US3456725A

US3456725A - Apparatus for selectively completing an oil well

Info

Publication number: US3456725A
Application number: US615851A
Authority: US
Inventors: John R Hatch
Original assignee: COMPLETION TOOLS Inc
Current assignee: COMPLETION TOOLS Inc
Priority date: 1967-02-13
Filing date: 1967-02-13
Publication date: 1969-07-22
Anticipated expiration: 1986-07-22

Description

July 22, 1969 J. R. HATCH 3,456,725

APPARATUS FOR SELECTIVELY COMPLETING AN OIL WELL Filed Feb. l5, 1967 3 Sheets-Sheet 1 `uly 22, 1969 J. R. HATCH 3,456,725

APPARATUS FOR SELECTIVELY CQMPLETNG AN OIL WELL Filed Feb. 1s, 1967 s sheets-sheet 2 July 22, 1969 .1. R. HATCH 3,456,725

APPARATUS FOR SELECTIVELY COMPLETING AN OIL WELL //r Ha ILC/7 g INVENTOR.

2 maj;

ATT/P/VEKS 3,456,725 APPARATUS FOR SELECTIVELY COMPLE'IING AN UIL WELL .Iohn R. Hatch, Big Spring, Tex., assigner to Completion Tools, Inc., Eig pring, Tex., a corporation of Texas Filed Feb. 13, i967, Ser. No. 615,851 Int. Cl. E21b 23/00 U.S. Cl. 166-147 22 vClaims ABSTRACT F THE DISCLOSURE An oil well completion apparatus having dual expandable packer jackets inflatable by a fluid pressure responsive valve and having removable plugs for ow of well fluid therethrough. A method of completing an oil well by inating the dual packer jackets and cementing above or above and below the packer and removing plugs for production of well fiuid. An oil well casing shield device having an expandable packer jacket infiatable by a first fiuid pressure and deflatable by a second and higher fluid pressure.

Background of the invention The present invention generally relates to an improved Well packer apparatus for shielding or protecting a producing zone within an oil well and to a method for producing oil or gas from such zone. Completion tools of the inflatable packer type and methods of their use are known in the art as indicated, by way of example only, in United States Patents Nos. 3,194,312 and 3,196,949. Such inflatable jacket type packers are useful in completing an oil well to produce liuid therefrom after drilling is complete by shielding the producing formation from cement. Moreover, such completion tools have eliminated costly perforation of the casing and consequent damage to the casing and cement by explosive charges through the use of sliding sleeves to allow communication of well fluid with the interior of the completion tool for recovery of such duid. Other advantages of the inatable jacket type completion tools have been realized through reduction of completion time and expense, use of the tools in series to reduce chances of communication between close producing zones, and selected simulation and testing of a well during the completion operation by use of such tools.

Notwithstanding the innovations brought about by infiatable jacket type completion tools, it would be highly advantageous to increase the effective recovery and production ability of an individual completion tool without necessarily increasing overall size of such tool. Also, manipulation of the tool downhole by fluid or hydraulic means as opposed to mechanical means is quite desirable in view of the high cost of eliminating mechanical malfunctions in a relatively deep well. Furthermore, prior art methods of cementing have been limited to cementing around a producing formation without the ability to selectively cement and complete the well to permit further activity below the cement as is accomplished by the present invention.

Summary of the invention The present invention relates to an improved valve unit and formation protecting device for selectively completing an oil well wherein the tool has dual inflatable jackets with the provision of increased effective production area without decrease of effective sealing of the well bore from cement. Further provided in the improved completion tool are fluid pressure responsive means for inflating the packer jackets to decrease the possibility of mechanical malfunction downhole as well as Huid pressure operated production ports or plugs to further reduce the possibility of mechanical malfunctions in the well.

Patented July 22, 1969 It is, therefore, an object of the present invention to provide an improved apparatus for selectively completing an oil well through the provision of a valve unit and formation protecting device having spaced dual expandable jackets which increase production area afforded by the tool `without loss of effectiveness of the inflated jackets as seals to shield the producing formation from cement.

A further object of the present invention is the provision of such an improved apparatus wherein the dual expandable jackets are infiated by pressurizing fluid within the tool with consequent elimination of mechanical eX- pansion actuators to reduce the likelihood of malfunction of the tool downhole.

Another object of the present invention is the provision of an improved well completion device wherein production and recovery of well fluid is accomplished by manipulation of pressure of fluid within the tool to further decrease the likelihood of mechanical malfunctions downhole in either low or high pressure production zones.

Other and further objects, features and advantages will be apparent from the following description of presently preferred embodiments of the invention, given for the purpose of disclosure, and taken in conjunction with the accompanying drawings.

