CN101583774A - Imputing strength gradient in pressure vessels - Google Patents

Abstract

A process to manufacture an oilfield component comprises selectively reinforcing a base material with an age-hardenable clad material and age-hardening the clad material for a selected time and at a selected temperature profile, wherein the age-hardening results in the clad material developing a selected strength gradient. A body of a ram blowout preventer comprises, a low-ally base material, a vertical bore through the body, and a horizontal bore through the body intersecting the vertical bore, wherein at least a portion of the body is selectively reinforced with a clad material, and wherein the clad material is age-hardened for a selected time and at a selected temperature profile resulting in the clad material developing a selected strength gradient.

Description

In pressure vessel, set up the method for intensity gradient

The cross reference of related application

The application requires the U.S. Patent application No.11/528 that is entitled as " Reinforcement of Irregular Pressure Vessels " that submitted on September 28th, 2006,873 right as the part continuation application according to 35U.S.C. § 120.The application also requires the U.S. Patent application No.11/555 that is entitled as " Heat Treatment Method of Inlaid PressureVessels " that submitted on November 2nd, 2006,984 right as the part continuation application according to 35U.S.C. § 120.The application also requires the U.S. Patent application No.11/626 that is entitled as " Heat TreatmentMethod of Inlaid Pressure Vessels " that submitted on January 23rd, 2007,148 right as the part continuation application according to 35U.S.C. § 120.The application also requires the U.S. Patent application No.11/680 that is entitled as " Imputing Strength Gradient in Pressure Vessels " that submitted on March 1st, 2007,860 right as the part continuation application according to 35U.S.C. § 120.The full content that is incorporated herein four U.S. Patent applications as a reference.

Technical field

Present invention relates in general to the oil field parts and the equipment that use during the production of hydrocarbons.Particularly, the present invention relates to the method for heat treatment oil field parts.

Background technology

The existing multiple design that is used for drilling well and produces hydrocarbon comprises land and unit is produced in offshore drilling.Offshore drilling is produced the unit design and can be changed according to the type (for example floating platform, semisubmersible platform, tension leg platform (TLP), spar type platform (spar-type platform) and other platform known in the art) of the depth of water and used platform.The type and the position of the control device of marine unit also can change, and comprising: the wet tree system, and its control device is set in place in the top of the well head in seabed; And the dry type tree system, its control device is arranged on the platform.

The parts that oil well probing and production period use, no matter which kind of position and design all suffers burn into wearing and tearing and fatigue.For example, for offshore drilling and production, employed parts and equipment stand dynamic environment, and near surface and underground undercurrent can cause bending, stretching and/or rotation stress under this environment.In typical deep water offshore production, for example, standpipe is extending between the floating platform on sea level and the well head in the seabed.Because well head is statically placed in the seabed, and standpipe peace platform or rig are movable, thereby the stress that is produced can cause producing parts fatigue, produces parts and comprises that buoyant device, stress eliminates joint, the pad-eye connector (pad-eye connections forballast or tension line) that is used for ballast or tension force pipeline, stress joint, preventer (BOP), control well group spare, mud lifting subassembly (mud lift module), ballast weight (ballast weight) and other parts known in the art.These parts (connector, standpipe joint and the wellhead component that comprise the platform place) all may stand the stress and strain that the dynamic characteristic owing to maritime environment causes.

As being worn and torn, corrode and another examples of tired parts, the normal insert pump that uses in the reservoir hydrocarbons manufacturing process.This deep well pump is by the starting of beam pumping unit (walking beam pumping unit) machinery, one end of beam pumping unit is connected on the power supply, and the other end connects on a string steel pole (for example sucker rod), steel pole is interconnected to form the drill string that stretches in the well, and the other end of drill string is connected on the deep well pump.In the pumping process, the drill string that is made of bar moves back and forth or rotatablely moves, and this may cause drill string deflection.Sucker rod is owing to being worn and torn with the CONTACT WITH FRICTION of production tube inwall.Although fluid environment plays the effect of sliding agent, still wear and tear in the sucker rod surface.In addition, the instrument that uses in the assembling process for example is used for the instrument that drill string is felt relieved, and may cause the wearing and tearing on bar surface.For producing the hydrocarbon well, fluid comprises and may have the dissolved salts of additional abrasive action and dissolution of minerals not to the bar surface.When wearing and tearing took place, the severe corrosive that the metal in the sucker rod is caused by downhole chemicals corroded.These bars also stand high circulation axial tension and may stand axial fatigue in its whole application life.

Except the dynamic stress of above concise and to the point description, wearing and tearing stress and corrosion stress, the oil field parts also may stand the caused fatigue of HTHP that meets with in drilling well and the manufacturing process.Drilling process comprises the layer that penetrates various subsurface geologic structures or be called " stratum ".Sometimes, pit shaft is with the stratum 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.Normal operating pressure and high pressurized overflow cause the oil field parts to stand extra fatigue.

In the past, the oil field parts that stand the fatigue loading condition are by single metal alloy manufacturing.Alloy commonly used generally is a low-alloy steel, and low-alloy steel is heat-treated processing to obtain to be suitable for the mechanical performance of loading condiction.Using high strength, nickel based alloy to make these parts is unallowed usually with regard to cost.

Under many circumstances, these oil field parts may need to satisfy the design standard of oil gas field metal parts, for example stand various set of circumstances compounds, pH, temperature and H at metal ₂Performance during the S dividing potential drop, the requirement that NACE international organization (predecessor is a NACE, National Association ofCorrosion Engineers) and Europe corrosion federation (European Federation of Corrosion) establish.For example, for the low-alloy steel of quality adjustment condition, NACE MR0175 is restricted to Rockwell C 22 or Bu Shi 237 with the highest hardness of parts.

For most of low-alloy steel, the maximum yield strength that can reach under NACE highest hardness restriction is about 80,000-90,000psi.Only a few low-alloy steel can have the combination that realizes this yield strength and hardness on large-sized thickness of section easy to use arbitrarily.For example, when thickness of section during greater than four to six inches, a lot of low-alloy steel can not reach required mechanical performance by modified on its whole thickness of section when heat treatment.

Because the yield strength that may be subjected to relative material fatigue life acts on the influence of the amount of stress of material, thus when applied stress surpass material yield intensity 50% the time many material lists reveal the fatigue life of lacking.Thereby, if parts are used for the defined fatigue loading condition as NACE MR0175, then can will allow that applied stress is restricted to 50 to 65ksi or following

If under this stress level fatigue failure takes place, the then measure that except the load that acts on parts by reduction reduces applied stress, does not have other to take.Because under the situation of the highest hardness value that is no more than the NACEMR0175 requirement, can not obviously improve the mechanical strength of alloy, be the unique scheme that to take before this so reduce applied stress.In addition, fatigue strength also depends on ductility.Because ductility and intensity are into the material property of inverse relationship, thereby provide fatigue behaviour may not reach intended purposes by improving the strength of materials.

Fatigue failure is the phenomenon that the high tensile stress of material surface or next-door neighbour's material surface place causes.Thereby, adopt surface modification treatment, for example peening, by nitriding or carburized surface sclerosis and flame hardening or induction hardening (induction hardening) by making surface reservation residual compressive stress, improves the fatigue strength of material.Because crackle relatively was difficult to cause and/or expansion when parts had the residual stresses load, thereby the surperficial parts indefatigability that comprises residual compressive stress lost efficacy.

Although these surface modification treatment can help to reduce or eliminate fatigue failure, peening and nitriding are limited to the surface, and to reach the surface following greater than about 0.050 inch degree of depth and carburizing and flame or induction hardening can not improve material property usually.In addition, for equipment is used for acid-resistance gas attack or briny environment, these surface modifying methods may with the requiring inconsistent or deviate from the requirement of NACE MR0175 of NACE MR0175.For example, the hardness of surface or the generation of nearly surface may surpass the threshold value of sulfide or chloride stress cracking corrosion cracking.

