US2903070A

US2903070A - Apparatus for investigating earth formations

Info

Publication number: US2903070A
Application number: US536190A
Authority: US
Inventors: Blanchard Andre
Original assignee: Schlumberger Well Surveying Corp
Current assignee: Schlumberger Well Surveying Corp
Priority date: 1955-09-23
Filing date: 1955-09-23
Publication date: 1959-09-08
Anticipated expiration: 1976-09-08

Description

4 Sheets-Sheet 1 A. BLANCHARD APPARATUS FOR INVESTIGATING- EARTH FORMATIONS Sept. 8, 1959 Filed Sept. 23, 1955 l ylwmlmmll INVENTOR. ANDRE BLANCHARD. BY M4K/.r Aww HIS ATTORNEYA Sept. 8, 1959 A. BLANCHARD l APPARATUS FOR INVESTIGATING EARTH FORMATIONS 4 Sheets-Sheet 2 Filed Sept. 25, 1955 INVENTOR.

BY @2M M. A

Y Anc/fie 5/0/7 c/Mr/" *N kN NN ATTORNEY Sept. 8, 1959 A. BLANCHARD APPARATUS FOR INVESTIGATTNG EARTH FORMATIONS 4 Sheets-Sheet 5 Filed' sept. 25, 1955 FIG.3

INVENTOR.

l ANDRE BLANCHARD.

www4# HIS ATTORNEY.

Sept. 8, 1959 A. BLANCHARD 2,903,070

APPARATUS FOR TNVESTTGATTNG EARTH FORMATIONS Filed sept. 23, 1955 l 4 vsheets-shew 4 FIC-3.4

INVENTOR.

ANDRE BLANCHARD.

BY y

HIS ATTORNEY.

United States 2,963,670 Patented Sept. 8, 1959 hee APPARATUS Fon INvEsrioATlNG EARTH ronMArIoNs Andre Blanchard, Houston, Tex., assigner, 'by mesue assignments, to Schlumberger Well Surveying Corporation, Houston, Tex., a corporation of Texas Application September 23, 1955, Serial No. 536,190 Claims. (Cl. `16h- 100) This invention relates to apparatus for investigating earth formations, and more particularly, pertains to a new and improved projectile for use in an earthy formation iiuid sampler.

One type of `tluid sampler proposed heretofore come prises a hollow projectile disposed within a gun block adapted to be lowered through a borehole to a position adjacent a formationof interest. At the desired level, a propellant contained by the gun block is detonated thereby to fire the projectile into the formation. The projectile is connected to a reservoir by la flexible tube and has a normally closed front aperture which is opened so that formation fluid may pass through the projectile and the iiexible tube into the reservoir where lit is retained by means of a check valve. The apparatus may `then be raised to the surface where the sample can be recovered from the reservoir.

Experience has shown that when a solid object penetrates a formation, its lithology changes; usually the result is in the nature of a compaction of the formation. For example, if an object is forced into a sand body which does not change in volume, the voids in the sand body are decreased by the volume of the object. Such va decrease ordinarily takes `place in the innnediate vicinity of the object.

As these voids are decreased, `the `sand grains are pushed yinto one another in such a manner ,that they `are crushed into an extremely fne material, and the penne ability of the sand immediately adjacent to thensurface of the object approaches Zero. Thus it may be difficult, if not impossible, to obtain ,a sample of fluid from `many formations.

It is an object ,of the present invention, therefore, to provide a new and yimproved projectile for an earth formation iiuid sampler which overcomes the undesirable effects of compaction of formation material into which the projectile i's driven.

Another object ofthe present inventionis to provide a new and improved projectile for an earth formation lluid sampler for obtaining samples of formation iiuids with greater reliability than heretofore possible. In accordance with the present invention, a projectile for an earthformation fluid sampler comprises a hollow body adapted to be impelled toward a selected earth formation and having ajfrangible wallportion. An explosive material is lpositioned within ythe hollowbody chamber and means are provided for detonating the explosive material to rupture the frangible wall portion andto penetrate formation material. Thus, a `iiuid communication path `is established between the selected earth formation ,and a tube which may be l'uidly connected tothe hollow body. Y