Description of the drawings In the drawings forming a part of the disclosure herein, like character references designate like parts throughout the several views wherein:

FIGURE 1 is a cross-sectional elevational view of one embodiment of the present invention in a collapsed or inactive position within a well bore,

FIGURE 2 is a view similar to that of FIGURE l showing the device in a fully operable state,

FIGURE 3 is a horizontal cross-section taken along line 3 3 of FIGURE 2,

FIGURE 4 is a partial cross-sectional side view of a further embodiment of the present invention for cementing above the completion apparatus,

FIGURE 5 is a partial cross-sectional side view of a production portion of the tool of FIGURES 1 and 2 showing exterior screen filter means attached thereto,

FIGURE 6 is a cross-sectional side view of a casing shield device covering a cavity within a casing sidewall,

FIGURE 7 is a cross-sectional side View of means for defiating the casing shield device of FIGURE 6,

FIGURE l8 is a cross-sectional side view of production plug means prior to removal for recovery of fiuid from a well,

FIGURE 9 is a cross-sectional side view of jacket inflation means, and

FIGURE l0 illustrates the inflation means of FIGURE 9 subsequent to ination of the jacket.

Description of the preferred embodiments The embodiments of the present invention relate to methods and apparatus for selectively completing an oil well including an improved valve unit and formation protecting device having dual expandable jacket means inflatable by fiuid pressure from within the device wherein such fluid pressure is further manipulated to effect recovery of oil or gas from the well. Further provided are a method and device also operable by fiuid pressure within the device for cementing above the completion tool and producing fluid from the well. Finally provided by the present invention is a casing shield device for covering a cavity within a casing sidewall to prevent undesired ow of fluid through such cavity.

Referring now to FIGURE 1 of the drawings, the selective completion tool according to the present invention is generally designated by the reference numeral It) and is shown positioned within a well bore 12 of the required depth which has been drilled in any conventional manner. The completion tool is shown attached to and subtending from a conventional tubular string of casing 14 with a section of casing 16 secured at its lower portion, such lower casing in turn being attached to further similar completion tools if desired as might be dictated by well conditions. It will be noted that the completion tool 10 is positioned in the well bore 12 adjacent the producing strata 12a as might be determined by electric log or other similar such means.

The completion tool 10 comprises an inner pipe 18 for usual threadable engagement with the casing 14. An outer sleeve is concentrically spaced with the inner pipe 18 and attached thereto such as by welded extension pieces 22 at the midsection of the tool. Spacing wedges (not shown) also may be located at each end of the outer sleeve 20 to maintain concentric spacing thereof with the inner pipe 18. Thus formed between the outer sleeve 20 and the inner pipe 18 is an annular passageway 24 for flow of cement as will be explained hereafter.

Expandable packer means in the form of inflatable jackets 26 at the upper end and 28 at the lower end of the tool are secured to the outer sleeve 20 in spaced relation as shown. The inflatable`

jackets

26 and 28 may be formed from, for example, nylon reinforced rubber, and attached to the outer sleeve by steel clamps or bands 30. A conduit 32 is provided for uid communication of both

bladders

26 and 28 with valve means 34 to be described in more detail later.

Located centrally of the completion tool 10 are removable plug devices 36 secured between the inner pipe 18 and the outer sleeve 20 and intermediate the dual packers or

bladders

26 and 28. Upon actuation, the removable plug means 36 permit communication of oil or gas uids within the well with the interior of the inner pipe 18.

With reference now to FIGURE 9, the inflation valve means 34 for expanding the

jackets

26 and 28 comprises an enclosed cylinder 38 having an axial aperture 40 at one end and a radial aperture -42 in the side wall thereof. The conduit 32 permitting fluid communication of the jackets with the valve 34 is secured adjacent the aperture 4G while the conduit 44 permits communication of the cylinder 38 with the inner pipe 18 at the radial aperture 42 of the cylinder and a corresponding aperture 46 in the sidewall of the inner pipe. A piston 48 is axially slidable within the cylinder 38 but is normally maintained in the position shown in FIGURE 9 by a shear pin 50. A passage S2 is provided within the piston 48 so that iluid may be conducted from the aperture 46 of the inner pipe 18 through the connecting conduit -44 and to the aperture 40 within the cylinder 38 for communication with the conduit 32. Naturally, the shear pin 50 must be of such size and material to shear at a selected predetermined pressure.

