CN101517193A

CN101517193A - Method of designing blowout preventer seal using finite element analysis

Info

Publication number: CN101517193A
Application number: CNA2007800359012A
Authority: CN
Inventors: 谢菲克·卡恩多克
Original assignee: Hydril LLC
Current assignee: Hydril LLC; Hydril Co LP
Priority date: 2006-07-28
Filing date: 2007-07-30
Publication date: 2009-08-26

Abstract

The invention provides a method of manufacturing, certifying, and optimizing a seal for a blowout preventer. The method includes generating a finite element analysis seal model, smoothing the finite element analysis seal model, and analyzing a strain plot of the smoothed finite element analysis seal model based upon a displacement condition.

Description

Utilize the method for finite element analysis designing blowout preventer seal

The cross reference of related application

The application requires the rights and interests of following provisional application according to 35U.S.C.119 (e): the interim U.S. Patent application series No.60/820 that submitted on July 28th, 2006,723; The interim U.S. Patent application series No.60/847 that submitted on September 28th, 2006,760; The interim U.S. Patent application series No.60/862 that submitted on October 20th, 2006,392; And on April 19th, 2007 the interim U.S. Patent application series No.60/912 that submits to, 809, the full content that is incorporated herein them as a reference.

Technical field

The embodiment that the application discloses relates generally to the preventer (blowoutpreventer) that is used for oil and gas industry.Particularly, embodiment selected relates to design and makes the method for blowout preventer seal, and wherein seal can comprise elastic body and rigid material.

Background technology

Well control is the importance of oil-gas exploration.For example, when drilling well, safety device must be positioned over suitable position, to avoid the following fortuitous event that drillng operation takes place personnel to be damaged and equipment is damaged.

Drilling well comprises and penetrates various subsurface geological structures or " layer ".Sometimes, pit shaft is with the layer of earth penetrating pressure pressure in the pit shaft.When this situation occurring, claim well overflow.The pressure of following overflow to occur raises and is normally caused by formation fluid (can be liquid, gas or their combination) inflow pit shaft.The higher overflow of pressure often spreads (from the high-pressure area to the area of low pressure) from the position that enters pit shaft to well head.If allow overflow to arrive ground, then drilling fluid, drilling tool and other wellbore structure spare may be sprayed from pit shaft.This " blowout " can cause the heavy damage of drilling equipment (comprising for example rig) and rig operating personnel's heavy casualties.

In view of the risk of blowout, the device that will be called preventer is installed in the well head top that is arranged in the face of land or arranges at deepwater drilling and is installed on the seabed, with seal shaft effectively, until taking active measure control overflow.Can start preventer, be left system so that " circulation " controls also in overflow fully.Preventer has several, and wherein modal is annular blowout preventer (annular blowoutpreventer) (comprising spherical blow-out preventer) and ram blowout preventer (ram blowout preventer).To the preventer of these types be discussed in more detail.

Annular blowout preventer uses large-sized annular rubber or the elastic sealing element with metal insert usually, the sealing part is called " packing unit (packing units) ".Can start the packing unit in the preventer, with encirclement drilling rod and drilling tool, thereby between complete sealing drilling rod or drilling tool and the pit shaft " annular space ".Do not have in the hole of packing unit under the situation of drilling rod or drilling tool, compressible seal glue core is so that the hole of packing unit is closed fully.Thereby the packing unit role of the complete closure of annular blowout preventer is similar to stop valve.Usually, around the packing unit sealing drilling rod, wherein can be manually or by mechanical Fast Compression packing unit, to act on the seal around it, prevent from that well from pressing to cause blowout.

Authorize Knox and transfer the possession of the example that has disclosed annular blowout preventer in the U.S. Patent No. 2,609,836 of giving assignee of the present invention, be incorporated herein it in full as a reference with packing unit.The packing unit of Knox comprises a plurality of metal inserts that are embedded in the elastic body, and wherein the metal insert combines with elastic body is complete.The metal insert separates in the mode that is roughly annular in the sagittal plane that extends to pit shaft from the packing unit axis.When the radial compression packing unit seals when resisting well and pressing, insert provides support structure for elastic body.Around drilling rod compression seal glue core or compression seal glue core itself time, radially inwardly push elastic body, make the metal insert also radially move inward.

Refer now to Fig. 1, show the annular blowout preventer 101 that comprises shell 102.Annular blowout preventer 101 has and passes therethrough the hole 120 that matches with pit shaft 103.Around hole 120 and pit shaft 103 packing unit 105 is arranged in the annular blowout preventer 101 then.Packing unit 105 comprises elastic ring body 107 and a plurality of metal insert 109.Metal insert 109 is arranged in the elastic ring body 107 of packing unit 105, and described metal insert 109 distributes in the mode that is roughly annular and separates in the sagittal plane of extending from pit shaft 103.In addition, packing unit 105 comprises the hole 111 concentric with the hole 120 of preventer 101.

The fluid of the opening 113 by pumping into plunger shaft 112, actuating sleeve formula annular blowout preventer 101.Fluid is exerted pressure to piston 117, and piston 117 is moved upward.Along with piston 117 moves upward, piston 117 passes to packing unit 105 via lozenges 118 with power.Pass to the power of packing unit 105 upwards towards the also inside axis of the removable top 119 of annular blowout preventer 101 from lozenges 118 towards pit shaft 103 and annular blowout preventer 101.Because packing unit 105 is against the removable top 119 of annular blowout preventer 101, thereby packing unit 105 does not have to move up because piston 117 passes to its power.Yet packing unit 105 is pressed to packing unit 105 axis of the pit shaft 103 of annular blowout preventer 101 thus owing to the power of being transmitted moves inward.In the time of in drilling rod is in hole 120, under sufficient radial compression, around packing unit 105 sealing drilling rods, enter " make position ".Fig. 5 shows make position.When not having drilling rod to exist, under sufficient radial compression, packing unit 105 complete closed holes 111.

When fluid pumped into the opening 115 of plunger shaft 112 rather than opening 113, annular blowout preventer 101 carried out similar counter motion.Fluid passes to piston 117 downwards with power, thereby the lozenges of piston 117 118 allows packing unit 105 radially to be flared to " release position ".Fig. 4 shows the release position.In addition, the removable top 119 of annular blowout preventer 101 makes it possible to touch packing unit 105, thereby can safeguard or change packing unit 105 under the situation of needs.

Now, illustrate in greater detail the packing unit 105 and the metal insert 109 that are used for annular blowout preventer 101 simultaneously with reference to figure 2,3A and 3B.In Fig. 2, packing unit 105 comprises elastic ring body 107 and a plurality of metal insert 109.Metal insert 109 distributes in the mode that is roughly annular and separates in the sagittal plane in the elastic ring body 107 of packing unit 105.Fig. 3 A and 3B show the example of metal insert 109, and described metal insert 109 can be provided with and be embedded in the elastic ring body 107 of packing unit 105.Usually, metal insert 109 embeds elastic ring bodies 107 and combines fully with elastic ring body 107, thereby provides support structure for packing unit 105.Combination between annular solid 107 and the metal insert 109 has limited the relative motion between annular solid 107 and the insert 109, and described as can be known motion causes the elastic body in the elastic ring body 107 to lose efficacy.More discussion to combination between elastic body in the packing unit and the metal insert can be incorporated herein its full content as a reference referring to authorizing Simons and transferring the possession of the U.S. Patent No. 5,851,013 of giving assignee of the present invention.

Refer now to Fig. 4 and Fig. 5, show the example that is in release position (Fig. 4) and is in the close position the packing unit 105 of (Fig. 5).When being in the release position, packing unit 105 unclamps, and does not have pressurized and around the sealing drilling rod 151, makes to form the gap between packing unit 105 and drilling rod 151, thereby allow fluid to pass through annular space.As shown in Figure 5, when being in the close position, around packing unit 105 pressurizeds and the sealing drilling rod 151, thereby do not allow fluid to pass through annular space.Thereby, but preventer closing seam glue core 105 seals the generation wellbore pressure that blowout caused below resisting.

