US2191750A - Well cementing apparatus - Google Patents

Description

Feb. 27, 1940. L. L. BROWN 2,191,750 WELL CEMENTI-NG APPARATUS Filed March 14, was 2 Sheets-Sheet 1 [N VENTOR [AW/Pf/Vf A 520W A T NEY Feb. 27, 1940. 1.. L. BROWN WELL CEMEN'I'ING APPARATUS 2 Sheets-Sheet 2 Filed March 14, 1938 INVENTOR 1 4144947162 1 5G0 W/V CJL/ TTORNEY FIG. 7

FIG. 6

V ent formation pressure Patented Feb. 27, 1940 FWELUICEMENTING ArPAaa'rUsf I m x ,LLawrenceLQBrown,Lynwood,,Callfl, assignor-o! one-Iourtli'toRQH. Wellsgand one-fourth to RA. Graser,j both ol'Long Beach, Calif., and

My invention relatesxto'wellcernenting appa- -ratus and processwhich is particularly designed for use. in conjunction with oil wells. Amaterial problem in drilling; for oil is' the preventionof transfer of'liquid ,from,.one zoneto aanother through the annular space between a: well casing I and thewell bore. .Unless 'aseal is providedl'bek tween-the formation and the casing, belowivarious saturated zones, there is danger of transfer 1 and contamination of "the various liquids, For instance, a cement seal is required below the surface water sands, both-.to.prevent drainage of the surface water into a lower strata orcontamina- 1 tion of the surface water' by .up-welling-of salt rate the oil and the salt water sands,'one from the, other, as well as, producing sands of difler- The general practice has been to drill to a point below a saturated sand, or group-of sands, cement a string of casing in place, then proceed with the drilling through the'casing to the next zone. It is customary to run each string of tubing the full length of the, well bore so that at 25 the top there areconcentric strings'ofcasing which, except for the sealingoff of fluid, only one casing serves any useful function. Attempts have been made to eliminate or ,reduce' the number of casing strings by interposing in the casing 80 is landed, are opposite theproperlocations for the introduction of cement into the ;well bore These valves are operated by special plugs ortriggers and require a complicated and expensive-cementing program in order to-cernentat the desired point. Another procedure? is rto lower, a blank casing and gun-:perforate, the same opposite the desired zone, ,Both arrangements: are open to the objection that; the cementing; opera- 4 tions conducted intermediate the endsof the casing' are often unsatisfactorv {I'his-is due, primarily, to channeling of the cement that is,;"by reason of, the fact that the ,casing leans against the'si'de of the well bore the cernentisprevented from completelyencircling the; casing; r A further difliculty is that thecement, in leaving such special, valve or passing through;the gun,perforations,"flows upwardly so that thereis little; or no cement -below,the opening through the casing.

through such perforationsor valve l I Accordingly, among-the obieets of, my'inven- 'tlonare: m 5 First, to provideja wellcementing apparatus and channeling is" avoided; v

termediate the ends of the casing;' 1 1 Fourth, to provide an apparatus ofthis chara-result, particularly; if there'is gas pressure I below, there vis.a tendency -for fluids to comein' bnet ur htq J- R e -9 ule Califg FAppIicationQMarch; 14, 193s, Serial No. 195,856 a and process whereby a' positive seal ofcement may be provided at any predetermined point in-' *terr'nediate the ends of a well casing which not only serves-to prevent transfer of fluid along vthe well here but also insures againstlealgage betweenthe well here and the interior'oi the cas- Second, to providean apparatus of this 'haracter which insures adequate spacing of that portion of the wellcasing to .be' encased in cement, so that free flow of the cement may, be'had Third, to provide an apparatus and process of this character-which may or may not, as desired, water oroil. Also it ishighly desirable to sepabe used in conjunction with: a conventional cementing program," that is, the bottom'of a casing string'may be cemented in the usualnianner and thereafter'myapparatus and process may be used to' accomplish a cementing operation inacter wherein as many devices may be interposed ina tubing string as 'there'are regions in i the well 'bore' requiring cement seals, and, wherein any one of such apparatus may be opened to accomplish a cementing operation"without affectlng or interferingwith theother, so" that the various regions" may be cemented in stages and in anyorder'desired; 1

string special valves which, wh en the casing string the points of communication between the casing and chamber, andbetween the chamber and the I well here are offset axially, or otherwise, whereby v such cement as remains in the "chamber terms I vid'ed' between the casing and thewell bore, and a adequatesealto prevent any communication be-x tween the well bore and the interior ,of the casing stringy .7

Sixth, to' provide'an apparatus of this character which incorporates-special pressure responsive'closure devices and a' special" gun-"designed to flcreate 'suflicient pressure tobp'en the closure devices; such devices being so 'constructed that-they are capable of'resisting the hydrostatic 'heads of fluidTin the well ere and casingfas .well: as any pump pressure-that may be applied a so that the said closure' device's will'not'be accidentally'openedi acterxywhich provides a s'imple; yet elfe'ctive,

Eighth, toprovidetan apparatushof this.