As mentioned above, the life-span of oil field parts also may be subjected to corrosion as be exposed to H ₂The influence of S.For many years, the parts of oil field instrument industry (oil tool industry) only carry out the covering clad can on cannelure, seal area and wetting surface, avoid the infringement of pit shaft liquid to parent metal.For example, U.S. Patent No. 6,737,174 have disclosed the sucker rod that the surface is covered by copper alloy.In other covering clad can method, use corrosion resisting alloy (CRA) covering that thickness is generally 0.060 to 0.187 inch, for example nickel-base alloy 625 (being chromium ferronickel 625) is avoided corrosive attack with the protection parent metal.Other CRA also can be used for these and uses, but the industrial basic unified CRA covering that uses alloy 625 to carry out petroleum tool equipment.Before this, except the intensity that guarantees clad material is equal to or greater than the intensity of parent metal, do not give any concern to the intensity of clad material.

Expectation obtains the oil field component that prolong application life, comprises and stands high temperature, corrosive fluid, high stress level and/or the fatigue loading condition parts of (comprising the circulating load condition).Thereby, the oil field parts that need under various extreme conditions of work (comprising the fatigue loading condition), have the performance of improvement.

In the prior art, flashboard type and telescopic annular space BOP main body and ancillary service are made usually and are used for up to 15, the operating pressure of 000psi and the temperature up to 250.The example of annular blowout preventer is disclosed in U.S. Patent No. 2,609, and 836 and 5,819,013, the full content that is incorporated herein them is as a reference.The example of ram blowout preventer is disclosed in U.S. Patent No. 6,554, and 247,6,244,560,5,897,094,5,655,745 and 4,647,002, the full content that is incorporated herein them is as a reference.Can use single through roughing and heat treated low-alloy steel forging or use a plurality of low-alloy steel forging that weld together through roughing, heat treatment and technology to make the BOP main bodys.Foundry goods is the same with forging or only may to be used to be manufactured on the flashboard type BOP main body of using under this condition of work.

In the prior art, to can be by the integral type of F22 low-alloy steel manufacturing single, double or three flashboard BOP main bodys are quenched and final tempering, to satisfy final material specification requirement.Perhaps, can make assembling BOP main body by welding together through the modification 8630 low-alloy steel parts of quenching and final tempering.Then main body is machined as nearly end form, and welds clad can in other zone of use corrosion resistance alloy such as AISI 316 austenitic stainless steels or nickel-base alloy 625 appointment on API ring shape groove, valve gap face (bonnet face), interior roof seal area and engineering drawing.

After technology welding and/or clad can welding, according to routine, the grade of steel used according to manufacture component carries out postweld head treatment (PWHT) to the BOP main body at a certain temperature.The purpose of PWHT mainly is the hardness of the heat affected zone of welding position (HAZ) is reduced to highest hardness grade HRC 22 or the Bu Shi 237 that NACE MR0175 requires, to obtain resisting sulfide stress corrosion cracking (SCC) performance.

Control welding regulation (controlling welding specification), ASME Section IX requires this PWHT to carry out under the temperature that is lower than the temperature of parent metal own.PWHT operation has often reduced the mechanical performance of parent metal, and has limited before the mechanical property levels of parent metal is reduced to below the required parent metal minimum requirements of parts particular B OP main body and can weld time with postweld head treatment.After having carried out the PWHT operation, be final spatial configuration with main body fine finishining.

Describe in detail as this paper, can change existing manufacturing process, with the face of land or the heavily stressed zone of near surface in the covering BOP main body of using high strength, age hardening, corrosion resistance alloy CRA selective reinforcement integral type main body.This change can allow to be manufactured on to be higher than 15, the BOP main body of using under the operating pressure of 000psi and the operating temperature more than 350.

Yet as mentioned above, under the situation that adopts existing manufacture method, the PWHT temperature is enough to obtain desired maximum HAZ hardness number, but the PWHT temperature is low excessively for age hardening CRA facing material obtains desired mechanical performance.If the rising PWHT temperature for the mechanical performance that reaches the CRA facing material, then the PWHT temperature may equal or exceed the temperature of the F22 base material of BOP main body, and this is that ASME Section IX institute is unallowed.

For example, to fill metal be chromium ferronickel 725 and base material when being F22 low-alloy steel when being used for the deposited CRA of covering clad can welding, the F22 steel must carried out postweld head treatment under the minimum temperature of 1150 (621 ℃) 4 to 8 hours or more than.Pair cross-section thickness carries out modified at the F22 low-alloy steel more than 8 inches, to reach 85, the SMYS of 000psi.For reaching described SMYS, need went through 8 to 10 hours under the temperature of 1150 to 1250 (621 ℃ to 677 ℃) or more than.Yet, because chromium ferronickel 725 be age hardening alloy, thereby be about 120 in order to reach SMYS, the mechanical performance of 000psi, chromium ferronickel 725 must be the shortest 8 to 24 hours in 1200 (649 ℃) time timeliness.Temperature that all these are different and time, PWHT temperature and time and age hardening temperature and time may conflict mutually.

If parent metal is quenched and final tempering according to routine as mentioned above, then the age hardening temperature and time of chromium ferronickel 725 will make the further tempering of F22 parent metal, and the mechanical performance of F22 parent metal is reduced to below the minimum regulatory requirement.If as mentioned above chromium ferronickel 725 welding line joints on the F22 are carried out PWHT, then can satisfy maximum HAZ hardness and keep the mechanical performance of F22, but chromium ferronickel 725 weld metals may not reach mechanical performance required in clad can.

Thereby, need to obtain following member manufacturing method, these parts satisfy the fuel feeding field when using to the HAZ hardness of parent metal and covering clad can and the requirement of mechanical performance.

Summary of the invention

On the one hand, the present invention relates to the oil field member manufacturing method, this method comprises Use Limitation sclerosis clad material selective reinforcement base material, and make clad material plant the age hardening of going through seclected time at the chosen temperature branch, wherein age hardening produces the clad material with selected intensity gradient.

On the other hand, the present invention relates to the main body of ram blowout preventer, this main body comprises the low-alloy base material, pass the upright opening of main body, pass the lateral aperture that main body and upright opening intersect, wherein use at least a portion of clad material selective reinforcement main body, and wherein make clad material plant the age hardening of going through seclected time, thereby produce clad material with selected intensity gradient at the chosen temperature branch.

From the following description and the appended claims, others and advantage will be apparent.

Description of drawings

Fig. 1 illustrates the half sectional view of the whole model that stands applied load and fringe conditions according to an embodiment of the present invention.

Fig. 2 illustrates the The results of the model shown in Figure 1 of the pressure that stands 15ksi according to an embodiment of the present invention.

Fig. 3 illustrates the The results of the model shown in Figure 1 of the pressure that stands 20ksi according to an embodiment of the present invention.

Fig. 4 illustrates the The results of the model shown in Figure 1 of the pressure that stands 25ksi according to an embodiment of the present invention.

Fig. 5 illustrates the The results of model shown in Figure 1 of the internal temperature of the pressure that stands 20ksi according to an embodiment of the present invention and 350.

Fig. 6 is the sectional view of the flange neck strengthened according to an embodiment of the present invention.

Fig. 7 is a block diagram of making the method for oil field parts according to an embodiment of the present invention.

Fig. 8 A and 8B are the schematic diagrames that has the base material of various covering inlay structures according to an embodiment of the present invention.

Fig. 9 A and 9B are more according to an embodiment of the present invention by analog result of forcing cooling selective thermal processing covering inlay and the analog result of handling the covering inlay by the natural convection cooling selective thermal of base material.

Figure 10 illustrates the producible intensity gradient of age hardening of going through seclected time according to an embodiment of the present invention at chosen temperature distribution under-clad layer material.