Similarly, spherical blow-out preventer uses and has the large-scale hemispherical elastic sealing element of metal insert as packing unit.With reference to figure 6, show around the example of the spherical blow-out preventer 301 of pit shaft axle 103 settings.Fig. 6 is selected from U.S. Patent No. 3,667,721 (authorize Vujasinovic, introduce it in full as a reference).Thereby spherical blow-out preventer 301 comprises lower case 303 and the upper case 304 that removably is fixed together by a plurality of bolts 311, and wherein casing component 303,304 can have the curved surface spherical inside surface.Packing unit 305 is arranged in the spherical blow-out preventer 301, and generally includes curved surface elastic ring body 307 and a plurality of curved surface metal insert 309 corresponding to the curved surface spherical inside surface of casing component 303,304.Therefore, metal insert 309 is arranged in the annular solid 307 and in the sagittal plane that the axis from pit shaft 103 extends in the mode that is roughly annular and separates.

In addition, ram blowout preventer also can comprise the elastic sealing element with metal insert.Large sealing spare is arranged on the ram block usually or is arranged on the leading edge of ram block so that sealing therebetween to be provided.Refer now to Fig. 7, show the ram blowout preventer 701 that comprises shell 703, ram block 705 and top seal 711.For Fig. 7, only show a ram block 705, yet two corresponding ram blocks 705 are arranged at pit shaft 103 both sides respect to one another (being shown in Fig. 8) usually.Ram blowout preventer 701 comprises the hole 720 that passes therethrough, the valve gap 707 that is fixed in shell 703 and piston actuated bar 709, and centers on the axis setting of pit shaft 103.Bar 709 is connected on the ram block 705, but drive rod 709 moves inward towards pit shaft 103.Ram block 705 can be drilling rod flashboard (pipe ram) or variable bore ram (variable bore ram), shear ram (shear ram) or blank ram.During starting, tubulose and variable bore ram move, thereby engage and encirclement drilling rod and/or drilling tool, with seal shaft.Relative with it, shear ram joint and physics are sheared any logging cable, drilling rod and/or the drilling tool in the pit shaft 103, and blank ram seals pit shaft 103 under the situation that does not have obstruction.Can be incorporated herein its full content as a reference referring to authorizing Berckenhoff and transferring the possession of United States Patent (USP) 6,554,247 to more discussion of ram blowout preventer in assignee of the present invention.

Refer now to Fig. 8, illustrate in greater detail ram block 705A, the 705B and top seal 711A, the 711B that are used for ram blowout preventer 701.As shown in the figure, top seal 711A, 711B are separately positioned in the groove 713 of

ram block

705A, 705B, and between sealing blowout-preventing flashboard 705 tops and the shell 703 (being shown in Fig. 7).As shown in the figure, ram block 705A has going up of top seal 711A to shear ram block, and ram block 705B is the down cut ram block with top seal 711B.During starting,

ram block

705A, 705B move, thereby engage, and wherein cutting member (shear) 715A is bonded on the top of cutting member 715B, shear drilling rod 151 with physics.As ram block 705A, when 705B moves, top seal 711A, 711B can 703 are to avoid any pressure release or the earial drainage between shell 703 and ram block 705A, the 705B.

Refer now to Fig. 9 A and 9B, illustrate in greater detail top seal 711A, 711B.Specifically shown in Fig. 9 A, top seal 711A, 711B comprise elastic webbing 751, are connected in the elastic part (elastomeric segment) 753 of elastic webbing 751 each end, are arranged on the metal insert 755 in each elastic part 753.The top seal 711A of ram block 705A (promptly go up and shear ram block) also can comprise the supporting structure 757 that is connected between the elastic part 753.Shown in the sectional view among Fig. 9 B, the metal insert 755 that is arranged in the elastic part 753 has the H tee section.The H tee section of metal insert 755 is that elastic part 753 provides support and best rigidity.In addition, should be understood that top seal 711A, 711B can together use with drilling rod flashboard, blank ram or shear ram (being shown in Fig. 8).

Refer now to Figure 10, show the ram block 705A that is used for ram blowout preventer (for example 701 of Fig. 7) with top seal and flashboard packer (ram packer) 717A.Figure 10 is selected from the U.S. and announces No.US 2004/0066003A1 (authorize Griffen etc., be incorporated herein it in full as a reference).Replace shear ram (being shown in Fig. 7 and Fig. 8), Figure 10 shows the drilling rod flashboard assembly with variable bore ram packer 717A, and this variable bore ram packer 717A comprises elastic body and metal.As shown in the figure, variable bore ram packer 717A comprises half elliptic elastic body 761, and metal packer insert 763 is overmolded in this elastic body 761.Metal packer insert 763 be arranged in elastic body 761 hole 765 around.As above at as described in drilling rod flashboard or the variable bore ram, during starting, flashboard packer 717A (with the corresponding flashboard packer that is oppositely arranged with flashboard packer 717A) moves, thereby joint and encirclement are arranged at drilling rod and/or drilling tool in the hole 765, with seal shaft.

For any sealing mechanism that comprises elastic body and metal in the preventer (for example packing unit and top seal in the ram blowout preventer and the flashboard packer in annular and the spherical blow-out preventer), can apply load to bear the pressure between each parts of preventer.For example, for annular blowout preventer shown in Figure 1, when fluid pressure passes to packing unit 105 and during towards the axis closing seam glue core 105 of pit shaft 103 from piston 117 and lozenges 118, fluid pressure causes stress and strain in the face and the body place of contact seal surface (for example lozenges 117 and drilling rod 151) in packing unit 105, thereby sealing is to resist the wellbore pressure from the below.The stress that occurs in the packing unit 105 is approximated to direct ratio with the fluid pressure that passes to packing unit 105.

Because blowout preventer seal stands stress, thereby sealing member material will produce strain to adapt to stress and sealed engagement is provided.The strain capacity that occurs in the sealing member material depends on the modulus of elasticity of material.Modulus of elasticity be stress and strain ratio measure and can be described as distortion of materials trend when material is exerted pressure.For example, for any given stress, the strain of the material production that modulus of elasticity is high is less than the low material of modulus of elasticity.For the material that is used for blowout preventer seal, the modulus of elasticity of metal insert is obviously greater than the modulus of elasticity of elastic part.For example, the modulus of elasticity of steel (is generally about 30,000,000psi; 200GPa) be approximately most of elastomeric modulus of elasticity and (be generally about 1,500psi; 0.01GPa) 20,000-30,000 times.

According to routine, in check, design with when making blowout preventer seal for example preventer use packing unit, the position of stress and/or strain (be stress is concentrated, strain concentrate) appears in the seal and amount is most important, of greatest concern and analysis is maximum with carrying out.When seal stands load (for example the packing unit of annular blowout preventer is around drilling rod or periodically closed repeatedly around himself), estimate the size and Orientation of the stress and strain that occurs in the seal, to determine the performance of seal.The common method that is used to carry out this evaluation is finite element analysis (" FEA ").Particularly, FEA can be used for simulating and estimate the stress and/or the strain that occur in the given displacement state lower seal and concentrates.

Usually,, utilize finite element, to determine the performance of different displacement state lower seal with the blowout preventer seal modelling by FEA.For example, can pass through the FEA modelling, simulation is in the annular blowout preventer packing unit of following displacement state: move to the make position around drilling rod, be pressed between the piston and removable top and drilling rod of annular blowout preventer at this displacement state lower seal glue core.Can utilize the FEA model to generate the strain curve figure of seal (being packing unit in this example), concentrate with the strain that is presented in the particular displacement state lower seal.

