US2675080A

US2675080A - Oil well formation tester

Info

Publication number: US2675080A
Application number: US132284A
Authority: US
Inventors: Philip S Williams
Original assignee: Standard Oil Development Co
Current assignee: Standard Oil Development Co
Priority date: 1949-12-10
Filing date: 1949-12-10
Publication date: 1954-04-13
Anticipated expiration: 1971-04-13

Description

April 3, 1954 P. s. WILLIAMS 2,675,080

OIL WELL FORMATION TESTER Filed Dec. 10, 1949 3 Sheets-Sheet l i0) i5 Z9 58 -55 F I c, i 56 51 pblllllp slJ zuiams Gnvenbor bg ZMW7W Clbnorneg April 3, 1954 P. s. WILLIAMS OIL WELL FORMATION TESTER 3 Sheets-Sheet 2 Filed D80. 10, 1949 .r an m m m r v w. n b M s gs m MM 7 MW 5 mM H O A RI. M w 5 WW 5 m M {W w s m b P April 1954 P. s. WlLLlAMS OIL WELL FORMATION TESTER 3 Sheets-Sheet 3 Filed Dec. 10, 1949 l1. a I 4....

Zr/I4 G VIA I H 5 Philip CJZZZL'amS Savexzbor CLtLornegS Patented Apr. 13,1954

OIL WELL FORMATION TESTER Philip S. Williams, Tulsa, Okla., assignor to Standard Oil Develop n ration ofDe'l-aware ent Company, a corpo- Application December 10, 1949, Serial No.;1 32,284

6 Claims.

1 The present invention relates to an improved apparatus for testing oil Wells during the course of drillin to determine whether oil bearing strata have been encountered. More particularly the invention relates to an improved apparatus which may be attached to ordinary drill pipe wherein an inflatable pa ker is employed to seal off a portion ,of the well and wherein novel means are provided for inflating and deflating the packer.

In conventional oil well ,drilling operations fluids known as drilling muds are employed to aid in carrying away cuttings and also to maintain a hydrostatic head in the well to prevent the uncontrolled escape .of gases prliquids from various formations encountered during drilling. One disadvantage of drilling with a drilling mud is that the sampling of natural ,ifiuids occurrin in various formations is thereby rendered difficult. To overcome this disadvantage various types of formation testers have been devised which are provided with means for reducing the hydrostatic pressure in the vicinity of the formation to be tested in order that a sample .of the natural fluids can beta-ken.

Many of these formation testers are provided with inflatable elastic sleeves or packers for sealing off the portion of the Well in which itis desired to reduce the hydrostatic pressure. The use of such elastic packers :is particularly desirable since they can be expanded to give a thonough seal and yet may be readilyvremoved from the well after being deflated. Furthermore it is possible to position the elastic packers at any desired point in the well with very little difficulty.

In formation testing using an inflatable elastic packer run on drill pipe or tubing some means must be providedfor inflating the packer. The conventional means for doing this involves pumping drilling mud or otherfluid such as plain water down the pipe, so that with aqsuitablearrangement of valves the necessary:infiation pres sure can be applied to the inside of the packer. The valve system is so designed .as .to hold the pressure in the packer until released, 'say by a trip valve actuated by (for example) a go-devil dropped into the pipe from the surface. After the packer is set the desirable procedure is to reduce the pressure in the pipe until formation fluids can flow through it to the surface. An alternate to this, namely utilization of a previously evacuated sample chamber, may not remove infiltrated drillin fluid and hence may fail to obtain a true sample of the formation fluids, The above-,mentionedlpressure reduction,

if (more reduction is necessary than can be attained merely by using plain water rather than drilling mud in the pipe, can be obtained only by laboriously swabbing down the fluid level in thei ipe to the d sired extent.

One Obj ct of the present invention is to provide means for formation testin in which inflatable packers are used but in which swabbing operations are not necessary. It is a further ob- ,ieot to provide a formation testing device utilizmean inflatable packer which is inflated by rot l n th drill pipe r ther an by mp drilling mud down through the drill pipe itself,

thus permitting the use of an empty drill pipe to avoid .the aforementioned swabbing operation.