The specific embodiment

On the one hand, the present invention relates to make or strengthen the method for oil field parts.On the other hand, the present invention relates to heat treatment, to reduce or eliminate stress and/or fatigue failure through the oil field of selective reinforcement parts.Again on the one hand, the selective thermal that the present invention relates to the selective reinforcement zone of oil field parts is handled.

As used herein, " oil field parts " are meant flange, valve gap, spool, stress joint, preventer, sucker rod, subsea well assembly, valve (as choke valve), valve body, well head and drilling well and production of hydrocarbons miscellaneous equipment and parts commonly used.Although it should be recognized by those skilled in the art that not concrete the disclosure or detailed description, the present invention also can be applicable to other oil field parts.

Parts design and analysis

In pressure testing, transportation, installation and the course of work, the oil field parts stand the stress and strain based on the fatigue loading condition, and wherein most of fatigue loading conditions can continuous, semicontinuous or circulation appearance.Loading condiction can comprise heat requirement, pressure load or mechanical load.For example, when pit shaft hotter (for example 300) and when being arranged in 10,000 feet 32 the water heat requirement may appear.Pressure load may be pressed by interior (pit shaft) that outwards act on the oil field parts and be caused or caused by inside hydrostatic (for example under water) external pressure.In addition, mechanical load may comprise fastening preloading, axial tension and compression load, the bending moment of valve gap and flange bolt.Thereby, loading condiction can comprise interior pressure, external pressure, axial tension, axial compression, longitudinal stretching, vertically compression, axially bending moment, vertically bending moment, promote at least a in stretching and deflection, temperature extremes and other load condition.The intensity that acts on the local stress state of equipment under these loading condictions can have remarkable influence to the cycle life of equipment.Can improve the design and/or the performance of oil field parts to the performance analysis of the oil field parts that stand various fatigue loading conditions, thereby prolong the application life of oil field parts.

Finite element analysis (FEA) is to too complicated and the structural member of analytical that can not be by strictness or the effective and powerful method that the stress and strain in the parts is analyzed.Adopt FEA, structural member or parts are decomposed into a large amount of junior units (a limited number of unit) of all kinds, size and dimension.Suppose described unit have the deformation pattern of simplification (linear, two inferior) and usually " node " on angle that is positioned at described unit or limit locate to connect.Then, the basic principle of utilization structural mechanics, promptly the continuity of equilibrium of forces and load obtains large-scale simultaneous equations systems (grid), comes mathematics to assemble described unit.

Can be by means of this large-scale simultaneous equations system of computer solving, obtain the deformed shape of structural member under the load effect or parts, can be based on this calculated stress and strain.The appropriate software of carrying out this FEA comprise ABAQUS (can be available from ABAQUS, Inc.), MARC (can available from MSC SoftwareCorporation) and ANSYS (can be available from ANSYS, Inc.) etc.Can adopt the finite element of arbitrary shape known in the art.Yet, may be comparatively favourable during usually highly stable and the heavily stressed and strain in simulation model of hexagonal cells.

Can adopt the oil field parts design and/or the model of simplification, to help the analysis of oil field parts.For example, can simplify the analysis that the stress and strain of this design is concentrated by " smoothing " complicated parts design.As used herein, term " smoothing " is meant that the complex geometry of simplified design is to be used for the whole bag of tricks of FEA.For example, can improve interior angle and attempt reducing or eliminate its radius, to simplify the model that makes up subsequently.These methods can allow the analysis of the level and smooth model FEA model of sawtooth design structure (promptly by) to be associated with definite result and converge on this to determine result (impossible when analyzing without the model of smoothing).Thereby, can analyze the model of constructing by FEA by sawtooth design, determine integral body or volumetric strain state.The analysis volume strain be can pass through, the performance and the contingent inefficacy of oil field parts under the various fatigue loading conditions predicted.

The purpose of FEA may be to isolate heavily stressed or strain is regional and the zone of determining to be tending towards to reduce cycle life.The resulting The results of performance of analyzing various fatigue loading condition lower member can be used for determining the zone of standing fatigue failure in the parts of oil field.In case determine to stand the zone of fatigue failure, can redesign these zones, perhaps can mark these zones and carry out metallurgical processing, for example subsequently with the selective reinforcement that is described.

Should determine that load condition that parts are possible or fatigue loading condition are with input FEA.As mentioned above, described load condition or fatigue loading condition can comprise service pressure, high pressurized overflow, promote stretching and deflection, temperature extremes and other load condition.The data of fatigue loading condition should comprise the frequency of representative value or desired value and maximum and/or minimum value and these load variations, can carry out complete analysis.

Also should be identified for forming the performance of the base material of oil field parts, thereby determine maximum permissible stress peak value (SB peak value).Can determine material property by empirical experiment, perhaps alternatively, can provide material property by the performance data that is purchased material.For example, can determine described value based on the field trial that under the NACE environment (be NACE international organization establish at the oil gas field equipment test environment) carries out, stress should satisfy that cycle life requires and the stress when sulfide-stress cracking takes place.

More specifically, can determine the tensile property of base material.The hot strength of material is stress (stretching) maximum value that material may stand before losing efficacy.When stress acted on material, the material production strain was to adapt to this stress.In case stress is excessive for this material, then this material can not produce strain again, thereby loses efficacy.The failpoint of material is called ultimate tensile strength.

Then, can adopt method, utilize loading condiction and material property that the oil field parts are analyzed based on FEA.Should think that all arrangements of design and live load generate the complete analysis result of parts.Also should use the suitable bolt preloading and the material property data that reduce rated value according to temperature.

The model (being the grid of simultaneous equations) that generates the oil field parts is to be used for finite element analysis.Can generate parts threedimensional model with specific design feature.Can select these design features to produce the specific performance properties feature.Thereby generation model also can comprise the steps: the design that the input block design is imported with generation model and smoothing.Various smoothing methods can be applied to design analyzes to simplify FEA.Can be by computer aided design (CAD) (CAD) program package (for example available from Autodesk, Inc. AutoCAD and available from the Pro/Engineer of Parametric Technology Corporation) according to the design generation model, and with this model input FEA program package.Alternatively, can pass through the generation model of FEA program package (for example ABAQUS and PATRAN) own.

Then, can adopt model to pass through the loading condiction of FEA dummy activity in parts.Preferably, these simulation fatigue loading conditions reflect load condition or the stress that oil field parts may stand when normal the use.In addition, after the fatigue loading condition that acts on model is simulated, can analyze the stress curve figure under the described loading condiction, this stress curve illustrates stress and the distortion that occurs in the partial model of oil field.Stress curve figure can determine and be illustrated in position and the size that occurs stress under the simulation loading condiction that acts on the oil field parts in the partial model of oil field.

Can analyze and estimate stress curve figure to determine the performance and the feature of model.If further improved model then can generate alternate model or regenerate (improvement) current model.Be able to further simulation model thus, to determine further improvement or the modelling performance of model afterwards by FEA.In addition, if think that model can be accepted and satisfy any and/or all specific criterias, then can as described below this model be used to make the oil field parts.

The FEA simulative example

Refer now to Fig. 1, show the example of the threedimensional model of the 183/4 inch flashboard type BOP that comprises suitable design.Based on ASME Section-VIII Div-3 standard, designed the BOP model that is used for high pressure-temperature (HPHT) or high pressure high temperature (XHPHT) application.Before using said method, the geometry of BOP main body is designed, to satisfy all main standard of high pressure (more than the 15ksi) and high temperature (more than 250) application.Based on ASME Section-VIII Divsion-3 standard, think that the structural load up to 350 has carried out suitably design to BOP under test up to 25ksi and temperature in wellbore at wellbore pressure.Modelling and can help any existing BOP design more to the analysis result of model makes sulphide stress corrosion fracture, SSCC or the maximum conditions relevant with corrosion weld covering by the selectivity of the high strength material that is applicable to the NACE environment and deals with.

