21, 1941 INVENTOR ERNEST L. POTTS Patented Jan. 12 1943 TESTER Ernest L. Potts, Duncan, Okla, assignor to Halliburton Oil Well cementing Company, Duncan,

Okla.

Application November 21, 1941, Serial No. 420,009

4 Claims.

This invention relates to oil well equipment, and more particularly to an apparatus to be used in drill stem testing.

In the process of completing oil wells it is common practice to perform what is known as a drill stem test in order for the operator to obtain a sample of the fluid contained in a formation adjacent the bore hole. Apparatus and methods for this purpose are disclosed in the Simmons Patent No. 1,930,987, and the Halliburton Patent Reissue No. 20,688.

It is also common practice to use, in connection with drill stem testers, equalizing and bypass valves of the type disclosed in IianesPatent No. 2,144,842 and Zeigler Patent No. 2,201,281.

It is also common practice to use a pressure recording device in connection with a drill stem tester, in accordance with the patent to Moore No. 2,189,919.

In this art a by-pass valve has come to mean one which allows fluid to by-pass the packer in seating it. For example, if a cone packer is being seated in a rat hole, provision is made for allowing fluid to flow from the rat hole to some point above the packer, so that fluid does not have to be squeezed into the formation to allow the packer to seat properly.

The term equalizing" valve has come to mean one which performs a diflerent function. It allows the packer to be unseated by permitting pressure above and below the packer to equalize, for example, as a packer is being pulled out of a rat hole.

The addition of these various valves, in addition to the regular tester valve, has come to make a drill stem tester quite complicated and moreover still left much to be desired. For example, it has become important in connection with the use of a pressure recording device in accordance with the Moore patent, to determine the closed-in bottom hole pressure of a well during a drill stem test,that is, the natural formation pressure at a time when the well is not flowing but at the same time not subjected to the hydrostatichead of mud or other fluid in the hole. Drill stem testers, as heretofore constructed, have not been designed in such a way as to be practical in making a determination of this closed-in pressure.

Accordingly, it is one object of this invention to provide a simple and compact testing tool with a minimum of parts and yet one which will have incorporated therein means for performing all the necessary functions of testing, by-passing and equalizing.

It is another object, of the present invention to provide means of obtaining the closed-in bottom hole pressure of a Well during a drill stem test and after a sample of the fluid from the formation being tested has been entrapped by the tester valve.

It is another object of the present invention to provide a tester with which the operator may be positive as to when the tester valve is in open or in closed position, when the equalizing valve and the by-pass valve are in open or closed position, and when the tool is in the closed-in position to obtain the closed-in bottom hole pressure.

It is a further object of the present invention to provide a tester which has all the advantages recited and which, in addition, is balanced by 0 hydrostatic pressure of the fluid in the bore hole,

so that it can easily be manipulated.

Figure 3 is a-diagram illustrating the principles of the present invention and showing the parts in the same position as in Figure 2;

Figure 4 is a similar diagram showing the U pasts in the position they occupy when testing; an

Figure 5 is a similar diagram showing the parts with the valve closed, the apparatus now being in position for obtaining the closed-in bottom hole formation pressure.

Referring to the drawing in detail, it will be seen that the bore of an oil well is illustrated at H), the well being provided with a rat hole ll. Seated at the top of the rat hole is a cone packer H for sealing oif the rat hole from the main bore of the well. A perforated pipe or strainer may extend into the rat hole and contain a. pressure recording device i3. s

Directly above the cone packer I2 is located the tester M. This tester and packer assembly ar lowered into the well 10 on the drill pipe IS. The present invention is concerned only with the testing tool i4 and it is shown more in detail in Figure 2, and diagrammatically in Figures 3, 4 and 5.

As shown in Figure 2, a drill pipe I 5 is threaded into the top of a coupling l8, which also serves as a conduit, being provided with a plurality of lluid passages i8. At its lower end the coupling I6 is threaded to a tubular differential cylinder 20 and a sleeve |3 which surrounds it. The cylinder 20 contains a floating piston 2| which is provided with a packing 22, clamped in position by a nut 23.