Briefly the invention consists of providing a pump actuatable by rotation of the drill pipe, together with suitable dogs to lock the pump case and packer to the bore hole wall and thus absorb torques which might otherwise damage the packer, and with suitable valves so that the following cycle of operations is possible in the formation testing ,process:

'Ihe drill pipe, with the packer-pump-lockingdogassembly on it, iis loweredinto the well empty, or with any desired Water cushion in it, until the packer is opposite the formation to be tested; p p,

The pipe is rotated a predetermined number of turns, and then stopped. These turns first operate the Fpump sufficiently to fully inflate the packer, and then open a valve connecting the interior of the pipeto the formation, Formation fluids can then flow through the pipe to the surface, if the formation is productive of fluid, and the custom ry bser-vations are made;

After the above test period the pipe is rotated a predetermined number of additional turns to close the valve connecting the interior of the pine 56.0 the formation and then open a valve permitting the packer to deflate. may then be withdrawn frornithe hole.

The nature of the invention and the objects to be accomplished will he more fully understood from the ensuing description and from the accompanying drawing-in which i V Figure 1 is a vertical sectional view of a portion 'of the apparatus in position in a bore hole;

Figure 2 is a lower continuation of Figure i tune which :may ,be substituted for the lower portion pf Elam-e2.

The assembly Referring now to Figures 1 and 2 of the drawing in detail, the apparatus is attached to a section of drill'pipe by means of a sub I which terminates at its lower end in a shaft-like member 2. The bottom of member 2 has attached thereto a bearing 3 on which is rotatably supported a cylindrical case 5. The lower end of case has attached thereto an elongated mandrel 8. The upper end of case 5 is provided with annular grooves containing packing or sealing material I which fits around shaft 2. This portion of case 5 is also provided with an annular space e which communicates with the interior of sub I through conduit 8.

Supported within case 5 is a gear box I2 from which project a plurality of shafts II, I3, I5 and I1. Attached to shaft II is a gear), meshing with gear 4 which is fixed to member 2 below bearing 3. Gear box I2 is provided with a suitable arrangement of gears, cams, cranks, etc., so that when shaft II is rotated by gear Ill, shafts I3 and I5 .will be given a rotary motion and shaft U will be given a reciprocating motion. Shafts I3 and I5 communicatewith rotary valves I4 and 16 respectively. Exact description of the Working parts of gear box I2 is not considered necessary here since the arrangement will be a matter within the skill of a competent designerto impart the proper relation of rotational and reciprocating motions to the various shafts to meet the requirements outlined below.

Placed below gear box I2 is acylinder Is within which is fitted a piston I8 attached to shaft IT. The upper end of cylinder I9 is in open communication with the interior of case 5 and the lower end of cylinder I9 is provided with an inlet valve 20 and an outlet valve 2| so that these valves and the associated piston and cylinder constitute a pump. Valve 2|] communicates with the exterior of case 5 through port 24, while valve 2| communicates with conduit 22 which extends downwardly through mandrel 6. Conduit 22 also is connected to a pressure relief valve 28 communicating with the exterior of case 5. The purpose of valve 28 is to prevent the fluid pressure in conduit 22 and hence in the inflated packer 4| (discussed later) from exceeding the fluid pressure in the borehole by more than a predetermined amount. Conduit 22 is connected to one opening of valve II; by means of conduit 25. The otheropening of valve It leads to the exterior of case 5 through port 29. One opening of valve I4 is connected to annular space 3 by means-of conduit 26 and the other opening of valve I4 is connected to conduit '27 which extends downwardly through case 5 and mandrel 6. The operating sequence of valves i4 and IE5 and of the pump constituting piston I8 'andcylinder I9v will be discussed in detail later in the specification. It should be noted in this connection, however, that a port 23 is provided in the wall of case 5 to equalize pressures inside and outside the casein order that the pump will operate properly.

Attached to mandrel 6. immediately below case 5 is a locking dog assembly which is adapted. to lock the device against rotation in the bore hole. The locking dog assembly consists of a pair of slidable collars 3| which are fitted around mandrel 6 and which are provided with keys 32 which fit into slot members 33 in mandrel 6 so that collars 3| are permitted to slide to a limited extent in the direction of the longitudinal axis of mandrelt but which are prevented from rotating around the mandrel. Thetwo slidable collars 3| are connected by arcshaped heavy springs 36 which are provided in their mid-sections with hardened knife edge members 31 adapted to engage the walls of bore hole 6|. Stops 34 are provided on mandrel 6 in the vicinity of collars 3| so as to prevent the latter from coming into contact with

shoulders

33 and 39 and thus prevent the buckling of springs 3% as the device is lowered into or raised out of the borehole. Although only two springs 35 are shown on the drawing it is preferred that at least three or four be employed.

