US3441095A - Retrievable through drill pipe formation fluid sampler - Google Patents

Description

A. H. YOUMANS April 29, 1969 3,441,095

` RIIRIEVABLB THROUGH DRILL PIPE FORMATION FLUID SAMPLER Filed Nov. 28, 1967 V c ww g M QQM United States Patent O 3,441,095 RETRIEVABLE THROUGH DRILL PIPE FORMATION FLUID SAMPLER Arthur H. Youmans, Houston, Tex., assignor to Dresser Industries, Inc., Dallas, Tex., a corporation of Delaware Filed Nov. 28, 1967, Ser. No. 686,206 Int. Cl. E21b 43/116, 7/00; E21c I9/00 U.S. Cl. 175-59 9 Claims ABSTRACT OF THE DISCLOSURE Background of the invention This invention relates to the retrieving of formation fluid samples during drilling operations and more particularly, it concerns retrievable fluid samplers of the type adapted to be lowered through a tubular drill string to receive a sample of rock formation fluids at the bottom of a well bore and subsequently withdrawn for an analysis of the fluids collected in the sampler, as well as a method for retrieving such samples.

`Formation fluid samplers of the type to which the present invention relates have been widely used in the well drilling field rfor collecting a test sample of fluids present in subterranean formations penetrated by a drilling bit. Test samples collected in this manner are helpful in providing information |which might lbe used, for example, to determine the ultimate depth to which a well should be drilled for -best production or easiest completion. v It is conventional practice yin well drilling operations, to use a tubular drill string through which drilling mud is circulated downwardly and then upwardly in the annulus between the drill string and the well bore. The circulated drilling mud, therefore, serves to lubricate and cool the drilling bit as well as to carry drilled particles upwardly out of the bore hole. The presence of the drilling mud at the bottom of the bore hole being drilled, however, poses problems in the collection of a formation fluid at the bottom of the hole. Specifically, any formation fluids thatl may be collected by a wire line retrievable sampler in the tubular drill string will more than likely be contaminated by the drilling mud in situations where conventional drill rigs are used. Such contamination of the sample makes it diliicult to analyze the sample after it has been retrieved and brought to the surface.

Summary of the invention In accordance with the present invention, the problems heretofore experienced with contamination of formation samples by drilling mud are substantially overcome by employing a special drill collar having an internal seat to complement the lower end of a uid sampler adapted to be lowered into and withdrawn fromthe tubular drill string by a wire line or cable. The special drill collar also includes an expansible packer near its lower end which is inflated after the sampler is seated and thus expanded against the bore hole under the pressure of drilling mud within the drill string to block a central orifice in the collar. A suitable perforator means is carried in the lower portion of the sampler including means to actuate it from the surface. When actuated, the bottom of the bore hole is penetrated, or fractured, for a signifi- Mice cant distance ahead of the drill bit. Fluids in the undrilled formation immediately beneath the drill bit then are able to move upwardly under formation pressure into the uid sampler. The packer serves to isolate the bottom of the bore hole so that the amount of drilling mud that might enter the sampler is insuflicient to contaminate the sample collected by any significant amount.

Therefore, the objects of the present invention include: the provision of a retrievable formation fluid sampler by which drilling mud contamination of the formation uid is reduced to a minimum; the provision of a fluid sampler arrangement which facilitates the collection of a formation fluid sample originating from the formation preceding the drill bit; the provision of a formation fluid sampler of the type referred to which is simple in construction and adaptable to existing drilling equipment without extensive modification; and the provision of a unique method for retrieving formation fluids from a well bore during drilling operations.

Other objects and Ifurther scope of applicability of the present invention ywill become apparent from the detailed description to follow taken in conjunction with the accompanying drawings.

Brief description of the drawings FIG. l is a vertical cross-section through a Well bore and a drill collar adapted to receive the liuid sampler of this invention;

FIG. 2 is another vertical cross-section through the drill collar shown in FIG. l with the retrievable fluid sampler of this invention in place; and

FIG. 3 is a further vertical cross-section to illustrate the fluid sampler of this invention during the collection of a formation fluid.

Description of the preferred embodiment In FIG. 1 of the drawings, a conventional drill bit 10, having a centrally disposed mud circulation port 12 and a threaded shank 14, is shown mounted on the lower end of a drill collar, generally designated by the reference numeral 16, as it would be arranged in operation on the lower end of a conventional drill string 1S during the drilling of a well bore 20. Also in accordance with conventional drilling practice, drilling mud is circulated downwardly through the drill string 18 and through the drill collar 16 by surface equipment, including a pump 22, and then, upwardly in the annulus between the drill string 18 and the sides of the well bore 20 by appropriate apparatus, including a pump 24. The circulation of drilling mud through the drill string 18, the drill collar 16 and the port 12 in the drill bit 10 is depicted by the arrows a in FIG. 1 of the drawings.