Yet the evaluation that this strain is concentrated may not provide the most accurate prediction and the expression of blowout preventer seal performance.Usually, blowout preventer seal is owing to the stress that may stand bears great strain capacity.For example, when sealing around one section drilling rod in that packing unit is pressed into make position, the elastic body of packing unit may bear in the strain concentrated area and surpass 300% strain.In addition, under the situation that does not have drilling rod to exist, packing unit may begin to bear about 400-450% when sealing is around himself strain.This high strain, particularly repeatedly, when periodically acting on seal, cause the seal ultimate failure usually.

In addition, as mentioned above, metal in the blowout preventer seal and elastic body have visibly different modulus of elasticity usually.Because the difference between this modulus of elasticity, when combining, under the situation of pressurized, metal is often controlled elastomeric " flowing " and distortion in seal in preventer.In a large amount of strains, particularly under the strain that periodically displacement causes repeatedly, there is notable difference between the modulus of elasticity of sealing member material in addition, FEA estimates strain and concentrates the performance that may not show seal exactly.

In FEA used, the geometric similarity image (geometrically similar representation) (being commonly referred to grid) that is made of a plurality of finite elements (being discrete domain) can be represented and comprise rigid material and elastomeric seal.Finite element interacts with the simulation seal and the analogue data and the result of different displacement states is provided.Yet the modulus of elasticity of material has heavily stressed and/or strain (being that stress and/or strain are concentrated) the interior finite element in zone of notable difference and may be out of shape improperly.The common improper distortion of the finite element that may occur comprises that unit self caves in, footloose distortion or suffer the loss of stress, strain and/or energy.Except that other improper distortion of finite element, these improper distortion can produce the inaccurate result of the stress and strain that occurs in the model.

According to routine, when FEA produces error result, increase the finite element quantity of grid, to obtain The better resolution at some select locations (for example heavily stressed or zone that strain is concentrated) at least.Thereby, when carrying out modelling, to compare with other zone by FEA, the zone that stress and/or strain are concentrated usually receives more concentrated " concern ".Yet this process can allow this analysis mainly to concentrate on the stress and/or the strain concentrated area of seal model, may limited and/or inaccurate separating thereby draw.For example, FEA usually increases the finite element quantity (thereby further complicated) of these concentrated areas in the seal model, improves the accuracy of simulation stress and strain in the concentrated area.Also can take same way to the strain concentrated area of seal model.Yet, should be understood that increasing finite element quantity or reducing size of mesh opening to increase the time of finding the solution and the inferior amount of calculation of required power.This may cause separating and stop (because error of calculation) and/or draw inaccurate result.

Refer now to Figure 11, show the relation curve of strain among the FEA (y axle) and iterations (x axle).Particularly, the simulated strain that is shown in the y axle can be the size of the principal strain that occurs along specific direction when being in the seal model finite element of given displacement state of simulation.For example, those skilled in the art should be understood that, the size of the principal strain (for example strain that occurs along the z direction of principal axis, the shear strain that occurs in y axle and the z axial plane) that occurs in the finite element when but the y axle display simulation of this figure is in the seal model of certain displacement state (for example around drilling rod closing seam glue core).The FEA analog quantity of being carried out when in addition, being shown in the iterations representation model seal of x axle.Thereby a FEA process is carried out in each " iteration " expression, simulates the displacement of blowout preventer seal, thereby determines the strain size of seal model finite element.

In this approximate procedure, the resolution ratio of finite element improves along with each iteration in the grid (seal model).Particularly, as mentioned above, the way of often taking is to improve the resolution ratio of the grid finite element in the zone of bearing a large amount of stress and/or strain.Yet because metal strengthens the characteristic of elastomeric seal, this localization analysis may produce and test observed separate incoherent FEA stress and/or strain output.In addition, FEA stress and/or strain output may can not converge on owing to complexity and separate.

As shown in the figure, on the y of Figure 11 axle, determine and show the finite element theory strain that the blowout preventer seal that is in the certain displacement state occurs along the simulation principal strain directions.Along with the iterations of FEA model increases, the simulated strain that draws is separated (i.e. the Trendline of the strain point that draws of the each iteration that forms by FEA) and may be inconsistent and merge the theoretical strain that converges under the comparable displacement state.Show theoretical strain ± about 1% tolerance range, represent that acceptable simulated strain separates convergence range.The notion of FEA stress and/or strain output convergence can be regarded as, and separates when the simulation stress/strain to reach when dropping on separating in the tolerance range, and along with the further iteration of separating is proceeded, the simulation stress/strain is separated and continued to keep dropping in the tolerance range.

Thereby, as shown in the figure,, may there be tangible deviation between the theoretical stress by the FEA prediction and strain and true stress and the strain when design with when making the high strain elastic sealing element comprise the rigidity insert.Therefore, present modelling and analyze design and the manufacturing that the method for blowout preventer seal can not provide enough information to improve blowout preventer seal.

Summary of the invention

On the one hand, the embodiment of the application's disclosure relates to the method for making blowout preventer seal.This method comprises: select seal designs, generate the first finite element analysis seal model according to selected seal designs, the smoothing first finite element analysis seal model, based on the strain curve figure of the displacement state analytical smoothingization first finite element analysis seal model, and make seal.

On the other hand, the embodiment of the application's disclosure relates to the method for checking blowout preventer seal.This method comprises: generate the first finite element analysis seal model, the smoothing first finite element analysis seal model, based on the strain curve figure of the displacement state analytical smoothingization first finite element analysis seal model, and strain curve figure and at least one specific criteria of the smoothing first finite element analysis seal model compared.

In addition, on the other hand, the embodiment that the application discloses relates to the method for optimizing blowout preventer seal.This method comprises: the smoothing first finite element analysis seal model, strain curve figure based on the displacement state analytical smoothingization first finite element analysis seal model, strain curve figure based on the smoothing first finite element analysis seal model of being analyzed generates the second finite element analysis seal model, the smoothing second finite element analysis seal model, analyze the strain curve figure of the second level and smooth finite element analysis seal model based on displacement state, replicate analysis and the level and smooth finite element analysis seal model of generation are until obtaining to optimize the sealing model.

From the following description and the appended claims, the others of the embodiment of the application's disclosure and advantage will be apparent.

Description of drawings

Fig. 1 is the sectional view of annular blowout preventer.

Fig. 2 is the sectional view of annular blowout preventer with packing unit.

Fig. 3 A is the phantom drawing of annular blowout preventer with the metal insert of packing unit.

Fig. 3 B is the lateral view of annular blowout preventer with the replaceability metal insert of packing unit.

Fig. 4 is in the sectional view of the existing annular blowout preventer of released position with packing unit.

Fig. 5 is the annular blowout preventer that the is in the close position sectional view with packing unit.

Fig. 6 is the sectional view of spherical blow-out preventer.

Fig. 7 is the sectional view of ram blowout preventer.

Fig. 8 is the phantom drawing of the flashboard cutting member of ram blowout preventer.

Fig. 9 A is the phantom drawing of top seal of the ram block of ram blowout preventer.

Fig. 9 B is the sectional view of top seal of the ram block of ram blowout preventer.

Figure 10 is the phantom drawing of variable bore ram packer of the ram block of ram blowout preventer.

Figure 11 is the graph of a relation of strain and FEA iterations.

Figure 12 is a flow chart of making the method for blowout preventer seal according to the embodiment that the application discloses.

Figure 13 is that the annular sealant core sectional axis of embodiment two-dimensional curve figure (utilizing x axle and the z axle) form that discloses according to the application is to outline drawing.

Figure 14 is the annular sealant core cross-section radial outline drawing according to embodiment two-dimensional curve figure (utilizing x axle and the y axle) form of the application's disclosure.

Figure 15 is the part according to the seal model of the annular sealant core of embodiment three-dimensional curve diagram (utilizing x, y and the z axle) form of the application's disclosure.