Seventh,- to provide an apparatus of this char- ;-means for registering the pressure exerting "gun in, approximate relation with. s the pressure" re- :sponsive closure devicesy l acter which may incorporate a special gun designed to pierce openings into an intermediate chamber, but which will notpenetrate the outer walls 01 said chamber.

With the above and other objects in view, as may appear hereinafter, reference is made to the accompanying drawings, in which:

Figure 1 is a fragmentary sectional view of a well bore with-a casing incorporating two of my cementing units shown in position and in par- .tial section, the lower apparatus being shown as it appears when cemented in the well, and the upper apparatus being shown as it appears before use;

Figure 2 is an enlarged longitudinal sectional view through 2-2 of Figure l, with my special partition rupturing gun shown in position;

Figure 3 is a transverse sectional view thereof through 33 of Figure 2;

Figure 4 is a fragmentary sectional view on an enlarged scale, showing a modified form of my apparatus wherein a special projectile is used to penetrate into one wall only of my apparatus; Figure 5 is a similar sectional view showing the bullet after it has penetrated;

Figure 6 is an elevational view of a modified form of my cementing unit, wherein hollow spiral ribs are provided to introduce the cement into the well bore with a rotary motion Figure '7 is an enlarged longitudinal sectionalview thereof taken through 1-1 of Figure 6;

Figure 8 is a fragmentary cross sectional view through 8-8 of Figure 7, illustrating one of the outlet ports and its sealing disc; and

Figure 9 is a fragmentary longitudinal sectional view of a modified form of my gun.

My cementing apparatus may be utilized in a variety of ways. One possible installation is illustrated in Figure 1, wherein two cementing units A areinterposed in a casing string B. The lowermost cementing unit may be placed immediately above the liner C and the other below the surface water stands.

Each cementing unit includes an inner shell I, the upper end of which is provided with a conventional pipe thread for connection to a collar of the casing string. The lower end of the inner shell I is screw-threaded into a special collar 2 which, in turn, is screw-threaded to a stem 3 equal in diameter to the inner shell I and the casing string B. The lower end 01' the stem 3 fits into a collar of the casing string.

The upper end of the collar 2 is enlarged to form a shoulder 4 for receiving the lower end I of an outer shell 5 and to facilitate a welded connection therewith. The outer shell 5 encases the lower portion of the inner shell I and its upper end is welded to a spacer ring 6 filling the space between the shell, andwhich may or may not be welded to the inner shell. The spacer ring 6' is provided with ports I therethrough which communicate between the chamber 8 formed between the two shells and the exterior of the casing string. The outer end of each port I is adapted to be closed by a flap 9 in the form of a thin" sheet of metal such as sheet iron, spot-welded to the spacer ring. The purpose of the flap 3 is merely to prevent plugging oi the port I by material which may fall down the well bore.

Near its lower end the inner shellI is provided with apertures adapted to receive plugs I. Each plug I I includes a suitable mounting ring I2. The mounting ring is provided with an internal shoulder, against which rests a rupturable disc I3 held in place by a retainer ring I4. The plug II may be press-fitted or welded in the shell I.

The rupturabie discs I3 are designed to withstand the hydraulic pressure of any fluid within the casing or well bore and, in addition, any pump pressure that may be applied. They are designed, however, to give 'way' to the momentary percussive pressure built up when a small charge of explosive is set oil! in close proximity. This is accomplished by a special gun structure designated generallyby D.

A cylindrical gunbody 2| is provided, having a centrally disposed chamber in which fits a cylindrical cartridge 22. The cartridge 22 comprises a fibre shell containing an explosive powder. The ends of the cartridge 22 are provided with contacts 23, and a filament wire 24 extends therebetween so that upon. application 01' electrical energy the filament wire is heated to incandescence and ignites the powder.

A plurality of lateral bores 25 radiate from the cartridge chamber. Their outer ends terminate in conical muzzles 26 which form, with the bores 25, shoulders adapted to receive sealing discs 21.

