Method of forming well screens

Application filed April 19,

To all whom it may concern:

Be it known that I, Mahlon E. Layne, a citizen of the United States, residing at Houston, in the county of Harris and State 5 of Texas have invented a new and useful Method' of Forming Well Screens, of which the following is a specification.

This invention relates to the general subject of well-screens, and is particularly di10 rected to a method of forming well-screens in wells.

An object of the invention is to provide a method of forming well screens, by which the screen apertures may be positively initially 15 opened to a predetermined degree and subsequently positively opened to a greater degree.

Another object is to provide a method of forming well screens, by wifi ch the screen 20 apertures may be repeatedly Jmd accurately engaged after the screen has been installed within a well, by means manipulated from the well surface and under full control of the operator. · :

Various other objects and aidvantages will be more fully apparent from the following description of t^e accompanying drawings which form a . girt of this disclosure, and which illustrate a^referred form of em30 bodiment of the invention.

Of the drawings:

Figure 1 is a vertical section through a well-screen casing showing the toot of the present invention in elevation therein.

Fig. 2 is an enlarged section through the well-screen casing and tool showing the parts positioned for a perforating operation.

Fig. 3 is a side elevation of the tool looking at the left-hand side of Fig. 2.

-Fig. 4 is a section similar to Fig. 2, illustrating the use of the emergency connection for preparing the tool for withdrawal.

Fig. 5 is a section on line 6—5 of Fig.2.

Fig. 6 is a section on line 6—6 of Fig.2.

Fig. 7 is a section'on line 7—7 of Fig.2.'

Fig. 8 is a detail view showing a modified form of perforating element.

. The method and means herein referred to are especially adaptable for use in the for50 mation of well screens which are manufactured with normally closed screen apertures . to be subsequently opened after the screen is positioned in a well bore at the desired point of production, and are more partics5S ulariy Adapted for use in the formation of doubffi wall well screens in which an inner

1923. Serial No. 633,084.

apertured casing functions as a means of positively guiding a mechanical perforating device or tool in a perforating operation to open screen apertures in the outer wall or so casing.

In making and installing well screens of this general character it has heretofore been proposed to open the screen apertures by hydraulic or explosive pressure, but such 65 methods are objectionable, first for the reason that in producing a pressure within the casing of a degree sufficient to open the screen apertures, and especially in the use of explosives, there is great danger of in- 70 jury to the well casing, it having been found that in some cases the explosion was so sharp as to open or stretch the connecting couplings to such an extent that when attempting to lift the casing the couplings would 75 slip oft' the threads of the casing sections, and second for the reason that the degree to which the screen apertures are opened cannot be accurately determined or controlled, for instance those screen apertures which 89 happen to, be adjacent hard formations will not be opened to the same extent as those adjacent softer formations.

With the herein described apparatus, the screen apertures are positively opened to a 8® predetermined degree regardless of the nature of the, formation contacting the various portions thereof. And further, with the present apparatus it becomes possible to open the screen perforations to a limited eo extent in the first instance and to further open said perforations as conditions may require, and with a certainty of accurately re-engaging the previously formed perforations. This is of great advantage in bring- 95 ing in wells under high initial pressure, necessitating a screen with only limited openings or screen apertures, and where later the pressure subsides and a more liberal opening,is needed. Further in wells 100 in sand formations,'the fineness or coarse,ness of the screen openings should vary according to the fineness or coarseness of the sand in such formations and should be under positive control of the operator, so 105 that in a well bore through formations of different characters it is possible to opeQ_oone portion of the screen more than another. It will be. understood that that por-? tion of the screen adjacent hard formations 110 should be opened to a greater degree than that which is adjacent soft formations for

1,500,828 the reason that large screen apertures adjacent soft formations will usually admit too much sand into the well, and further it will be evident that with the heretofore pro5 posed methods of opening the screen apertures by hydraulic or explosive pressure the reverse will be true, tiiat is, in hard formations there is a greater resistance to the opening of the screen apertures, resulting 10 in limited apertures where larger apertures are desired and in soft formations where such resistance is least the apertures will be relatively large where smaller apertures are desired.