Figure 16 is the part according to the seal grid of the annular sealant core of embodiment three-dimensional curve diagram (utilizing x, y and the z axle) form of the application's disclosure.

Figure 17 A is the end-view of annular blowout preventer with the metal insert of packing unit.

Figure 17 B is an end-view of using the metal insert of packing unit according to the embodiment annular blowout preventer that the application discloses.

Figure 18 A is the top view of annular blowout preventer with the metal insert of packing unit.

Figure 18 B is the top view of annular blowout preventer with the metal insert of packing unit.

Figure 19 A is the strain curve figure according to the seal model of the embodiment annular sealant core of the application's disclosure.

Figure 19 B is the strain curve figure according to the seal model of the embodiment annular sealant core of the application's disclosure.

Figure 20 A is the strain curve figure according to the seal model of the embodiment annular sealant core of the application's disclosure.

Figure 20 B is the strain curve figure according to the seal model of the embodiment annular sealant core of the application's disclosure.

Figure 21 A is the strain curve figure according to the seal model of the embodiment annular sealant core of the application's disclosure.

Figure 21 B is the strain curve figure according to the seal model of the embodiment annular sealant core of the application's disclosure.

Figure 22 is according to the embodiment strain of the application's disclosure and the graph of a relation of FEA iterations.

Figure 23 A is the strain curve figure according to the seal model of the annular sealant core of the embodiment Selective Separation of the application's disclosure.

Figure 23 B is the strain curve figure according to the seal model of the annular sealant core of the embodiment Selective Separation of the application's disclosure.

Figure 24 A is the strain curve figure according to the sealing model of the annular sealant core of the embodiment Selective Separation of the application's disclosure.

Figure 24 B is the strain curve figure according to the seal model of the annular sealant core of the embodiment Selective Separation of the application's disclosure.

Figure 25 A is the strain curve figure according to the seal model of the annular sealant core of the embodiment Selective Separation of the application's disclosure.

Figure 25 B is the strain curve figure according to the seal model of the annular sealant core of the embodiment Selective Separation of the application's disclosure.

Figure 26 illustrates the employed computer system of embodiment designing blowout preventer seal that discloses according to the application.

Figure 27 A is the strain curve figure according to the seal model of the embodiment annular sealant core of the application's disclosure.

Figure 27 B is the strain curve figure according to the seal model of the embodiment annular sealant core of the application's disclosure.

Figure 28 is the seal model according to the embodiment annular sealant core of the application's disclosure.

The specific embodiment

On the one hand, the embodiment of the application's disclosure relates to the manufacture method of blowout preventer seal.On the other hand, the embodiment that the application discloses relates to the method for optimizing blowout preventer seal, is used in combination strain curve figure in the method.On the other hand, the embodiment of the application's disclosure relates to the method for utilizing FEA generation strain curve figure to check the blowout preventer seal model after corresponding to certain displacement state model being carried out smoothing and volumetric analysis.

Used as the application, " rigid material " is meant that the seal that can be preventer provides any materials of support structure, comprises metal and nonmetal.The example of rigid material can include but not limited to steel, bronze and high strength composite (for example carbon composite, epoxy composite material, thermoplastic).In addition, used as the application, " seal " is meant can the isolated high-voltage district and the device of low-pressure area.The example of blowout preventer seal includes but not limited to annular sealant core, top seal and variable bore ram.

As mentioned above, be generally used for design and make the method for blowout preventer seal (having elastic body and rigid material) and model may not provide information accurately to improve the performance of seal designs.Thereby, when the embodiment design that discloses according to the application, manufacturing and check blowout preventer seal, can adopt the method that comprises volumetric strain and generate the FEA of strain curve figure, restrain the result under the given displacement state more accurately to draw.Except generating and improving the certain methods of seal model, this FEA method can be calculated the strain in the seal more accurately, and this is because the FEA method is suitable for a large amount of stress and strains that blowout preventer seal stands.The appropriate software of carrying out this FEA include but not limited to ABAQUS (can be available from ABAQUS, Inc.), MARC (can available from MSC software company) and ANSYS (can be available from ANSYS, Inc.).

Particularly, embodiment and method that the application discloses can advantageously provide following method: generate and analysis seal model by FEA, determine the reaction in the displacement state lower seal that is characterised in that a large amount of strains.The method that the application discloses can adopt the seal designs and/or the seal model of simplification, to help the analysis of seal.For example, the method for the application's disclosure can avoid the stress and strain of Analysis of Complex seal designs to concentrate by " smoothing " described design.

Used as the application, term " smoothing " is meant that the complex geometry of simplifying seal designs is to be used for the whole bag of tricks of FEA.These methods can allow the analysis of the level and smooth model FEA model of sawtooth design structure (promptly by) to be associated with the observed state of experiment and converge on definite result (impossible when analyzing without the model of smoothing).Thereby, can determine whole or " volume " state of strain by the model of FEA analysis by the smoothing design structure.By analyzing this volume (being non-localized) strain, can predict the performance of various displacement state lower seal and/or possible inefficacy more accurately.After the volumetric strain state of level and smooth model is analyzed, thus obtained information can be introduced (without the smoothing) seal designs that to make.

Refer now to Figure 12, show the flow chart of the manufacture method of the seal that comprises elastic body and rigid material.As the first step 1210, determine the performance of sealing member material (for example elastic body and rigid material).Can test definite material property by experiment, or provide material property according to commercially available material property data.Subsequently, generate tri-dimensional sealed the model (being grid) 1220 of seal.Thereby, generate the seal designs 1222 that seal model 1220 can comprise that also input seal designs 1221 and smoothing are subsequently imported and analyze to simplify FEA.

Then, use level and smooth seal model 1230, by FEA mimotope shifting state.Preferably, these mimotope shifting states reaction seals are expected power, load condition or the strain that may stand in use.In addition, after the mimotope shifting state, the strain that occurs in generation and the analysis demonstration seal model and strain curve Figure 124 0 of distortion.Ideally, strain curve illustrates corresponding to the position and the amount that occur strain in the mimotope shifting state seal model.Can analyze and estimate 1240 strain curve figure, determine the performance characteristic of seal model.If the seal model needs to improve, then this method is capable of circulation returns 1210, determines the material property of another kind of sealing member material, perhaps capable of circulationly returns 1220, generates and analyze another seal model.This circulation allows further to simulate the seal model by FEA, to determine the performance of seal model after further improving or simulating.In addition, if think that the seal model can accept and satisfy specific criteria, then can use sealing part model to make blowout preventer seal 1250.

In initial step 1210, determine the performance of sealing member material.In these materials, the modulus of elasticity of elastomeric material is lower than the modulus of elasticity of rigid material.Thereby, when seal stands a large amount of stress, partly to compare with rigid material, should changing that the elastic part of seal produces is many.For example, when the packing unit in the annular blowout preventer is pressed into make position, compare with the metal insert, what the elastic body of packing unit produced answers apparition more.Since for arbitrarily given stress input flexibility body answer apparition more than rigid material, thereby be identified for the elastomeric material property of seal, particularly elastic body internal stress and strain relation may be particularly important.

Under constant stress, in viscoelastic material, strain can increase (being creep) in time.On the contrary, under constant strain capacity, the stress in the viscoelastic material descend in time (being relaxation).In addition, higher strain capacity and the lower temperature modulus of elasticity that can cause viscoelastic material increases.The elongation rate of material is meant the percentage change of length of material.Material before losing efficacy can be stood or extend the maximum tension strain that reaches to be called elongation at break.Material can have high modulus of elasticity or low modulus of elasticity, but can show low elongation at break, makes material lose efficacy under the situation that does not experience obvious strain.In addition, the tensile strength of material is the maximum stress (with tensiometer) that material can stand before losing efficacy.When stress acted on material, the material production strain was to adapt to stress.In case when excessive, material will no longer can produce strain to stress, material failure for material.The failpoint of material is called ultimate tensile strength.