Each *sealing disc is in the form of a flat metal plate with a skirt 28 around the margin, which is directed outwardly so that the pressure of liq uid thereagainst tends to force the sealing disc.

provided behind each sealing connected to a yieldable terminal 33.

The yieldable terminal 33 and the head of the screw plug 30 are positioned within a socket 34 formed at the upper-end of the gun body, which socket is internally threaded to receive the lower end of a cable head 35. The cable head carries a terminal 36 which, when the cable head is screwed into the socket 34, engages the yieldable terminal 33. The cable head is secured to a supportingand conducting cable. 31 having a single conductor therein, whereby electric current may be furnished to the cartridge.

Thelower end of the gun body 2| is secured to aweight bar 38 on which is mounted a cage 39 comprising a fixed collar 40 and sliding collar 4| connected by how springs 42. The bow springs 42 are adapted to ride against the inside walls of the casing and inner shell. Each bow spring is provided with a shoe 43 which. is adapted to fit into a channel I5 formed in the collar 2. The

distance between the channel I5 and plugs -I I is approximately the same as the "distance between the shoes 43 and the lateral bores 25 of the gun, so that when the shoes fit into the channel I5 the muzzles of the gun are approximately opposite .the rupturable discs I3.

provided the shoes may be so arranged that they do not ride past the channel, but tend to engage therein. While it is preferred to provide a special channel I for engagementwith the shoes, which channel has a greater width than the recesses formed between adjacent casing ends screwed into the conventional coupling or collar, in order that such recesses will not interfere with the movement of the gun, it should be borne in mind that such conventional recesses may be utilized. In such case-reliance is bad on the weight indicator and measuring device associated with the cable. These structures are conventional and are not illustrated herein.

Operation of my cementing apparatus is as follows: In making up the casing string oneor more of the cementing units are interposed so that when the casing is landed they occur opposite the desired points in the well bore. For example, the lowermost unit may be positioned above the producing zone and the uppermost unit positioned below the surface water sand.

When it is desired to conduct a cementing operation through one of the cementing units the gun D is lowered to a position opposite. the cementing unit, as shown in Figure 2. It should be understood that the casing is full of fluid. Consequently, when the gun is discharged a material surge of pressure is built up, which is ample to rupture the discs l3 if the gun is in any proximity thereto. As a matter of fact, it is unnecessary for the muzzles of the gun to be directly opposite the rupturable discs, but the position of the gun may vary an appreciable distance above or below the rupturable discs. The pressures so generated are materially higher than any pump pressure plus hydrostatic pressure that may be exerted against the discs. Consequently, all operations within the well bore may be conducted without dangerthat the discs may rupture accidentally.

around all sides.

After the discs are ruptured the gun is withdrawn and a conventional cementing operation is undertaken. A cementing job of this type is commonly referred to as a squeeze" job, and the procedure is well established in the industry. By such process cement is forced outwardly through the plugs II into the chamber 8 formed between the two shells and out of the ports I. The flaps 9 readily give way or break off so that the cement is free to flow upwardly around the casing. Inasmuch as the cement is introduced by flow down the interior of the casing and outwardly through the openings in the cementing unit, and thereupon upwardly along the outside of the casing, little or no cement is deposited below the discharge port I. However, the chamber 8 remains full of cement so that a complete seal is provided between the plugs II and the discharge port. It should be noted here that in conducting a conventional squeeze job through open perforations in the casing, or through a special valve, that because little or no cement accumulates below the perforations a very inadequate seal is formed between the well bore and casing below the cement. Furthermore, the outer shell serves to center the casing thereabove in order to insure the distribution of cement If desired, baffle vanes i6 may be provided in the chamber 8 to insure complete distribution of cement around the inner shell between the plugs ii and the port I.

quired pressure.

imbed itself without penetrating the outer shell. In Figures 4 and 5 a gun body 5| is provided having a cartridge chamber 52 adapted to receive a cartridge 53 similar to the cartridge 22. The cartridge 53 is covered at the discharge end of the chamber with an expansion delaying disc 54 i which is spot-welded to a projectile 55. The projectile 55 comprises a head 56 and a point 51. The head is relatively thin, and the point 51 is relatively abrupt and preferably forms a shoulder at its intersection with the head 56. The gun body 5| is counterbored outwardly from the car' tridge chamber 52 to receive a gun barrel 58 adapted to be screw-threaded into position. The gun barrel 58 is provided with a bore 59 in which the projectile 55 extends. Fitted over the pointed end of the projectile is a guide plug 50 which serves to maintain the projectile in proper position within the gun barrel until it is discharged therefrom. The guide plug 80 is formed of relatively fragile material so that it readily breaks apart or disintegrates as soon as the bullet, or

projectile, leaves the gun barrel.

