US2872230A

US2872230A - Borehole apparatus

Info

Publication number: US2872230A
Application number: US451487A
Authority: US
Inventors: Desbrandes Robert
Original assignee: Schlumberger Well Surveying Corp
Current assignee: Schlumberger Well Surveying Corp
Priority date: 1954-08-23
Filing date: 1954-08-23
Publication date: 1959-02-03
Anticipated expiration: 1976-02-03

Description

Feb. 3, 1959 R. DESBRANDES BOREHOLE APPARATUS Filed Aug. 23, 1954 INVENTOR.

ROBERT oEsaRANoEs HIS ATTORNEY BUREHLE APPARATUS Robert Deshrandes, Houston, Tex., assigner, by mestre assignments, to Schlumberger Weil Surveying Corporation, Houston, Tex., a corporation of Texas Application August 23, 1954, Serial No. 451,487

Claims. (Cl. 283-6) This invention relates to borehole apparatus and, more particularly, pertains to a new and improved packer which may be hydraulically inflated so as to provide a seal in a well bore.

One type of hydraulically inflatable packer heretofore employed includes an arrangement of helicoidally-disposed reinforcing strands having a predetermined lead which is a function of the ratio of deflated to inflated diameters. While this construction may operate satisfactorily insofar as prcdetermining the expansion of the packer is concerned, the distance between the ends of the packer element must necessarily change as the packer expands. Accordingly, the apparatus which carries the packer into the borehole is undesirably complex because of the mechanism for accommodating such a change Vin the longitudinal dimension of the packer element.

it is therefore an object of the present invention to provide a new and improved hydraulically inflatable packer which is not subject to the foregoing deficiency of prior art arrangements.

Another object of the present invention is to provide a new and improved hydraulically inflatable packer wherein the longitudinal distance between the ends of the packer element remains substantially unchanged as the packer is operated between deflated and inflated conditions.

Yet another object of the present invention is to provide a new and improved hydraulically inflatable packer which is relatively simple and inexpensive to construct, and yet is entirely ellicient and reliable in operation.

A hydraulically inflatable packer constructed in accordance with the present invention comprises a flexible inner tube and a pressure-actuated layer extending circumferentially and longitudinally relative to the inner bore of the tube. The pressure-actuated layer includes a first portion including helicoidally-disposed strands having an angle of pitch larger than 35 16' and a second portion including heliccidally disposed strands having an angle of pitch smaller than 35 16. The packer may also comprise a flexible outer tube encircling the pressure-actuated layer and having the same length or a lesser or greater length. The tubes may be constructed of rubber and the entire assembly may be vulcanized so that the pressure-actuated layer is embedded in an aggregate of rubber.

inasmuch as the first portion of the pressure actuated layer includes strands whose angle of pitch is larger than 35 l5', this portion of the packer expands when pressure is applied to the flexible inner tube. Of course, as the first portion of the pressure-actuated layer expands, its longitudinal dimension decreases. However, since the second portion of the pressure-actuated layer includes helicoidally-disposed strands whose angle of pitch is smaller than 35 lo", this portion increases in its longitudinal dimension and contracts radially in part when pressure is applied to the flexible inner tube. Accordingly, the overall'longitudinal dimension of the pressure-actuated layer remains substantially unchanged as the packer is operated between its deflated and inflated conditions.

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 advantages thereof, may best be understood by reference to the following description taken in connection with the accompanying drawing in which:

Fig. l is a View in side elevation of a borehole tool including a hydraulically inflatable packer embodying the present invention represented in deflated condition, portions of the tool being shown cut away and in section so as to reveal interior details thereof; and

Fig. 2 is a side elevational View of the packer illustrated in Fig. 1 shown in inflated position within a well bore.

In Fig. 1 of the drawing, the well tool which includes a hydraulically inflatable packer constructed in accordance with the present invention is shown to comprise a housing 9 adapted to be lowered into a well o-r a borehole. A hollow mandrel or tube It@ is secured to the lower end of housing 9 from which it extends in essentially coaxial relation therewith. A packer element 1l is clamped at its upper end between a collar or flange l2 of tube itl and an annular clamping member i3 which is threaded to the lower end of housing 9. Clamping member 13 is arranged in a known manner to provide a suitable clamping force whereby a pressure seal is obtained between packer element 11 and flange 12, and another clamping element 14 similarly provides a pressure seal between the lower end of packer element 11 and a flange ILS at the lower end of tube 10.