For XHPHT BOP under test, the F22 material that to have selected minimum material yield intensity be 85ksi.To reduce yield strength because necessary back sweating heat is handled (PWHT), thereby can think that the final SMYS of material is 80ksi.For SSCC or NACE environment,, finished suitable material test based on TM0177 method A.Based on industry experience and obtainable experimental data, observe in TM0177 method A test and lost efficacy under the yield stress level of sample 80%.Based on this,, think that the minimum yield stress of 0.8* or the upper limit of 64ksi are acceptables for the F22 material.

At three kinds of different maximum working pressure (MWP)s, promptly the wellbore pressure of 15ksi, 20ksi and 25ksi (not having heat requirement) is analyzed BOP.Also considering heat requirement and aforesaid other load of 350, is that the situation of 20ksi is analyzed separately to folding pressure.

Fig. 1 shows typical load and the fringe conditions that is used to analyze.As shown in the figure, wellbore pressure is 24.45ksi (differing 20ksi with external pressure), and temperature in wellbore is 350 °F, and external temperature is 37 °F.In conjunction with possible loading condiction, BOP has under test been carried out finite element analysis (FEA).Load comprises wellbore pressure, top stretching and flexural loads, pressure terminal load.

Form with plasticity equivalent stress (von mises stress) VMS curve map in Fig. 2 to 5 shows The results.For the VMS curve map among Fig. 2 to 5, use 64ksi than the higher zone of all stress of lower boundary stress isolation.In all these accompanying drawings, only show stressed zone greater than 64ksi.Stress when Fig. 2 shows wellbore pressure and is 15ksi on the semi-section of (not having thermal stress) whole model.(not having thermal stress) similar curve map when Fig. 3 shows wellbore pressure and is 20ksi.The VMS stress of (not having thermal stress) when Fig. 4 shows wellbore pressure and is 25ksi.

It is 20ksi and the VMS stress when considering 350 heat requirement (well bore face temperature) simultaneously that Fig. 5 shows folding pressure.To be applied to be exposed to the zone of seawater by the convective heat-transfer coefficient hf that CFD analytical calculation independently obtains.

The result that FEA analyzes shows the hole side that does not apply heat requirement of the most heavily stressed BOP of appearing at.The heat of compression stress that applies has obviously reduced internal stress, but external carbuncle increases.Think that the external carbuncle zone is subjected to the minimum that influences of SSCC (or NACE is relevant) constraints.Model shows that thermal stress state is the non-conservation situation that high pressure (HPHT) is used, and particularly considers to meet the NACE material requirements.

Then, observing under test, BOP is fit to the NACE application that wellbore pressure is 15ksi.Except that VMS stress some local locations greater than 64ksi, whole BOP stacked body is applicable to the NACE environment.Minimum improvement to model, refining grid can be eliminated this minimum heavily stressed (greater than 64ksi) position.

Respectively as shown in Figure 3 and Figure 4, for the folding pressure of 20ksi and 25ksi, the VMS stressed zone greater than 64ksi among the result is high-visible.These stress curves figure has determined the position and the degree of depth greater than the high VMC stressed zone of 64ksi.For the wellbore pressure FEA of 20ksi, the most heavily stressed 108ksi that keeps below is for the wellbore pressure FEA of 25ksi, the most heavily stressed 112ksi that keeps below.Around the recess region on BOP top, observe the zonule that stress surpasses 112ksi.The contact stress that the rigidity that the analysis showed that the top mating flanges and the bolt preloading of whole assembly is caused has reduced this peak stress.The maximum VMS stress that keeps 120ksi is to be suitable for the application that wellbore pressure is 25ksi.

Can calculate the degree of depth of the shown region of high stress of VMS stress curve figure.The NACE compatible material is the chromium ferronickel 725 of 120ksi as SMYS, can have 90% yield strength (0.9 * 120=108) and satisfy TM0177 method A test of 108ksi.Thereby, but the higher corrosion resisting alloy selectivity of working strength coats the base material in these zones, has confirmed that described alloy satisfies the requirement of NACEMR0175/ISO15156.

FEA result shows that in addition the local stress of material appears near 183/4 inch through hole or this through hole apart from 0.250 to 0.500 inch on the ID surface of flashboard type BOP main body with interior position.Can utilize the high strength material clad can that meets NACE MR0175 to coat affected high stress areas.

The thickness of covering clad can may need not exceed 0.375 inch, and cover may be near 75, the local stress of 000psi.Thickness is enough to cover local stress and SMYS is 120, and the covering clad can of 000psi may can make local stress keep below 2/3rds of the desired covering SMYS of parent metal.Can realize the clad can of high strength material by above-mentioned multiple diverse ways.

Selective reinforcement

The zone that the purpose of aforesaid numerical method (for example FEA analyze) comprises is definite, stand fatigue failure in isolation and the outstanding oil field parts.For example, can determine to cause the stress state of initial failure under the NACE environment.FEA result can be used for generating the stress and strain curve map, determines to stand in the parts zone of fatigue failure.

For example, these curve maps those shown in Fig. 2-5 can be used for isolating 90% the zone that stress surpasses the base material yield strength.In view of performance and test requirements document that oil gas field equipment is proposed, should be specifically noted that 90% the zone that surpasses yield strength.For example, for corrosivity (NACE) environment, the design coding can be restricted to maximum strain 90% of material yield intensity, makes and can keep the design cycle life-span.90% the zone that stress can surpass the base material yield strength comprises near BOP groove and the BOP endoporus (cross section of upright opening, lateral aperture, upright opening and lateral aperture) bottom tub (seat pocket), the valve gap.Described result also can be used for calculating the degree of depth above 90% high stress areas of yield strength.

When making the oil field parts, can improve determined zone of standing fatigue failure.For example, can in spatial image or drawing, mark described zone, indicate the degree of depth and the lateral extent (length and width) of the high stress areas that stands fatigue failure.Can draw outline drawing, length, width and the degree of depth in local stress zone is shown.For example, the surface location in tired zone can be transferred on the suitable fabrication drawing.Then, can utilize the higher material of intensity that combines with base material metallurgy, the determined tired zone of selective reinforcement.

In some embodiments, can or help to avoid fatigue failure by surperficial alternative method (surface substitution method) minimizing.For example,, replace and form metallurgy combining, then can reduce or eliminate fatigue failure with parent metal by the higher material of intensity if the low-alloy steel parts parent metal of certain depth is removed.The higher alloy of intensity can be to be convenient to any alloy that shows the desired intensity of oil field parts design, ductility and corrosion resistance that the user selects.

The higher material of intensity can comprise that other low-alloy steel or intensity and/or corrosion resistance are higher than the medium alloy steel of low-alloy steel parent metal, and can tolerate applied stress under the lower situation of applied stress and yield strength.The applied stress of the material that reduction intensity is higher can reduce the trend that applied stress causes fatigue cracking, crack Propagation and final fatigue failure with the ratio of yield strength.For example, high-strength alloy such as alloy 625 can be used for replacing the low-alloy parent metal and combine with the low-alloy parent metal.The selection that can replace the segment thickness of parent metal to reach 0.500 inch or above clad alloy can be made with the ratio of yield strength based on the applied stress of the used alloy of covering.

In some embodiments, can utilize embedded covering (inlay clad) optionally to strengthen base material.In other embodiments, can utilize clad can covering (overlay clad) optionally to strengthen base material.Can utilize pressure, heat, welding, soldering, roll bond, blast combination, welding clad can (weld overlaying), wallpaper or their combination, in conjunction with covering inlay or clad can and base material.In some embodiments, can use electric arc process such as submerged arc welding (SAW) method or tungsten inert gas (TIG) protection welding, in conjunction with covering and base material.In other embodiments, can use any combination of arc welding cladding technique, high temperature insostatic pressing (HIP) cladding technique (HIP cladding technique), self-tightening cladding technique, laser cladding method or these methods, in conjunction with covering and base material.In some embodiments, can use one or more coverings, for example have single covering, the double clad (having 3 layers) of two-layer (base material and covering) or reach 7 layers or more multi-layered covering.