The outer end of the gun barrel 58 may be closed by a sealing disc GI and gasket 52 to prevent the entrance of liquids.

It is preferred, in conjunction with this embodiment of my invention, to substitute an inner shell 53 for the inner shell I, and an outer shell 64 for the outer shell 5, the difference being that the inner shell 63 is made as thin as possible and the outer shell 64 is designed to carry thetensional load of the casing string. The purpose for doing this is to insure penetration of the inner shell 63, as shown in Figure 5, without penetration through the outer shell 54. As shown in Figure 5, the projectile makes a. hole 55 in the inner shell 53, but merely embeds itself without penetrating the outer shell 64.

Reference is now made to Figures 6, 7 and 8: In the structure herein illustrated a shell H is provided, which is threaded for connection at'its upper end to a conventional collar and at its lower end to aspecial collar 12. The collar 12 is similar to the collar 2 in that provision is made for a channel 13 between the ends of the pipe connected by the collar for the purpose of receiving the shoes 43 of the collar locating cage 39.

Welded to the shell II are a plurality of hollow helical ribs 14 which are preferably semi-cylindrical in cross section, closed at their upper ends and provided with openings 15 at their lower ends. Immediately below each hollow rib I4 is mounted a V shaped baiile 16 which protects the opening 15 as well as serving as a deflector for cement discharged through the opening 15.

The upper end of each hollow rib 14 covers a port 11. Each port TI is enlarged at its outer end to form a shoulder against which fits a sealing disc 18. Each sealing disc is initially cupped. as indicated by dotted lines in Figure 8, whereby. when forced into position, the margins form a fluid-tight seal capable of withstanding the re- The particular sealing disc here contemplated is known to the trade as a "Welch" disc.

The modified structure shown in Figures 6'to 8 is installed in the casing string as in the first described structure, and a gun such as shown in Figure 2 is employed, with the distance between the gun muzzles .and the shoes 43 increased to correspond to the distance between the ports 11 and the channel 13. After the discs 18 areruptured, or blown from the ports TI, the cement is introduced through these ports and flows downwardly through the several hollow ribs ll to discharge into the baifles 18 and be deflected backwardly and upwardly between the ribs 14. By reason of the helicaltorm of the ribs the cement is given a whirling action which tends to distribute it evenly around the shell H and the casing string thereabove. The ribs also serve to space the casing string from the walls of the well bore so as to insure complete distribution of the cement.

Reference is now made to Figure 9, wherein a further modifled form of the gun is illustrated.-

In'this construction the gun' body 8| receives the cartridge 22 as in the flrst described structure.

However, in place of the laterally directed boresv intersecting the cartridge chamber a single downwardly directed bore 82 continues from ,the chamber. A sealing disc 85 is pressed into position above the bore 82, said bore being slightly place, as in Figure 2. Also that portion of the gun body surrounding the chamber is relatively massive so that there is little or no danger of the gun body rupturing by reason of the pressure. Except for the above noted differences, the gun structure shown in Figure 9 is similar to the gun structure shown in Figure 2.

' My process of cementing well casing consists essentially of the following steps:

1. Interposing in the casing string a cementing unit having a chamber ported to the well bore but sealed from the casing.

2. Establishing by gun fire, avenues of communication between the casing and the chamber, such avenues being out of registry with the ports of the chamber.

3. Introducing cement through said avenues of communication and chamber to the well bore.

Though I have shown and described certain embodiments of my invention, I do not wish to be limited thereto, but desire to include in the scope of my invention the constructions, com-- binations and arrangements substantially as set forth in the appended claims:

I claim:

1. In an apparatus for introducing cement into a well bore around a well casing for the purpose of efiecting a seal against transfer of fluid along the well bore externallyof the casing, of: a shield incorporated on the casing string opposite the region to be cemented, said shield defining with the casing string a chamber having an inlet communicating with the interior of the casing and an outlet communicating with the well bore, said inlet and outlet being offset with respect to each other to form a passage therebetween adapted, when filled with cement, to form a pressure-tight seal against exchange of fluids between the well bore and interior of the casing; a

sealing means within and initially closing said inlet, said sealing means being capable of withstanding the hydrostatic and pump pressures exerted by fluid in the casing; and an explosively operated device adapted to create a localized surge pressure materially exceeding such hydrostatic and pump pressure for opening said sealing means.