The novel features of the present invention are set forth with particularity in the appended claims. The present invention, both as to its organization and manner of operation, together with further objects and advantage'sthereof, may best be understgod by` referenceV to the following description taken in connection with the accompanying drawings in which:

Fig. 1 is a view in longitudinal cross section of an earth 'formation iluid sampler incorporating a projectile embodying the present invention, the liuid sampler being represented schematically and in one condition of operation;

Pigs. lA-lF are cross-sectional views of the apparatus illustrated in Fig. 1 taken along lines lA-lF, respectively, and drawn to au enlarged scale;

Fig'. 2 is a view similar to the one shown in Fig. 1, but drawn to a smaller scale and illustrating the fluid sampler in another condition of operation;

Figs. 3 and l4 represent a modification which may be made to the apparatus of Figs. 1` and 2 according to auother embodiment of the invention; and

'Fig 3A is an enlarged view in longitudinal cross section of a portion of the projectile shown in Figs. 3 and 4.

In Fig. 1 of the drawings there is illustrated diagrammatically a portion of a sampler unit =10 including a gun blockhll and a sample-receiving chamber 12. Sampler unit 1t) (excluding the projectile of the present invention) may be constructed in the manner described in the copending application of R. Q. Fields, filed September 23, 1955, bearing the Serial No. 536,204 and assigned to the same assignee as the present invention. Although but a single unit is illustrated, any desired number of units may be employed, and the entire assembly is suspended in a borehole 13 by a cable (not shown) in the customary manner.

Borehole 13 ytraverses earth `formations such as the ones designated 14, 15, and 16 and may be filled with a drilling liuid 9. It is assumed that formation `15 is the selected one from which a uid sample is to be taken and the sampler vunit 10 is positioned in the borehole with its gun block 11 opposite this formation.

Disposed within a cylindrical, transverse bore 17 of gun block 11 is a cylindrical, hollow projectile 18 embodying the present invention. The projectile 18 includesa Irear Vend portion 19 slightly smallerthan bore 17 and an O ring 20 seated in an annular groove 2-1 provides a fluid seal )between end portion 19 aud the wall of bore 17. A tapered sectionZZ extends between rear `portion 19 and a forward portion 23 of a smaller di'- ameter terminated by a conical formation-penetrating nose 24. This type of construction is disclosed in the copenfding application of Maurice Mennecier, filed Septe'mber 23, 1955, bearing the Serial No. 536,251 and assigned to the same assignee as'the present invention. The wall of nose 24 is strong enough to resist the impact of the projectile on the formation, but is frangible at a central section 24 in response to the explosive force produced by the detonation of an explosive charge 25 disposed in a forward chamber 26. The required physical characteristics for projectile 18 may be provided by theuse of anappropriate material, such as steel, selected in a known manner. The forward end of chamber 26 is connected by a frusto-conical transition section 26 to a smaller cylindrical depression 26" that terminates within wall section 24.

The charge Z5 is comprised of ahollow cylindrical container 27 lled with an explosive material 28, such as cyclonite. The forward end of the explosive material is hollow and is fitted with a suitable conically shaped Iliner 29. Thus, charge 25 will be recognized as a conventional form of shaped explosive charge which upon detonation produces a perforating jet extending forwardly along a jet axis aligned along the principal longitudinal axis for the projectile 1S, denotedjby broken line 3u. Cylindrical container 27 has a diameter smaller than the diameter of chamber 26 to provide a void or cushion lspaceforv the expansion of gases resulting from the detonation of charge 25.

lf desired, the rear end of explosive material 28 may comprise a lead azide booster adjacent a disk-like flange 31 that effectively closes the rear end of retainer 27. Flange 31 is an integral part of another retainer having a cylindrical body portion 32 somewhat smaller than retainer 27. Body portion 32 extends along axis 30 from the first-mentioned chamber 26 into a second chamber 33.

Flange 31 and the body portion 32 have an axial opening 34 lled with a delay explosive 35, such as black powder, as may also be seen in Fig. lA. Cylindrical body portion 32 of the retainer has a diameter smaller than the diameters of

chambers

26 or 33 to provide an expansion space for gases resulting from the detonation of explosive 35. The interior of body portion 32 communicates with the expansion space via a plurality of openings 32a. The rearmost end of the delay explosive is in contact with a primer cap 36 received by an enlarged section 37 of the body portion 32, also shown in Fig. 1B. Section 37 has a diameter essentially equal to the diameter of chamber 33 and is provided with a plurality of uid passages 38 extending parallel to axis 3).

