CN103857870A

CN103857870A - Method and system for hydraulic fracturing

Info

Publication number: CN103857870A
Application number: CN201280047074.XA
Authority: CN
Inventors: B·M·理查德; 徐阳
Original assignee: Baker Hughes Inc
Current assignee: Baker Hughes Holdings LLC
Priority date: 2011-09-27
Filing date: 2012-08-22
Publication date: 2014-06-11
Also published as: DK2761122T3; RU2604600C2; EP2761122A4; RU2014116958A; EP2761122B1; CA2848205C; BR112014007068A2; WO2013048643A1; AU2012316663A1; CA2848205A1; AU2012316663B2; MX343581B; MX2014003649A; EP2761122A1; PL2761122T3; BR112014007068B1

Abstract

A fracturing operation is done in open hole without annular space isolation. The annular space is spanned by extendable members that are located behind isolation valves. The extendable members can comprise a biodegradable plug that allows extension of the extendable members by application of pressure. With the plug remained in place, additional pressure can be delivered until at least a portion of the degradable material is pushed onto the surface of the formation. At least a portion of the pushed degradable material provides a seal between the end of the extendable members and the surface of the formation to allow pressure to build until the formation fracture gradient is exceeded and the formation is fractured.

Description

Hydraulic pressure fracturing process and system

Technical field

The present invention relates to the system and method for pressure break Oil/gas Well subsurface formations.

Background technology

In completion method, exist two kinds of conventional technology to carry out pressure break.Fig. 1 shows the wellhole 10 with casing string 12, fixes casing string 12 by cementing 14 in annular space 16 around.This normally realizes by the cementing shoe (not shown) of casing string 12 lower ends.In many cases, if intend further to creep into, just described footwear milling is fallen and further continues to creep into.After solidifying with cement stationary pipes post 12 and cement 14, perforating gun (not shown) be lowered to and launch to form perforation 18, then after these perforations 18 of fluid fracturing by transmitting from earth's surface, installing and set packer or bridging plug 20 so that perforation 18 is isolated.After this, be repeated below process: perforating gun perforation, then pressure break, then above the perforation of up-to-date formation pressure break, set another packer or bridging plug.In order from bottom 36 to Oil/gas Well earth's surface 38 by perforation and packer/bridging plug to 22,24; 26,28; 30,32; With 34 be arranged on position suitable in well.

A modification of this scheme is to cancel perforation by telescoping member being arranged in casing wall, and described telescoping member can optionally be extended through cement in cement solidification, enters the passage on stratum and passes cemented annular space to form.At U.S. Patent number 4,475, set forth the technique of replacing perforation by extendible members in 729.After these members stretch out, in annular space, inject cement and open filtration channel so that can safeguard and use this Oil/gas Well in injection by the member stretching out in the situation that this is special.Although eliminated perforation by extendible members, the cost that cementing work adds drilling time may be very high, in some occasions, the logistics complexity in Oil/gas Well place may increase cost.

At present, in Oil/gas Well fluid, expand or for example 40 in Fig. 2 of the outside packer that can otherwise lay, 42,44,46 and 48 can be placed in the

region

50,52 that wherein has valve on the outside of tubing string 49 with isolation, 54 and 56, described valve is generally the slide bushing 58,60,62 and 64 in regional.Tubing string 49 is left sleeve pipe 66 by hanging and its lower end 67 is capped.Use for making the various known devices that lining moves open lining so that can isolate two annular spaces 68 between packer with any required order, 70,72 and 74, so that the fracturing fluid of supercharging can be sent in described annular space and still, pressure is directly introduced in stratum around.This fracturing process need to be placed packer when tubing string suitably at composition, and makes these packer inflations have time delay to isolate aspect described region.Also there is potential uncertainty, such as whether all packers realized sealing so that the pressure forming in tubing string along with the pressure being sent in tubing string 49 at earth's surface place arrives required region reliably.Some examples of swell packers are U.S. Patent numbers 7,441,596; 7,392,841 and 7,387,158.Also there is potential uncertainty, such as the position of the situation fracturing of the possibility forming in the packer place of alternative valve in crack.

