US2391609A - Oil well screen - Google Patents

Description

Dec. 25, 1945. K. A. WRIGHT OIL WELL SCREEN Filed May 27, 1944 2 Sheets-Sheet l MY C I N VEN TOR.

Ildllllllllll Patented Dec. 25, 1945 UNITED STATES PATENT .QFFICE OIL WELL SCREEN Kenneth A. Wright, Los Angeles, Calif.

Application May 27, 1944, Serial No. 537,559

(Cl. 16S-6) 15 Claims.

This invention relates to deep well equipment and relates more particularly to strainers or screens for oil wells and the like. A general object of this invention is to provide a simple, practical and effective multi-barrier oil Well screen.

This application is filed as a continuation in part and to take the place of my pending application entitled Oil well screen, Serial No. 441,279, filed May 1, 1942.

An object of this invention is to provide an oil Well screen incorporating the advan-tages of the multiple barrier type of screen and yet embodying only one wall thickness of casing so that it may be large in internal diameter to be readily cut and removed from the well if and when such removal becomes necessary.

Another object of this invention is to provide an oil well strainer or screen in which a selected multiple 'barrier screening material is confined or retained in openings in the wall of the casing, thus utilizing the wall thickness of the casing to carry the screening material so that the casing may be of maximum internal diameter to be readily washed, cut and iished out by conventional tools of adequate dimensions.

It is another object of this invention to provide a simple, practical insert for application to a liner or casing, which insert is such that the lling or screening material can be quickly and accurately applied without requiring great skill in manipulation of the parts and without utilizing special equipment or involved methods.

Another!` object of this invention is to provide an oil well screen of the character referred to presenting maximum drainage opening area for the producing well fluids. The drainage area provided by the multiplicity of inserted bodies of screening material is greater or is at least comparable to the drainage area of a typical slotted, perforated or gravel packed screen.

' Another object of this invention is to provide a well screen of the character mentioned in which the provision of the screening material in lthe wall of the casing -does not weaken the casing wall to any appreciable extent. The screening material is contained in metal inserts which in turn are arranged in the openings in the wall of the casing and are integrally joined with the casmg.

A further object of this invention is to provide an oil well screen that can be readily modified or adapted to any producing condition by merely employing a screening material having the desired porosity and other characteristics.

Another object of the present invention is to provide an insert for a well string such as I have referred to above in which the screening material is normally yieldingly held under pressure in its holder or retaining body, so that all danger of working or looseness between the particles of the screening material is avoided and the structure is such that it can be handled freely or transported over long distances under severe conditions without injury or deterioration.

A further object of the invention is to provide an insert of the general character hereinabove referred to which presents a substantial metal body part or mass to he joined to the tubular body by welding. By my invention I form the sheet metal elements or parts which are to be secured to the tubular body so that they aii'ord parts that can be practically and effectively welded in spite of the fact that comparatively light sheet metal is being joined to the body which is of substantial mass.

The various objects and features of my invention will be fully understood from the following detailed description of typical preferred forms and applications of my invention, throughout which description reference is made to the accompanying drawings, in which:

Fig. 1 is a fragmentary side elevation of a well screen of the present invention. Fig. 2 is a transverse sectional view of the parts shown in Fig. 1 taken to show the circumferential arrangement of the inserts in the body. Fig. 3 is an enlargediexterior or face view of a portion of the well screen taken to show one of the inserts embodying the invention. Fig. 4 is a detailed sectional view taken as indicated by line 4 4 on Fig. 3. Fig. 5 is a detailed sectionalV view taken as indicated by line 5-5 on Fig. 3. Fig. 6 is a sectional view taken at one end of an insert showing it removed from the tubular body and showing the closure tongue open so that the lling opening of the insert is clear for the reception of screening material. Fig. 7 is a view taken as indicated by line 1-1 on Fig. 6. Fig. 8 is a view similar to Fig. 6 showing the closure tongue closed and the filling material and pressure unit in place. Fig. 9 is a view similar to Fig. 3 showing a somewhat different form of construction, that is, showing a form in which round openings are employed in the insert in place of slots. Fig. 10 is a view similar to Fig. 3 showing another form of the invention. Fig. 11 is a sectional view of the construction shown in Fig. 10, being a view taken as indicated by line II-H on Fig. 10. Fig. 12 is a sectional view taken as indicated by line I2-I2 on Fig. 10. Fig. 13 is a view similar to Fig. 6 but illustrating the form of construction shown in Figs. 10, 11 and 12. Fig. 14 is a view taken as indicated by line II-II on Fig. 13. Fig. 15 is a view similar to Fig. 8 but showing the type of construction shown in Figs. 10 to 14, inclusive. Fig. 16 is a transverse sectional view of a form of the invention in which the inner end or Wall of the insert is curved concentric with the body or pipe and is arranged flush with the inner wall of the pipe as a continuation thereof.

The improved well screen of the present invention illustrated in Figs. 1 to 8, inclusive, may be said to comprise. generally, a tubular body I having openings II in its wall, inserts I2 set or secured in the openings I I and screening material I3 in the inserts.

The body I 0 of the screen may be a simple tubular member comprising one or more sections or joints of casing or pipe. The body III is usually of suilicient length to extend through the `producing zone or stratum of the well. In the drawings I have shown a portion of the body I0 connected at its lower end with a length of blank casing I4 by a suitable coupling Il". A conventional shoe (not shown) may be provided at the lower end of the assembly and the upper end of the body I0 or screen assembly may be provided with a packer or other required equipment. It will be understood that the screen may be installed and equipped in any selected or required manner and that the present invention is not primarily concerned with such details. It is to be observed that 'the simple body I0, just described, has a single wall thickness and that it may be that conventional well casing which for a given size may be of maximum internal diameter.

In accordance with the invention the body I0 is provided with a multiplicity of openings II to receive the inserts I2. In the form of the invention illustrated in Figs. 1 to 8, inclusive, the openings II are rectangular and are disposed longitudinally of the body III. The size or area of the individual openings II may, of course, vary in different applications of the invention. In a typical case where the body I0 is formed of four inch O. D. casing the openings II are three inches long and seven-eighths of an inch wide.

'I'he openings II may be related and disposed in selected manners but are preferably uniform or alike in size and shape. In the preferred arrangement the slots or openings I I are in spaced vertical rows with the openings of the adjacent rows in vertically odset or staggered relation, With this relationship of the openings I I the wall of the body I0 is weakened to a minimum extent. 'I'he endmost openings II are spaced some distance from the ends ofthe body I0 and the coupling I4* or other elements at the ends of the body. While it is to be understood that the spacing of the openings II may be varied as required it has been found practical :to make the adjacent slots or openings II of any given row six inches on center when the body I0 and the openings are proportioned as set forth in the above example. The side walls of the openings II. that is, the vertical walls of the openings are flat and parallel and the end walls of the openings may be inwardly convergent as a result of their mode of formation.

'I'he inserts I2 are provided to act as barriers or screens and carry or contain the multiple barrier screen material I3. The inserts I2 are shaped and designed to occupy the openings II so that the material I3 is contained Within the asaaeoo confines of the body wall. It is preferred tc make the several inserts I 2 alike or identical and there is an insert arranged in each opening II.

The inserts I2 are preferably sectional, each comprising a main section or body I5 and a. plate or cover I6. In the particular form of the invention being described the body sections of the inserts I2 are elongate members shaped and proportioned to closely t the openings II. The bodies are concaved or cupped to have vertical side walls I1 which are preferably parallel to conform to the side walls of the openings II, inwardly convergent, end walls I8 which lie against the end walls of the openings II, and bottom or inner walls I9. The slots or openings II in the body III, as shown in the form of the invention under consideration, are milled or cut so that their end walls I8* are pitched or diagonally disposed, making the openings longer at the outer side I0* of the body than they are at the inner side l0". Y

The inner walls I9 of the inserts are vertical and although they may be arcuate or curved in horizontal cross section so that their inner surfaces may lie in the samevcircle as the internal surface of the body, as shown in Fig. 16, it is preferred to make them fiat, as shown in Fig. 5. When the inserts are formed so that the inner walls I9 are fiat, as shown in Fig. 5, they are preferably limited as to depth or radial extent. so that the inner walls do not project inward beyond the line of curvature of the inner wall IIIb of the body I0. With this construction the inserts I2 do not form projections, restrictions or obstructions on the interior of the body I0.