Extending through chamber 33 in close fitting relation with the wall thereof is a metal sleeve 39 having its foremost end engaging section 37 and a rear end portion threaded to the Wall of chamber 33. Disposed at equally spaced intervals about its inner periphery are a plurality of ridges 4t) which are parallel to axis 30. These ridges form a guide (Fig. 1C) for a tiring pin 41 having a forward projection 42 aligned with primer cap 36, and the space between the ridges provides a bypass around pin 41. As best seen in Fig. 1C, openings 40 through the solid rear section of element 39 are aligned with the spaces between the ridges 40. The firing pin 41 has a lateral opening 43 which receives one end of a shear pin 44 that extends laterally into an opening 4S in sleeve 39. Thus, the tiring pin is normally held in a quiescent position as shown; however, in response to a force at least equal to a predetermined inertia force developed by the deceleration of projectile 18 as it enters the selected earth formation, shear pin 44 issheared and the ring pin moves to an active position in engagement with primer cap 36, as will be more apparent from the discussion to follow.

At the rearmost end of chamber 33 there is positioned a fluid lter 46 comprised of three disk-like screens 47 (Fig. 1F) separated by spacers 48 having appropriate fluid passages. These passages are in the form of inner and outer groups 48a and 48h of openings terminating in respective

annular grooves

48C and 48d in a face of the spacer, as may be best seen in Fig. 1E. A closure 49 fluidly seals the rear end of projectile 18 and has an axial opening t) for receiving one end of a ilexible tube 51 to which it is mechanically connected in an appropriate manner. For example, the tube may be silver soldered to the wall of opening 50, with a mass of bonding material 52 being provided on the tube. Thus, the tube is uidly sealed to the wall of opening 50, while a strong mechanical connection for forward movement with closure 49 is afforded. Tube 51 is in fluid communication with chamber 33 and is wound into a plurality of helical turns disposed at the rear end of gun bore 17. The remaining extremity of tube 51 is iluidly connected to a conduit 53 that extends to sample-receiving chamber 12.

A propellant such as an explosive material 54 is disposed at the rear end of gun bore 17 and within the convolutions of tube 51. An electrical igniter 55 extends through a transverse opening 56 in gun block 11 into bore 17 where it is in contact with explosive 54.

To condition the fluid sampler for operation, chamber 12 may be evacuated or filled with a uid at a pressure lower than the pressure of formation fluids. For example, chamber 12 may contain air at atmospheric pressure before it is installed and the apparatus is lowered into borehole 13. When gun block 11 is opposite formation 15, an appropriate electrical circuit is completed between a Source of electrical energy (not shown) and igniter 55 thereby to detonate explosive 54 and projectile 18 is impelled out of gun bore 17 into the formation. As pointed out earlier, formation-penetrating nose 24 is strong enough to withstand the impact as projectile 18 passes into formation 15. Of course, tube 51 uncoils and thus extends from the gun bore 17 as shown in Fig. 2. When projectile 18 strikes the formation, the resulting inertia force on firing pin 41 breaks shear pin 44 and permits the firing pin to move forward and strike primer cap 36 thereby to ignite delay explosive 35. The length and composition of the delay explosive are chosen so that there is sufficient time for projectile 1S to come to rest in the formation before explosive 2S is detonated. Thus, after the projectile is imbedded in formation 15, the perforating jet from shaped charge 25 ruptures the frangible wall portion 24 of nose 24 and the perforating jet penetrates into the formation as illustrated by the cone shaped opening 57 in Fig. 2. The differential pressure between the column of drilling mud 9 and the formation fluid helps to hold the projectile in place during this portion of an operating cycle.

lt is apparent that a fluid communication path is completed between formation 15 and chamber 33 via openings 26, 26' and chamber 26. Accordingly, formation iluid may How through

chambers

26 and 33, filter 46, tube 51, conduit 53 and into sample-receiving chamber 12.

