US2144026A - Packer - Google Patents

Description

T. S. PARK Jan. 17, 1939.

PACKER Filed Feb. 6, 1956 1N VEN TOR.

Patented Jan. 17, 1939 "UNITED STATES PATENT OFFICE PACKER Tracy S. Park, Houston, Tex., assignor to Leslie A. Layne, Houston, Tex.

Application February 6, 1936, Serial No. 62,555

9 Claims.

The invention relates to an improvement in packers of the type which are set in well bores to form a seal either between different sized strings of pipe or between a pipe and the well bore.

Packers of the type here embodied may take various forms and configurations, some being used to support the liner in the casing, others to pack 01f the tubing, others to pack off the casing, and

various other types of packers which may be necessary to form a seal in the well. i

A majority of such packers are made of fabric in which the fabric iswrapped about the pipe over a considerable length to form the desired thickness. When the packer is to be set this cylinder of fabric is compressed and it will expand radially so that itwill form the desired seal.

In actual practice this fabric or canvas packing is lowered into the well bore which is usually filled with water, oil or slush. Needless to say this canvas fabric absorbs water or moisture from the liquid or fluid in the well and begins to swell immediately while it is being lowered into the well. This swelling is objectionable prior to the time when the packing is to be set in position because the desired amount of expansion cannot be obtained and in some instances where a close set is being made the packer will swell sufficiently to become lodged in the well prior to reaching the elevation where it is to be set.

It has also been found that in lowering the fabric packing into the well that the operator may lower the string of, pipe carrying the packer at such a rate that there will be a rush of abrasives which will cause scouring or channeling of the outer surface of the packer.

It is therefore one of the objects of the inven: tion to provide a protecting coating for the fabric so that it cannot absorb moisture on the one hand and will be protected against abrasion on the other hand.

Another object of the invention is to form a rubber coating on the surface of the fabric packer to make it impervious against moisture.

Another object of the invention is to vulcanize a coating of rubber upon the surface of the packing which will be tough and durable enough to withstand abrasives as the packer is lowered into the well.

A still further object of the invention is to provide a coating for the packing which is made up of a sheet of fabric strands impregnated with rubber, which may be vulcanized on the outer surface of the packing.

through the restricted rea around the packer Other and further objects of the invention will be readily apparent when the following description is considered in connection with the accompanying drawing wherein:

Fig. 1 is a side elevation of a packer assembled 5 and ready to be lowered into the well bore, showing certain of the parts in section to illustrate how the structure collapses to expand the packing.

Fig. 2 is an enlarged sectional view of approx- 10 imately actual size and illustrating the metal, the fabric and the impervious coating.

Fig. 3 is an enlarged view of a magnified section of the sheet of material which may be used to form the surface layer.

A usual and standard form of packer is shown in Fig. 1 and includes a coupling 2 which carries the support pipe or mandrel 3 thereon. This mandrel extends upwardly and is of less diameter than the coupling 2 so as to form a recess to re- 20 ceive the packing 4. The surface of the mandrel 3 may or may not be serrated as at 5 to form ratchet teeth to be engaged by a hold-down latch 6 on the setting sleeve or tool 1. The lower end of the setting tool is formed with an enlarged 25 shoulder 9 which confines the upper end of the packing 4.

With the parts in the position shown in Fig. 1 layers of fabric will be wrapped usually in a spiral direction around the mandrel 3 until the recess 30 is practically filled between the coupling 2 and the shoulder 9. Suitable wires such as H] are then positioned to insure that the fabric will be held in position and binder wires I l and I2 are positioned at the top and bottom to closely confine the packing and hold it between the shoulders. This is the usual and standard method of making packers.

As above pointed out, a fabric exposed to the moisture and water in the well will swell to such 40 an extent that it may become unserviceable or stick in the well when it is being lowered and is also damaged in many instances by the flow of sand and abrasive mud past the packer as it is lowered. ,To avoid this a covering or coating 20 has been applied to the surface of the packing and is indicated by the dark heavy line on the right-hand side of Fig. 1. This covering will be applied prior to the attachment of the wires in, I l and I2 as previously described so that it will form a close compact covering which will make the fabric impervious to moisture and will also prevent abrasion.

