Apparatus for completing a well

Oct. 20, 1964 F. E. CHANCELLOR ETAL 3,153,451

APPARATUS FOR COMPLETING A WELL

Filed Feb. 7, 1963 ² Sheets-Sheet 1

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FORREST RO3ERT BY

INVENTORS.

CMWOEELOR CMRA/CELLOR

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RTTORA/EH.

Oct. 20, 1964

3,153,451

F. E. CHANCELLOR ETAL

APPARATUS FOR COMPLETING A WELL

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INVENTORS.

TOGGCSr £. CH/JA/CCLLOH £Οδ££Γ O. CH/WC5H.O2

BY I

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3,153,451

Patented Oct. 20, 1964

United States Patent £?/·ϊ ' ·

153 451

APPARATUS FOR’ COMPLETING A WELL

Forrest E. Chancellor and Robert O. Chancellor, feoth of 2917 Pierce Road, Bakersfield, Calif.

Fifed Feb. 7, 1963, Ser. No. 257,005 5

Claims. (Cl. 166—51)

This invention relates to the deep well completion art and a particular object of the invention is to provide a novel.apparatus for gravel packing a liner in a deep oil or jp water well.

The common practice in a gravel packing operation starts with suspending a perforated production liner on a liner hanger from the lower end of the well casing with a port collar assembled therewith just below the hanger and 15 with a packer forming a seal between the hanger and the casing. This liner may be run into the well on a special tool for gravel packing, the latter being suspended on a running-in string and having temporarily threaded connection· with the liner hanger, and, when unscrewed from 20 the latter, being packed off from the port collar above and below gravel ports in the latter. A stinger pipe extends downward from the gravel packing tool to a point just above the lower end of the liner and communicates at its upper end through a bypass passage in the tool with an 25 outlet port at the upper end of the latter, opening into the space between the running-in string and the well casing. The running-in string communicates through a central passage in the tool with ports opening into the port collar. Thus a suspension of gravel in water or other light 30 liquid may be pumped down the running-in string and through the tool into the port collar and then outwardly through the ports in the latter into the space between the open well hole and the upper end of the perforated production liiier. 35

Continuation of this flow of a liquid suspension of gravel into said space forces said suspension downwardly between the hole and the liner, and the liquid in the hole displaced by the inflowing suspension flows inwardly through the perforations of the liner and travels down- 40 wardly until it passes into the lower end of the stinger pipe, causing an upward flow of liquid in the latter which escapes through said by-pass in the gravel packing tool into the. lower end of the body of liquid occupying the well casing. 45

Theoretically, the suspension thus pumped into the upper end of the space between the liner and the well hole will gradually move downwardly displacing the liquid already in this space and the liquid in the suspension will escape from the same flowing inwardly through the 50 perforations in the liner, leaving the gravel progressively compactly packed in said space, from the bottom of the well· upward, until no more gravel suspension can be pumped into the upper end of said space. Unfortunately the above described process does not work out as theoreti- 55 cally intended. For some reason, and there are various theories as to what the precise cause is, this process does not always result in the space between the well hole and the liner being completely packed with gravel. Failure in this respect is indicated by persistence of the sand problem, the overcoming of which was sought by the gravel packing operation.

One of the theories for such failure is that bridging of the gravel between the liner and the well hole takes place at a point located a substantial distance above the bottom of the hole, such bridging blocking further downward flow of the gravel suspension. After such a blockade occurs, the liquid in the suspension delivered into the well hole space above the blockade escapes inwardly γθ through the perforated liner and said space is progressively packed with-gravel from the blockade upward but leaving the space below the blockade sealed off from penetration by the gravel suspension. This theory for explaining failures in gravel packing is supported by the fact that such failures increase in direct proportion to increases in the length of the liner.

It is an object of the present invention to provide an apparatus for gravel packing a liner in a deep well which will give assurance to the operator, that the space between the liner and the well hole is being progressively packed with gravel from the bottom of the liner upwardly.