Summary of the invention

According to an aspect of the present invention, provide a kind of frac pressure that accurately location applies to required stratum, saved simultaneously or reduced expensive program, such as cementing and ring seal packer, wherein formation characteristics is that wellhole will keep its integrality.Pressure in tubing string is by engaging hermetically the extensible pipeline transmission on stratum.Multiple pipeline group are connected with spacer assembly, so that only have and will be selectively opened by the region of pressure break in any given time.The pressure transmitting by the pipeline stretching out directly arrives stratum and gets around annular space therebetween.

In one embodiment, the method comprises the step of a part for pipeline being put into wellhole, and wherein said pipeline has multiple extendible members and stops up at least a portion of the opening of extendible members with multiple degradable plugs.The method also comprises step: at least one extendible members is stretched out from described pipeline, and at least a portion of the front end of wherein said extendible members engages the part on stratum around; And transmit charging fluid at least a portion of degradable plug is shifted onto around on stratum by extendible members; And use the charging fluid pressure break that transmits by extendible members stratum around.

In another embodiment, degradable plug is configured to stop up completely the opening of described extendible members.In another embodiment, the method also comprises and utilizes the front end that is pulled to part on stratum sealing extendible members of degradable plug and the step in the gap between stratum around.

In another embodiment, the method also comprises provides control to pipeline and the fluid turnover of described opening between stratum, by extendible members around.In one embodiment, this control utilizes multiple slide bushings to realize.In another embodiment, the method also comprises and opens at least one slide bushing charging fluid is sent to the step of the extendible members associated with the described slide bushing of opening.In another embodiment, the method comprises the step of closing the slide bushing of opening and the slide bushing that opens and closes subsequently other and transmit with the opening of the extendible members by associated with described other slide bushing fluid.

According to another aspect of the present invention, provide a kind of and need not inject cement or similar annular space isolation program and implement the system of fracturing operation at open hole well.The annular space of this system is crossed over by the extendible members being positioned at after isolating valve.Can given extendible members group and these extendible members of not capping stretch out to cross over described annular space and engage stratum with sealing means.These extendible members can be telescoping member and comprise biodegradable plug, the described opening that described biodegradable plug is configured to stop up extendible members temporarily makes extendible members can extend to the surface on stratum to flow to the pressure of telescoping member by applying, thereby forms the flexible passage that leads to stratum.Engage with stratum in extendible members and described plug is held in place in the situation that, can by the fracturing fluid of supercharging, extra pressure be sent to the extendible members of obstruction, until at least a portion of degradation material is shifted onto on surface of stratum.At least a portion degradation material being pulled on surface of stratum contributes to provide sealing between extendible members and surface of stratum by filling the leakage paths of any existence.This sealing authorized pressure increases, until exceed formation breakdown gradient and at telescoping member interface fracturing stratum, thus guarantee the accurate location that crack forms.In suitable stratum, do not need to inject cement and keep wellhole integrality.Extendible members can optionally have filtration members.Conventionally, the character on stratum does not need gravel pack yet.Mining tubular column can be inserted into exploiting interested ground layer segment in the tubing string of stretching device and by the extendible members of selectively exposing.

In one embodiment, extendible members comprises degradation material.In another embodiment, extendible members comprises multiple telescopic elements.In another embodiment, this system also comprises at least one slide bushing, this slide bushing be configured to control pipeline and around between stratum, by the fluid turnover of described extendible members.In one embodiment, described slide bushing is configured in response to receiving the object control with specific dimensions by the fluid turnover of described extendible members.

In one embodiment, this system configuration becomes without packer to implement fracturing operation.Alternatively, this system can be configured to utilize some packers that are placed between the extendible members of stretching out to implement fracturing operation.

Description of content above instead of feature of the present invention has been described widely and technological merit so that can understand better detailed description of the present invention below.Below will the other feature and advantage that form claim theme of the present invention be described.Those skilled in the art be to be appreciated that disclosed concept and particular embodiment can be easily with making an amendment or describing the basis of the structure for implementing identical object of the present invention.Those skilled in the art it will also be appreciated that these structures of equal value do not depart from as described in the claims marrow of the present invention and scope.Think the novel features of characteristic of the present invention, such as its formation and method of operating, will from the following description in the time considering by reference to the accompanying drawings, understand better together with advantage with other object.But, being obviously understandable that, every width figure is not being intended to as the restriction to scope of the present invention of only providing for the object of explaining and describe.