At its lower end, the sleeve i8 is threaded to another coupling member 28, which carries a packing 21, through which a mandrel 28 is adapted to slide. 1

The packing 21 is held in position by an annular nut 28. The mandrel 28 is hollow for most of its length but closed or solid at the top and is provided with ports 30, so as to cooperate with the coupling 25 and packing 21 to act as a valve depending on whether the ports 30 are above, opposite or below the packing 21.

Surrounding the mandrel is a guide and control sleeve 3| which is provided with a shoulder 32 that acts as an abutment for an enlarged section 33 of a conduit 34, which is threaded to the lower end of the mandrel 28. It is the conduit 34 which carries the packer l2, as shown in Figure 1. Thus, while the packer is seated, the conduit 34 and the mandrel 28 are stationary, and the piston 2| is practically stationary since it rests upon the top of the mandrel. As a matter of fact the piston 2| might be integral with the mandrel except for inconvenience in assembling.

The sleeve 3| is provided with two control slots 35 in which pins 31 ride. The pins are threaded into the enlarged section 33 of the conduit 34. (Only one pin and one slot are shown.) These slots are provided with lug portions 38 which prevent the traveling of the pins 31 in an upwardly or downwardly direction without the sleeve 3| being turned'in a clock-wise direction (from that shown in Figure 2, as viewed from above) a suflicient amount to allow pins to pass into sections 39 of the slots 36.

The coupling member I6 is provided with a fluid passage 40 which admits well fluid to the interior of cylinder 20 above piston 2|, so as to allow hydrostatic pressure of the fluid above the testing tool to balance the piston 2|.

The piston 2| should be equal or greater in diameter than the diameter of the mandrel 28, so that the downward force on the piston, due to the hydrostatic head of well fluid, is equal to or greater than the force on the mandrel 28, caused by about the same head of well fluid, tending to move the mandrel upwardly. Unless this is so, the mandrel may move, and the packer unseat when the sleeve 3| is moved to bring the pins 31 into the portions 39 of the slots 36.

An advantage of the present construction resides in the fact that the cylinder 20 and piston 2| can readily be replaced with a cylinder and piston of a different diameter so that the difierential force which holds the mandrel 28 down and the packer |2 in place in the rat hole can be varied at will.

To make a drill stem test, the apparatus is lowered into the bore hole with the parts in the position illustrated in Figures 1, 2 and 3. The apparatus may either be provided with a cone packer such as shown or other means such as a wall packer suitable for sealing off the formation to be tested from the rest of the bore hole. It a aaoaser cone packer is used, it will be seen that a by-pass is provided, for as the packer seats in the rat hole, fluid may flow i'rom the rat hole up through the conduit 34, mandrel 23, ports 38 and out into the main bore of the well through the slots 38.

The sleeve 3| may be provided with holes other than the slots 36, if desired, or the lower portion and shoulder 32 may be grooved to provide a passageway for fluid, especially it it is desired to enclose the slots 38.

In seating the packer, the weight oi the drill v pipe is transmitted downwardly to the packer through the parts l8, I9, 28 and sleeve 3| to the lugs 38, which are then above the pins 31 and transmit the force to them and hence to the conduit 34 to which the packer is attached.

Upon the packer l2 becoming seated, the operator may then place the tester in an open position such as illustrated in Figure 4, in order to obtain a fluid sample.

To do this, the drill pipe is rotated to the right, as viewed from above, and lowered to allow the pins 31 to disengage the lugs 38 and pass through the portions 38 of the slots 36 until they take the position shown in Figure 4. In assuming this position, the conduit 34 and the mandrel 28 remain stationary, while the drill pipe i5 and the parts I6, |3, 28 and 23 connected to the drill pipe, telescope upon the conduit 34 and mandrel 28. When the tool is in this position, fluid from the fonnation surrounding the rat hole may enter the tool through the perforated tail pipe and pass in an upwardly direction through the conduit 34 and the mandrel 28, out the ports 38 in the mandrel, the ports 38 now being above packing 21, through the annular space between the tubular member 20 and sleeve i9, and then through the fluid passages i8 into the drill stem I5.