The inflation valve 34 is illustrated in FIGURE 10 in a condition subsequent to inilation of the

packer jacket members

26 and 28 wherein the shear pin 58 has been sheared by pressure of uid in the passage 52 acting against the piston 48. In other words, by increasing pressure of fluid within the inner pipe 18 as it communicates with the packer jackets through the conduit 32 by means of the passage 52 of the piston 48, the pin 50 can be sheared upon the uid reaching a predetermined pressure. Under such conditions, the piston 48 slides into the position shown in FIGURE l() so that the passage 52 no longer registers with the apertures 40y and 42 of the cylinder 38. Thus no further fluid may be passed to the

jackets

26 and 28 for ination thereof. It will be noted that O rings 54 are provided as shown in FIGURES 9 and l0 to promote slidability of the piston 48 as well as to provide a seal between the piston 48 and the inner walls of the cylinder 38. Also illustrated in FIGURE 9 L1 are holes 56 which vent the lower chamber of the cylinder 38 to the well bore to promote slidability of the piston 48 within the cylinder 38 upon shearing of the pin S0.

Referring now to FIGURE 8, the removable production plug means 36 is illustrated in more detail. The plug means includes a tubular member 58 secured such as by welding within a radial port which is preferably formed within the welded extension pieces 22 between the inner pipe 18 and the outer sleeve 28. The tube 58 thus forms a passageway 62 between the inner pipe and the outer sleeve. The tube 58 also is provided with an annular shoulder 64 within its outer end to limit outward movement of a piston or plug `66 which is slidable therein. The piston or plug 66 is normally retained within the tube 58 as shown in FIGURE 8 by a shear pin 68. When uid pressure within the inner pipe 18 reaches a predetermined level, the pin 68 shears causing the plug 66 to slide until it engages the shoulder 64 of the tube whereupon pressure of oil or gas within the well outside of the outer sleeve 2t) forces the plug 66 back into the inner pipe 18 where it drops harmlessly to the bottom of the casing. An O ring 70 secured about the plug 66 promotes slidability of the plug and seals the annular clearance between the plug 66 and the tube 58 before the plug is removed by pressure of fluid.

Operation of the completion tool device 10 and cooperation of the detailed embodiments thereof are best understood by reference to FIGURE 2. Thus when the tool 18 is lowered into the well bore 12 to a point adjacent a producing formation 12a, the packers or

inflatable jackets

26 and 28 are expanded against the well bore 12 by passing fluid such as drilling mud down through the casing 14 and into the inner pipe 18. The fluid then passes through the aperture 46 in the sidewall of the inner pipe 18 and thence through the inflation valve assembly 34 as shown in FIGURES l and 9. The pressurized iiuid then flows through the passageway 52 of the piston member 48 within the cylinder 38 (FIGURES 1 and 9) whereupon it communicates with the

jackets

26 and 28 by means of the conduit 32. The

jackets

26 and 28 are then expanded to engage the sides of the well bore 12 as shown in FIGURE 2. Pressure of the tluid is increased to a predetermined pressure (by way of example only, typically 300 psi.) at which point the shear pin 50 retaining the piston 48 within the cylinder 38 as shown in FIGURE 1 shears causing the piston 48 to slide within the cylinder 38 into the configuration as shown in FIGURES 2 and l0. In this manner, the

jackets

26 and 28 are fully expanded against the well bore 12 to seal the producing strata 12a from the remainder of the well bore 12. Such seal is permanent for practical purposes of this invention since the piston 48 within the cylinder 38 is maintained in a position as shown in FIGURES 2 and 10, by pressure of the fluid within the jackets such that the passage 52 cannot register with the

apertures

40 and 42.

Once the sealing operation as just explained has been completed, the casing may be circulated further by the drilling mud as desired. At this point, cement 72 is forced downwardly through the casing 14, through the inner pipe 18, and then outwardly from the bottom of the inner pipe 18 or from the bottom of the lower section of casing 16 and then upwardly around the exterior' of the casing 16, inner pipe 18 and casing 14. Thus the cement is forced upwardly through the annular passageway 24 formed between the inner pipe 18 and the outer sleeve 20. It will be noted by reference to FIGURE 3, that the cement 72 can pass upward freely through the annular passageway 24 since the radial production tubes 58 do not occupy the full cross-sectional area of the tool. When the cementing operation is completed and the cement has been `allowed to set and cure as is known in the art, it will be recognized that the producing strata 12a is effectively sealed by the cement 72 and the

inflatable jackets

26 and 28 whereby oil or gas may flow only to the production port plug means 36. Advantageously, spacing of the

jackets

26 and 28 increases the amount of producing strata area 12a that is communicable with and producable by the production port plug means 36.

