Wireline well treating apparatus

July 24, 1962

G. E. BRIGGS, JR

3,045,756

WIRELINE WELL TREATING APPARATUS

Filed Aug. 26. 1958 2 Sheets-Sheet 1

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July 24, 1962 ο (we vef!

G. Ε. BRIGGS, JR .5,1140,/00

WIRELINE WELL TREATING APPARATUS

Filed Aug. 26, 1958 2 Sheets-Sheet 2

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United States Patent Office

3,045,756

Patented July 24, 1962

3,045,756

WIRELINE WELL TREATING APPARATUS George E. Briggs, Jr., Houston, Tex., assignor to Halliburton Company, a corporation of Delaware

Filed Aug. 26, 1958, Ser. No. 757,338

Claims. (CI. 166—162)

This invention relates to well tools and more particularly to well tools that are lowered into and raised from a well by means of a cable. The invention is especially concerned with tools for applying fluids under pressure to a well formation and specifically relates to a wire line squeeze cementing tool.

An object of the invention is to provide a well tool that is lowered into the well on a cable to a predetermined level and there operated to apply fluid, such as cement slurry, under high pressure to the walls of the well, or through casing perforations to the annulus between the casing and the surrounding earth formation.

Another object of the invention is to provide a well tool of the foregoing character wherein the tool is actuaated by the pressure of powder gases generated within the tool to anchor the tool in the well, to pack off a well zone and to eject a mass of cement slurry carried by the tool into the packed-off zone.

Another object is to provide, in such a tool, means whereby the pressure created in the packed-off zone is relieved and the packer and anchor are disengaged from the walls of the well in a reliable manner, in order that the tool may be readily withdrawn from the well after a cementing operation has been performed.

Another object is to provide a well tool having packer means that will securely pack-off a well zone under very high pressure.

The foregoing and other objects and advantages of the invention are realized in a well tool including an elongated hollow carrier or body containing a fluid, means for lowering and raising the carrier in a well, a longitudinally extending packer sleeve surrounding a portion of the exterior of the carrier, one end of the sleeve being sealingly secured to the carrier and the other end of the sleeve providing a skirt or cup laterally expandable into sealing engagement with the wall of the well, a packer expander member slidable into the skirt for expanding the same into such sealing engagement, a fluid motor having a fluid inlet port communicating with the fluid in the carrier and a fluid outlet port communicating with the well fluid surrounding the carrier, means drivingly connecting the fluid motor to the expander member to slide the expander member into the skirt, means for increasing the pressure of the fluid in the carrier to a pressure substantially in excess of the pressure of the Well fluid surrounding the carrier, and valve means operable from the surface of the well for venting the pressure in the carrier to the exterior thereof.

The well tool, described in general terms in the immediately preceding paragraph, will be described with greater particularity and other advantages of the invention will be set forth in or apparent from the following detailed description of an exemplary embodiment of the invention illustrated in the drawings wherein:

FIG. la is a vertical cross-sectional view of the upper part of a well tool positioned in the casing of a well;

FIG. lb is a cross-sectional view of the lower portion of the well tool shown in FIG. la, it being understood that FIG. la and FIG. lb are taken together to show the entire tool;

FIG. 2 is an enlarged vertical elevational view of the hold-down anchor of the well tool of FIGS, la and lb, parts being broken away to show interior construction;

FlG. 3 is an enlarged vertical sectional view of the packer mechanism of the well tool; and

FIG. 4 is an enlarged vertical sectional view of the pressure relief valve structure of the well tool.

Referring to the drawings, particularly to FIGS, la and lb thereof, the well tool shown is suspended in the casing 10 by means of a conductor cable 11 having an insulated electrically conductive wire 12 tfierein. The cable is anchored in a cable head 13 and from the latter depends a firing unit and pressure relief valve assembly 14. A powder chamber housing 15 is secured to the bottom of the assembly 14. A powder chamber orifice sub 16 is fitted to the bottom of the powder chamber unit and this sub, in turn, supports a check valve sub 17. Suspended from the bottom of the check valve sub is a hydraulic hold-down anchor 18 from which depends a packer assembly 19. A fill-port sub 20 is threaded to the bottom of the packer assembly and a cement container 21 is suspended from the fill-port sub. The well tool is thus seen to provide an elongated hollow carrier.

The powder chamber unit 15 has a thick-walled cylindrical housing 22 capable of withstanding not only the external pressures to which it is subjected as the tool is lowered in a well, but also the high internal pressures created when the powder within the chamber is ignited. The upper end of the housing is closed by the lower end of the firing unit and pressure relief valve assembly 14 which is threaded into the upper end of the housing, the joint being sealed by O-rings 23. A plug 24 is threaded into the lower end of the housing 22, the plug being axially bored to receive the powder gas outlet orifice ring 25. The orifice sub 16 has a central bore 26 that is closed by a plug 27 seated against a shoulder formed in the bore. The shoulder prevents the plug 27 from being forced upwardly by external pressure and permits the plug to be blown down and out of the orifice sub when the pressure in the powder chamber substantially exceeds external pressure.