Brief description of the drawings

Understand for the present invention being had more completely, referring now to following description by reference to the accompanying drawings, wherein:

Fig. 1 be to sleeve pipe cementing follow perforation and set inner packer or bridging plug with the existing system of area of isolation when by region perforation pressure break;

Fig. 2 uses outside swell packers another existing system with the isolation palp region of slide bushing valve in annular space;

Fig. 3 shows an embodiment of the invention that use the passage that enters stratum being formed by extendible members, and described passage can optionally be realized and opening and closing so that can be directly from tubing string fracturing stratum in walking around annular bore hole space with valve; And

Fig. 4 a shows the extendible members that comprises the telescoping member in retracted position, and Fig. 4 b shows the telescoping member of the flexible passage of formation in extended position;

Fig. 5 a-5f shows the various placement configurations of polymer plug in telescoping member;

Fig. 6 shows the part of described plug in extendible members, and described plug has been pulled on surface of stratum to guarantee the sealed engagement between extendible members and stratum;

Fig. 7 a shows telescoping member and the slide bushing in initial position, and Fig. 7 b shows the telescoping member of stretching out, and wherein slide bushing is opened; And

Fig. 8 a shows the extensible device of telescoping member and running string, and it is configured to make telescoping member to stretch on initial position, and Fig. 8 b shows and the telescoping member of stretching out together with the extensible device of running string.

Detailed description of the invention

Fig. 3 shows the open hole well 100 below sleeve pipe 102.Bushing pipe 104 utilizes liner hanger 106 to hang on sleeve pipe 102.Pressure break assembly 108 is representatives of other pressure break assemblies shown in Fig. 3, one of ordinary skill in the art would recognize that and can use any amount of assembly 108, but its major part is similarly can changes to adapt to the actuating with desired sequence as explaining below.As shown in Figure 4, each assembly 108 has closing device, and this closing device is slide bushing 110 preferably, and it can optionally operate with sitting the ball 114 being placed on bearing 112.In one embodiment, these bearings and to sit the ball that is placed on them are all different sizes, by first make less ball sit on the less bearing being placed on lower assembly 108 and little by little fall will sit the larger ball being placed on different bearings with shut off valve 110 with lining described in orderly close-down from top to bottom.

These extendible members 116 can comprise telescopic element, and such as telescopic element or

extension

120 and 122, these extendible members 116 can realize stretching, extension by these telescopic elements.Extendible members 116 can be by optionally capping of valve 110, and described valve can be any quantity or array or size as required in this application, to obtain the desired flow rate for pressure break or follow-up exploitation.Fig. 3 and 4a show the extendible members 116 on retracted position.Especially, Fig. 4 a shows the zoomed-in view of the extendible members 116 on retracted position.Fig. 3 also show the extendible members on extended position 116 against borehole wall 100 '.Fig. 4 b show extendible members 116 on extended position ' zoomed-in view.Although these legends, as 4a and 4b only show the extendible members 116 that comprises two flexible extensions or element, it should be understood that extensible assembly is the relative motion component that action need can comprise suitable quantity.For example, the width of annular gap 126 can be controlled this quantity or other factors.

In this preferred embodiment, most of or all extendible members 116 start to stop up with stopper 118 most, so that can extendible members 116 be stretched by apply internal pressure in bushing pipe 104.Polymer plug 118 stops up or seals the opening of extendible members 116 at least substantially, thereby when opening the valve 110 at each assembly 116 places and for example in the time that bushing pipe 104 is exerted pressure, these members can being stretched.In addition, in some embodiments, these stoppers 118 are filled leakage paths or the gap between extendible members 116 and stratum, thereby have improved the sealed engagement of extensible assembly interface and the position of guaranteeing accurately to locate frac pressure.Although be discussed in more detail below the material of stopper 118, it should be understood that by the modification of the replacement to these descriptions and change and do not depart from marrow of the present invention and scope and be construed as within the scope of the invention.For example, can substitute described material or be combined to realize the function of stopper 118 with described material with having with any polymer of those similar characteristics described below or material.