Referring again at this point to FIGURE 8, the slidable plug 66 of production port means 36 is maintained within the tubular passageway 58 by a shear pin 68. The shear pin 68, of course, is selected of such size and material so that it will withstand a predetermined pressure and will not shear during the process of inflating the

dual packer jackets

26 and 28 nor will it shear during the cementing operations. However, upon completion of the cementing operation, fluid such as drilling mud is again introduced into the casing 14 and the inner pipe 18 and is pressured whereby the shear pin 68 shears causing the plug 66 to slide within the tubular passage 5.8 until the plug engages the shoulder 64 which prevents further outward movement of the plug. At this point pressure of the oil, gas or other well fluid within the producing zone 12a (as shown in FIGURE 2) forces the plug 66 (as shown in FIGURE 8) inward whereupon the plug 66 drops harmlessly into the inner pipe 18 and to the bottom of the casing section 16. It should be noted that four sets of the combination of the tubular passageway 58, the plug 66 and the shear pin 68 are provided as shown in FIGURE 3 so that l,there are four effective production ports. The shear pin 68 for each such production port assembly is of the same shear characteristics as each of the other pins so that all of the pins 68 shear simultaneously at a predetermined pressure.

Thus the oil, gas and other well lluids of the producing strata 12a may pass through the aperture 62 of cach of the production port assemblies whereupon the well fluid is introduced into the inner pipe 18 and casing 14 to effect production of the well.

The foregoing discussion of the method and apparatus relating to the removable plug means 36 (production port assemblies) has necessarily assumed that the producing strata 12a is a relatively high pressure production zone such that the plug 66 as shown in FIGURE 8 is forced inwardly whereupon it drops harmlessly into the bottom of the casing 16. It will now become apparent that if the producing strata 12a is a relatively low pressure zone, each combination of the tube 58, plug 66 and shear pin 68 may be mounted within the extension pieces 22 in reverse position from that shown in FIGURES l, 2 and 8. In the latter situation, when fluid pressure is exerted against the plug 66, such plug may drop harmlessly outside of the outer sleeve 20 into a position represented by the dotted outline indicated by the reference numeral 66a.

Referring now to FIGURE 5, illustrated is an outer screen filter means particularly useful with the completion tool of the present invention in a high pressure zone wherein the producing strata would otherwise tend to plug the aperture 62 of the production port tube S8. The screen lter means comprises preferably an inner screen 74 and an outer screen 76 wherein retained between the screens is a layer of sand or other porous lllter media 78. The screens and filter media are readily attachable about the outer sleeve over the aperture 62 of the production port tube 58, serving to prevent pluggage where well conditions dictate use of such screen filter means.

Turning now to a further embodiment of the present invention and with reference to FIGURE 6, a slight modification of the present invention as just described permits cementing only above a producing strata or formation within a well bore. It is highly desirable in some instances when completing an oil well to cement above a producing zone so that activity below the zone is not foreclosed. In such instance, packer jackets 100 (only an upper jacket is shown) may be secured as by steel band 102 to the inner pipe or tubing 104. Preferably, however, a mandrel 106 is provided on which to mount the packer jacket 100.

Thus when a well is to be completed by cementing only above the producing formation (such formation represented by the reference numeral 108), the packer jacket on the tubing 104 is lowered into the well bore 110 on the tubular string or casing 104. When the packer jacket (or jackets) 100 are adjacent the producing zone 108, the jackets are inflated by fluid pressure means as described previously in relation to tool 10 so that the jackets engage and seal the producing formation in the well. With the packer jackets 100 engaging the well bore adjacent the producing formation, a shoe or plug 112 is lowered into the casing 104 such as by a wire line 114. The shoe 112 presents a barrier within the tubing 104 to cement 116 which is passed downwardly through the string and outwardly of the string into the Well bore through an aperture 118 within the tubing 104.

Prior to introduction of the cement, however, a concentric sleeve 120 within the casing 104 is moved into the position as shown from the dotted outline position represented by the reference numberal 120:1. The sleeve, of course, serves to shield the aperture 118 for purposes of preventing flow of drilling mud or other such fluid used to inflate the packer means 100. Thus the sleeve 120 is moved into position as shown so that the cement may be introduced and passed outwardly of the string to cement above the packer jacket 100. After the cement has set and cured, the shoe or plug 112 is removed such as by the wire line 114 to allow introduction of fluid once again into the string and casing 104. At this point, the pressure of such fluid is raised to a predetermined pressure to release the production plug means as has been described previously in relation to the tool 10 to produce fluid from the well formation. The embodiment of the present invention according to FIGURE 4 thus permits either production of well fluid below the cement 116 or treatment of the well formation such as acidizing, etc. as may be required by the well conditions encountered.