Even though compaction may occur in formation material immediately adjacent the forward end of projectile 18, the perforating jet produces the opening 57 in the formation which extends through the compacted zone and iluid may ow readily. Thus, by using a projectile embodying the present invention, samples of formation fluid may be consistently and reliably taken.

After chamber 12 is lled, unit 10 is drawn upwardly to close a valve (not shown) in the fluid path to the chamber 12 and to break tube 51. Thereafter, the unit may be raised to the surface of the earth where the sample is removed.

In the modication illustrated in Fig. 3, elements which correspond to like elements in Fig. 1 are identified by the same reference numerals. As shown in Fig. 3, an elongated cylindrical projectile 18 is received with the cylindrical, transverse bore 17 of the gun block 11. Instead of a shaped charge explosive as shown in Figs. 1 and 2, an explosive charge 60 of generally cylindrical coniiguration is disposed in a forward chamber 26a (Fig. 3A) of projectile 18. An annular wall portion 61 of the projectile in the vicinity of explosive charge 60 and nose 62 are constructed of a frangible material. Disposed rearwardly of the explosive charge 60 are a delay explosive 35, a tiring pin 41 in the rrward chamber 33, a lter unit 46 and a lluidly connected iiexible tube 51.

The delay explosive 35 is received by a cylindrical container 27 disposed in the forward chamber 26a and has at its rear end a disc-like flange 31 that effectively closes off the rearward end of retainer 27. Flange 31' is an integra-l part of another retainer having a cylindrical body portion 32' somewhat smaller than retainer 27. Body portion 32 extends along the central axis of the projectile from the first-mentioned chamber 26a into the rearward chamber 33.

Flange 31 and body portion 32 have an axial opening 34 which contains a portion of the delay explosive 35. Cylindrical body portion 32 has a plurality of openings 32h therein and is smaller than the diameters of

chambers

26a or 33 to provide an expansion space for gases resulting from the detonation of explosive 35'. The rearmost end of the delay explosive is in contact with a primer cap 36 received in an enlarged section 37 of the body portion 32'. Section 37 has a diameter equal to the diameter of chamber 33 and is provided with a plurality of {iuidpassages 3s' extendingp'arallei to the central axis of l the' projectile.

Extending through chamber 33 inv close' fitting relation with' the" wall thereof is a tubular rneta'l sleeve 39 having its foremost end engaging section 37 and a rear portion threaded to the wall ofch'arnbe'r 33. Sl'idably disposed in sleeve 39' is a cylindrical firing pin 4I' havinga forward projection 42 aligned with primer cap 36. Pin 41 has" axial' openings 4i extending therethrough to permit llluid flow through the pin, and a transverse opening 45 which receives a shear pin 44 that. extends laterally into an opening 45 in sleeve 39. Thus, the firing pin is normally heldin a quiescent position as shown; however, in response' to a force at' least equal to a predetermined ifieitia force developed by the deceleration of projectile 18 as it enters the selected eartlr formation, shear pin dfi ssheared and the firing pin movesto anA active position in' engagement with the primer cap 36'.

Aty thev rear-most end of chamber 33 there is positioned a uid filter do composed of a cylindrical body 46 threaded to the sleeve 39 and having lateral openings in communication with a central opening 50'. A screen Sti of suitable mesh surrounds the body 46 to filter fluid flow therethrough. `Onel end of a flexible tube 51 is receivedin opening Sti and is mechanically connected in a suitable manner'. In operation, as may be evident in Fig. 4, when the explosive 60 is detonated after the projeotile 18 comes to rest in the selected formation, explosive forces rupture portions 61' and 62 and the entire corneal foreward end of the projectile is blown out. The explosive force also produces an opening 63 in the formation material of generally spherical, although irregular configuration. While the type of explosion produced by the cylindrical charge may tend to compact the formation in the immediate vicinity of projectile 18', it also produces cracks which effectively increase the formation permeability. Accordingly, a fluid communication path is establis-hed between the formation and the tube Si through the projectile i8v in essentially the same manner described inconnection with the embodiment of Figs. 1 and 2.

While particular embodiments of the present invention have been shown and described, it is apparent that changes and modifications may be made without departing7 from this invention in its broader aspects, and therefore, the aim in the appended claims is to cover all such changes and modifications as fall within the true spirit and scope of this invention.