This preferred embodiment in, described stopper 118 is degradable.By making degradable stopper 118 seal or stop up at least in part the opening of extendible members 116, system and method for the present invention has been guaranteed extendible members full extension and has been engaged with stratum.Because surface of stratum is always not level and smooth, so likely the periphery of the abutting end of the telescoping member of full extension can't all parts all contact with surface of stratum.As a result, the telescoping member of full extension may not provide optimum pressure to seal for fracturing operation, for example the transmission of the fracturing fluid by flexible passage with contact point place or near fracturing stratum.Therefore, the degradation material of method and system of the present invention seals the one or more gaps between telescoping member and the stratum of stretching out, and guarantees for the enough wiper seal of fracturing operation and the accurate location of the position of exerting pressure.

In one embodiment, once all extendible members stretch and formation passage, described in the time being sent to the pressure increase of the extendible members clogging, stopper 118 is held in place substantially until the pressure increasing promotes at least a portion of described stopper 118 or actuate on surface of stratum, as shown in Figure 6.In the time that at least a portion of degradation material is shifted onto on surface of stratum, degradation material has been improved the sealing that engages between the end of extendible members and surface of stratum by filling joint interface place or near leakage paths, thereby allows increase pressure until exceed formation breakdown gradient and by formation breakdown.

In addition the degradation material being pulled on surface of stratum that, comes from stopper 118 is further guaranteed to maintain the sealing between extendible members and stratum after formation breakdown.Especially, degradation material prevents the loss that charging fluid for example, enters annular space by the gap between telescoping member and the stratum of stretching out (leakage paths).Like this, degradation material maintains described sealing, prevents that described gap from further widening by erosion, and guarantees to exist enough pressure to make fracture extension.In addition in the time of formation breakdown, easily some degradation materials are pushed in stratum.Because described material configuration become can degraded, as described below, it will can not stop exploitation in the future or recovery process or to exploitation or recovery process cause any problem in the future.In one embodiment, degradation material is environmentally friendly, for example biodegradable, and can significantly not endanger environment.

In one embodiment, at least some or all elements of extendible members comprise degradation material as described above.Preferably, select the degradation material of the element that is used as extensible materials to be configured to along with the time can degrade or disappear, thereby remove the exploitation that is improved formation hydrocarbons by the flow path forming across the extendible members of described annular space and permission.

Referring to Fig. 5 a-5f, described stopper 118 can be fixed to extendible members 116, for example, be fixed to telescopic element 122, at least substantially to stop up or to seal the opening of the extendible members 116 in various configurations.For example, described stopper 118 can near end bushing pipe 104 on or near and be fixed on away from stratum in the opening of extendible members, as shown in Fig. 5 a.In another embodiment, described stopper 118 can be fixed into the opening that covers extendible members 116, as shown in Figure 5 b.Although Fig. 5 b shows described stopper 118 at the element 122 that covers extendible members 116 away from the end on stratum, can predict alternatively or combinedly in other embodiments described stopper 118 can cover extendible members 116 near the end on stratum.In another embodiment, stopper 118 can be between two ends of assembly, be fixed to described extensible assembly 116 in the opening of extensible assembly 116, as shown in Figure 5 c.In another embodiment, stopper 118 can front end place or near be fixed in the opening of extensible assembly 116, as shown in Fig. 5 d.In another embodiment, described stopper 118 length of the opening of fill assembly 116 substantially, as shown in Fig. 5 e.Can predict these configurations described in Fig. 5 a-5e can use with various combinations.In addition, in other embodiments, the combination of any configuration shown in Fig. 5 a-5e or configuration can also be included near the degradation material front end that is configured to the element that engages stratum, for example 118 in Fig. 5 f.On front end, have extra degradation material near on the end on stratum, the configuration of Fig. 5 f can further guarantee in the time that extendible members 116 engages stratum that leakage paths is by sealed.In some embodiments, described stopper 118 is fixed to extensible assembly with base closed or stops up described opening.For example, in described stopper, hole or gap can be set.In one embodiment, extendible members is configured to stretch in the time applying about 1000psi to the pressure of about 5000psi.In other embodiments, can predict extendible members can be configured to stretch in other pressure limits.