Yet another embodiment of the present invention as illustrated in FIGURE 6 provides an effective shield device for covering or patching a cavity that may have formed within casing due to rusting, etching by acid, etc. Such cavities or holes require either removal and replacement of the casing or patching by what has heretofore been a somewhat expensive and involved procedure of forming an impression of the hole or cavity and thereafter inserting an annular and expandable piece of metal within the casing at the point of the cavity to seal the hole. In the present invention, an expandable packer or jacket iS provided to seal the hole wherein the packer may be removed for reuse at any time as when a well is abandoned.

Referring now to FIGURE 6, a segment of casing 200 is illustrated within a well bore 202 wherein the casing has a hole or cavity 204 which is to be sealed. An expandable packer jacket 206 is secured to a pipe 208 which is in turn connected to a tubing string 210 and is lowered into the casing 200 adjacent the cavity 204. The packer jacket 206 is preferably secured such as by steel bands 212 to an outer mandrel 214 which itself is secured to the pipe 208.

When in position as shown in FIGURE 6, the packer jacket 206 is expanded or inflated by the introduction of fluid such as drilling mud, etc. into-the tubing string 210 and pipe 208 whereby such fluid passes through an aperture 216 to an inflation valve assembly 234 similar to that illustrated in FIGURES 9 and l0 (designated by reference character 34). Then the fluid passes through a conduit 218 for communication with the packer jacket 206 to inflate such jacket. Upon reaching a predetermined pressure, a shear pin within the inflation valve assembly pressure, a shear pin within the inflation valve assembly pressured fluid to the packer by means identical to that discussed above in relation to FIGURES 9 and 10. The mandrel 214 to which the jacket 206 is preferably secured is advantageous in that a plurality of axial bypass tubes 220 may be provided within the mandrel for passage of solvents, etc. outside of the tubing string 210 and pipe 208 yet within the casing 200 when desired.

When conditions of the well require that the casing shield device of the embodiment of FIGURE 6 be removed (such as when a well is abandoned), a deation valve assembly 222 illustrated in detail in FIGURE 7 is actuated. As is the case with previously described embodiments herein, the deation valve assembly 222 is responsive to uid pressure to relieve fluid within the packer jacket 206 for detlation of the jacket. The deflation valve assembly includes a cylinder 224 sealably secured at one end 226 to the pipe 203 and open at the other end 228. A piston 230 is axially slidable within the cylinder 224 but is normally maintained within the cylinder by shear pin 232. O rings 236 and 23S serve to promote slidability of the piston 230 within the cylinder 228 as well as to seal the annular clearance between the piston and the cylinder.

An aperture 240 is provided within the sidewall of the pipe 208 while a radial aperture 242 in the cylinder 224 is engaged by a conduit 244, the latter conduit being in iiuid communication with the packer jacket 206 of FIG- URE 6. A check valve in the form of a shoulder or seat 246 within the conduit 244 and a ball 24S to engage the seal is provided adjacent the cylinder 224 to prevent flow of fluid from the deflation valve means 222 to the packer jacket 206.

Thus, in order to deflate the packer jacket 206, iiuid is again introduced into the tubing string 210 and pipe 208 and is pressured to a predetermined pressure whereupon the shear pin 232 (set to shear at the desired pressure) shears causing the piston 230 to slide out the aperture 228 of the cylinder 224. The ball 24S seats against the shoulder 246 of the check valve within the conduit 244 to prevent the pressurized liluid from owing to the packer jacket 206 thereby preventing its rupture. Once the piston 230 is free of the cylinder 224 it drops into the casing and the iluid pressure within the tubular string 210 is then reduced so that fluid within the packer jacket 206 is relieved through the conduit 244 into the casing whereupon the jacket is deflated.

It will be recognized that the shear pin 232 of the deflation valve means 222 must be designed, as will be apparent to those skilled in the art, to shear at a pressure higher than the shearing pressure of the shear pin of the ination valve assembly. in other words, the deation valve assembly 222 must withstand pressure of the iluid when the ination valve assembly 234 is actuated to inflate the packer 206.

Once the packer bladder 206 is deflated as has just been described, the entire assembly secured to the pipe 208 is removed from the well casing for further use. Thus provided is an effective shield for covering a casing cavity yet removable when desired.

As is apparent from the foregoing description of the preferred embodiments of the present invention, methods and apparatus for selectively completing an oil well are effectively provided by the embodiments herein where iluid pressure responsive means are provided to decrease the probability of mechanical malfunction of completion tools downhole of an oil well. Thus an improved valve unit and formation protecting device for cementing above or above and below such device permits increased production area around the completion tool without increasing overall size of such tool. In addition, a unique casing shield device is provided for purposes of covering or patching a cavity or hole within oil well casing whereby the device is removable when desired.