The lower end of tube i0 is provided with a closure or seal i6 and a plurality of openings i7 are distributed about a central portion of the tube. The upper end of tube itl is iluidly connected to a pump it which may be of any conventional type or of the particular variety illustrated in Patent No. 2,441,894 which issued to Maurice Mennecier on lviay i8, 1948. An electric motor (not shown) may be provided for actuating pump 18 and the motor may be selectively energized from the earths surface in a known manner. A fluid connection 19 extends between pump i8 and the exterior surface of housing 9.

The hydraulically inflatable packer element il embodying the present invention may be formed of an inner tube Ztl constructed of a flexible material which can expand and contract radially as well as vary in its longitudinal dimension. For example, a resilient material, such as rubber, may be suitably employed. A pressure-actuated layer comprised of a plurality of fabric or metallic strands coextends with and encloses inner tube Ztl. Layer 2l includes a first portion 22 having helicoidally-disposed strands wound with an angle of pitch or lead angle larger than 35 16. In other words, the angle of the plies or strands in portion 22, relative to the generatrix of the cylinder bearing the helix, is no greater than 54 44. Layer 2l also includes a seco-nd portion 23 and a third portion 24, each cornprised of helicoidally-disposed strands having an angle of pitch or lead angle smaller than 35 16. That is, the angle of the strands in

portions

23 and 24 is larger than 54 44' relative to the generatrix of the cylinder defined by the helix.

Preferably, layer 2l is comprised of a plurality of continuous strands wound so that the angle between the strands and the generatrix of the cylinder bearing the helix changes progressively from approximately .12 at reference vplane 25 passing horizontally through the centerof portion 2.2 a oroximatelv te 54 44 at the Patented Feb. 3, i959 Y 3 upper end of layer portion 22.. Thereafter, the angle with the generatrix changes progressively from 54 44 approximately to 70 at the upper end of portion 23. The angle of the strands below plane Z5 relative to the generatrix changes progressively in the manner just described from 12 to 54 44 in portion 22, and from the latter value to 79 in portion 24.

Another pressure-actuated layer 26 encloses layer 2l and is constructed of a plurality of strands having the same angle of pitch considerations ascribed to

portions

22, 23 and 24 of layer 21. However, the strands in layer 26 are wound in a direction opposite to the winding direction of layer 21. A flexible outer tube 27 encloses and is coextensive with pressure-actuated layer 26. Tube 27 is constructed of a tiexible material and may be fabricated of the same rubber material employed for tube 20 and the entire assembly may be vulcanized to form a rubber aggregate. Preferably, element ll is provided with

rubber terminations

23 and 2? at its ends wherein it is clamped.

In operation, the tool illustrated in Fig. l is lowered in a conventional manner into a borehole 3i?, shown in Fig'. 2, lined with a casing 3l and iilled with a drilling fluid 32, such as a water base mud. After the tool is positioned at a desired level at which a seal is to be provided, pump ltd is actuated and drilling fluid 32, in troduced via tube if), is pumped into hollow mandrel l0. Thus, fluid pressure is applied through openings i7 to the interior of the hydraulically inflated packer element lli and the pressure-actuated

layers

21 and 26 act in the following manner.

Since the strands in layer portion 22 have an angle of pitch larger than 35 16', the diameter of the section of element il including such strands increases while the longitudinal length of this section decreases. However, since the angle of pitch of strands in

layer portions

23 and 24 is smaller than 35 16', the diameters of the central portions of these sections of element lll decrease with an attendant increase in longitudinal length. Accordingly, although the section of packer element l1 which includes portion 22 expands into sealing engagement with the inner wall of casing 31;, the overall longitudinal length of packer element il remains substantially unchanged.

lf it is desired to remove packer element 1l from engagement with casing 3l, pump 18 is de-energized so that fluid pressure between the inner and outer surfaces of element 11 is equalized. By reason of the resiliency of inner and outer tubes 2t? and 27, the packer element thus is returned to the deated condition illustrated in Fig. l and the tool may be removed from the borehole in the customary manner.

inasmuch as packer element 1l exhibits essentially no change in longitudinal dimension when operated between its deflated and inflated conditions, it is evident that a borehole tool including the packer embodying the present invention requires no mechanical provisions to accommodate for such changes. Accordingly, the tool is relatively simple and inexpensive to construct and is not subject to the complexity of prior devices. it operates reliably and efliciently in selectively establishing a seal on the sidewall of the borehole or casing, as desired.