In some embodiments, can utilize the covering inlay optionally to strengthen base material.In various embodiments, but recess that covering inlay shrink-fit or pressure fitted cut in the article body of oil field and seam weldering/seal welding are in suitable position.In other embodiments, can determine the shape of covering inlay according to FEA stress curve figure.

The thickness of covering inlay or clad can or average thickness in some embodiments can be up to 0.625 inch or more than, can be in some other embodiment up to 0.75 inch or more than, can be in some embodiments again up to 1.0 inches or more than.The average thickness of covering inlay can be about 0.010 inch to about 0.75 inch in some embodiments, can be about 0.050 inch to about 0.625 inch in some other embodiment, can be about 0.125 inch to about 0.5 inch in some embodiments again.

In other embodiments, pressure fitted or the shrink-fit parts of being made by high-strength alloy can use in conjunction with the oil field parts.For example, in solid parts (for example flange, valve gap, the valve body etc.) pressure fitted that will make by high-strength alloy (for example the chromium ferronickel 725) or shrink-fit after main body, can be with described solid parts seal welding in the low-intensity matrix.

In other embodiments, can utilize the higher material of intensity that combines with base material metallurgy to replace parent metal in the determined tired zone.For example, can polish or the machine region of high stress in the higher material replacement region of high stress of the intensity combine with base material metallurgy of parent metal and utilize in parent metal.

In some embodiments, selective reinforcement is the covering clad can of the higher material of intensity on base material.In other embodiments, selective reinforcement can be the higher material of intensity in base material polishing or the covering clad can in the machine recess.

The selection of clad alloy can and strengthen it based on the corrosion resistance (comprising stress corrosion cracking) of clad alloy and use and the ability (for example by combining with low-alloy matrix metallurgy) of the mechanical strength of the oil field parts part that is intended to protect.In typical clad can, for example, the intensity of expectation clad material equals the intensity of its parent metal of using at least.That is, expectation hardfacing alloy (as alloy 625) mates with the yield strength of low-alloy steel parent metal (for example yield strength is 75, the low-alloy steel of 000psi).Can use the covering that the higher material of intensity constitutes, the thickness of this covering covers the local stress in this higher-strength covering, thereby forms NACE or the intensity of other standard and satisfied design simultaneously and the oil field parts that fatigue requires that satisfy oil gas field parts and equipment.For example, can make that the present invention discloses through the flashboard type BOP of selective reinforcement main body with under high pressure and hot conditions, work (for example 20, the maximum internal pressure of 000psi and higher design work pressure down or the high situation of local stress).

In some embodiments, base material can be a F22 low-alloy steel, and this steel contains have an appointment 2 weight % chromium and 1 weight % molybdenum.Alternatively, base material can be 4130 or 8630 modification low-alloy steel (modified low-alloy steel).One skilled in the art will appreciate that and also can use other material as base material with suitable corrosion resistance, hardness and tensile property of being applicable to oil and gas environments.

In some embodiments, covering clad can or inlay can be formed by high-yield strength precipitation-hardening corrosion resistance alloy such as chromium ferronickel 725 or chromium ferronickel 725NDUR.In other embodiments, covering clad can or inlay can be formed by high-yield strength precipitation-hardening corrosion resisting alloy such as alloy 718 or chromium ferronickel 718SPF.In other embodiments, covering clad can or inlay can be formed by other precipitation-hardening corrosion resisting alloy such as 17-4PH, chromium ferronickel 625 or heat-resisting nickel chromium iron 925.One skilled in the art will appreciate that other high-strength corrosion-resisting material also can be used as covering.Preferably, clad material and base material are compatible and be precipitation hardening alloy.

The alloy that can obtain welding wire, powder or belt filling metallic forms is used as covering to weld covering, and the alloy that also can obtain powder type is operated to be used for the HIP covering as covering.Also can obtain to can be used for the alloy of other form of self-tightening covering operation.

In case selected the combination of cladding technique or multiple cladding technique, can determine the minimum thickness and the position of covering according to FEA stress analysis result.The desired thickness of covering or the degree of depth can be according to the combinations that forms between the alloy that is used to form covering, covering and the base material, be derived from the clad material dilution that is used in conjunction with the technology of clad material and base material changes.In case determined to stand the value and the position in the zone of fatigue failure, can select clad alloy.May need not to coat the whole oil filed parts.Particularly, only the part of parts needs covering.For example, the part of BOP main body only comprises that the restriction choke and the kill-job side outlet of wetting, flashboard chamber and flashboard type BOP main body needs covering.In addition, can arrange obviously less cladding thickness, thereby prevent the zonal corrosion that contacts with wellbore fluids in the lower regioselectivity of stress.

For example, refer now to Fig. 6, show through strengthening to control the schematic diagram of tired flange neck.Container body 10 is connected with integral type flange 12 by flange neck 14.The caused fatigue loading condition of interior pressure that the parts that flange neck 14 may stand to be connected with flange 12 move, the fluid extrapolation in the bolt tensioning in bolt hole 16, hole 18 acts on container body 10, and other loading condiction.The external diameter surface 20 of flange neck 14 and often stand high fatigue loading condition from the inside diameter surface 22 that flange neck 14 passes the container 10 that wall thickness arrives, and can use covering inlay or covering clad can 24,26 selective reinforcements by said method.For example, the flange neck that stands the fatigue loading condition is to be used for the flashboard type of underwater well head assembly and the lower flange on the annular blowout preventer main body.Flashboard type in the assembly and annular blowout preventer main body stand great reversed bending load, cause flexural fatigue situation serious on the flange neck thus.Selective reinforcement can additionally give the zone of standing the fatigue loading condition bigger stress-corrosion-cracking resistance.

Again for example, alternative drilling well or the production riser stress joint strengthened is to reduce or eliminate fatigue failure.Before this, this stress joint is by the high strength titanium alloy manufacturing, because the modulus of titanium alloy is starkly lower than low-alloy steel, thereby compares titanium alloy with low-alloy steel and can tolerate bigger amount of deflection.Yet titanium part is very expensive and do not possess " fatigue strength " characteristic.Steel part shows fatigue strength, can not lose efficacy with lower member at this fatigue strength, and irrelevant, but titanium part is ultimate failure with cycle-index, and irrelevant with the size of circulating load.Thereby by selective reinforcement low-alloy steel, the material that possible use cost is lower produces and can tolerate stress joint crooked and the deflection longer time (promptly more circulations).

Again for example, the alternative sucker rod that stands high circulation axial fatigue and other parts of strengthening insert pump are to reduce or eliminate fatigue failure.For example on the OD surface of sucker rod, use the high strength surface course also can prolong the application life of this base part.In addition, the high-strength corrosion-resisting material may reduce the random corrosion fatigue effect that environment for use produces.

Again for example, the alternative valve body of strengthening is to reduce or eliminate fatigue failure, to reduce or eliminate burn into and/or make in more economical mode.For some valves (for example choke valve), selective reinforcement also can reduce or eliminate the erosion that choke valve downstream (being a low pressure) side flow at high speed causes.

Again for example, except that the flange neck, the preventer main body also may stand tired and can carry out selective reinforcement to reduce or eliminate fatigue failure.As mentioned above, preventer may be influenced by high pressurized overflow with restriction equipment is installed.Preventer has several, and wherein modal is ram blowout preventer and annular blowout preventer (comprising spherical blow-out preventer).For example made the ram blowout preventer of various pore diameter ranges at present, these ram blowout preventers can have 2,000 to 15, the working pressure range of 000psi.Yet, may be under more high pressure and higher temperature condition (greater than 15,000psi and greater than 250 °F) use ram blowout preventer.Particularly, may need rated operating pressure is 20,000psi, 25,000psi and more high pressure and operating temperature up to 350 °F or higher ram blowout preventer.For example, referring to Huff that submitted on September 28th, 2006 and the U.S. Patent application No.11/528 that is entitled as " Reinforcement of IrregularPressure Vessels " of Khandoker, 873, be incorporated herein it in full as a reference.The above-mentioned FEA result of the preventer that uses under high temperature and/or condition of high voltage shows, to the selective reinforcement of preventer different parts such as restriction choke and kill-job groove (kill pocket) preventer can be used under higher temperature and pressure.