The present invention, therefore, is well adapted to carry out the objects and attain the ends and advantages mentioned as well as those inherent therein. While presently preferred embodiments of the invention have been given for the purpose of disclosure, numerous changes in the details of construction and arrangement of parts can be made which will readily suggest themselves to those skilled in the art and which are encompassed within the spirit of the invention and the scope of the appended claims.

I claim:

1. An improved valve unit and formation protecting device for selectively completing an oil well, comprising: an inner pipe for connection in a tubular string adjacent a producing formation of the Well, an outer sleeve concentrically spaced with and secured to the inner pipe whereby an annular passageway is formed between the pipe and sleeve, dual expandable packer means secured to either end of the outer sleeve in spaced relation, uid pressure responsive means for expanding the dual packer means upon increase of the fluid pressure within the inner pipe and for maintaining the packer means in such expanded condition at a predetermined fluid pressure, said means including:

a conduit for fluid communication of the dual packer means with the inner pipe, cylinder means forming a part of said conduit, piston means axially slidable within said cylinder means and having a passage for conducting iluid therethrough and through the cylinder means, and means for maintaining the piston means normally in uid conducting relation with the cylinder means but yieldable when the piston means is subjected to a predetermined fluid pressure within the inner pipe whereby said piston means is removed from such iluid conducting relation with the cylinder means, and at least one removable plug means secured between the inner pipe and outer sleeve intermediate the dual packer means for communication of well duid with the interior of the inner pipe upon removal of said plug means.

2. An improved valve unit and formation protecting device for selectively completing an oil well, comprising:

an inner pipe for connection in a tubular string adjacent a producing formation of the well,

an outer sleeve concentrically spaced with and secured to the inner pipe whereby an annular passageway is formed between the pipe and sleeve,

dual expandable packer means secured to either end of the outer sleeve in spaced relation,

lluid pressure responsive means for expanding the dual packer means upon increase of the uid pressure within the inner pipe and for maintaining the packer means in such expanded condition at a predetermined uid pressure, said means including:

an enclosed cylinder having an axial aperture at one end 'and a radial aperture in the side Wall thereof,

a -rst conduit for uid communication of the inner pipe with the radial aperture of the cylinder and a second conduit for uid communication of the axial aperture of the cylinder with the dual packer means, and

a piston axially slidable within the cylinder and having a passage therethrough for conducting iluid through the cylinder upon registry of the passage of the cylinder with the axial and radial aperture of the cylinder,

shear pin means for maintaining the piston means normally in fluid conducting relation with the cylinder but yieldable When the piston is subjected to a predetermined fluid pressure within the inner pipe whereby said piston is removed from such fluid conducting relation with the cylinder, and

a vent port in the end of the cylinder opposite the axial aperture therein, and

at least one removable plug means secured between the inner pipe and outer sleeve intermediate the dual packer means for communication of well fluid with the interior of the inner pipe upon removal of said plug means.

3. The invention of claim 2, and means for sealing the piston within the cylinder bore in a fluid tight manner.

4. An improved valve unit and formation protecting device for selectively completing an oil well, comprising:

dual expandable packer means secured to either end of the outer sleeve in spaced relation, fluid pressure responsive means for expanding the dual packer means upon increase of the fluid pressure within the inner pipe and for maintaining the packer means in such expanded condition at a predetermined fluid pressure, and at least one removable plug means secured between the inner pipe and outer sleeve intermediate the dual packer means for communication of well fluid with the interior of the inner pipe upon removal of said plug means, said plug means including:

a tubular passageway between the inner pipe and outer sleeve, said tubular passageway having an annular shoulder within its outer end, a cylindrical plug slidable within the tubular passageway, and means for maintaining the cylindrical plug within the tubular passageway in spaced relation with the annular shoulder of said passageway but yieldable when the cylindrical plug is subjected to a predetermined fluid pressure within the inner p1pe. 5. The invention of claim 4 wherein the means for maintaining the cylindrical plug within the tubular passageway more specifically comprises a shear pin secured to the tubular passageway and engaging the cylindrical plu".

6. The invention of claim 5 and means for sealing the cylindrical plug within the tubular passageway in a tluid tight manner.