Another object of the . invention , is to provide such apparatus largely utilizing the equipment above described but which prevents escape of the liquid from said gravel suspension inwardly into said liner until after said suspension reaches the lower end of the space between the liner and the well hole whereby the liquid pressure of the stream of gravel suspension delivered into the upper end of said space will continue to be applied downwardly throughout the length of said space to the suspension previously introduced into said space thereby effectively preventing bridging caused by premature separation of the liquid from said gravel suspension.

A further object of the invention is the provision of a simple and inexpensive expedient which, when combined with the prior art equipment first above described, will effect a distinct change in the mode of operation thereof and facilitate realization of the objects af©restated.

It is a still further object of the invention to provide apparatus applicable as above noted to a gravel packing operation and which, with or without modification, may also be utilized in the setting of a liner in a well hole by reversing the direction of flow of the circulation of fluid in the well.

The manner of accomplishing the foregoing objects as well as further objects and advantages will be made manifiest in the following description taken in connection with the accompanying drawings in which

FIG. 1 is a diagrammatic vertical sectional view of a lower portion of a well hole and illustrating an apparatus of the prior art (with which the present invention is adapted to be associated) with said apparatus performing a gravel packing operation in said well hole in accordance with the method of the prior art first hereinabove described, and showing a premature bridging of the gravel between the well hole and the perforated liner which prevents the realization of satisfactory gravel packing job.

FIG. 2 is an enlarged vertical sectional view of an upper portion of the gravel packing apparatus shown in FIG. 1 and taken on the line 2—2 thereof.

FIG. 3 is a view similar to FIG. 1 and illustrates the apparatus shown therein with this modified to embody the apparatus of the present invention and shows this modified apparatus functioning to perform the method of the present invention in satisfactorily accomplishing a deep well gravel packing operation.

FIG. 4 is a horizontal detail sectional view taken on the line 4—4 of FIG. 2 and illustrates the gravel suspension ports in the port collar of the liner hanger and similar ports in the gravel packing tool.

FIG. 5 is an enlarged detail fragmentary view of one of the joints formed in the stinger pipe of the apparatus of the invention as this pipe appears before it is inserted downwardly into the perforated liner, and shows one of the fluid flow control baffles of the invention mounted on said pipe at said joint with this baffle in section and with the radial flange thereof lying in a flat plane in which it is normally disposed when free from restraint.

FIG. 6 is a view similar to FIG. 5 and shows the baffle of the invention with the radial flange thereof cupped upwardly as occurs when a stinger pipe equipped with said baffle is fed downwardly into the perforated liner in the well. This view also shows in broken lines the position

3,153,451 taken by said radial flange of said baffle when the latter is reversely cupped by application of a sufficient downward hydraulic pressure thereon during the gravel packing operation.

Referring specifically to the drawings FIG. 1 shows a deep well hole 10 having a well casing 11 within which a gravel packing apparatus 12 of the prior art is shown engaged in the performance of a gravel packing operation. The apparatus 12 includes a liner hanger 13 having a lead packer 14 on the lower end of which is connected a port collar 15 having gravel suspension ports 16. Suspended from the port collar 15 by a coupling 17 is a perforated liner 18 having perforations 19 throughout its length, the lower end of said liner either resting on the bottom of well hole .10 or being supported relatively close to said bottom.

The liner hanger 13 is provided with wickered slips 20 which, in FIG. 1, are shown as set against the inner surface of the casing 11 so as to suspend the liner hanger and the perforated liner 18 on said casing. The lead packer 14 is also shown as having been set against the well casing 11 to pack off the space between the liner hanger and said casing. The liner hanger 13 has internal threads 25 by which it is adapted to be engaged by an externally threaded head 26 of a gravel packing tool 27. This tool is suspended on the lower end of a running-in string 28 on which said tool is run into the well with the liner hanger 13 screwed onto the head 26 and thus suspended on said tool. Because of the diagrammatic nature of the drawings the detailed structure of the various elements of the apparatus are not shown which permit the slips 20 to be manipulated by manipulation of the running-in string 28 so as to set these slips in the casing 11 and cause the lead packer 14 to pack off the space between the hanger and the casing. After these steps have been performed, the running-in string 28 is rotated to unscrew the head 26 from the internal threads 25 of the liner hanger 13, after which the string 28 may be set down with the head 26 supported on the upper end of the liner hanger 13 thereby firmly setting the wickered slips 20 in the metal of the casing 11. The head 26 is shown in this position in FIGS. 1, 2 and 3.