That the purpose of above-mentioned numerical method (FEA analysis) comprises is definite, be in the zone of high-stress state or peak stress (SB peak value) state in isolation and the outstanding BOP equipment.For example, can determine to cause the stress state of initial failure under the NACE environment.The FEA result of BOP can be used for generating the stress and strain curve map, determines the zone of high stress concentrations in the container.

In addition, the critical cross-section thickness (critical section thickness) that the stress and strain curve map can be used for limiting foundry goods that the oil field parts use or forging (CST), to determine the proper heat treatment time under chosen temperature exactly.Critical cross-section thickness is defined as the maximum ga(u)ge that must in whole thickness range, have the parts of some minimum mechanical performance.For example, the stress of pressure vessel or BOP is little, the part of wall thickness may not need have 80 in its whole thickness range, the yield strength of 000psi, but thin part may have 80, the yield strength of 000psi in the whole thickness range of this part; In this example, thin part can have CST.Total heat treatment time can comprise and adding and together very first time (in minute/inch CST) and second time (in hour).For the purpose of this paper, will be called " pressurize " time (" dwell " time) very first time, second time was called " immersion " time (" soak " time).For example, typical conventional heat treatment time can comprise the dwell time of 30 minutes/inch CST and 1 hour soak time.In this example, CST is forging that 10 inches oil field parts the use heat treatment time that needs 6 hours under chosen temperature (i.e. 10 inches * 30 minutes/inch dwell time+1 hour soak time).

In addition, the stress and strain curve map can be used for isolating the zone that stress exceeds the selected percentage of base material yield strength.For example, particularly, for the alloy as base material, NACE requirement (as described below) may not be satisfied in the zone that surpasses yield strength 80%, may not provide enough engineering safety coefficients when perhaps for example working under the particular combinations of interior pressure and temperature in application-specific.For example, the zone that stress may exceed the selected percentage of base material yield strength among the BOP comprises near BOP groove and the BOP endoporus (cross section of upright opening, lateral aperture, upright opening and lateral aperture) bottom tub (seat pocket), the valve gap.These stress and strain curve maps also can be used for calculating the degree of depth of the high stress areas that exceeds the selected percentage of base material yield strength.

When making BOP, can improve determined high stress areas.For example, described zone be can in spatial image or drawing, mark, the degree of depth and the lateral extent (length and width) that surpass the high stress areas of allowing the SB peak stress indicated.Can draw outline drawing, length, width and the degree of depth in the local stress zone that exceeds the selected percentage of base material yield strength is shown.For example, the surface location in peak stress district can be transferred on the suitable fabrication drawing.Then, can utilize the higher material selectivity of intensity to strengthen determined high stress areas.In some embodiments, the higher strengthening material of this intensity can combine with base material metallurgy.

Sclerosis

The oil field parts of selective reinforcement, comprise flange neck, preventer, sucker rod and other parts, particularly be exposed to those of corrosive fluid, may need to satisfy the design standard of oil gas field metal parts, for example stand various set of circumstances compounds, pH, temperature and H at metal ₂Performance during the S dividing potential drop, the requirement (comprising NACE MR0175, NACETM0177 and NACE TM0284) that NACE international organization (predecessor is National Association of Corrosion Engineers) and European Federation of Corrosion establish.For example, for the low-alloy steel of quality adjustment condition, NACEMR0175 is restricted to Rockwell C 22 or Bu Shi 237 with the highest hardness of parts.Except reaching the desired yield strength in selective reinforcement zone, also must satisfy these hardness restrictions.

Yet satisfying the hardness restriction when reaching required yield strength may change present manufacture method by needs.The postweld head treatment temperature and time may conflict mutually with the age hardening temperature and time.For example, under the situation of using corrosion-resistant nickel-based alloy (CRA) selective reinforcement low-alloy steel base material, the postweld head treatment temperature may be enough to reach the desired highest hardness value in heat affected zone in the covering clad can welding process, but the PWHT temperature may be low excessively for age hardening CRA facing material is obtained for the desired mechanical performance.

For overcoming the temperature and time requirement of these antagonism, develop the method for making selective reinforcement oil field parts, so that optionally strengthening the material of base material, base material and being used for obtains required performance.In one approach, foundry goods, forging or the high temperature insostatic pressing (HIP) rolled-up stock of the use of oil field parts can be by the base material manufacturings that includes but not limited to low-alloy steel.Suitable low-alloy steel can include but not limited to modification 4130,8630 and F22.

Then base material is carried out normalizing.For example, F22 low-alloy steel forging can add 1 hour in 30 minutes/inch thickness of 1750 normalizings.If necessary, can be required structure also then with foundry goods, forging or the roughing of high temperature insostatic pressing (HIP) rolled-up stock.

After the normalizing, can quench and prompt tempering (Q﹠amp to foundry goods, forging or high temperature insostatic pressing (HIP) rolled-up stock; ST) to prevent cracking.As used herein, " prompt tempering " is meant slight softening alloy and reduces the middle Low Temperature Heat Treatment of cracking (particularly so-called autoclasis) probability.For example, the parts of being made by F22 can reach 900-1000 Q﹠amp; ST goes through the dwell time of about 30 minutes/inch CST and 1 hour soak time.Randomly, can after prompt tempering, carry out above-mentioned roughing.Forging, casting and pressed part may be crisp especially, and the prompt tempering after quenching can allow them to be used, to transport and/or further machine and can not ftractureing.

Usually, in conventional way, can carry out complete heat treatment to foundry goods, forging and the rolled-up stock that the oil field parts use by normalizing, austenitizing, solution annealing, tempering, age hardening, heat treatment and other method known in the art, with embedded or outside reach required final material property before covering the CRA material.For example, according to conventional way, low-alloy steel for example 4130,8630 or the BOP main body made of F22 on for example flange connector on the ring liner groove in the embedded CRA material of welding for example before the chromium ferronickel 625, this BOP main body is carried out complete heat treatment and machine at least in part.In conventional way, this embedded BOP main body is carried out stress eliminate (i.e. annealing) being lower than under a certain temperature of base material temperature then, to guarantee to keep the yield strength of base material.

According to this paper, use in the oil field equipment through Q﹠amp; The foundry goods of ST, forging and rolled-up stock can not have to carry out under the situation of complete tempering fine finishining and use clad material to carry out selective reinforcement (as mentioned above).In case, can carry out fine finishining (if necessary) to reach final geometry to clad material through selective reinforcement.In addition, after selective reinforcement, the oil field parts can experience the independent step of heat treatment that this paper is called " final tempering " in the selected time under chosen temperature.In one embodiment, Xuan Ding time is between the required time of required time of base material complete tempering and clad material age hardening.In addition, selected final tempering can realize one or more in following: (a) reach the required mechanical performance of base material, (b) postweld head treatment of the heat affected zone of weld seam and (c) age hardening of clad material (being also referred to as " precipitation-hardening ") between base material and the clad material.

In another embodiment,, can further strengthen clad material by " additional heat-treatment " by after optionally final tempering is carried out in heating.For example, can use ceramic electric heating blanket known in the art to make clad material " additional timeliness ".In the exemplary of the additional timeliness of clad material, use ceramic electric heating blanket heat packs layer material surface, make and between clad material and base material, set up temperature gradient, thereby make the temperature of base material always be lower than final temperature (perhaps, particularly, than low about 50-100 of final temperature).

In another embodiment, the age hardening clad material can be used for the selective reinforcement (as mentioned above) of conventional quenching and final tempering oil field parts, can make covering " additional timeliness " then as mentioned above and not influence " finally " tempering.