I claim:

1. In an earth formation Jfluid sampler having a fluidconveying tube, a projectile comprising: a hollow body having an opening therein adapted to be liuidly connected to the fluid-conveying tube, said body being adapted to be impelled toward a selected earth formation, and having a formation-penetrating frangible wall portion; an explosive material positioned within said hollow body; and means in said body operative subsequent to penetration of said wall portion in a formation for detonating said explosive material to rupture said frangible wall portion thereby to permit fluid flow between the selected earth formation and the fluid-conveying tube.

2. In an earth formation fluid sampler, a projectile comprising: a body adapted to be impelled toward a selected earth formation and including a formation-penetrating end portion having a frangible wall, said body having a first chamber disposed adjacent said frangib'le wall, and a second, samplereceiving chamber fluidly communicable with said first chamber; a shaped explosive charge positioned in said first chamber and having a forward end from which a perforating jet emanates upon detonation of said charge, said forward end facing said frangible wall; and means in said body `operative subsequent to penetration of said body in a formation for detonating said explosive charge to rupture said frangible wall portion thereby to permit fluid flow between thc selected earth formation and said second chamber.

3. In an earth formation uuid. sampler, a projectile comprising: a body adapted to be impelled toward a selected earth formation and including a formation-pene trating forward end having a frarigible wall and a rearward end having an opening therein arranged to be mechanically connected to a sample-conveying tube, said body having a chamber extending along a principal axis intersecting said forward and said rearward ends and including a first section adjacent said frangible wall portion and a second, sample-receivihg' section uidly communicable with the sample-conveying tube; a shaped explosive charge having -a forward end from which a per# forating jet emanates along a jet axis upon detonatiori of said charge, said shaped explosive charge being positioned in said first chamber with said jet axis sub'- stantially aligned with said principal axis and with said forward end facing said frangible wall; means in said body operative subsequent to penetration of said body in a formation for detonating' said explosive charge to rupture said frangible wall thereby to permit fluid flow between the selected earth formation and said second section of said chamber. y Y

4. In an earth formation fluid sampler, a projectile comprising: a body adapted to be impelled toward a selected earth formation arid including a hollow front section defining an essentially cylindrical first chamber having an annular frangible wall portion, and a* hollow rear section defining `a second, sample-receiving charn-` ber fluidly communicable with said `first chamber and having an opening therein arranged to be coupled to a sampleeconveyingl tube; an explosive material positioned in said first chamber to apply radially directed' rupturing forces to said frangible wall portion when detonated thereby to permit fluid ow between the selectedr earth formation and said second' chamber; and means in said body operative subsequent to penetration of said body in the formationvfo'r detonatingsaid explosive material'.

5. In an earth formationfiuid sampler, a projectile comprising: a body adapted yto 'be impelled toward a selected earth formation and having a' forward extremity adapted to initially penetrate an earth formation, said forward extremity including a formation-penetrating frangible wall portion, said body further having a first chamber disposed adjacent said frangible wall portion and a second, sample-receiving chamber in a rearward portion of said body flui'dly communicable with said first chamber; an explosive material positioned in said first chamber adjacent to said frangible wall portion; and means in said body operative subsequent to penetration of said `body in a formation for detonating said explosive material to rupture said frangible wall portion thereby to permit huid flow between the selected earth formation and said second chamber.

6. In an earth formation fluid sampler, a projectile comprising: a body adapted to be impelled toward a selected earth formation and having a forward extremity adapted to initially penetrate an earth formation, said forward extremity including a formation-penetrating frangible wall portion, said body further having a first chamber disposed adjacent said frangible wall portion, and a second sample-receiving chamber in a rearward portion of said body fluidly communicable with said first chamber; an explosive material positioned in said first chamber adjacent to said frangible wall portion; and inertiaresponsive means in said body operative subsequent to the penetration of said body in a formation for detonating said explosive material to rupture said frangible wall portion thereby to permit fluid flow between the selected earth formation and said second chamber.