This material is shown in Fig. 2 on a somewhat larger scale to indicate how the coating adheres to the fabric packing 4.

Obviously various methods or practices may be followed in applying this impervious coating to the packing, but it has been found satisfactory to use a sheet of material such as is illustrated in a magnified form in Fig. 3 which sheet comprises a plurality of parallel strands of string or cord such as H. The sectional view of Fig. 3 is taken at an angle with respect to the axis of the strands 2| because it is a vertical section where the sheet of coating has been wrapped spirally upon the packing. One form of the sheeting which has been found satisfactory is a sheeting wherein three-ply strand of sturdy cord such as a small fishing cord has been positioned in parallel relationship and impregnated and coated with a body of rubber or other similar material such as 22 in order to make up the composite sheet 23.

It has been found that a sheet made up in the manner just described of unvulcanized material is entirely satisfactory and thissheet of material can be arranged in strips and wrapped spirally around the surface of the fabric packing which has previously been applied. The wires W, H and I2 can then be applied and the entire assembly inserted in an oven and subjected to vulcanizing I temperature so as to give the rubber body 22 the desired tenacity and resistance to avoid absorption and to completely seal the fabric against the entrance of water or moisture from the outside.

While rubber has been described as the body a substance known as Duprene can be used or other somewhat similar materials which will form a water impervious coating which will be more or less flexible.

It is to be understood that this coating is not to remain permanently in position nor is it to permanently prevent the entrance of moisture, but is preferably to protect the packing while it is being lowered, but will be distorted as the packing is expanded so that moisture will be admitted.

To allow for the necessary circumferential enlargement of the coating to accommodate the expansion of the packing, it may be wrapped spirally so that as the spiral is shortened it will enlarge. In this manner the coating will have strength due to the embedded cords but will also enlarge with the packing. This is desirable because then the swelling operation of the packin will occur after it has been set and will tend to increase the sealing effect obtained.

The present invention has been found to be of particular advantage in the very deep wells where packers are set, first because of the considerable length of time which it takes to lower the packer to the elevation where it is to be set, and second, because of the enormous pressures of the large volume of abrasive materials which are encountered. As an instance of this, if a well is filled with a 10 pound per gallon drilling fluid or slush a 10,000 foot well would have a static head of 6,000 pounds per square inch pressure. Such enormous pressures tend to impregnate the fabric with moisture and the sealing naturally occurs. With a coating of the type here described the fabric will be protected against the entrance of moisture as well as against the abrasion by the flow of slush past the packing and in this manner the operator feels confident that his packing is in proper form when it reaches the elevation where it is to be set.

What is claimed is:

1. A well packer comprising a support, a setting member, a fabric packing carried by said support and to be expanded by said member, and a rubber coating over said fabric packing to seal the fabric against the entrance of liquid whereby the fabric will not absorb liquid and swell while being positioned in the well.

2. The combination with a fabric packing to be lowered into a well filled with slush of an impervious coating on the outside and over-lying the packer to avoid swelling of the packer by the absorption of moisture.

3. A waterproof packer covering to prevent the entrance of moisture to an assembled fabric packer comprising a coating of rubber vulcanized in position on the packer to seal the packer.

4. A packer support, a fabric packing assembled thereon, a rubber coating sheath over said fabric, and means to hold said fabric and coating to said support.

5. A method of protecting wrapped fabric well packers from swelling while being set which comprises the steps of vulcanizing an impervious coating over the assembled fabric.

6. A method of protecting fabric well packings while they are being lowered into position in the well including the steps of forming a coating of water and abrasive resistant material over the outside of the fabric packing.

7. A well packer including a fabric packing, a covering for the fabric comprising a corded. rubber material wrapped spirally over the outside of said packing to protect said packing against moisture and abrasion during setting.

8. A corded resilient coating for well packers comprising a sheet of resilient material, cords embedded longitudinally therein, said sheet being wrapped spirally about the packer.

9. A corded resilient coating for well packers comprising a sheet of resilient material, cords embedded longitudinally therein, said sheet being wrapped spirally about the packer whereby said cords will be extended circumferentially upon setting or the packer.

IRAN S. PARK.

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