With those types of mechanical perforators which are not positively guided in their perforating operation, an accurate spacing of the perforations is not possible, and in cases where it is desired to reperforate a 20 screen to provide a more open screen or to • clean previously made perforations, such unguided perforator cannot be depended upon to engage or follow the previously made screen apertures and is exceedingly liable to form a new set of perforations so close to the first formed set as to seriously weaken the strength of the entire screen.

My improved method permits me to positively open the. screen apertures in any por30 tion of the screen to any degree desired, and after the screen has been set in the well bore, and to subsequently, accurately and positively re-engage said apertures to increase the degree of opening or to clean out 35 such of the apertures as may have become clogged or cemented shut by the lime or other incrusting contents of the formations.

In the drawings I have illustrated a wellscreen structure which consists of an inner 40 casing 1 having a plurality of circularly spaced rows of holes 2 equally spaced vertically, and an outer casing 3 which is vertically slit as at 4 with each slit extending across one of the holes 2 in the inner easing. 45 The slits are normally closed and in such condition the screen is lowered into the well to position of use, and means are subsequently manipulated within the screen to widen the slits to form screen apertures 5 50 in communication xvitli the respective holes 2 of the inner casing.

A screen structure of this type is fully illustrated and described in my copending application entitled “Well screen and method 55 of making same,” Case B, Serial No. 633,083, filed April 19, 1923, to which reference may be had if desired.

It will be stated that in so far as the present invention is concerned, the. specific con60 struct ion of the screen is immaterial so long as it embodies the general characteristics of the type, of screen shown, it being evident that other specific forms of screens (are adaptable for use with the mechanism dis05 closed herein, one of such other forms being shown and described in my copending application entitled “Well screen and method of making same,” Case A, Serial No. 633,082, filed April 19, 1923, and still another in the Patent #1,304,493 to Ollyn A. 70 Layne, patented May 2(), 1919.

The means for forming the well screen as herein illustrated has a two-part body comprising a tubular member 10 which carries the. perforating element, and a hS/id 11 75 slidable within the upper portion of the member 10 and screw-threaded into the lower end of a tubular shank 12 which preferably consists of a plurality of tubing sections extending to the well surface, from 80 which, point the tool is manipulated. The two body members 10 and 11 are joined by a pin and bayonet slot connection comprising, in the present instance three radial pins 13 carried by the head 11 and project- 85 ing into slots 14 in the member 10 (see Figs. 1 to 5). With particular reference to Figs. 1 and 3, it will be seen that normally with the pins 13 in the lateral portions of the slots 14, the two body members may be Ion- 80 gitudinally translated within the well as a unit and a. rotation of the shank 12 and head 11 in one. direction will correspondingly rotate the body member 10. Further it will be evident that upon an independent 05 reverse rotation of the head 11 the pins 13 will be brought, into the vertical portions of the slots 14 and the head 11 then permitted a limited independent vertical movement, the purpose of which will later be ex- 100 plained.

The tubular body member 10 is longitudinally slotted as at 15 and pivoted on a pin 16 carried by the member 10 is a depending frame comprising two relatively spaced io5 plates 17 joined together by a block 18. The frame 17 is positioned within the slot 15 and journaled to rotate on a stud 19 carried by the lower end of said frame., is a perforating element or wheel 20 having circu- no larly spaced punch members 21 projecting from its periphery in the manner of a 'sprocket wheel. Attached to the inner wall surface of the tubular body inemlwr 10 and adjacent the block or shoe 18, is r companion 115 block or shoe 22, the adjacent surfaces of the blocks or shoes 18 and 22 having tapered half-circular recesses 18“ and 22“ cooperating to form a tapered bore for cooperation with a wedge element or mandrel 23, said man- 120 drel being in the form of a round rod having a tapered lower end, and provided with means 24 at its upper end for attachment to a cable leading to the well surface.