7. In an earth formation fluid sampler, a projectile comprising: a lbody adapted to be impelled toward a selected earth formation and having a forward extremity adapted to initially penetrate an earth formation, said forward extremity including a formation-penetrating '7 frangible wall portion, said body further having a rst chamber disposed adjacent said frangible wall portion and a second sample-receiving chamber in a rearward portion of said body uidly communicable with said first chamber; an explosive material positioned in said first chamber adjacent to said frangible wall portion; and a detonating system in said body operative subsequent to penetration of said body in a formation for detonating said explosive material torrupture said frangible wall portion thereby to permit fluid flow between the selected earth formation and said second chamber, said detonating system including a delay explosive adjacent said explosive material, a primer cap adjacent said delay explosive and la tiring pin movable from a quiescent position to an active position in engagement with said primer cap in response to a force at least equal to a predetermined decelerative force developed upon entry of said body into the selected earth formation.

8. In an earth formation fluid sampler, a projectile comprising: a body adapted to be imbedded in a selected earth formation and having a forward extremity adapted to initially penetrate an earth formation, said forward extremity including a frangible wall portion, said body further having a rst chamber disposed adjacent said frangible Wall portion and a second sample-receiving chamber in a rearward portion of said body uidly communicable with said rst chamber adjacent to said frangible wall portion; an explosive material positioned in said first chamber for generating an explosive force greater than required to rupture said frangible wall portion; and means in said body operative subsequent to the imbedding of said body in the selected earth formation for detonating said explosive material to rupture said frangible wall portion and to penetrate the formation thereby to permit fluid flow between the formation and said second chamber.

9. In an earth formation uid sampler, a projectile comprising: a body adapted to be impelled toward a selected earth formation and having a forward extermity adapted to initially penetrate an earth formation, said forward extremity including a wall portion strong enough to resist forces developed by entry of said body into the formation, but frangible in response to a given force, said body further having a rst chamber disposed adjacent said wall portion and a second sample-receiving chamber in a rearward portion of said body fluidly communicable with said chamber adjacent to said frangible wall portion; an explosive material positioned in said rst chamber for developing an explosive force greater than said given force; and means in said body for detonating said explosive material to rupture said frangible wall portion thereby to permit fluid ow between the selected earth formation and said second chamber.

10. In an earth formation fluid sampler, a projectile comprising: a hollow, generally cylindrical body including a closed formation-penetrating forward extremity adapted to initially penetrate an earth formation, said body being adapted to be impelled toward a selected earth formation, and said body having a frangible wall in at least a portion thereof including said formationpenetrating end and an annular zone contiguous to said end, said body further having a rst chamber disposed at least in part adjacent said frangible wall, and having a second sample-receiving chamber in a rearward portion of said body iluidly communicable with said first chamber; an explosive material positioned in said rst chamber adjacent to said frangible wall portion; and means in said body operative subsequent to penetration of said body in the formation for detonating said explosive material to rupture said frangible wall portion thereby to permit fluid flow between the selected earth formation and said second chamber.

References Cited in the file of this patent UNITED STATES PATENTS 2,286,673 Douglas June 16, 1942 2,408,419 Foster Oct. 1, 1946 2,545,306 Pollard Mar. 13, 1951 2,582,719 Ramsey Jan. 15, 1952 2,679,380 Sweetman May 25, 1954

Claims

1. IN AN EARTH FORMATION FLUID SAMPLER HAVING A FLUIDCONVEYING TUBE, A PROJECTILE COMPRISING: A HOLLOW BODY HAVING AN OPENING THEREIN ADAPTED TO BE FLUIDLY CONNECTED TO THE FLUID-CONVEYING TUBE, SAID BODY BEING ADAPTED TO BE IMPELLED TOWARD A SELECTED EARTH FORMATION, AND HAVING A FORMATION-PENETRATING FRANGIBLE WALL PORTION; AN EXPLOSIVE MATERIAL POSITIONED WITHIN SAID HOLLOW BODY; AND MEANS IN SAID BODY OPERATIVE SUBSEQUENT TO PENETRATION OF SAID WALL PORTION IN A FORMATION FOR DETONATING SAID EXPLOSIVE MATERIAL TO RUPTURE SAID FRANGIBLE WALL PORTION THEREBY TO PERMIT FLUID FLOW BETWEEN THE SELECTED EARTH FORMATION AND THE FLUID-CONVEYING TUBE.