A screen 28 is positioned in the bottom of the powder chamber and a number of propellant grains 29 which may be made of powder, separated by perforated metal spacer rings 30, are stacked on the screen. Each grain 29 may have a sleeve 31 of metal on its vertical cylindrical surface to inhibit burning at this surface and to confine burning to the ends of the powder grains.

The propellant grains 29 are ignited by an igniter unit 32 having a charge 33 of black powder that is initiated by an electric squib 34. The squib is fired by current conducted from the surface of the well to the squib through the conductor wire 12, insulated circuit elements (not shown) in the cable head 13, and insulated conductor 34α in the firing unit and pressure relief valve assembly 14. The firing circuit is returned to the surface through ground.

The check valve 35 in the sub 17 opens inwardly of the tool. Thus, as the tool is lowered in a well and the pressure of the fluid surrounding the tool increases, the valve will open to admit well fluid into the interior of the tool below the plug 27 to equalize pressures inside and outside of the tool. However, as will be seen as the description proceeds, the check valve closes when the pressure inside the tool exceeds ambient well pressure, thus preventing loss of fluid pressure from the tool through the check valve.

Details of the hydraulic hold-down anchor 18 arc shown to advantage in FIG. 2. The anchor has a vertically elongated, hollow, cylindrical body 36. Three vertical rows of pistons 37 are evenly spaced circumferentially of the body. The pistons slide in radially recessed cylinders 38 that communicate through openings 39 with the hollow bore of the housing. The outer faces 40 of the pistons are knurled or roughened to grip securely the inner walls of the casing. Each piston has a pair of diametrically opposed slots 41 into which the retaining

3,045,768 fingers 42 extend, the fingers being mounted on the body 36 by means of screws 43. Compression springs 44 act between the fingers 42 and the inner ends of the slots 41 to urge the pistons inwardly of their cylinders. Shoulders 45 at the inner ends of the cylinders limit inward movement of the pistons.

The packer assembly 19 appears in enlarged vertical sectional view in FIG. 3. It has an adapter 46 that is threaded to the bottom of the anchor 18 and that forms an upper cylinder head for the cylinder 47. Sliding within the cylinder is a piston 48 having an upper piston guide 49 and a lower piston guide 50, the guides being shdable in the end walls of the cylinder. The piston and the upper and lower guides are provided with an axial bore 51 extending therethrough. Radial bores 52 communicate the axial bore 51 with the interior of the cylinder at the lower side of the piston. The cylinder chamber at the upper side of the piston is vented to the exterior of the tool through ports 52α in the walls of the cylinder 47. As will be explained more fully hereinafter, the piston 48 and cylinder 47 are the principal components of a fluid motor for actuating the packer expander.

A packer sleeve or cup 53 of thick, flexible rubber or neoprene or similar material is mounted on the bottom of the cylinder 47 by means of a mounting ring 54. The mounting ring is fastened to the cylinder 47 by retainer screws 55 and the ring carries the packer sleeve which is supported thereon by vertical pins 56 bearing against a metal reinforcing ring 57 molded into the sleeve. The upper edge of the sleeve is of reduced thickness and is received in a recess of the mounting ring.

A vertically bored mandrel 58 is threadedly secured to the bottom of the lower piston guide 50 and sealed thereto by an O-ring 59. The outer cylindrical surface 60 of the mandrel conforms to the inner wall of the packer sleeve 53 and slides therein.

To the bottom of the mandrel 58, an annular packer expander member 61 is threaded. The expander has a ,_{ne nr}essiir? in n downwardly and outwardly flaring conical surface 62. 40 resultant force exerted The diameter of the upper portion of the conical section is equal to the diameter of the mandrel 58 and the diameter of the lower portion of the conical section is somewhat less than the inside diameter of the casing 10. Vertical passages 63 extend through the expander 61 from the upper end of the conical surface 62 to the bottom face 64 of the expander. Eight or ten such passages are circumferentially spaced around the expander and serve an important purpose which will be explained hereinafter.

As seen in FIG. lb, the fill-port sub 20 is screwed into the bottom of the packer expander. The fill-port sub has an axial bore 65 therethrough. A port 66 is cut through the side wall of the sub 20 and the port is closed by a sliding sleeve 67 that may be raised to uncover the port 66 for purposes of filling the tool with cement slurry. The sleeve is retained in the illustrated closed position by a removable locking screw 68.