Also, as shown in FIG. 1 of the drawings, the drill collar 16 has an inwardly ared surface at its lower end defining a seat 26 concentric with the port 12. The seat 26 is in tluid communication with the port 12 in the drill bit, and the yfunction of the seat 26 will be described in more detail presently.

The lower end of the drill collar 16 is circumscribed by an expansible packer 28 formed of elastomeric materials conventionally used for this purpose and is secured to the drill collar 16 by clamping bands 30 at its upper and lower ends. The cylindrical wall of the drill collar 16 is provided with an oriiice 32 located between the clamping bands 30 to enable drilling mud under pressure within the collar to act outwardly against the packer 28 and to expand it outwardly against the well bore 20.

It might also be mentioned at this point that the relative size of the smaller orifice 32 and the larger port 12, together with the balance of hydrostatic pressure across the walls of the drill collar 16, operate to prevent expansion of the packer 28 during normal drilling operations, the orifice 32 becoming effective when the port 12 is covered.

The fluid sampler of this invention is illustrated in two stages of operation in FIGS. 2 and 3 of the drawings and is designated generally by the reference numeral 34. The fluid sampler 34 includes an elongated cylindrical receptacle 36 to enclose a sample-receiving chamber 38. The upper end of the receptacle 36 is closed and is formed with a threaded shank 40 to facilitate connection of the fluid sampler 34 to a wire line or cable 42 by a suitable coupling 44.

A shoe 46, at the lower end of the receptacle 36, is shaped to form a downwardly converging curved seating surface 48, complementing the drill collar seat 26. Because of the complementing, or matching, configurations of the Seating surfaces 26 and 48, the interior of the drill collar 16 is isolated from the area of the drill bit 10, when the fluid sampler 34 is in the position shown in FIG. 2. The respective seating surfaces 26 and 48 may be formed, if desired, with a coating or other layer of resilient material to facilitate an even more effective seal. Y

As shown in FIGS. 2 and 3, a counterbore 50 is formed through the lower end of the shoe 46 to form a chamber to receive a bullet 52 and an explosive charge 54 behind the bullet 52. The bullet and charge are retained within the counterbore 50 by a displaceable pressure plug 56. An orifice 58 extends between the counter-bore 50 and the chamber 38 and is normally closed from communication with the chamber 38 by a valve 60.

In the disclosed embodiment, the valve 60V is retained in its closed position Iby a helical seating spring 62 acting between the valve head and a bracket 64 secured on the inside of the receptacle 36. It is contemplated, however, that the valve 60 may be of a type other than that disclosed in the drawings. For example, remotely controlled or time controlled valves may be used in place of the spring biased valve shown, thereby to enable positive control over the open and closed positions of the valve.

Also in the disclosed embodiment, an igniter 66 is connected by wires 67 to the surface, for the purpose of igniting the explosive charge 54. Obviously, however, other forms of remote igniting means may be used, such as a wave form signal from the surface, or a suitable timing circuit.

Further, it should be noted that whereas a bullet together with an associated explosive charge is indicated as the preferred means for producing the sampling bore 70, it is to be understood that a shaped charge of the type used in oil well casing perforating may be employed.

In operation, when it is desired to take a sample of fluid from the formation in advance of the drill bit 10, the fluid sampler 34 is lowered on the cable 42 into the position shown in FIG. 2 of the drawings. Thereafter, the pump 22 or other suitable means is operated to pressurize the drilling mud in the string 18 and drill collar 16. Because the port 12 is closed by the lower end of the shoe 46, the pressurized drilling mud will pass through the orifice 32 and expand the packer 28 against the sides of the well bore 20, las shown in both FIGS. 2 and 3 of the drawings. In this condition the area in the vicinity of the bit 10, is completely isolated or packed off from the remainder of the well bore 20.

After the packer 28 has been expanded against the well bore 20, the explosive charge 54 is fired to project the bullet 52 downwardly through the orifice 12 and into the formation beneath the bit 10. The final position of the bullet 52 is depicted in FIG. 3 yat the lower end of a relatively small sampling bore 70. Fluids in the formation will migrate to the sampling bore 70 and under formation pressure, move upwardly through the now empty counterbore 50, through the orifice 58 against the head of the valve 60. The pressure of the formation fluid will raise the valve 60 causing the fluid to rise upwardly in the chamber 38. After a predetermined time, or when the pressure within the chamber 38 balances the pressure of the formation fluid, the valve 60 will seat to isolate the chamber 38 from the well bore 20. The fluid sampler 34 then is withdrawn to the surface for an analysis of the formation fluid sample.