2. In an apparatus for introducing cement into a well bore around a well casing for the purpose of efl'ecting a seal against transfer of fluid along the well bore externally oi the casing,-of: a shield incorporated on the casing string opposite the region to be cemented, said shield defining with the casing string a chamber having an inlet communicating with the well bore, said inlet and outlet being oilset -with respect to each other to form a passage therebetween adapted, when filled with cement, to form a pressure-tight seal against exchange of fluids between the well bore and interior of the casing;,a sealing means initial- 1y closing said inlet, said sealing means being capable of withstanding the hydrostatic and pump pressures exerted by fluid in the casing; an explosively operated device adapted to create a localized surge pressure materially exceeding .such hydrostatic and pump pressure for opening said sealing means; and means for locatingsaid device in approximate registry with said sealing means.

3. A cementing apparatus comprising: a hollow double walled casing section interposed in the casing string and defining a cylindrical chamber having a relatively thin imperforate inner wall and a relatively thick outer wall; outlet ports from said chamber into the well bore: and gun means including a projectile adapted, when fired, to pierce the inner wall only.

4. A cementing apparatus comprising: a hollow double walled casing section interposed in the casing string, and defining a cylindrical chamber having a relatively thin imperforate inner wall and a relatively thick outer wall;.outlet ports from said chamber into the well bore: a gun adapted to be lowered into said casing string and including a projectile adapted, when fired, to perforate the inner wall only; and a locating means for positioning said gun to fire said pro- Jectile in longitudinal offset relation with the outlet port, whereby a passage is established be! tween the gun perforation and outlet port, adapted, when fllled with cement, to form'a pressuretight seal against exchange of fluids between the well bore and interior of the casing,

5. A cementing apparatus comprising: a hollow, double-walled casing section interposed in a casing string and having an unobstructed passage therethrough approximating the internal diameter of said casing string; outlet ports from the outer wall of said casing'section to the wellbore; inlet ports in the interior wall of said casing section; sealing means for said inlet ports set within the walls of the casing section clear of the passage therethrough; and pressure-producing means for opening said sealing means;

6. A cementing apparatus comprising: a hollow, double-walled casing section interposed in a casing string, including an inner wall initially free of ports and defining an unobstructed passage approximating the intemal diameter of the casing string in which it is interposed, an outer wall forming, with the inner wall, a chamber, and having outlet ports communicating between said chamber and the well-bore; perforating the inner wall only.

7. A cementing apparatus comprising: a hollow, double-walled casing section interposed in a' casing string in which it is interposed, an outer,

wall. forming, with the inner wall, a chamber, and

, having outlet ports communicating between said and means for chamber and the well-bore; and means operable subsequent to landing of said casing string, for establishing inlet openings in said inner wall.

8. A structure as specified in claim 6 wherein said means comprises an explosive-operated device adapted to be lowered into the casing string after said casing string is landed, and operated to establish inlet openings in the inner wall only.

9. A well casing cementing apparatus comprising: an unobstructed casing section interposed in a casing stringand having an internal diameter equal to the nominal internal diameter of said casing string whereby tools may pass freely therethrough; a shell positioned on said casing section forming therewith an elongated chamber in communication with the well bore but initially sealed from the interior oi. the casing; and a tool adapted to be lowered into said casing for establishing a port through said casing section into .said chamber.

10. A well casing cementing apparatus comprising: a casing string adapted to be lowered into a well bore; interposed in said casing string, each unit including means defining a chamber having an outlet port in communication with the well bore but sealed from communication with the interior or said casing; and a tool adapted to be lowa plurality of cementing units ered to any of said units for establishing communication between the interior of said'casing string and the chamber of the selected unit, said units having an internal diameter equal to the nominal internal diameter of the casing string and being free of obstruction or constriction, whereby said tool may pass freely to the selected unit.

11. In an apparatus for establishing communication through a casing: a casing section having preformed openings therein; pressure responsive discs initially sealing said openings, whereby said string may be lowered into a well bore in an initially imperforate condition; and, pressure generating means for forcing said discs through said openings.

12.1n an apparatus munication-through a casing string subsequent to landing said string within a well bore; a casing section incorporated in said string and having preformed openings'therethrough; pressure for establishing com responsive sealing means for said openings adapted to withstand the normal pressure of fluid in said well bore; and an explosive operated tool for generating surge pressures capable of opening said sealing means.

LAWRENCE L. BROWN.

Images