In one embodiment, described stopper 118 comprises or is to be degraded or the degradation material of decomposing is made by meeting at least in part.As discussed above, stopper material is designed to separate from extendible members in the time applying certain pressure, with: (1) provides the flow path through described extendible members, (2) between extendible members, provide the sealing of improved stratum, and (3) guarantee to exert pressure the accurate location of position with fracturing stratum.The suitable degradation material of described stopper 118 comprises but need not be confined to be degraded into sour biodegradable polymers.A kind of such polymer is the PLA(PLA that comes from the NATURE-WOKS.TM. of branch of Cargill Dow LLC.) polymer 4060D.Along with this polymer unwinds of variation of time and temperature becomes lactic acid, it not only dissolves the filter cake constraining between lining, pipe fitting or barriers and borehole wall, but also can stimulate near flow path region, stratum.The TLF-6267 polyglycolic acid that comes from Dupont Specialty Chemicals is another kind of polymer, and it resolves into the glycolic with identical function.Other polyester materials such as the mixture of polycaprolactam and PLA and PGA decompose in a similar manner and provide similar filter cake to remove function.Such as the solid acid keeping together with wax or other suitable binder of the sulfamic acid in non-limiting example, trichloroacetic acid and citric acid and so on is also suitable.In the situation that liquid and/or suitable temperature exist, cementing agent will be dissolved or fusing and solid acid particles is liquefied and in place, with part contact and remove filter cake from wellhole face and acid stimulation flow path near ground layer segment.Polypropylene homopolymer and solid paraffin are also the materials that in the inventive method, degradable barriers can be used.The product of barriers degraded comprises but the unnecessary similar items such as acid, alkali, alcohol, carbon dioxide and their combination that are confined to.

Existence can be for the material of stopper 118 controlled other kinds that remove.Polyalkylene oxide (such as PEO) and polyglycols (such as polyethylene glycol) are some materials that are widely used in most in other environment.These polymer can slowly dissolve in water.The speed of dissolving or speed depend on the molecular weight of these polymer.Acceptable rate of dissolution can be with 100,000 to 7,0000, and 000 molecular weight ranges is realized.Therefore, can design 50 degrees Celsius of rate of dissolutions to 200 degree celsius temperature scopes by suitable molecular weight or molecular weight mixture.Except provided material, other suitable materials comprise the degradation material as known in the art of stopping up object for various interim down-holes, and they have the chemical characteristic that is suitable for various Oil/gas Well states.

In a non-limiting embodiment of the present invention, degradation material is being degraded within the time period of about 240 hours from about 1.In a substituting non-limiting embodiment, the time period is from about 1 to about 120 hours, from 1 to 72 hour alternatively.In another non-limiting embodiment of the present invention, degradation material is degraded in the temperature range from about 50 degrees Celsius to about 200 degrees Celsius.In a substituting non-limiting embodiment, this temperature can be from about 50 degree to about 150 degrees Celsius.Alternatively, the lower limit of these scopes can be about 80 degrees Celsius.Certainly, will be understood that time and temperature can one work with by described material degradation.Certainly the use of water, (as its be conventionally used in creep into or well completion fluid in) or some other materials can use separately or use together with time and/or temperature with by described material degradation.Operable other fluids or chemical substance comprise but be unnecessaryly confined to alcohol, mutual solvent, such as fuel oil of diesel oil and so on etc.In the context of the present invention, if at least half barriers can dissolve or dissolve in fluid, degradable barriers is considered to " can substantially in described fluid, dissolve ".

In other embodiments, described stopper 118 may further include and postpones degradable material layer, and this material layer is similar to but can be different from described degradation material.This is because wish to postpone degradable material layer and in most of the cases apply or be arranged on degradable stopper.An object that postpones degradable material layer is to be lowered to and to protect between resting period this instrument and degradation material at instrument.Some materials that postpone degradable material layer can be identical or different with the material of stopper 118.

Postpone that degradable material layer can comprise but unnecessary be confined to polyurethane, saturated polyester, polyvinyl alcohol, low molecular weight polyethylene, PLA, polyglycolic acid, cellulose, polyamide, polyacrylamide, polyketone, cellulose derivative, in and high molecular weight silicone and their combination.Cellulose derivative is defined as and comprises but be unnecessaryly confined to CMC (CMC), hydroxyethylcellulose (HEC), polyanion cellulose (PAC), methylol hydroxyethylcellulose (CMHEC) and their combination.Middle molecular weight silicone resin is defined as to be had from about 10, those silicones of weight average (M.sub.w) molecular weight of 000 to about 100,000, and macromolecule two silicones are defined as and have from about 100,000 those silicones to about 750,000 weight average molecular weights.Specially suitable low molecular weight polyethylene comprises but the unnecessary POLYWAX.RTM polyethylene that is confined to come from Baker Petrolite, and it has the number average molecular weight between about 450 to about 3000.