Lips or flanges 20 extend along the outer margins of the side and end walls I1 and I8. The flanges 20 project outwardly or laterally to lie against the exterior face of the body III and are curved or shaped to conform to the cylindrical surface of the body.

The plates or covers I6 extend across the open or outer sides of the bodies I5 and serve tc retain the material I3 and the pressure unit A in the body, as will be hereinafter described. The cover conforms, generally to the shape of the outer end of the body and in'most instances will be substantially rectangular, as I have shown throughout the drawings. The covers I8 may be curved or arcuate to follow the general contour or curvature of the outer surface III* of the body I0. It is preferred to form each cover so that it has a center section I 6l which is nat or parallel with the bottom wall I8 of the body I5 and has flange parts 20* which conform to and overlie the flanges 20 of the body I5.

In practice I prefer to complete or assemble the bodies I5 and cover plates I6 together to form units preparatory to introducing the material I3 or unit A into the holder formed by the body and cover. In practice this may be done by suitably joining the flange parts 20 and 2l, as by welding or the like. When welding is employed it may be merely at selected spots. However, I prefer to extend it continuously throughout the lengths of the flanges so that the bodies I5 and cover plates I6 are, in eil'ect, solid or integral structures having great strength and rigidity.

In the preferred form of the invention I secure the unit or holder above described to the body I8 by welding. To provide an effective part for welding to the exterior or outer surface III* of the body I0 I extend the iiange 20 so that it has a projecting margin 2lib that extends outward beyond the ange 20 of the body I5, and I turn the extremity of the extension 20.1 inward or back upon itself as clearly shown in Fig. 5, so that a marginal body of metal double the thickness of the ange 20 is presented entirely around the unit for reception of the weld 20. In practice the double thickness or heavy marginal body of metal presented by the insert can be effectively joined to the outer surface I of the body I0 by a continuous weld 2I'Ic extending entirely around the margin of the unit, as shown in Fig. 3.

In accordance with the invention the insert I2 is perforated to permit the drainage of fluid therethrough and to act as a screen or baiile. In practice I may form the bodies of the inserts I2 and the covers I6 of pre-perforated stock. The material of which the inserts I2 is formed may have any desired number of openings or perforations of the selected or required shape and dimensions.

In the case illustrated, the body I5 and the cover I6 of each insert is formed of sheet stock having slot-shaped openings 23 equally spaced apart throughout. The openings 23 are preferably confined to the inner walls I9 and the center section IEa of the body I5 and cover I6, respectively. The center section of the cover which is perforated is preferably flat so it is somewhat shielded or protected. In the preferred arrangement illustrated the openings 23 are disposed in the same direction in the body I5, the wall I9 and the center section I6, and they are disposed horizontally or in the direction of planes transverse of the longitudinal axis of the screen structure, generally.

In practice in any particular case the number, width and spacing of the openings 23 may vary as circumstances require, it being preferred in most instances to provide openings in such number and of such character as to cooperate with the filling material I3 in giving the device maximum capacity. The openings 23 may be arranged throughout the entire extent or area of either or both the wall I3 and center section |68. However, in the preferred construction I leave a plain or unperforated area at the ends of the wall I9 and center section I6,as will be apparent from an examination of Fig. 4 of the drawings.

In Fig. 9 of the drawings I show a form of perforation somewhat different than that just described. In this modified construction I make the perforations round or in the form of drilled holes instead of in the form of slots. This particular formation of perforations may be used to advantage in some instances, and when it is employed it can be used in either the cover I6 or the body I5, or both.