A packer element, such as the one just described, may be constructed by disposing a first layer of raw rubber on a removable steel core. A plurality of strands are suitably aixed in the vicinity of one end of the tube and each strand is passed through an individual hole in a ring-shaped winding wheel. Accordingly, the strands are evenly distributed about the circumference and the wheel is rotated about the core as the core is displaced longitudinally. By arranging the speeds of the core and the wheel in a known manner, the desired lead angles for the strands, described hereinbefore, are obtained. A similar larger wheel is provided for winding Yet, e

the outer layer of strands. In applying each of the layers, it may be desirable to apply a strip of outer rubber after a selected small length is completed and the lead angle changed, so that, instead of a continuous change in lead angle, the angle changes in steps. Finally, an outer layer of rubber tubing is applied and the entire packer element is vulcanized in a known manner.

Obviously, by suitably arranging the lead angles and lengths or" compensating

sections

23 and 24 of packer element l, changes in the longitudinal dimension of the packer element may be minimized to as great a degree as required.

An alternative packer construction employs an arrangement similar to the one described in Fig. l, however, instead of including the portions of element 11 shown below plane 25, a suitably flexible sealing element of rubber may be provided to close the packer element il, and the packer element and Vtube it? are terminated above this sealing element. Obviously, this type of construction features the same advantages ascribed to the embodiment illustrated in Figs. 1 and 2 wherein the longitudinal length of the packer remains substantially unchanged as it is operated between its deflated and inated conditions.

Although the packer embodying the present invention has been shown for use in sealing a well bore, it may be suitably modified and connected to a sampling tube in the manner illustrated in the aforementioned Mennecier patent so that the tool may be utilized for obtaining a sample of formation fluid. Alternatively, the packer element may be modified to carry electrodes into engagement with the sidewall of the borehole for electrical logging as illustrated in Patent No. 2,669,689 which issued to Henri-Georges Doll on February 16, 1954.

While a particular embodiment of the present inven tion has been shown and described, it is apparent that changes and modifications may be made Without departing 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:

l. A hydraulically inflatable packer comprising: a

J tiexible tube and means coacting with said tube and extending circurnferentially and longitudinally relative to the inner bore of said tube, said means including a plurality of helicoidally disposed, substantially non-extensible strands each including a first portion having an angle of pitch larger than 35 l6 and a second portion having an angle of pitch smaller than 35l6', the strands in each of said first and second portions being longitudinally aligned.

2. A hydraulically inilatable packer comprising: a

' liexible tube, a pressure-actuated layer extending circumferentially and longitudinally relative to the inner bore of said tube and embedded in said tube, said layer including continuously wound strands wherein a first portion of said strands are helicoidally disposed at an angie of pitch larger than 35 16, and a second portion of said strands are helicoidally disposed at an angle of pitch smaller than 35 16.

3. A hydraulically inilatable packer comprising: a flexible tube, a pressuroactuated layer extending circumferentially and longitudinally relative to the inner bore of said tube embedded in said tube, said layer including continuously wound strands wherein a rst portion of said strands are helicoidally disposed at an angle of pitch larger than 3516, and wherein second and third portions of said strands are disposed adjacent the respective ends of said first portion, said second and third portions being helicoidally disposed at an angle of pitch smaller than 35l6.

4. A hydraulically inllatable packer comprising: a iexible tube, a pressure-actuated layer extending circumf'erentially and longitudinally relative to the inner bore of said tube and embedded in said tube, said layer including continuously wound strands wherein a first portion of said strands are helicoidally disposed at an angle of pitch larger than 35l6', and a second portion of said strands are helicoidally disposed at an angle of pitch smaller than 3516'; another pressure-actuated layer enclosing said first-mentioned pressure-actuated layer and embedded in said tube, said other layer including first and second portions substantially coextensive with and similar to said first and second portions of said iirst mentioned pressure-actuated layer but having helicoidally disposed strands wound in a direction opposite to the direction in which the strands of said first-mentioned pressure-actuated layer are wound.

5. A hydraulically inflatable packer comprising: a eXible tube; a pressure-actuated layer extending circumferentially and longitudinally relative to the inner References Cited in the file of this patent UNITED STATES PATENTS 1,190,790 Moser July l1, 1916 2,441,894 Mennecier May 18, 1948 2,611,437 Lynes Sept. 23, 1952 2,630,864 Lynes Mar. 10, 1953 2,643,722 Lynes June 30, 1953