The mandrel 23 is adapted to slidably 125 engage through a bore 25 in the body memtar 11, which bore is aligned with the tapered bore formed by the recesses 18“ and 22“ m the shoes, the upper surface· of the body member 11 being formed to guide the man- 130

1,500,829 ® drel 23 into the bore 25 when lowered through the tubular shank 12, a shoulder 26 on the mandrel limiting its insertion into said bore 25.

In carrying out the method of the present, invention‘the well screen with the slits 4 closed, is positioned in the well bore. The perforating tool, with the pins 13 in the lateral portions of the slots 14, is then io lowered into -the well casing to location of the screen. Due to the absence of the mandrel 24, the frame 17 carrying the perforator element, is free to swing laterally and upon reaching the screen the tool is rotated from 15 the well surface, in a right hand direction, and is moved slightly up and down if necessary, until the punch members 21 engage one of the row of holes 2 in the screen (as shown in Fig. 1) this engagement of the 20 punches with the holes in the screen being automatically effected by gravity by reason of the pin 16 being located considerably to one side of the vertical axis of the tool.

With the punch members 21 so engaged 25 the mandrel 23 is lowered into the tubular shank of'the tool and entering through the bore 25 in“the body member 11, drops downwardly between the wedge shoes 18 and 22, forcibly separating said shoes and forcing 30 the frame 17 and its perforator element laterally to drive the punch members 21 outwardly through the holes 2 in the inner casing 1 to open the sh’ts 4 in the outer casing 3. In this operation the opposite wall of the 35 tool body 10 engages against the inner periphery of the screen.

The tool will next _xbe longitudinally translated to open a row of slits 4 to form the screen apertures 5, the perforator wheel 40 20 cooperating with the holes 2 in the inner casing 1 in the manner of a rack and pinion.

Upon completion of the first row of screen apertures, the mandrel 23 is withdrawn from between the opposed shoes 18 and 22 t® re45 lease the perforator frame 17, after which the tool is elevated or lowered above or below the rows of holes 2 so that the punch members 21 engage an unbroken portion of the inner casing 1. The tool is then slightly 50 rotated to bring the punch members 21 between the row of holes previously engaged and the next row and is then translated to bring the punch members 21 between said rows and subsequently rotated until the 55 punch members find and engage in said next row.

The mandrel 23 is then again lowered and the tool operated as above explained, this sequence of operation being repeated until 60 all of the screen apertures desired, are' formed, after which the tool is withdrawn from the well.

In some instances it may happen that the mandrel cable is lost in the tool shank or that said cable becomes broken, and in this 85 event the bayonet slot arrangement provides a means by which the tool may be conditioned for removal independently of a manipulation of said cable.

To accomplish this result, the shank 12 70 of the tool will be rotated in a left hand direction to bring the pins 13 in line with the vertical portions of the bayonet slots 14 and the tool shank 12 then elevated relative to the body member 10. By reason of the en- 75 gagement of the body member 11 with the shoulder 26 on the mandrel 23 thiff~independent vei-tical movement of the too! shank 12 and body member 11 will cause the mandrel to be elevated and withdrawn .from 80 between the shoes 18 and 22 and in. this manner allow the frame 17 and the perforating roller 20 to freely swing inwardly. When the pins 13 reach the upper ends of the bayonet slots 14 (see Fig. 4) a continued 85 upward movement of the tool shank 12 and body member 11 will also carry upward the body member 10 and associated parts in a removal of the tool from the well.

In Fig. 8 I have shown a slightly modified ⁸⁰form of perforating element in which the round nose punch members 21^a are designed to punch through an outer casing which has not been previously slit, the term perforating as, used herein having a broad meaning ⁸⁵including punching or forming of screen apertures.

While the form of mechanism herein illustrated and described is well adapted to fulfil ’ the objects primarily stated knd to ₁₀₀cany into effect the herein described method, it is to be understood that I do not wish to limit the invention to specific embodiment herein disclosed, for it is susceptible of embodiment in various other forms all 105 coining within the scope of the following claims.