Also attached to mandrel 6 below the locking dog assembly is an inflatable packer assembly. This consists of an elastic packer 4| which is attached at both its upper and lower ends to mandrel 6 by means of clamping collars 40. The packer is shown in its deflated condition in the drawing. Its appearance in the borehole when in an inflated condition is indicated by dotted lines 4Ia. 'Disposed within packer 4| is a flexible tube 4! attached at one end to conduit 21 and communicating at its other end with pocket 4a which has been formed by indenting the wall of packer 4| slightly. To present a permeable medium through which the formation fluids may readily flow, pocket 48 is preferably filled with pellets 43 or other suitable packing material made of glass, plastic, metal or the like and held in place in the pocket by a covering made of a permeable material such as a closely woven fabric 44 which may be of metal or of heavy cloth made from natural or synthetic fibers. If desired, packing material 43 may also be placed in flexible tube 41 or the latter may otherwise be designed to withstand an external pressure of at least as high as the expected hydrostatic pressure of the fluid in the bore hole. Although only one assembly of flexible conduit 41 and communicating pocket 48 is shown, a plurality of such assemblies will ordinarily be employed. Conduit 22 communicates with the interior of packer 4|.

. An additional conduit 45 is placed within mandrel 6 to communicate with the exterior of the assembly above and below packer 4| in order that the fluid pressure above and below the packer will be equalized when the latter is inflated against the walls of the borehole. Provision for such equalization of pressure minimizes the strain that is put on the packer.

It will be seen that when the apparatus of this invention is placed in a borehole, case 5 and packer 4| will be fixed against rotation in the borehole by virtue of the walls of the hole being engaged by the locking dog assembly. Thus when the drill string is rotated shaft 2 will be rotated and will in turn rotate gears 4 and Ill and thus the assembly of gears and cams within gear box I2. To arrive at a proper design for the mechanism within gear box i2, suppose that it takes revolutions of shaft 2 relative to case 5 to inflate packer 4i. The number of revolutions required will, of course, depend on such factors as the capacity of the pump comprising elements I'I, I8, and IS, the volume increase in the packer during expansion, the ratio of gears 4 and IE], etc. However, on the assumption that 100 turns of shaft 2 and hence of the drill pipe are required to inflate the packer,

gear box l2 should be designed to operate valves I4 and I6 as follows:

(a) Valve I4 to be closed from turn 0 (of the drill pipe) to turn 325; opening from turn 325 to turn -'350;-- open from turn 350 to turn 550;

51 closing from .turnfifill to: turn 575; closed from turn 5'75to turn 775. (b) Valve IE to be open from turn to turn 100; closing from turn 100to turnl25; closed from turn 125 to turn-650; opening from turn 650 to turn 675;open from turn6'75 to turn 775. (0) Above cycle to repeatstarting at turn 775. (d) During this time piston I8 operates continuously.

In view of the above descriptionof the functioning of the device can easily be understood. The tool is lowered into the hole with sub at approximately turn 0 relative to case 5,and thus during lowering the packer is deflated and the interior of sub I is sealed off by valve l4. Sub l and the drill pipe may thus be empty or carry a suitable water load, as desired. The packer is stopped opposite the formation to be tested, and sub l is rotated approximately to turn 450, and stopped. This rotation, in sequence, closes valve l6, gives the pump about twice the minimum number of strokes necessary to inflate the packer (the excess fluid escaping through valve 28) and opens valve I4 which connects the earth formation to the interior of the drill pipe through port 48, conduits 41, 21, 26 and 8 and sub 1.

The tool is left in this condition (valve I6 closed and valve [4 open) for sufficient time for formation fluids to flow through sub I and the drill pipe to the surface (if the formation can produce fluid) and to gauge their flow. The

sub l is then rotated to approximately turn 7'75.

This, in sequence, closes valve M, to keep mud out of the drill pipe and to retain in the latter any fluids already there, and opens valve IS in order to permit the packer to deflate. After allowing a few minutes for this deflation the tool may be withdrawn from the hole. Alternatively, if a test has yielded no fluid, or if relatively little fluid has com-e in, the tool may be run again adjacent another formation without removal from the hole. This may, of course, be done in any case if swabbing is carried out on second or later tests where too much fluid has entered the drill pipe.

Analysis of the above turn counts will indicate that the turn 0, and turn 450, and turn 7'75 (which is zero for the next sequence) stopping points are in the middles of regions 200 turns wide in which the appropriate valve configurations exist. Thus extremely exact turn counts are not essential, and slight rotations Of case or of sub l relative to each other as the tool is moved vertically will do no harm.