The material I3 occupies the interiors of the inserts I2 to form multiple barrier screens for the incoming fluid. The material I3 may vary in nature, for example, it may be gravel, steel balls or fragments, glass balls or fragments, carborundum balls or fragments, or the like. As is well known the capacity or size of lthe interstices or spaces between the adjacent grains or members of the gravel is determined by the mesh or size of the gravel. Accordingly, the screen may be readily conditioned for use under any given producing conditions by merely providing the inserts I2 with gravel, or the like, of the neness or size to provide the pore spaces that are best suited to the well conditions. The preferred form of the invention provides roughened or corrugated inner faces 22 on the side walls I1 of the body I5, the roughening or corrugating being such as to conform more or less to the grains or texture of the filling material I3. By thus roughening or corrugating the side walls which confine the screening material I eliminate the danger of direct channels or passages that may occur or become established if the faces of the walls are flat and smooth.

In accordance with my invention I maintain the screening material I3 in the holder formed by the combination of the body I5 and cover I6 so that the material is constantly held under pressure, that is, I provide means for yieldingly pressing the material I3 to keep it packed tight and to prevent shifting or movement between the individual particles. In accordance with my invention I accomplish this by a pressure unit A which I preferably insert in the holder with the material I3 so that it is initially compressed or distorted and when in place acts to constantly bear on the material I3.

In practice the pressure unit A may vary wide.. ly in form and character. However, I prefer to employ a body of material 60 having the characteristics of rubber, and I sh-ape and proportion that body of material so that when it is confined in the holder with the screening material I3 it is compressed or distorted or both, and acts to bear on the material I3 exerting the desired pressure and keeping the material I3 tight. Since the device of the present invention is designed primarily for use in an oil well, or the like, and since rubber made from natural stock is subject to deterioration in the presence of petroleum I do not employ natural rubber but rather a synthetic rubber not subject to attack or deterioration under the conditions encountered. Such a synthetic rubber is commonly known under the trade name Neoprene However, in practice I do not wish to confine myself to this particular material and wish it understood that I can use any material that will, when '.onned with the screening material I3, bear thereon to hold the material I3 under pressure- In accordance with my present invention I assemble or fabricate the holder for the screening material by permanently joining the body I5 and cover I6 together, as by welding, all of which I have described above. In such case it is necessary to provide a filling opening in the holder through which the material I3 and the unit A can be inserted.

In accordance with the preferred form of construction I provide a lling opening that is initially open or uncovered and which is designed to be closed by a closure tongue integral with thel holder. In the particular construction illustrated I provide two suitably spaced cuts 65 in the body I5 to extend inward from the outer edge of ange 20 and into one of the walls of the body. In the case illustrated the cuts 65 extend into one of the end Walls I8 of the body. These two cuts 65 establish a closure tongue 66 whichv or joined to the flange of the cover but is en-k tirely free, as will be seen in Fig. 6. v

The opening 61 is shaped, located and proportioned so that it will readily receive the screening material I3 and when the desired amount of screening material has been filled into the holder somewhat through the opening 61. is then closed by bending or deilecting the through the opening 81 the pressure unit A is inserted. When the pressure unit is initially arranged in place in the holder it may project The holder tongue-like closure 66 from the position shown in Fig. 6 to that shown in Fig. 8 where it forms a continuation of the wall .I8 and flange 20 and squeezes or presses the u nit A tight within the holder to exert pressure upon the material I3.