In addition to obtaining la fluid sample for subsequent analysis, it is often desirable also to determine the ambient fluid pressure in the formation from which the sample is taken. This may be accomplished by measuring the pressure in the chamber 38 after it has been removed from the borehole. Alternatively, it may be desired to observe the pressure during the interval when chamber 38 is filling with the formation fluid. This may be accomplished by means of a pressure transducer 71 inside the chamber 38 and coupled by the necessary electrical conductors to surface indicating and recording means. The electrical conductors, not shown, may comprise conductors in the supporting cable 42, which may be a conventional logging cable. Conductors 67 which provide means for detonating the explosive 54 may similarly be conductors of the cable 42.

Thus, an extremely effective retrievable formation fluid sampler is provided by this invention and by which the above mentioned objectives are completely fulfilled. Also, it is contemplated that various changes and/or modifications can be made in the apparatus shown and described herein. Accordingly, it is expressly intended that the foregoing description is illustrative of a presently preferred embodiment only, not limiting, and that the true spirit and scope of the present invention is to be determined by reference to the appended claims.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. Apparatus for collecting formation fluid samples from a well bore during drilling operations, said apparatus comprising:

a tubular drill collar adapted to be connected at its upper end to a tubular drill string and to support an apertured drill bit at its lower end,

said drill collar being open at its lower end and having an inwardly facing seating surface formed there- 1n,

an expansible packer mounted exteriorly about the lower end of said drill collar,

means to expand said packer outwardly against the wall of the well bore, and

a fluid sampler adapted to be lowered into said drill collar, said sampler comprising:

means defining a fluid receiving chamber having upper and lower ends,

said lower end having an exterior seating surface to engage the inwardly facing seating surface in said collar to plug the lower open end of said collar,

means defining a passageway extending through said lower end of said chamber,

valve means operable to close off said chamber from said passageway,

means to support a perforating means in said lower end of said chamber, and

means to actuate said perforating means, whereby the formation preceding the drill bit may be penetrated to release fluids therein for flow upwardly into said chamber.

2. The apparatus recited in claim 1 wherein said means to expand said packer outwardly includes an orifice in the wall of said collar over said outwardly facing seating surface whereby said packer may be expanded by fluid pressure on the inside of said collar after said sampler plugs the lower end thereof.

3. The apparatus recited in claim 1 wherein said perforating means includes a bullet and a propelling charge within a counterbore extending a predetermined distance from the lower end of said passageway whereby said passageway is initially blocked by the bullet and the charge but opened upon ignition of said charge and projection of said bullet downwardly into the formation preceding the bit.

4. The apparatus recited in claim 1 including means for connecting a retrieving line to the upper end of said chamber defining means.

5. A formation fluid sampler for use with a tubular drill string having a drill collar at its lower end to carry a drill bit having a central aperture establishing a circulation path for drilling mud passed down through the drill string and u-p through the yannulus between the drill string and the well bore being drilled, the drill collar having also an expansible packer mounted exteriorly about its lower end and an orifice communicating with the interior of the packer for expansion thereof by pressurized uid in the drill string, said sampler comprising:

a receptacle means to provide a sample receiving chamber; means on the upper end of said receptacle to connect a retrieving line;

an exterior seating surface on the lower end of said receptacle co-operable with the drill collar and bit to plug the drilling mud circulation path provided therein,

means to define a passageway extending from the lower end of said receptacle to said chamber;

valve means movable between yan open position and a closed position blocking communication of said passageway with :said chamber;

means to support a bullet and a propelling charge in said lower end of said receptacle; and

means to ignite said charge.

6. The apparatus recited in claim 5 in which said passageway includes a restricted portion opening to said chamber at its upper end *and a counterbore between the lower end and said restricted portion.

7. The apparatus recited in claim 6 in which said bullet and charge supporting means comprises an expansive plug in the lower end of said counterbore, the bullet and c'h-arge being located initially in said counterbore.

8. The method of retrieving a formation iluid sample from the bottom of a well bore during drilling operations of the ty-pe in which drilling mud is circulated throughy a tubular drill .string and a drill bit carried on the lower end thereof, said method comprising the steps of lowering a sample collecting receptacle into the tubular drill string and isolating the interior of the drill string from the bit, packing off the annulus between the drill string and the well bore at the lower end of the well bore to isolate the bit from the remainder of the bore,

propelling a perforating means into the formation p-receding the bit to release iluids for collection in said receptacle, iand withdrawing the receptacle and the iluid sample therein from said tubular drill string.

9. The method recited in claim 8 wherein the lower end of the well bore is packed off by pressurizing the interior of the tubular drill string to expand an expansible packer against the well bore.

References Cited UNITED STATES PATENTS 1,560,815 11/1925 Hill 175-4.52 X 2,265,982 12/1941 Bolton 175-4.58 X 2,544,573 3/1951 Vincent 175-4.59 X 2,923,204 2/ 1960 Mohaupt 175-4.58 X 3,115,932 12/1963 Reynolds 175--4.52 3,394,767 7/1968 Terry 175-4.52 3,032,108 5/ 1962 Bielstein 175-4.52

NILE C. BYERS, JR., Primary Examiner.

U.S. C1. XJR.

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