7. An improved valve unit and formation protecting device for selectively completing an oil well comprising: an inner pipe for connecting in a tubular string adjacent a producing formation of the well, an outer Sleeve concentrically spaced with and secured to the inner pipe whereby an annular passageway is formed between the pipe and sleeve, first and second jackets expandable by fluid pressure for engagement with the oil well formation wherein each jacket surrounds the outer sleeve and is secured thereto in spaced relation with the other jacket,

fluid pressure responsive means for expanding the first and second jackets, said means including:

a conduit for iluid communication of the first and second jackets with the inner pipe,

cylinder means forming a part of said conduit,

piston means axially slidable within said cylinder means and having a passage for conducting fluid through the cylinder means, and

means for maintaining the piston means normally in fluid conducting relation with the cylinder means but yieldable when the piston means is subjected to a predetermined fluid pressure within the inner pipe whereby said piston means is removed from said lluid conducting relation with the cylinder means, and

at least one removal plug means including,

a tubular passageway between the inner pipe and outer sleeve, said tubular passageway having an annular shoulder within its outer end,

a cylinder plug slidable within the tubular passageway, and

means for maintaining the cylindrical plug within the tubular passageway in spaced relation with the annular shoulder of said passageway but yieldable when the cylinl@ drical plug is subjected to a predetermined lluid pressure within the inner pipe.

8. The invention of claim 7 including screen lter means secured exteriorly of the outer sleeve adjacent the removable plug means.

9. In a valve unit and formation protecting device for selectively completing an oil well of the type having an inner pipe for connection in a tubular string adjacent a producing formation of the well and an outer sleeve concentrically spaced with and secured to the inner pipe whereby an annular passageway is formed between the pipe and sleeve, the combination with said inner pipe and outer sleeve of the improvement comprising:

fluid pressure responsive means for expanding the dual packer means upon increase of fluid pressure and for maintaining the packer means in such expanded condition at a predetermined fluid pressure, said fluid pressure responsive means including:

a conduit for fluid communication of the dual packer means with the inner pipe,

cylinder means forming a part of said conduit,

means for maintaining the piston means normally in fluid conducting relation with the cylinder means but yieldable when the piston means is subjected to a predetermined fluid pressure within the inner pipe whereby said piston means is removed from such fluid conducting relation with the cylinder means, and

10. in a valve unit and formation protecting device for selectively completing an oil well of the type having an inner pipe for connection in a tubular string adjacent a producing formation of the well and an outer sleeve concentrically spaced with and secured to the inner pipe whereby an annular passageway is formed between the pipe and sleeve, the combination with said inner pipe and outer sleeve of the improvement comprising:

fluid pressure responsive means for expanding the dual packer means upon increase of fluid pressure and for maintaining the packer means in such expanded `condition at a predetermined fluid pressure, said fluid pressure responsive means including:

an enclosed cylinder having an axial aperture at one end and a radial aperture in the side wall thereof,

a rst conduit for fluid communication of the inner pipe with the radial aperture of the cylinder and a second conduit for fluid communication of the axial aperture of the cylinder means with the dual packer means,

a piston axially slidable within the cylinder and having a passage therethrough for conducting fluid through the cylinder upon registry of the passage of the piston with the axial and radial apertures of the cylinder,

shear pin means for maintaining the piston nor- Inally in iluid conducting relation with the cylinder but yieldable when the piston is subjected to a predetermined fluid pressure within the inner pipe whereby said piston is removed from such lluid conducting relation with the cylinder, and

a vent port in the end of the cylinder opposite the axial aperture therein, and

at least one removable plug means secured between l. "i the inner pipe and outer sleeve intermediate the dual packer means for communication of well tiuid with the interior of the inner pipe upon removal of said plug means.

11. The invention of claim and means for sealing the piston within the cylinder bore in a uid tight manner.

12. In a valve unit and formation protecting device for selectively completing an oil well of the type having an inner pipe for connection in a tubular string adjacent a producing formation of the well and an outer sleeve concentrically spaced with and secured to the inner pipe whereby an annular passageway is formed between the pipe and sleeve, the combination with said inner pipe and outer sleeve of the improvement comprising:

fluid pressure responsive means for expanding the dual packer means upon increase of tiuid pressure and for maintaining the packer means in such expanded condition at a predetermined fluid pressure, and

at least one removable plug means secured between the inner pipe and outer sleeve intermediate the dual packer means for communication of well uid with the interior of the inner pipe upon removal of said plug means, said removable plug means including:

a cylindrical plug slidable within the tubular passageway, and

means for maintaining the cylindrical plug within the tubular passageway in spaced relation with the annular shoulder of said passageway but yieldable when the cylindrical plug is subjected to a predetermined fluid pressure within the inner pipe.

13. The invention of claim 12 wherein the means for maintaining the cylindrical plug within the tubular passageway more specifically comprises a shear pin secured to the tubular passageway and engaging the cylindrical plug.

14. The invention of claim 13, and means for sealing the cylindrical plug within the tubular passageway in a iiuid tight manner.