In addition, if lagging behind (phase lag) then may appear in the periodically displacement of elastomeric material experience, cause the mechanical energy dissipative in the elastomeric material.When having softening that stress causes, may occur lagging behind.This can be described as the instantaneous irreversible softening of material, described instantaneous irreversible softening taken place when the displacement increase of being experienced surpasses previous arbitrarily maximum value, cause the load-deformation curve skew of material.Thinking this induces softening (also can be described as Mullins effect) at least in part owing to the micro-fracture of connector in the elastomeric material.This makes elastomeric material weaken in the initial deformation process, thereby makes material more weak in material deformation subsequently.

Thereby, In one embodiment of the present invention, as mentioned above, can adopt the elastic body test, determine the elastomeric at least a material property of blowout preventer seal.Particularly, can test to determine the performance of elastomeric material.The example of the test that can carry out includes but not limited to single shaft tensile test, single shaft compression test, lap shear test (lap shear test) and twin shaft tensile test.The single shaft tensile test applies tensile stress and measures the corresponding strain that produces in the material to material along a direction.The single shaft compression test applies compressive stress and measures the corresponding strain that produces in the material to material along a direction.The relevant shear strain that lap shear test applies shear stress and measures material to material.In addition, the twin shaft tensile test corresponding strain that applies tensile stress and measure material to material along both direction.Except that other test well known in the art, the employing of these tests can help to analyze and determine elastomeric material property.In addition, one skilled in the art will appreciate that the material property Yin Wendu owing to most of materials changes, thereby, under different temperatures, carry out test of many times and determine that certain material property may be comparatively suitable.

In step 1220, generate the model (being grid) of seal.When generating the seal model, select the design of rubber seal feature and this design feature is applied to model.For example, for the annular blowout preventer packing unit, when generating the seal model, can select insert consumption, rigid material insert width and be used for the concrete material of rigid material insert.Can (for example can be available from Autodesk at computer aided design (CAD) (" CAD ") program package, Inc. AutoCAD and can be available from the Pro/Engineer of Parametric Technology Corporation) in, set up the seal model, and with sealing part model input FEA program package, perhaps, in alternative, can pass through FEA program package (for example ABAQUS and PATRAN) itself and generate the seal model.

Refer now to Figure 13-16, show the method that the embodiment that discloses according to the application generates the seal model.Particularly, as shown in the figure, can generate the model of annular blowout preventer by the seal designs of using CAD software to make with packing unit 105.As shown in figure 13, can the two-dimensional curve diagram form (using x axle and z axle) generate the sectional axis of seal designs of annular sealant core 105 to outline drawing 1301.Packing unit 105 comprises elastic body 107 and has rigidity (for example metal) the material insert 109 in hole 111.Can generate several radial and axial cross section profile figure to present the different piece of seal.For example, can generate the outline drawing that packing unit 105 has the part of metal insert 109 or do not have the part of metal insert 109.

Then, as shown in figure 14,, can generate the cross-section radial outline drawing 1401 of seal designs, thereby present the different radial components of seal with two-dimensional curve diagram form (using x axle and y axle) except that generating sectional axis to outline drawing 1301.Because the symmetry of packing unit 105, thereby only need generate the radial component of cross-section radial outline drawing 1401 as shown in the figure.Thereby, as shown in figure 15, by built-up shaft to radial contour Figure 130 1,1401, can generate tri-dimensional sealed design 1501, thereby present at least a portion of packing unit 105 with three-dimensional curve diagram form (using corresponding x, y and z among Figure 13 and Figure 14).In tri-dimensional sealed design 1501,, generate metal insert 109 and elastic body 107 with form that can interactional separate component.Complexity according to seal (promptly being packing unit in the case) design can generate more seal outline drawing 1301,1401, to present the more details of seal designs 1501.

In addition, as shown in the figure, seal designs 1501 and model or grid 1601 (subsequent discussion) can only present the radial component of packing unit 105.Yet, can utilize the symmetric geometry of packing unit 105, easily generate the remainder of packing unit 105.One skilled in the art will appreciate that for the radial symmetric model, can utilize and duplicate symmetric part and outline drawing, the generation that comes simplified model.

Refer now to Figure 16, can be with the seal designs 1501 input FEA softwares that use CAD software to make, to generate model or the grid 1601 that a large amount of finite elements 1603 constitute.When stress application and pressure, finite element 1,603 one same-actions of grid 1601 are simulated seal and packing unit.The finite element 1603 of the elastic body 107 of packing unit 105 is corresponding to material property simulation and the response stress and the pressure (promptly showing strain) of elastomeric material.

Similarly, the finite element 1603 of the metal insert 109 of packing unit 105 is corresponding to material property simulation and the response stress and the pressure of metal insert.Thereby finite element 1603 distortion also produces strain, with their response of material property simulation according to the different materials (for example elastic body and rigid material) of seal.Although finite element 1603 is shown eight node units (being brick shape unit (brick element)), can use the finite element of arbitrary shape known in the art.

In addition, when generating seal model 1220, multiple smoothing method can be applied to seal designs 1222.In many cases, as mentioned above, when a large amount of stress and strain of simulation, the actual manufacturing geometry that utilizes FEA to analyze seal may cause complicated.Particularly, the manufacturing geometry of metallic seal parts comprises that fillet and other reduce the feature that stress is concentrated, thereby stress is distributed in the parts that it acted on more equably.Yet, find that these methods may cause the adverse effect that increases the model complexity to the FEA model among the FEA and may hinder FEA generation accurate result.Thereby the seal model that is generated by the smoothing design can comprise the feature that elimination manufacturing stress is concentrated, to improve the result of FEA.

The rigid material that can improve in one embodiment, (being smoothing) seal designs is to reduce its complexity.Refer now to Figure 17 A, show the end-view of metal insert 1701, this metal insert 1701 comprises the beam (flange) 1703 that is connected by the soffit of girder (web) 1705.Metal insert 1701 generally includes round interior angle 1707 and square exterior angle 1709.Yet, in a kind of embodiment of smoothing design, the angle that can improve the metal insert.For example, refer now to Figure 17 B, show the end-view of metal insert 1711 designs of the embodiment that discloses according to the application, these metal insert 1711 designs comprise the beam 1713 that is connected by the soffit of girder 1715.When smoothing should design, can improve interior angle 1717 and attempt reducing or eliminate its radius (as shown in the figure), to simplify the model that makes up subsequently.In addition, when level and smooth seal designs, can improve exterior angle 1719 and attempt increasing or increasing its radius (as shown in the figure), to simplify the model that makes up subsequently.Can analyze the volumetric strain of the seal model that makes up by this way, thereby can obtainable result compare with the method that adopts aforementioned more " localization ", FEA can produce more accurate and definite result.

In addition, in another embodiment, smoothing can comprise shape and its position in elastic body of improving the rigid material insert, rather than comes the smoothing design by the interior angle and the exterior angle of improving the rigid material insert.Refer now to Figure 18 A, show the top view of metal insert 1801, this metal insert 1801 is arranged in the part of elastic body 1802 of annular sealant core.Shown in the beam 1803 and the soffit of girder 1805 (shown in the profile) of metal insert 1801 have rectangular profile, soffit of girder end 1806A, the 1806B of the beam end 1804A of its central sill 1803,1804B and the soffit of girder 1805 are limited by straight flange.End 1804A, 1806A than end 1804B, 1806B diametrically more near axis 103.