In some embodiments, the relation between the age hardening temperature of the temperature of base material and clad material has promoted final drawing process.In some embodiments, the base material aging temp that can have with clad material differs 100 °F with interior temperature.In other embodiments, described two temperature can be separated by 75 °F or 50 °F.

Thereby, in some embodiments, required tempering circulation and required age hardening both required times that circulate make that they are consistent on total final tempering time (dwell time adds soak time), thereby reach base material and the desired performance of covering.In other embodiments, tempering circulation and age hardening both required times that circulate make total final tempering time between required tempering time and required age hardening time, thereby can reach base material and the desired performance of clad material.

As mentioned above, final tempering can realize base material and the required performance of clad material.In some embodiments, final tempering can make base material reach the yield strength of 80ksi to 95ksi.In other embodiments, finally tempering can make clad material reach the yield strength of 115ksi at least.In other embodiments, the final tempering highest hardness that can produce base material is the oil field parts of HRC 22 or Bu Shi 237.In selected embodiment, each parts all satisfies these performances.

Final temperature in some embodiments can be between about 1200 °F to about 1300 °F, in other embodiments can be between about 1225 °F to 1300 °F, can be between 1215 °F to 1225 °F in some embodiments again, in some embodiments, final temperature can be greater than the postweld head treatment temperature of base material.

In some embodiments, the final tempering time of selective reinforcement oil field parts can add 1 to 2 hour " immersion " time for 30 to 60 minutes/inch CST " pressurize " time.In other embodiments, the final tempering time of selective reinforcement parts can add 1 to 2 hour " immersion " time for 30 to 45 minutes/inch CST " pressurize " time.In some embodiments again, final tempering time can add about 1 hour " immersion " time for 38 to 42 minutes/inch CST " pressurize " time.

As mentioned above, the present invention can provide the method for making selective reinforcement oil field parts.The oil field parts can comprise the base material that uses the clad material selective reinforcement, and this method can be included in the selected time and temperature is carried out final tempering to the oil field parts, so that base material tempering and make the clad material age hardening.

Refer now to Fig. 7, show the block diagram of the method for selective reinforcement constructed in accordance oil field parts.Manufacture method 50 can be included as the step 52 that the oil field parts provide base material.One skilled in the art will appreciate that the step 52 that base material is provided can include but not limited to the forging of base material or the normalizing of casting, high temperature insostatic pressing (HIP), roughing and base material.Then, manufacture method 50 can comprise the quenching and the prompt tempering (Q﹠amp of treated base material; ST) 56.After prompt tempering 56, can use clad material that base material is carried out selective reinforcement 58.Selective reinforcement 58 for example can comprise the embedded base material of use corrosion resisting alloy, and wherein corrosion resisting alloy can have the intensity that is higher than base material.After selective reinforcement 58, oil field parts (being base material and clad material) can experience final tempering 60.Final tempering 60 can be included in the selected time and temperature is carried out final tempering to the oil field parts, so that base material tempering and make the clad material age hardening.

Final tempering

Can be according to the present invention the above-mentioned existing manufacture method of following improvement.Can be according to forging main body with roughing flashboard type BOP with at present identical mode, but will improve the heat treatment of roughing BOP main body.Identical with the measure of taking at present, also will under suitable temperature, carry out normalizing and austenitizing and carry out liquid hardening main body.After finishing liquid hardening, change temperature, reduce to lower value, carry out " fast " tempering or middle lonneal.As previously mentioned, prompt tempering purpose is to prevent the autoclasis during until final tempering in process of low-alloy steel material through quenching.

Acquisition is behind roughing and the heat treated forging of prompt tempering, and the BOP main body can prepare to weld clad can.Can carry out those zones that the clad can welding is determined by above-mentioned stress analysis with selective reinforcement to the BOP main body then, can be to engineering drawing with described zone-transfer.After all welding was finished, the tempering furnace of the BOP main body can being packed into was with the associating heat treatment of the welding line joint that carries out final tempering and low-alloy steel matrix upper sheathing clad material.

Final tempering is made of the tempering of parent metal, to reach the desired parent metal mechanical performance of material specification.The HAZ that tempering also can be welding line joint provides PWHT, and this is because tempering/aging temp is higher than base material/CRA welding line joint PWHT temperature commonly used.At last, tempering can be filled metal to high strength CRA clad can and be played the heat treated effect of age hardening.

This final drawing process is feasible, and this is because for example can be much at one at the aging temp of suitably selecting and handle the temperature of situation lower substrate metal of base material and CRA clad can and CRA facing material.Tempering circulation and age hardening both required times of circulating make them can reach balance and obtain two kinds of desired performances of material.

Can use test sample QTC independently to determine the mechanical performance of alloy, can be independent of parts itself this sample is heat-treated, condition is to produce the concrete standard that the parts of industry formulate sample is heat-treated at being used for oil exploration according to API.For example, for checking BOP main body meets material performance requirement, can make two test sample QTC by the same stove steel of making the BOP main body.Can adopt identical circulating temperature and time with the main body forging while or be independent of the main body forging and carry out normalizing, austenitizing, liquid hardening and tempering by two test sample QTC of the same stove low-alloy steel manufacturing of forging main body.One of them QTC can obtain to carry out tempering under the required temperature and time of the desired mechanical performance of material specification.Another QTC can carry out final tempering with selective reinforcement BOP.These QTC can be delivered to the mechanical experiment chamber then, carry out mechanical test, meet specific requirement to guarantee base material and clad material.

By this way the BOP main body is carried out final tempering and can allow base material and clad material to satisfy required performance, comprise that yield strength, hardness and/or NACE are to the stress corrosion dehiscence resistant performance demands.In addition, the CRA inlay should have better axially anti-or flexural fatigue failure performance and help to reduce axially or flexural fatigue lost efficacy.

For example, as mentioned above, can be according to manufacture manufacturing and the processing F22 forging or the foundry goods of routine.But can improve heat treatment.Normalizing and austenitizing temperature circulation and time and liquid hardening can remain unchanged.Temperature can be become 900 °F (482 ℃) to 1100 °F (593 ℃), time of going through under this temperature is shortened or remain unchanged.The BOP main body that can use chromium ferronickel 725 or other age hardening alloy or CRA selective reinforcement to forge then.

In case finish welding operation, the heat-treatment furnace of the BOP main body of selective reinforcement can being packed into, to carry out final tempering (can be associating tempering, timeliness and PWHT), thereby make the HAZ stress relief annealing of F22 parent metal, make the age hardening of chromium ferronickel 725CRA weld metal inlay, reach the mechanical performance of F22 forging.Also can use other age hardening alloy and/or CRA for example chromium ferronickel 718SPF (alloy 718) be used for this application as filling metal.Can determine and confirm the temperature and time of final tempering (associating tempering/PWHT/ age hardening heat treatment) according to the qualified record of soldering (PQR) according to soldering regulation (WPS).After finishing final tempering, the QTC through same treatment can be delivered to the metallurgy laboratory, determine also with the mechanical performance of determining material whether the mechanical performance of material satisfies the requirement of material specification.

Because PWHT and tempering circulation can be carried out simultaneously with the age hardening of covering inlay metal, thereby any loss that may occur when after the tempering of low-alloy steel parent metal, not carrying out PWHT separately of the mechanical performance of parent metal.

In one embodiment, flashboard type BOP main body forging is made by the F22 alloy.Rough forge spare is carried out normalizing in 1750 °F, go through " pressurize " time of 30 minutes/inch CST and 1 hour " immersion " time.Carry out shrend then and add 1 hour in 30 minutes/inch CST of 900 prompt temperings.