The gravel packing tool 27 has a tubular downward extension 29 which connects at its upper end with the head 26 and at its lower end with a sectionally assembled stinger pipe 30. The downward extension 29 of the tool 27 has an internal bore 31 which extends upwardly through the head 26 and connects with the lower end of the running-in string 28. The tool 27 is provided with a wall 32 extending vertically in the bore 31 which divides the space within said bore into a gravel suspension passage 33 and a liquid by-pass passage 34. The passage 33 connects with the lower end of the running-in string 28 at its upper end and at its lower end communicates with gravel suspension ports 35, and passage 33 is closed by a wall 40 just below said ports. The head 26 of tool 27 has a neck or sub 41 which connects with the running-in string 28, the neck 41 having a liquid port 42 with which the upper end of liquid by-pass passage 34 connects. The lower end of said by-pass passage connects with the bore 31 below the wall 40, and thus communicates with the upper end of the stinger pipe 30.

The tubular downward tool extension 29 is provided with upper and lower double packers 43 and 44 which pack off the space between said tool on the one hand, and the liner hanger 13 and port collar 15 on the other hand, just above and below the ports 16 of the port collar and the ports 35 of the gravel packing tool 27. These packers thus create a chamber 45 within the port collar 15 which connects the ports 35 of the gravel packing tool 27 with the ports 16 of the port collar. Thus when a suspension of gravel in liquid is pumped down the running-in string 28 it is delivered through the passage 33 and ports 35 into the chamber 45 from which it flows outwardly through ports 16 into the space 46 between the well hole 10 and the perforated liner 18.

Reference is now had particularly to FIG. 1 which illustrates the prior art gravel packing apparatus 12 in the midst of a gravel packing operation, this view also illustrating a fault of said apparatus in the method performed by it resulting in the development of a bridging or blockade 47 of the space 46 at a point a substantial distance above the lower end of said space so that the gravel operation is prevented from reaching a substantial lower portion of the space 46 with the result that the packing operation fails to accomplish its intended purpose. The premature formation of the bridge 47 in the space 46 as illustrated in FIG. 1 results from the fact that the upper portion of the perforated liner 18 acts as a strainer into which the water or other liquid contained in the suspension delivered into space 46 trickles through the perforations 19 of the liner and escapes downwardly inside the liner into the lower end of the stinger pipe 30, this liquid then flowing upwardly through the stinger pipe, the bore 31, the by-pass passage 34 and out through the liquid port 42 into the body of liquid occupying the space 48 between the running-in string 28 and the well casing 11.

Loss of liquid from the gravel suspension tends to make the gravel pack prematurely as it travels down the space 46 between the well hole and the perforated liner. Our diagnosis is that this is one of the major causes of failures of the method and apparatus illustrated in FIG. 1 to reliably perform a complete gravel packing operation. The theory behind the present invention is, therefore, that if loss of water from the gravel suspension as it passes down the space 46 can be prevented, this suspension will be kept in fluid condition until it reaches a solid obstruction such as the bottom of the well hole 10 where, of course, the gravel will be forced to settle out of the suspension and the liquid in the suspension will be forced to flow through the perforations 19 of the liner 18. In pursuing this theory, it was noted that it is common practice to make up the stringer pipe 30 by assembling a plurality of pipe sections 55 end-to-end, each of these sections generally being about 30 feet in length. Each section 55 of the stinger pipe 30 has a female threaded receptacle 56 into which the male threaded pin 57 of the section 55 thereabove screws as shown in FIG. 5. Above the pin 57 of each section 55 is a swelling or annular shoulder 58.