It will b e apparent that the means just described provides a very simple, practical way for lling the material I3 into the holder and for closing the filling opening. Further, it will be readily understood that when the unit is finished or completed, as above describedl the material I3,

is established therein under pressure and that pressure remains constantly on the material I3 due to the fact that the unit A has been compressed or distortedby the closing of the tongue In the form of the invention shown in Figs. 10 to 15, inclusive, the end walls II!b of the openings Il in the body I are not pitched or inclined but are at right angles to the inner and outer walls of the body. In this case the endwalls I8c of the body of the insert are not inclined or pitched, but are disposed to flt against the walls Ib. 'I'his will be apparent from examination of Fig. 11 of the drawings. In this form of the invention the tongue closure 66* is shaped somewhat differently from the closures shown in Figs. 1 to 8, inclusive, in that it has a right angle bend at the point X where the inner wall portion 'I0 joins the outer or flange portion 1I. Apart from this difference in form the tongue 66a will act substantially the same as the tongue 66 above described.

It is to be noted that in the form of the invention shown in Figs. to 15, inclusive, the end walls I8 as well as the side walls II are corrugated or roughened to yconform to the texture of the filling material I3. It will also be noted that in the form of th'e invention shown in Figs. 10 to 15, inclusive, the projecting marginal portion 20b provided on the flange 2Ill of the cover is not folded back on itself to be of double thickness, but merely has its edge 80 turned in presenting a substantial surface to receive the weld employed for joining the unit with the body I0.

In Fig. 16 the insert or unit has its inner wall curved instead of being flat. In this case the curvature and corrugation is such that the wall of the insert is flush with and forms a continuation of the inner wall of the body or pipe. I have shown the insert with round holes for passing well fluid. It will be understood that slot type openings can be used in this case as well as in the other construction described.

The inserts areunitary devices th'at can be inexpensively manufactured to have accurate perforations and to have eiractly the desired screening material therein. Premanufactured or fabricated units I2 can be maintained in stock, ready for immediate application to casings or bodies I 0, as circumstances require. In this connection it will be apparent that units having perforations of different sizes or spacings can be manufactured and screening materials of different grades can be employed as circumstances require.

The screening material I3, in accordance with the invention, is confined under pressure in the holders and is not subject to working loose under conditions of jarring or vibration. Should there be any tendency for the material I3 to loosen as by sluiting or by reason of fracture of a few of th'e particles, this is immediately compensated for or taken up by the expansion unit A.

The units I2 inserted in the body Itas above described, and made fast therein by the welding 20, constitute a multi-barrier screen having all the advantages of the conventional gravel packed screen without the disadvantages common thereto. 'I'he screen of the present inventionis confined to the tubular body I0 so that the opening therethrough is in no way restricted and the thin sheet metal parts which project from the exterior do not even project as far as the collar Il'. Further it is significant that the holders of the units built up of the bodies I5 and the covers I6 secured together by welding, form rigid stmotures having substantial strength and when these units are welded to the body I0 they materially strengthen and reinforce that structure, compensating to a large extent for the weakening of the body I 0 due to the formation of the openings II. Due to this feature a very large number of inserts can be applied to a body IIl without materially or seriously weakening it and, consequently, a large or high capacity screen can ybe obtained in a limited length of the body I0.

Having described only typical preferred forms and applicationsof my invention, I do not wish' to be limited or restricted to the speciilc details herein set forth, but wish to reserve to myself any variations or modifications that may appear to those skilled in the art and fall within the scope of the following claims.

Having described my invention, I claim:

l. A holder for screening material applicable to the wall of a tubular well part including two sheet metal parts, one a cupped body, and the other a. cover secured over the body, the parts h'aving apertures to pass fluid and one of said parts having a filling opening, there being a tongue formed on one part at the opening to be deflected to close the opening.

2. A holder for screening material including a cupped body, and a sheet metal cover for the body having a marginal flange projecting beyond the body and turned to present a body for reception of welding.

3. In combination a tubular body having an opening therein, a fluid screening insert including a perforated cupped body arranged in the opening and having a marginal flange to engage the outer wall of the tubular body, and a perforated cover arranged over the cupped body with a flange overlying th'e flange of the cupped body and having a projecting marginal portion turned in and engaging the outer wall of the tubular body, and welding joining said marginal portion and the outer wall of the tubular body.