Yet with reference to figure 18B, but the shape of smoothing metal insert and orientation are to carry out the volumetric strain analysis.In Figure 18 B, show the top view of metal insert 1811, this metal insert 1811 is arranged in the part of elastic body 1802 of annular sealant core of the embodiment that discloses according to the application.As shown in the figure, the beam 1813 of metal insert 1811 and the soffit of girder 1815 (shown in the profile) have curved end, and limiting with axis 103 is the radial contour at center.Particularly, side 1814C, the 1814D of beam 1813 can be along from axis 103 radially-protruding radial line 1817.Side 1816C, the 1816D of the soffit of girder 1815 be the line (not shown) equally radially.Thereby, as shown in the figure, in this case, can have radian along arching trajectory at beam end 1814A, 1814B between beam side 1814C, the 1814D and soffit of girder end 1816A, 1816B between soffit of girder side 1816C, 1816D.Preferably, curved end 1814A, 1814B, 1816A, 1816B are along the radial trajectories 1818 that limits around axis 103.Thereby as shown in the figure, the width of the beam 1813 and the soffit of girder 1815 increases from end 1814A, 1816A to end 1814B, 1816B along its side 1814C, 1814D, 1816C, 1816D.Thereby, the seal model of Gou Jianing possibility simulated strain more accurately in the FEA process by this way, thus more accurate and definite result produced.

In addition, the level and smooth elastic body of seal designs also.Refer again to Figure 15, elastic body 107 comprises the compression face 108 corresponding to the lozenges 118 of piston (117 among Fig. 1).When starting piston 117, lozenges 118 contacts also press packing unit 105 so that well is sealed.In one approach, can following level and smooth seal designs: improve compression face, to have and the approximately uniform angle of the lozenges of piston.Perhaps, can improve lozenges and compression face, to increase contact area between the two.By improving compression face or lozenges or changing both simultaneously, the seal model of Gou Jianing may the strain of simulated strain curve map more accurately in the FEA process thus.Because elastomeric compression face has the angle different with the piston lozenges in addition, thereby can simplify the output of FEA, thereby when displacement, produce more accurate or definite result.

One skilled in the art will appreciate that except described smoothing and improving one's methods, also can adopt other method.For example, in another embodiment, can improve the soffit of girder of rigid material insert, for example make the soffit of girder hollow of insert, as long as the rigid material insert provides sufficient support structure to bear the pressure that is applied thereto for seal under any and all displacement states.

Preferably, when generating the seal model in step 1220, particularly during the seal designs 1222 of level and smooth seal model, the volume of the elastic body of seal model and rigid material insert remains unchanged substantially.Do not keep constant as fruit volume, then result and the simulated strain that obtains from the strain curve figure that makes by FEA may be inaccurate or inconsistent.For example, when exert pressure in the unit, the pressure that acts on this unit makes the unit be subjected to stress, causes the unit to produce strain to adapt to stress.The stress that acts on the unit is directly proportional with the pressure that acts on the unit and is inversely proportional to the area or the volume of unit.Thereby the pressure of unit increases and/or the volume of unit reduces the then corresponding increase of the stress in the unit if act on.

Utilize this design, elastic body and rigid material insert volume separately preferably remain unchanged substantially, to produce accurate result.For example, if the volume of whole seal model is obviously different with actual seal, then the strain curve figure of seal model can be presented at the increase of the strain in the elastic body under the corresponding displacement state.In addition, if be applied to the stereomutation that the smoothing method of the seal designs of seal model makes the seal model, for example increase the elastomeric volume of seal model in smoothing process, then the strain curve figure of level and smooth model can be presented at that simulated strain reduces under the corresponding displacement state.Whether thereby if the volume of the elastic body of seal model and rigid material insert increases or reduces, then the simulated strain in the model changes inherently, be to obtain any improvement and the seal model is improved and do not rely on.In addition, if the cumulative volume of seal is consistent for level and smooth model peace sliding formwork type, and the relative volume of elastic body and rigidity insert changes, and then can be in harmonious proportion strain curve figure similarly.

Now continue step 1230, use the seal model that is generated to simulate the displacement state of blowout preventer seal by FEA.Preferably, the mimotope shifting state is that seal is expected the load and the strain that may stand in the course of the work.For example, the packing unit model of annular blowout preventer can require and be pressed into make position to seal one section drilling rod relevant mimotope shifting state on every side.In addition, if there is no drilling rod, then model can experience with the pressurized sealing around himself with the relevant mimotope shifting state of closed hole.

In step 1240, can analyze and estimate strain curve figure to determine the performance of modelling seal, this strain curve figure shows strain and the distortion that occurs corresponding to displacement state in the seal model.Refer now to Figure 19-21, show the cross section strain curve figure of the seal model of the embodiment that discloses according to the application.Particularly, the seal model is the model of the packing unit of annular blowout preventer, wherein under the displacement state around the sealing drilling rod 151, begins to simulate the packing unit model.Then, show and simulate the packing unit that the packing unit that is under this displacement state is in original state before, but the strain that the mimotope shifting state is caused is superimposed upon on the packing unit of not displacement.This method can followingly be carried out: the strain of each unit of displacement calculating state lower seal model, and the strain of each corresponding units of the seal model that is in original state is shown.This strain reverse " mapping " that can allow to occur in the mimotope shifting state lower seal glue core is to its initial position in packing unit.

Refer now to Figure 19 A, the strain curve of packing unit model illustrates the maximum main logarithmic strain (maximum principal log strain) that occurs in the mimotope shifting state lower seal model around the packing unit sealing drilling rod 151.In Figure 19 B, the strain curve of seal model illustrates initial packing unit before the seal modeling displacement state among Figure 19 A, but the maximum main logarithmic strain curve map of Figure 19 A is superimposed upon not on the deformable seal spare model.Particularly, the strain that is in each unit in the seal model of displacement state among Figure 19 A is superimposed upon among Figure 19 B not on each unit of deformable seal spare model.This makes strain curve figure can demonstrate the position that strain is concentrated under the displacement state not.

Similarly, with reference to figure 20A, the strain curve of packing unit model illustrates the axial logarithmic strain that occurs in the mimotope shifting state lower seal model around the packing unit sealing drilling rod 151.In Figure 20 B, the strain curve of seal model illustrates initial packing unit before the seal modeling displacement state among Figure 20 A, but the axial logarithmic strain curve map of Figure 20 A is superimposed upon not on the deformable seal spare model.

Similarly, with reference to figure 21A, the strain curve of packing unit model illustrates the shearing logarithmic strain that occurs in the mimotope shifting state lower seal model around the packing unit sealing drilling rod 151.In Figure 21 B, the strain curve of seal model illustrates initial packing unit before the seal modeling displacement state among Figure 21 A, but the shearing logarithmic strain curve map of Figure 21 A is superimposed upon not on the deformable seal spare model.

Shown in Figure 19-21, packing unit stands a large amount of strains to adapt to the make position mimotope shifting state that utilizes the seal modeling., these big strains, the finite element of model or grid converge on accurate or definite result because may not suitably being out of shape.Yet,, can obtain to determine the result by the volumetric strain curve map of analytical smoothing model in step 1240.Can utilize the FEA of evaluation volume strain, produce result more accurately.

Refer now to Figure 22, show the graph of a relation of strain among the FEA (y axle) and iterations (x axle).Simulated strain on the y axle is under the given displacement state finite element of seal model to be simulated the size along the principal strain of specific direction that obtains.The FEA simulation quantity that is adopted when in addition, the iterations on the x axle is meant the modelling seal.Yet relative with the FEA iteration of Figure 11 (wherein iteration make more localization of model) (promptly complicated), each iteration of Figure 22 can make the model analyzed level and smooth (keeping constancy of volume simultaneously) gradually, thereby makes this analysis complexity reduction in essence.Thereby, proceed to volumetric strain analysis (being the right side part of x axle) along with analyzing from strain analysis (being the left side of x axle) than localization, separate convergence and be included in approximately ± 1% tolerance range.Particularly, as shown in Figure 11 FEA separate convergence, this is because separate when reaching separating in the tolerance range when simulated strain, still keeps in the tolerance range even proceed multiple iterative.Desired is, the simulated strain of seal model can be converged in theoretical strain at least about in 0.5% the tolerance.