The hollow cement container 21 is secured to the fillport sub 20, as seen in FIG. lb. A closure is provided for the bottom of the cement container. This closure includes a ring 69 welded into the bottom of the cement container. A metal disk 70, for example an aluminum disk, is received in a recess in the bottom of the ring 69 and is retained in the recess by a sleeve 71 locked in the ring 69 by set screws 72. ¹

In FIG. 4, the firing unit and pressure relief valve assembly 14 is shown with the relief valve in open position as distinguished from the closed position of the relief valve illustrated in FIG. la. The assembly 14 has a lower threaded member 73 that forms the upper closure of the powder chamber and an upper member 74 slidable on the lower member. The upper member 74 is coupled to the cable head 13 by the threaded sleeve 75.

The lower relief valve member 73 has a flange 76, a 75 reduced upstanding cylindrical portion 77, a further reduced upstanding guide rod 78, and a collar 79 threaded to the upper end of the guide-rod. The upper relief valve member 74 has a cylinder 80 that slidingly receives the cylindrical portion 77 of the lower member, a bore 81 in which slides the guide rod 78, and a cylinder 82 slidably receiving the collar 79.

A shear pin 83 is normally engaged under the collar 79 to hold the upper and lower relief valve members in the position shown in FIG. la. When the shear pin is broken by pulling up on the cable 11, the upper and lower relief valve members assume the positions shown in FIG. 4 and fluid pressure in the tool below the lower relief valve member 73 is vented to the exterior of the tool through the passages 84.

In operation, the tool is assembled as shown in FIGS, la and 16. A charge of cement slurry is introduced into the cement container 21 through the fill port 66. The tool is then lowered into the well to be cemented. As the tool is lowered through the liquid in the well bore, the check valve 35 operates to equalize the pressure in the tool below the powder chamber closing plug 27 with the pressure of the well liquid.

When the tool has reached the desired location in 25 the well, the firing circuit is energized from the surface of the earth. The igniter 32 is thus fired and the powder grains 29 are ignited. Powder gases build up pressure in the powder chamber 15 and, when the internal pressure exceeds the external pressure by a sufficient 30 amount, the plug 27 is blown out of the orifice sub 16 and down the interior of the tool. Powder gases rush out of the powder chamber while the screen 28 retains unburned powder particles within the powder chamber.

Fluid pressure increases in the tool. When the pres35 sure in the anchor 18 exceeds the external pressure by a small amount, the pistons 37 are forced out and into engagement with the inner wall of the casing 10 to hold the tool against vertical movement in the well.

As the pressure in the tool increases still further, the 1---------—J on the bottom of the piston 48 becomes great enough to move the piston upwardly in the cylinder 47 to force the packer expander 61 into the interior of the packer sleeve 53 to expand the sleeve into tight sealing engagement with the bore of the casing 10, as shown in FIG. 3. It will be observed that upward movement of the piston 48 lifts the fill-port sub 20 and cement container 21 as well as the expander 61.

A further increase in fluid pressure within the tool forces the disk 70 from the bottom of the cement con50 tainer 21 and ejects the cement slurry from the cement container through its open bottom under high pressure. The cement is forced through the casing perforations 85 and into the space around the casing to cement the latter to the surrounding earth formation. Pressure is held 55 on the cement until it has acquired an initial set.

After the cement has taken an initial set and it is desired to withdraw the tool from the well bore, an upward pull is applied to the cable 11 to shear the pin 83 in the firing unit and pressure relief valve assembly 60 14 and to open the pressure relief valve as illustrated in

FIG. 4. Fluid pressure within the tool and within the casing below the set packer sleeve 53 is equalized with the well pressure above the set packer sleeve through the open relief valve passages 84. With the pressures 65 above and below the packer thus equalized, gravity acting on the tool components that are suspended from the piston 48 pulls these components down and effects withdrawal of the expander member 61 from the packer sleeve 53 allowing the latter to contract. Also, since the pressures inside and outside of the tool are equalized, the springs 44 effect retraction of the anchor pistons 37 thus freeing the tool and allowing it to be withdrawn from the well.

The tool is readily prepared for another cementing op70

3,046,750 eration in a manner that will be apparent from the foregoing description.

The vertical passages 63 in the packer expander 61 have been found to increase the ability of the packer assembly to pack-off high pressure zones. Without the passages 63, the packer assembly may hold a pressure differential of about 2,000 pounds per square inch across the flexible sleeve. In contrast, when the passages 63 are provided, the packer assembly will effectively hold a pressure differential of 6,000 pounds per square inch across the flexible sleeve. Moreover, the passages 63 make for easier withdrawal of the packer expander from the packer sleeve after the cement has been expelled from the tool and pressures have been equalized preparatory to withdrawal of the tool from the well.

Frorn the foregoing description, various modifications of the invention will occur to those skilled in the art without departing from the spirit of the invention.