4. An oil well screen including a tubular body having an opening in its wall, and a screen unit for the opening comprising a cupped sheet metal section set in the opening to have its inner wall substantially flush with the internal surface of the body so no part of the insert projects inwardly from the inner wall of the body, an outwardly extending flange on the mouth of the cupped section, gravel in the cupped section forming a multi-barrier screening body, a cover plate extending over the flange and across the mouth of the section to retain the gravel in the section, the cover plate and the inner wall of the section being foraminous to pass the well fluids, and means securing the flange and cover plate to the outer surface of the body forming a pressure tight seal along the edges of the structure formed by the flange and cover plate to prevent the entrance of ti'liuid pressure between the body and such strucure.

5. A well screen including-a tubular body having an opening in its wall, and a unit inserted in said opening including a cupped section arranged in said opening and having a flange at the outer side of the body, the inner wall of the cupped section being perforate and substantially flush with the inner wall of the body, granular filtering material in the cupped section, a perforate cover plate extending across the outer side of the cupped section and pressing inwardly against the illtering material to retain the same in a closely packed condition in the cupped section, welding securing the cover plate to said flange in a position where the filtering material is under substantial compression to remain very tightly packed in the cupped section, and means for securing the ange to the body, the last named means including a continuous weld joining the edges of the flange and cover plate with the body and forming a iluid tight seal to prevent the entrance of fluid between the ange and the exterior of the body and between the flange and cover plate.

6. A well screening unit including, a permanently closed holder forming a container of ilxed size and shape, means for mounting the holder on a well part, screening material confined in the holder, and a body of rubber-like material coniined in the holder with the screening material and maintaining pressure on the screening material.

7. A well screen including, a tubular body with a side opening, a perforate holder secured at the opening, screening material conned in the holder, and a body of rubber-like material confined in the holder maintaining pressure on the material in the holder.

8. A well screen including, a tubular body with a side opening, a sheet metal holder occupying the opening and having perforate inner and outer walls, a body of granular screening material confined in the holder, and a body o1' rubber-like material coniined in the holder with said material remote from the perforate parts to maintain pressure on said material.

9. A holder for screening material including two sheet metal parts, one a cupped body, and a cover secured over the body, the parts having apertures to pass iluid and one of said parts having a filling opening, screening material in the holder, a resilient pressure member in the holder to bear on the material, there being a tongue formed on one part at the opening bent to close the opening and bear on said member.

10. A unit for a well screen including a perforate holder having a sheet metal part with an opening through it and a tongue-like closure at the opening, screening material in the holder, and a body of rubber-like material in the holder at the opening bearing on said material, the closure being bent to a position to close the opening and bearing on the rubber-like material.

11. A unit for insertion in an opening in a tubular well part including, a holder having a cavity therein and perforate at its inner and outer ends and having a side wall .to fit in the opening and said side wall having an aperture therein communicating with the cavity and a tongue at the aperture to close it, and screening material in the holder, the tongue being bent toa position to close the opening.

12. A unit for insertion in an opening including, a holder having a cavity therein and perforate at its inner and outer ends and having a peripheral mounting ange projecting from its outer end and having a side wall to fit in the opening and having an aperture therein communicating with the cavity and a tongue at the aperture, and screening material in the holder, the tongue being bent to a position to close the opening.

13. A unit 4ior insertion in an elongate opening in the wall of a tubular body including an elongate holder having a cavity therein and a periorate top and a periorate body and an end wall with an aperture communicating with the cavity and a tongue at the aperture to close it, and screening material in the holder, the tongue being bent to a position to closev the aperture and to be at said wall of the opening when the unit is in working position in the opening.

14. A unit for insertion in an elongate opening including an elongate holder having a cavity and a perforate top and a perforate body and an inclined end wall with an aperture communicating with the cavity and a tongue at the aperture to close it, screening material in the holder and a body of rubber-like material in the holder at the aperture, the tongue being bent to a position to close the aperture and bear on the rubberlike materiel to hem the contents of the helder 1n the center section ena the body to pees mud.

KENNETH A. WRIGHT.

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