Although the embodiment of the invention depicted in Figs. 1 and 2 is adapted for up-hole testing, relatively little modification is needed to adapt it to bottom-hole testing, as shown by Fig. 3 which represents a sectional elevation of a structure substituted for the lower portion of Fig. 2. The lower portion of mandrel 6, here identified as 6a, is modified so that a sampling chamber 50 is provided connecting with conduit 21. Attached to the lower end of mandrel 6a is a production head 52 having perforations 53 communicating with chamber 50 through which the sample to be collected may pass. It is usually desirable to place a layer of gravel or similar material 65 at the bottom of the hole adjacent the formation to be tested, e. g. formation 63, in order to facilitate flow of formation fluids into the sampling chamber, the gravel pack also serving to support the formation tester structure and thus minimize strain on the packer. The sequence of packer inflation and testing with the lbottom-hole sampler is the same as that described above for the up-hole tester.

It is to be understood that the invention is to be limited only by the following claims, and not by the exact description contained in the foregoing specification, which has been presented merely by way of example and not of limitation.

What is claimed is:

1. A well tester for sealing off a portion of an oil well and sampling fluids in the vicinity thereof comprising a supporting member adapted to be attached to the lowerend of a drill pipe, a case rotatably attached to said supporting member, an elongated mandrel appended to said case, a plurality of arcuate spring members slidably attached to said mandrel for limited motion longitudinally thereof, but fixed against rotational movement thereon, a lug carried by each of said springs in a middle portion thereof and adapted for engagement with the Walls of a borehole whereby said case will be prevented from rotating with said supporting member, fluid sampling means supported by said mandrel, an inflatable elastic packer carried by said mandrel, at least two rotary valves disposed within said case, the second of said valves being provided with a fluid exit port communicating with the exterior of said case, a reciprocating pump carried by said case and provided with inlet and outlet valves, a gear assembly, including a driving gear, carried by said case, shafts associated with said gear assembly adapted to turn said rotary valves and to actuate said reciprocating pump, a second gear engaged by said driving gear and adapted to be rotated by the drill pipe through said supporting member, a first conduit connecting the interior of said drill pipe through the first of said rotary valves to said fluid sampling means whereby a fluid sample may be conducted to said drill pipe, a second conduit connecting the outlet valve of said reciprocating pump to the interior of said packer whereby said pump will inflate said packer, and a third conduit connecting said second conduit to the second of said rotary valves whereby fluid may be released from the interior of said packer to deflate the same, said gear assembly being arranged so as to open and close said rotary valves in a predetermined sequence upon rotation of said supporting member a predetermined number of times relative to said case.

2. Well tester according to claim 1 in which said fluid sampling means comprises at least one port in the side wall of said elastic packer and a flexible tube connected to said first conduit means.

3. Well tester according to claim 1 in which said fluid sampling means comprises a perforated head on the lower end of said mandrel and a communicating chamber within said mandrel.

4. A well testing assembly for sealing ofl a portion of an oil :well and sampling fluids in the vicinity thereof comprising a supporting member attachable to the lower end of a drill pipe,

a case rotatably attached to said supporting member, flexible gripping means attached to said case and adapted to engage the walls of a borehole whereby said case will be prevented from rotating with said supporting member, an inflatable elastic packer attached to said case, a pump carried by said case, a first conduit connecting the outlet of said pump to the interior of said packer, whereby said pump may inflate said packer, said conduit having an exit port communicating with the. exterior of saidease, a

firstvalve said exit port, fluid sampling means supported boy-said assembly; a second conduit connecting said sampling means with, th interior of said drill ,pipe,whereby a fluid sample may be conducted to said drill pipe, a second valve in said second conduit, and driving means connected to said supporting member and associated with said pump and saidvalves, said driving means Fbeing adapted to actuate said pump and to open and close said valves in a predetermined sequence upon rotation of said supporting member relative to said case a predetermined number of times, said sequence being such that said secondvalve is initially closed, said first valve is then closed to cause said pump to inflate the packer, said second valve isthenclosed to retain said sample in said drill pipe, and said first. valve is then .opened-t'oxcause escapeiot fluid from within said packer whereby to deflate the'same.

5. Assembly as defined by claim 4 wherein said fluid sampling means ,is positioned in the side wall of said elastic packer. a 6. Assembly as defined by claim 4 wherein said fluid sampling means is positioned on thelower end of said assembly below said packer.

References Cited in the file of this patent UNITED STATES PATENTS Number Name 3 Date 2,218,155 Rusler et al. Oct. 15, 1940 2,441,894 Mennecier'n; May 18, 1948 2,458,631 Parks Jan. 11, 1949 2,511,759 Williams June 13, 1950 2,552,433 Kirby II May 8, 1951