In addition, each or some of them member 116 can have the screen material 128 in the passage forming after these members 116 stretch.The valve 110 associated with each telescopic component 116 can also be with lining Move tool with any required operation in tandem.Each valve can have unique profile that can be engaged on identical stroke or in independent stroke by Move tool, prepares to accelerate pressure break for valve 110 of pressure break and associated flexible array 116 thereof or more than one valve 110 and flexible array 116 to utilize.

As to the another kind of alternative of closing described valve 110, can use hinged ball seat, this ball seat is accepted to be had the ball of given diameter and makes described valve 110 be operated and to make described ball to pass through described ball seat carries out specific movement after: the specific movement of described ball seat makes another ball seat in another valve 110 be configured to that reception and first falls that object has same diameter but another object of operating different valve 110.Can in the single stroke in Oil/gas Well, operate more than one valve by other technologies.For example, can be lowered to and activate hinged Move tool so that on the path of turnover Oil/gas Well, based on the upper unique fillet of each valve (preferably slide bushing) or arrive need mobile particular valve before or even use the known location of each valve to utilize common mobile profile and Move tool to activate to open or close more than one valve.

Alternatively, can be by the order of setting the rupture diaphragm destroying for determine that telescoping member is opened under setting pressure, with particular order under different pressure ratings.But once rupture diaphragm is destroyed to open by the flowing of telescoping member group, in the time destroying another and organize rupture diaphragm and be used for entering another region, those passages cannot be closed again.In the situation that utilizing slide bushing, all available spaces and pressure can be guided to predetermined passage group, but in the situation that utilizing rupture diaphragm, if specific region will by with isolation pressure break, exist mutability still less.

Method of the present invention allows the direction that enters stratum with fracturing fluid in open hole well, to carry out pressure break, and does not need annular barriers; And pressure break is carried out in can the correct stratum in open hole well and without the fixing bushing pipe of cementing.This technology is combined and can be made pressure break carry out with required order on desired position with valve or all telescoping member at the most.After pressure break, can close some or all of valves, close whole well or optionally open one or more positions for exploit and enter mining tubular column (not shown) by bushing pipe with the place occurring in pressure break.The method obtaining has been saved and has been injected the cost of cement and the cost of annular barriers and the time of the whole process cost of pressure break operating point is less than such as those the existing methods described in Fig. 1 and 2.

Although telescoping member has been discussed as preferred embodiment, can expect that other designs can be in the mode that engages stratum effectively across the gap of annular space around, so that pressure transmission minimizing enter the fluid pressure loss in annular space around.One of ordinary skill in the art would recognize that the method focuses on the stratum of strengthening, wherein wellhole is subsided and is not important problem.

To realize mechanically to make the alternative that described member 116 stretches by hydraulic way.As 130 in Fig. 7 a, telescopic unit is retracted in sleeve pipe so that do not exceed its external diameter 132 while installing.In the time that the slide bushing 134 in Fig. 7 b moves, such as sitting when ball 138 while being placed on bearing 140, slide bushing 134 has tapered portion 136, this tapered portion is applied on telescopic unit 130 by mechanical force and makes them stretch to contact stratum, as with shown in 131.Although slide bushing is preferred, can make mechanically telescopic unit stretch with any mechanical device.An example shown in Fig. 8 a and 8b is to use running string 142, and it has the push piece 144 that can collapse so that telescopic unit is released, as shown in Fig. 8 a and 8b.Can use internal pressure or by another kind of device, these push pieces be stretched out.In this case, closing device is best.

That expansion in conjunction with bushing pipe 104 is so that these members arrive stratum around to utilizing pressure to use telescopic element another kind of alternative that member 116 is released.This can be the combination of the telescopic component that is connected with tubulose expansion.The expansion of bushing pipe can be to utilize tube expander, and during being lowered to, the propelling of tube expander can be released at the member of bushing pipe 104 inside.Alternatively, described expansion can utilize and not only make the pressure of bushing pipe expansion but also the pressure that described member 116 is stretched.