Thereby situation about believing with those skilled in the art's intuition is opposite, compare with complicated refined model, the level and smooth model of simplification can produce more convergence and accurately FEA separate.Shown in the present embodiment, the simulated strain and the observed decorrelation of experiment that utilize FEA to produce, and converge on approaching theoretical strain and drop on determining and correct result in the tolerance range limit.Along with the increase of iterations (and along with model further level and smooth), the strain in the seal that is equivalent to draw by test is separated in the simulated strain that obtains by FEA.Utilize these results, the simulation that volumetric strain FEA can be blowout preventer seal provides useful results, with the further design of rubber seal of improving.

For example, refer now to Figure 27 A, 27B and 28, the seal model can be presented at the strain of bearing on the strain curve figure when still being in displacement state not when simulating under displacement state.What this method made it possible to determine the seal model still is in the not zone of displacement state and the strain in the unit.In Figure 27 A, the enlarged drawing of the strain curve figure of packing unit model shows the maximum main logarithmic strain that occurs in the mimotope shifting state lower seal model around the packing unit sealing drilling rod 151.Mark and when determining under the closing displacement state, to simulate through strained three finite elements 2711,2713,2715.In Figure 27 B, the enlarged drawing of the strain curve figure of seal model shows initial packing unit before the seal modeling displacement state among Figure 27 A, but the maximum main logarithmic strain that occurs in the displacement state lower seal model among Figure 27 A is superimposed upon on the seal model.Since in Figure 27 A mark the unit 2711,2713,2715 when being in displacement state, thereby in Figure 27 B traceable unit 2711,2713,2715, determining the initial position of described unit in the seal model, thereby illustrate the size and Orientation of the strain that stands described unit.Figure 28 shows packing unit seal model and the grid with unit 2711,2713,2715 according to Figure 27 A, 27B.Adopt this and similar method, can more easily determine the region of stress concentration of seal model, thereby further improve the seal Model Design as required.

In addition, when in step 1240, analyzing strain curve figure, can utilize strain curve figure to check the blowout preventer seal model.Particularly, strain curve figure is compared with one or more specific criterias, whether satisfy necessary requirement with the performance of determining the seal model.Specific criteria for example can comprise performance requirement, customer requirement or the industrial requirements of seal.In addition, these standards are compared with the strain curve figure of the seal model of being analyzed, to determine whether meet these requirements according to the seal of model manufacturing.For example, the client may require the packing unit of annular blowout preventer can stand to surpass 300% strain.Thereby, the strain curve figure of the seal model of the packing unit that is in the close position displacement state is compared, to determine whether sealing part model can satisfy these requirements with specific criteria.

Again for example, industrial requirements such as API 16A/ISO 13533:2001 can be used as the specific criteria of comparison and check seal model.Particularly, API 16A, Section 5.7.2 relate to " the closed test " of ram blowout preventer, and API 16A, Section 5.7.3 relate to the closure test of annular blowout preventer.According to API 16A/ISO 13533:2001, can require packing unit to center on drilling rod and carry out closure six times, and can seal effectively to resist the pressure of about 200-300psi (1.4-2.1MPa) when closed at the 7th time.Thereby, can be in conjunction with the displacement state of simulation employing, to determine whether seal can satisfy these requirements according to industrial requirements.The method and the embodiment that can adopt the application to disclose are compared with these specific criterias by the strain curve figure that makes the seal model, check the seal model.

If the seal model that generates in the step 1220 and analyze in step 1240 can further improve (if for example model does not satisfy specific criteria), then this method step 1210 of returning capable of circulation is to determine the material property of another kind of sealing member material, and perhaps this method step 1220 of returning capable of circulation is to regenerate or to improve the seal model as required.The circulation of this generation seal model 1220 and analysis seal model 1240 can repeat for several times, until obtaining " optimization " seal model.

In one embodiment, when seal model 1220 is returned and regenerates in circulation, the elastomeric selected part of packing unit can with rigid material insert Selective Separation, to reduce strain and to reduce strain location.Discuss at prior art as above, the elastic body of packing unit combines to keep maximum rigidity fully with the metal insert usually.Yet, when stress diagram being shown,, may reduce the strain in the elastic body of packing unit if elastomeric selected part does not combine with the rigid material insert by FEA modelling packing unit.

Refer now to Figure 23-25, show the strain curve figure of the level and smooth seal model that has this Selective Separation.Particularly, sealing part model is the model of annular blowout preventer with packing unit, wherein begins to simulate the packing unit model under the displacement state around the sealing drilling rod 151.Then, show at the displacement state counterdie and intend being in the packing unit of original state before the packing unit, but the strain under the mimotope shifting state is superimposed upon on the packing unit.This method is similar to above Figure 19-21.Yet the elastic body of seal model is extra in Figure 23-25 optionally separates with the bottom surface 109B of the 109A back, top of metal insert 109.

Refer now to Figure 23 A, the strain curve with the elastomeric packing unit model of Selective Separation illustrates the maximum main logarithmic strain that occurs in the mimotope shifting state lower seal model around the packing unit sealing drilling rod 151.In Figure 23 B, the strain curve of seal model illustrates initial Selective Separation packing unit model before the seal modeling displacement state among Figure 23 A, but the maximum main logarithmic strain curve map of Figure 23 A is superimposed upon not on the deformable seal spare model.This makes strain curve figure that the position that stress is concentrated under the displacement state not can be shown.

Similarly, with reference to figure 24A, the strain curve with the elastomeric packing unit model of Selective Separation illustrates the axial logarithmic strain that occurs in the mimotope shifting state lower seal model around the packing unit sealing drilling rod 151.In Figure 24 B, the strain curve of seal model illustrates initial Selective Separation packing unit model before the seal modeling displacement state among Figure 24 A, but the axial logarithmic strain curve map of Figure 24 A is superimposed upon not on the deformable seal spare model.

Similarly, with reference to figure 25A, the strain curve with the elastomeric packing unit model of Selective Separation illustrates the shearing logarithmic strain that occurs in the mimotope shifting state lower seal model around the packing unit sealing drilling rod 151.In Figure 25 B, the strain curve of seal model illustrates initial Selective Separation packing unit model before the seal modeling displacement state among Figure 25 A, but the shearing logarithmic strain curve map of Figure 25 A is superimposed upon not on the deformable seal spare model.

Each strain curve figure (being Figure 23-25) with the elastomeric seal model of Selective Separation shows the strain curve figure that strain is less than does not have the elastomeric packing unit model of Selective Separation (being Figure 19-21).Particularly, the elastomeric volume that is close to bottom surface, rigid material insert top shows that when elastic body and rigid material insert Selective Separation, strain is less among the strain curve figure of seal model.Thereby, as shown in the figure,, can improve and regenerate the seal model for the Selective Separation packing unit, with the seal model of formation optimization, thereby reduce position and the quantity that occurs strain in the seal model.

Be similar to the above seal model that generates in step 1220, to seal modeling displacement state 1230 time, the volume of seal model and constituent element thereof preferably remains unchanged substantially.Do not keep constant as fruit volume, then among the FEA the possibility of result of strain curve figure and simulated strain and the observed result of experiment not have among related or the FEA result of strain curve figure and simulated strain may not have each other related, thereby produce inaccurate result.For example, if the volume of the seal model of the packing unit shown in the strain curve figure of Figure 19-21 is different with the volume of the seal model of the packing unit shown in the strain curve figure of Figure 23-25, then be difficult to strain curve figure is compared owing to increasing the volumetric change factor.Whether when the volume of the seal model of packing unit increased or reduces, the simulated strain in the packing unit changed inherently, be to obtain any improvement and the seal model is changed and do not rely on.