The improvement conceived in the present invention for modifying the apparatus 12 of the prior art to prevent the premature bridging of gravel above described as experienced in using this apparatus, comprises the installation of one of a series of fluid flow control baffles 59 on the stinger pipe 30 at each of the joints therein. Each of these baffles is preferably molded of neoprene although, of course, it may be made of natural rubber or any other kind of rubber substitute. Each baffle 59 includes a hub 60 having a bore 61 which snugly fits the pin 57, this hub having a metal ring 62 for reinforcing said hub this ring having an internal diameter which prevents it moving upwardly but a very short distance from engagement with the receptacle 56 of said joint, by the presence of the annular shoulder 58 of the section thereabove. The baffle 59 is preferably molded so that the hub of the baffle is intimately bonded with the metal ring 62 and is integrally united with an annular radial flange 63 which, when free from restraint, lies in a flat plane normal to the axis of the stinger pipe 30. The circular peripheral edge 64 of the radial flange 63 has a major rounded lower bevel 65 and a minor rounded upper bevel 66.

The apparatus 12 of the prior art modified by the application of fluid flow control baffles 59 to each of the joints of the stinger pipe 30 constitutes the improved apparatus 67 of the present invention. As clearly shown in FIGS. 3 and 6, when the gravel packing tool 27 of the apparatus 67 is extended downwardly into position to start a gravel packing operation as shown in FIG. 3,

3,153,451 ' : /5 all of the fluid flow control baffles 59 are cupped upwardly in the perforated liner 18 due to the fact that the outside diameter of these baffles exceeds by Vs of an inch to % of an inch the inside diameter of the liner 18. Each of these baffles, when so cupped upwardly, forms a yieldable but very substantial block to downward passage of liquid past this baffle within the liner 18.

Assuming that the baffles 59 are spaced 30 feet apart, which is normal, each adjacent pair of these baffles forms a liquid tight cell within the liner and the only way this cell can receive liquid through any of the perforations thereof located opposite said cell is of an equivalent amount of liquid to flow out of said cell through other of said perforations. Thus, if there is any tendency for liquid to leave the gravel suspension as it flows down the space 46 opposite the upper portion of one of said cells, this flow will force liquid out of the perforations in said liner adjacent a lower portion of said cell. The general tendency, however, of the division of the space within the liner into a series of consecutive tightly closed off cells, is to discourage the seppage of water out of the gravel suspension as it flows downwardly through the space 46 until the suspension comes against a solid obstacle such as the bottom of the well where there is no place for the suspension to go and the water is naturally strained therefrom through the perforations in the liner and the gravel starts to settle from the suspension thereby filling the space 15 from the bottom upwardly.

Whenever the gravel starts to pack out from the gravel suspension in the space 15, beginning with the bottom of this space, so that the packed gravel approaches the level at which one of the baffles 59 is located, there becomes a compelling necessity for the cell immediately above that baffle to receive water through the perforations in the liner opposite , said cell and this addition of water to the cell sets up an increased hydraulic pressure therein, until,. When this reaches approximately. 40 pounds to the square inch, this pressure reverses the direction in which said baffle is cupped whereupon this baffle offers relatively little resistance to the downward flow of water from the cell thereabove to the cell therebeneath.

This reversing of the cupping of the baffles 59 occurs progressively as the packing of the gravel rises in the space 46 and is well illustrated in FIG. 3 where the four lower baffles are shown as having had their cupped positions successively reversed by the packing of the space 46 from the bottom of the well until the level of packed gravel has reached the uppermost of these baffles the cupping of which has been reversed.

Each time the pressure rises in one of the cells between adjacent baffles 59 by virtue of the packing of the gravel rising, up close to the level of the lower of these two baffles, this resistance to the flow of the gravel suspension being pumped down the running-in string 28 is reflected on the pressure gauge at the top of the well. The operator is thus continuously kept informed by this gauge that the gravel packing in the space 46 is progressing section, by section upwardly in this space and he is able to follow this progress by counting the number of increases in pressure occasioned by the reversing of the direction in which the respective baffles 59 are cupped.

.While only a single embodiment of the present invention is disclosed in the above specification and illustrated in the drawings, it is to be understood that various changes and modifications may be made without departing from the spirit of the invention or the scope of the appended claims.