Alternatively, what the front end of outmost telescopic section 122 can do is hard and sharp-pointed, such as have carbide alloy or diamond plug-in unit with assist in insert into stratum and with its sealing.The point pattern that this front end can be made profile of tooth or comprise other penetrates stratum to assist.

Although described the present invention and advantage thereof in detail, it should be understood that here and can make a variety of changes, replace and change and not depart from as the marrow of the present invention and the scope that are defined by the following claims.In addition, scope of the present invention is not intended to be limited to the particular embodiment of process, machine, manufacture, composition of matter, device, method and the step described in this manual.The content that will disclose from the present invention as those of ordinary skill in the art, easily recognize can use according to the present invention implement essentially identical function with embodiment as described herein or obtain essentially identical effect current existence or improved process, machine, manufacture, composition of matter, device, method or step afterwards.Therefore, claims are intended to comprise these processes, machine, manufacture, composition of matter, device, method or step within the scope of it.

Claims

1. a method for fracturing stratum, comprises the steps:

Pipeline is put into wellhole, and described pipeline comprises multiple radially extendible members, and each extendible members has passage, and described passage radially extends to described pipeline and described passage extends axially with respect to extendible members,

Utilize degradable plug to stop up at least a portion of the described passage of described extendible members;

Make at least one extendible members in described multiple radially extendible members from described ducts stretched, at least a portion of the front end of wherein said at least one extendible members engages the part on stratum around;

Charging fluid is sent to the described passage of described at least one extendible members, with by least a portion ejection of described degradable plug to described stratum around; And

Stratum around described in the charging fluid pressure break that utilization transmits by the described passage of described at least one extendible members.

2. method according to claim 1, also comprises step:

Utilize described at least a portion by ejection of described degradable plug to seal the gap between the described front end of described at least one extendible members and the described part on described stratum around.

3. method according to claim 1, wherein said degradable plug is configured to stop up completely the described passage of described extendible members.

4. method according to claim 1, also comprises step:

To described pipeline and described around the fluid turnover of described passage between stratum, by described extendible members control is provided.

5. method according to claim 4, wherein said control utilizes multiple slide bushings to realize.

6. method according to claim 8, also comprises step:

Open at least one slide bushing charging fluid is sent to the extendible members associated with the described slide bushing of opening.

7. method according to claim 6, also comprises step:

The slide bushing of opening described in closing; And

The slide bushing that opens and closes subsequently other transmits charging fluid with the passage of the extendible members by associated with described other slide bushings.

8. method according to claim 1, also comprises step:

Remove the extendible members of described stretching, extension, to be provided for the fluid path of exploitation between stratum around described and the annular space of described pipeline.

9. method according to claim 1, wherein making at least one described step that radially extendible members stretches is that described blocked passage by pressure being sent to described at least one extendible members is realized.

10. method according to claim 1, also comprises step:

Packer is placed between the extendible members of two stretching, extensions.

11. 1 kinds of formation breakdown systems, comprising:

Comprise the pipeline of at least one extendible members, described extendible members comprises passage, described passage radially extends to described pipeline and described passage extends axially with respect to extendible members, and wherein said extendible members can extend radially outwardly substantially from described pipeline; And

Degradable plug, it is configured to a part for the described passage that stops up described extendible members, and at least a portion of wherein said plug is in described extendible members.

12. systems according to claim 11, wherein said degradable plug is configured to separate with described extendible members in the time being applied to the pressure of described substantially blocked extendible members and exceeding threshold value.

13. systems according to claim 11, wherein said extendible members comprises degradation material.

14. systems according to claim 11, wherein said extendible members comprises multiple contractable element.

15. systems according to claim 12, also comprise at least one slide bushing, and this slide bushing is configured to be controlled at described pipeline and the described fluid of described passage between stratum, by described extendible members around passes in and out.

16. systems according to claim 14, wherein said slide bushing is configured to have the object of specific dimensions and control fluid turnover in response to receiving.

17. systems according to claim 12, wherein said extendible members is configured to engage stratum around in the time stretching.

18. systems according to claim 12, wherein said extendible members is configured to stretch in the time exerting pressure.

19. systems according to claim 11, wherein said degradable plug is configured to stop up completely the described passage of described extendible members.

20. systems according to claim 11, also comprise at least one packer between the extendible members that is placed on two stretching, extensions.