1S. In a valve unit and formation protecting device for selectively completing an oil well of the type having an inner pipe for connection in a tubular string adjacent a producing formation of the well and an outer sleeve concentrically spaced with and secured to the inner pipe whereby an annular passageway is formed between the pipe and sleeve, the combination with said inner pipe and outer sleeve of the improvement comprising:

first and second jackets expandable by fluid pressure for engagement with the oil well formation wherein each jacket surrounds the outer sleeve and is secured thereto in spaced relation with the other jacket,

uid pressure responsive means for expanding the jackets including:

a conduit for fluid communication of the first and second jackets with the inner pipe,

cylinder means forming a part of said conduit,

piston means axially slidable within said cylinder means and having a passage for conducting iiuid through the cylinder means, and

removable plug means including:

a cylindrical plug slidable within the tubular passageway, and

means for maintaining the cylindrical plug within the tubular passageway in spaced relation with the annular shoulder of said l2; passageway but yieldable when the cylindrical plug is subjected to a predetermined iiuid pressure within the inner pipe. 16. The invention of claim 15 including screen filter means secured exteriorly of the outer sleeve adjacent the removable plug means.

1'7. An improved valve unit and formation protecting device for selectively completing an oil well comprising:

a pipe for connection in a tubular string adjacent a producing formation of the well, dual expandable packer means secured to the pipe in spaced relation, iluid pressure responsive means for expanding the dual packer means upon increase of fluid pressure and for maintaining the packer means in such expanded condition at a predetermined uid pressure, said iiuid pressure responsive means including:

a conduit for fluid communication of the dual packer means with the inner pipe, cylinder means forming a part of said conduit, piston means axially slidable with said cylinder means and having a passage for conducting uid through the cylinder means, and means for maintaining the piston means normally in fluid conducting relation with the cylinder means but yieldable when the piston means is subjected to a predetermined fluid pressure within the inner pipe whereby said piston means is removed from such fluid conducting relation 4 with the cylinder means, and at least one removable plug means secured in the side wall of the pipe intermediate the dual packer means for communication of well fluid with the interior of the pipe upon removal of said plug means.

18. An improved valve unit and formation protecting device for selectively completing an oil well comprising:

a pipe for connection in a tubular string adjacent a producing formation of the well,

dual expandable packer means secured to the pipe in spaced relation,

fluid pressure responsive means for expanding the dual packer means upon increase of uid pressure and for maintaining the packer means in such expanded condition at a predetermined fluid pressure, said fluid pressure responsive means including:

a first conduit for fluid communication of the inner pipe with the radial aperture of the cylinder and a second conduit for iiuid communication of the axial aperture of the cylinder with the dual packer means,

a piston axially slidable within the cylinder and having a passage therethrough for conducting fluid through the cylinder upon registry of the passage of the piston with the axial and radial aperture of the cylinder,

shear pin means for maintaining the piston normally in fluid conducting relation with the cylinder but yieldable when the piston is subjected to a predetermined Huid pressure within the inner pipe whereby said piston is removed from such fluid conduction relation with the cylinder, and

a vent port in the end of the cylinder opposite the axial aperture therein, and

at least one removable plug means secured in the side wall of the pipe intermediate the dual packer means for communication of well fluid with the interior of the pipe upon removal of said plug means. 19. The invention of claim 18, and means for sealing the piston within the cylinder bore in a uid tight manner. 20. An improved valve unit and formation protecting device for selectively completing an oil well comprising:

dual expandable packer means secured to the pipe in spaced relation,

fluid pressure responsive means for expanding the dual packer means upon increase of Huid pressure and for maintaining the packer means in such expanded condition at a predetermined fluid pressure, and

at least one removable plug means secured in the side wall of the pipe intermediate the dual packer means for communication of well fluid with the interior of the pipe upon removal of said plug means, said removable plug means including:

a cylindrical plug slidable within the tubular passageway, and

means for maintaining the cylindrical plug within the tubular passageway in spaced relation with the annular shoulder of said passageway but yieldable when the cylindrical plug is subjected to the predetermined fluid pressure within the plpe.

UNITED STATES PATENTS 2,177,601 10/1939 Smith 166--187 X 2,301,624 11/1942 Holt 166-127 X 2,633,200 3/1953 Humason 166-127 2,824,612 2/ 1958 Lynes 166-147 2,897,897 8/1959 Breukelman 166-186 X 3,130,783 4/1964 Orr 166-224 X 3,132,694 5/1964 McGlasson et al. 166-147 X 3,194,312 7/1965 Thomas 166-147 X 3,270,814 9/1966 Richardson et al. 166-187 X DAVID H. BROWN, Primary Examiner JAN A. CALVERT, Assistant Examiner U.S. C1. X.R. 166-186, 187, 224