After the tester has remained in this position a suflicient amount of time to allow a representative sample to enter the drill pipe, the sample may then be entrapped in the drill pipe by picking up on the drill pipe until the pins 31 abut against the top of the lugs 38. Such a position is illustrated in Figure 5. In this position the ports 38 are opposite the packing 21. Thus, the tester valve is closed so as not to allow any fluid to enter or leave the drill stem, or allow any fluid in the bore hole above the packer to enter the rat hole below the packer. The tool is in this position long enough to allow a maximum formation pressure to build up therein so as to obtain the closed-in bottom hole pressure of the formation by the use or the pressure recording device l3.

After this pressure record has been obtained, the testing equipment may be removed from the well. The packer |2 may be unseated by picking up on the drill pipe and again rotating the same to the right to allow the pins 31 to pass .downwardly through the portions 39 01 the slots 38 and thus resume the position shown in Figures 2 and 3. When again in this position, the fluid pressure below and above the packer are allowed to equalize in that fluid is now allowed to pass in through the slot, through the ports 33, and downward through the mandrel 28 and conduit 34 to the space below the packer i2.

Then by withdrawing the string of drill pipe i5 from the well, a representative sample of the fluid from the formation surrounding the rat hole l2 may be obtained.

Only one embodiment of the present invention has been illustrated and disclosed herein, but it will be obvious to those skilled in the art that various other arrangements may be adapted without departing from the spirit of the invention or the scope of the annexed claims.

I claim:

1. In a testing device for oil wells, a housing assembly adapted to be connected to the lower end of a drill pipe and having packing means therein, means for conducting fluid from a point within said housing assembly above said packing means to the interior of the drill pipe, means for connecting the interior of said housing beneath said packing means to the exterior thereof, a mandrel adapted to telescope within said housing assembly, said mandrel having a port so as to form a sleeve valve with said packing means,

a packer integrally connected to said mandrel, means for conducting liquid from a point beneath the packer to the interior of said mandrel and control means operable by manipulation of the drill pipe ior transmitting some of the weight the drill pipe from said housing to said mandrel when desired and for holding said mandrel in such relative position with said packing means that the port thereof is either below, opposite or above said packing means.

2. In a testing device for oil wells, a housing assembly adapted to be connected to the lower end of a drill pipe and having packing means therein, means for conducting fluid from a point within said housing assembly above said packing means to the interior of the drill pipe, means for connecting the interior of said housing beneath said packing means to the exterior thereof, a mandrel adapted to telescope within said housing assembly, said mandrel having a port so as to form a sleeve valve with said packing means, a packer integrally connected to said mandrel, means for conducting liquid from a point beneath the packer to the interior of said mandrel, diflerential pressure means including a cylinder having means connecting the interior thereof to the exterior of the housing assembly and a piston for exerting downward pressure on said mandrel, for holding said packer seated independently of the weight of the drill pipe.

'3. In a testing device for oil wells, a housing assembly adapted to be connected to the lower end of a drill pipe and having packing means therein, means for conducting fluid from a point within said housing assembly above said packing means to the interior of the drill pipe, means for connecting the interior of said housing beneath said packing means to the exterior thereof, a mandrel adapted to telescope within said housing assembly, said mandrel having a port so as to form a sleeve valve with said packing means, a packer integrally connected to said mandrel, means for conducting liquid from a point beneath the packer to the interior of said mandrel, a

pressure recording device exposed to the fluid pressure prevailing within said mandrel.

4. In a testing device for oil wells, a housing assembly adapted to be connected to the lower end of a drill pipe and having packing means therein, means for conducting fluid from a point within said housing assembly above said packing means to the interior of the drill pipe, means for connecting the interior of said housing beneath said packing means to the exterior thereof, a mandrel adapted to telescope within said housing assembly, said mandrel having a port so as to form a sleeve valve with said packing means, a packer integrally connected to said mandrel, means for conducting liquid from a point beneath the packer to the interior of said mandrel, diflerential pressure means including a cylinder having means connecting the interior thereof to the exterior of the housing assembly and a piston for exerting downward pressure on said mandrel, for holding said packer seated independently of the weight of the drill pipe, a pressure recording device exposed to the fluid pressure prevailing within said mandrel.

ERNEST L. PO'I'IS.

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