In step 1250, in generation, analysis and possible regenerating (if necessary) afterwards, the seal model can be used for making the seal of preventer 1250.Particularly, can adopt methods known in the art, make blowout preventer seal, for example the top seal of the packing unit of annular blowout preventer or ram blowout preventer or variable bore ram packer based on tri-dimensional sealed model.For example, can make as mentioned above and Figure 23-25 shown in have the seal model of the elastomeric annular blowout preventer of Selective Separation with packing unit, to be used for industry.Compare with the packing unit shown in Figure 19-21, the Selective Separation packing unit that generates by FEA has reduced when being in the close position the stress in the packing unit and has concentrated.Because this Selective Separation seal model has the performance of improving that surmounts other packing unit shown in the FEA, thereby can make this Selective Separation seal model to be used for preventer or to test at preventer.

Can realize the aspect of the embodiment that the application discloses by the computer (with the platform independence that uses) of any type, for example utilize FEA to generate and analyze the seal model of blowout preventer seal.For example, as shown in figure 26, the spendable networked computer system 3060 of embodiment that discloses according to the application comprises processor 3062, relational storage 3064, storage device 3066 and common a large amount of other parts and the function that has of computer now.Net-connected computer 3060 also can comprise input unit such as keyboard 3068 and mouse 3070, and output device such as monitor 3072.Networked computer system 3060 is connected with Local Area Network or wide area network (for example internet) (not shown) via the network interface (not shown).Those skilled in the art should be understood that these input and output devices can take multiple other form.In addition, computer system can be not and Internet connection.In addition, those skilled in the art should be understood that one or more parts of aforementioned computer 3060 can be in remote location and are connected with other parts by the internet.

Advantageously, method that the application discloses when adopting FEA and embodiment improvement can be provided and result more accurately.The performance characteristic of blowout preventer seal under the mimotope shifting state is determined in the strain that method that the application discloses and embodiment utilization draw by FEA.This makes that the finite element in the seal model can displacement when adapting to a large amount of strain.

In addition, analysis, the smoothing of the method that discloses of the application and the embodiment seal model that can be provided for FEA, simplify and improve one's methods.Use these methods, can improve the result's who utilizes the strain curve figure that FEA makes accuracy.In addition, use these methods, can improve the seal model, to reduce quantity and the position that occurs strain (for example strain is concentrated) on the simulated strain curve map in the seal model.

In addition, the method for the application's disclosure and embodiment can be given the working life that blowout preventer seal improves.For example, can simulate and be in the following packing unit of repeatedly closed mimotope shifting state (being that seal seals drilling rod or himself repeatedly), can prolong the design feature of packing unit working life (being closed number of times) with definite.

Although invention has been described at the embodiment of limited quantity, benefit from one skilled in the art will appreciate that under the situation that does not break away from the scope of the invention that this paper discloses of this paper and can design other embodiment.Thereby scope of the present invention should only be subject to claims.

Claims

1. method of making blowout preventer seal, this method comprises:

Select seal designs;

Generate the first finite element analysis seal model according to selected seal designs;

The described first finite element analysis seal model of smoothing;

Analyze the strain curve figure of the described level and smooth first finite element analysis seal model based on displacement state; With

Make seal.

2. the method for claim 1 also comprises:

Check the described first finite element analysis seal model according at least one specific criteria.

3. the process of claim 1 wherein that described smoothing comprises the interior angle of the rigid material insert that improves the described first finite element analysis seal model.

4. the process of claim 1 wherein that described smoothing comprises the exterior angle of the rigid material insert that improves the described first finite element analysis seal model.

5. the process of claim 1 wherein that described smoothing comprises the elastomeric compression face that improves the described first finite element analysis seal model.

6. the process of claim 1 wherein that described smoothing comprises the end of the beam of the rigid material insert that improves the described first finite element analysis seal model.

7. the process of claim 1 wherein that described smoothing comprises the end of the soffit of girder of the rigid material insert that improves the described first finite element analysis seal model.

8. the process of claim 1 wherein that described smoothing comprises the side of the beam of the rigid material insert that improves the described first finite element analysis seal model.

9. the process of claim 1 wherein that described smoothing comprises the side of the soffit of girder of the rigid material insert that improves the described first finite element analysis seal model.

10. the method for claim 1 also comprises:

Based on the strain curve figure of the described level and smooth first finite element analysis seal model of being analyzed, generate the second finite element analysis seal model; With

Analyze the strain curve figure of the described second finite element analysis seal model based on displacement state.

11. the method for claim 10, the wherein said second finite element analysis seal model is more level and smooth than the described first finite element analysis seal model.

12. the method for claim 10, at least one convergence in wherein said first finite element analysis seal model and the described second finite element analysis seal model drop in about 1% the tolerance.

13. the method for claim 10, at least one convergence in wherein said first finite element analysis seal model and the described second finite element analysis seal model drop in about 0.5% the tolerance.

14. the method for claim 10, the volume of the elastomeric volume of the wherein said second finite element analysis seal model and described level and smooth finite element analysis seal model is consistent substantially.

15. the process of claim 1 wherein that the elastomeric volume of the described first finite element analysis seal model remains unchanged substantially in the smoothing process.

16. the process of claim 1 wherein that described seal comprises elastic body and rigid material.

17. the method for claim 16, wherein said rigid material comprise a kind of in steel, bronze and the composite material.

18. the process of claim 1 wherein that described blowout preventer seal is the top seal of ram blowout preventer.

19. the process of claim 1 wherein that described blowout preventer seal is the variable bore ram packer of ram blowout preventer.

20. the process of claim 1 wherein that described blowout preventer seal is the packing unit of annular blowout preventer.

21. the process of claim 1 wherein that described displacement state comprises the strain at least about 300%.

22. the process of claim 1 wherein that described displacement state comprises the strain at least about 450%.

23. the process of claim 1 wherein that described strain curve figure comprises a kind of in major principal strain, axial strain and the shear strain.

24. the process of claim 1 wherein that described strain curve figure comprises the sectional view of the first finite element analysis seal model.

25. a method of checking blowout preventer seal, this method comprises:

Generate the first finite element analysis seal model;

The described first finite element analysis seal model of smoothing;

The strain curve figure of the described level and smooth first finite element analysis seal model is compared with at least a specific criteria.

26. the method for claim 25 also comprises:

Generate the second finite element analysis seal model based on the strain curve figure that is analyzed;

Analyze the strain curve figure of the described second finite element analysis seal model based on displacement state; With

The strain curve figure of the described second finite element analysis seal model is compared with at least a specific criteria.

27. the method for claim 26 also comprises the described second finite element analysis seal model of smoothing.

28. the method for claim 25, wherein said seal comprises elastic body and rigid material.

29. a kind of based on in performance requirement, customer requirement and the industrial requirements of seal of the method for claim 25, wherein said at least a specific criteria.

30. the method for claim 29, wherein said industrial requirements comprises API 16A/ISO13533:2001.

31. a method of optimizing blowout preventer seal, this method comprises:

The smoothing first finite element analysis seal model;

Analyze the strain curve figure of the described level and smooth first finite element analysis seal model based on displacement state;

Based on the strain curve figure of the level and smooth first finite element analysis seal model of being analyzed, generate the second finite element analysis seal model;

The described second finite element analysis seal model of smoothing;

Analyze the strain curve figure of the described second level and smooth finite element analysis seal model based on displacement state; With

Replicate analysis and the level and smooth finite element analysis seal model of generation are until the seal model that obtains to optimize.

32. the method for claim 31, wherein said seal comprises elastic body and rigid material.

33. the method for claim 31, the volume of the volume of the wherein said first finite element analysis seal model and the described second finite element analysis seal model is basic identical.

34. the method for claim 31 is wherein compared described optimization seal model with at least a specific criteria.