Randomly, to carrying out roughing, for example " weldering neck " carried out roughing so that flange is welded on the BOP main body then through the flashboard type BOP main body of quenching and prompt tempering.Randomly, then various annexes such as flange connector or anchor clamps are welded on Q﹠amp; On the ST main body, these annexes can be preferably equally by Q﹠amp; ST F22 alloy constitutes.Then to Q﹠amp; The ST main body is carried out fine finishining and is used the zone that chromium ferronickel 725 is embedded in to be needed selective reinforcement and/or improve corrosion resistance.Randomly, further process embedded zone.At last, the fine finishining main body with embedded reinforcement body is gone through " pressurize " time of about 40 to 42 minutes/inch CST and 1 hour " immersion " time in 1220 °F " final tempering ".After handling through this, the yield strength of F22 base material is about 85,000psi, and the yield strength of inlay chromium ferronickel 725 is greater than 115,000psi.In addition, final temper also plays the effect of eliminating residual stress in the weldment heat affected zone, thereby need not additional PWHT.

In another exemplary, can make telescopic annular space BOP main body by modification 8630 annular forging pieces, described forging is through quenching and having gone through " pressurize " time of 30 minutes/inch critical cross-sections and 1 hour " immersion " time in about 900 prompt temperings.Q﹠amp; The ST ring can be stacked and vertically carry out the full penetration welding.Can be to Q﹠amp; The welding stacked body of ST ring carries out machine and uses INCONEL725 welding inlay material to carry out selective reinforcement, then in about 1260 final tempering, goes through dwell time and the about 1 hour soak time of about 30 to 45 minutes/inch CST.

Replenish age hardening

As mentioned above, clad material can replenish age hardening to improve its yield strength.Additional age hardening can realize base material and the desired performance of clad material.At least a portion of heat packs layer material optionally, in some embodiments, clad material can reach the yield strength of 115ksi at least, simultaneously base material hardness keep Bu Shi 237 or below.

In some embodiments can be to selective reinforcement Q﹠amp; ST oil field parts replenish age hardening.For example, as mentioned above, the process Q﹠amp that uses in the oil field equipment; The foundry goods of ST, forging and rolled-up stock can carry out fine finishining, do not have at foundry goods, forging or rolled-up stock to carry out selective reinforcement under the situation of complete tempering, carry out final tempering in chosen temperature in the selected time then.Then, the oil field parts of the final tempering of process can replenish age hardening, with further reinforcement clad material, and do not make the further tempering of base material.

Also can replenish age hardening to oil field parts through conventional quenching and final tempering.Can carry out complete heat treatment to foundry goods, forging and the rolled-up stock that the oil field parts use by normalizing, austenitizing, solution annealing, tempering, age hardening, heat treatment and other method known in the art, with embedded or outside reach required final substrate performance before covering the CRA material.Then, the timeliness that the oil field parts of process conventional quenching and final tempering can add with further reinforcement clad material, and does not influence " finally " tempering.

In replenishing age-hardening process, can initiatively cool off at least a portion of oil field parts, thereby make base material keep below the temperature of base material.As used herein, " initiatively " cooling can comprise conduction cooling, forced convection cooling, carry out interchange of heat, spraying cooling (for example water being sprayed on the part on surface) or other cooling means well known by persons skilled in the art with medium such as actuation fluid (steam or liquid), does not comprise the cooling of natural convection or still air.For example, during greater than the temperature of base material, can adopt initiatively cooling in the age hardening temperature of clad material.

In some embodiments, base material can keep in clad material selectivity age-hardening process than low 50 of base material temperature at least; Low at least 75 °F in other embodiments; Hanging down at least 100 °F in some embodiments again.

In addition, the selective reinforcement of oil field parts may not form thickness homogeneous cladding material on whole surface.In some embodiments, the thickness variable of clad material.For example, shown in Fig. 8 A, can carry out selective reinforcement, thereby reduce to reach the thickness of base material 34 and surface interface 32 place's minimums of clad material 30 gradually in clad material 30 thick parts.In other embodiments, can be at the thickness of clad material 30 evenly or near position uniformly, even, carry out selective reinforcement as 32 places, interface of Fig. 8 B be shown in base material 34.

Add at clad material under the situation of timeliness, optionally the whole surface of heat packs layer material may make base material at the interface 32 places or surpass the base material temperature near 32 places, interface.For avoiding the interface or near surpassing the base material temperature at the interface, additional age hardening only can comprise that the part to the covering inlay optionally heats.For example, shown in Fig. 8 B, optionally heat the core 36 of covering inlay 30,, make base material 34 at the interface 32 or keep below the temperature of base material 34 near the temperature at 32 places, interface simultaneously wherein by the periphery of conduction clad material 30 age-hardenable.By this way, even base material 34 still can keep 237 or following Brinell hardness at 32 places, interface with clad material 30.

Refer now to Fig. 9 A and 9B, show the FEA Simulation result, carry out the FEA simulation and replenish the difference of in the age-hardening process covering inlay being carried out initiatively cooling and still air cooling to study.In this example, be that 12 inches, internal diameter are that 19 inches F22 cylinder has carried out the FEA simulation to thickness, used 0.5 inch covering inlay that chromium ferronickel 725 constitutes on the cylindrical internal diameter of this F22.For simplified model, suppose that inlay has homogeneous thickness.The surface of covering inlay is set at 1350 °F, and the temperature that makes the cylinder external surface is based on initiatively cooling and still air cool off and change.

Shown in Fig. 9 A and 9B, it is about 800 °F that the still air cooling can make outside wall temperature, and initiatively cooling can make outside wall temperature keep 75 low temperature.The more important thing is that initiatively cooling can make base material keep below 1180 of the temperature of the temperature of base material at (0.5 inch dark) at the interface with clad material.Relative with it, the still air cooling makes base material surpass temperature.These analog results show that initiatively cooling can provide the method for replenishing age hardening covering inlay, make base material keep below the temperature of base material simultaneously.

In selected embodiment, in replenishing age-hardening process, at least a portion of clad material optionally can be heated to about 1250 °F to 1400 °F.In some embodiments, in replenishing age-hardening process, at least a portion of oil field parts surface can remain on 250 °F or following; Remain on 200 °F or following in other embodiments; Remain on 150 °F or following in other embodiments; Remain on 100 °F or following in other embodiments; Remain on 75 °F or following in other embodiments; Remain on 50 °F or following in other embodiments.

Temperature Distribution/intensity gradient

As mentioned above, in some embodiments, oil field parts such as ram blowout preventer can be used for high pressure or high-pressure high-temperature environment.Thereby the oil field parts may need to satisfy the SMYS requirement at the surperficial certain depth of distance place.For example, be 20 for rated operating pressure, 183/4 inch ram blowout preventer of 000psi may require flashboard to have 120ksi or bigger SMYS at the about 0.375 inch degree of depth place of distance internal diameter.Higher rated pressure may require to have bigger yield strength at the certain depth place.As mentioned above, can utilize the FEA model to determine under the required rated pressure SMYS requirement to the certain depth place.

Must allow that the situation of hardness is issued to the SMYS that the certain depth place requires not making base material surpass maximum.Can utilize the additional age hardening of clad material, reach the desired properties of base material and clad material, as mentioned above, additional age hardening can comprise selectivity heating and initiatively cooling.

Make clad material go through the age hardening of seclected time for reaching the clad material SMYS that the certain depth place needs, can planting at the chosen temperature branch.Age hardening can produce the clad material with selected intensity gradient by this way." chosen temperature distribution " is meant via selectivity heating and optional active cooling and forms required temperature gradient in the parts of oil field, make the clad material age hardening not make the further tempering of base material with further reinforcement clad material.Owing to set up Temperature Distribution in the parts of oil field, thereby the clad material age hardening reaches different degree, and then produces intensity gradient in clad material.Thereby " seclected time " is meant that the minimum strength based on chosen temperature distribution and certain depth place requires to be enough to make the clad material age hardening to reach the time of certain depth desirable strength.

In some embodiments, can plant at the chosen temperature branch and make selective reinforcement Q﹠amp; ST oil field parts are gone through the additional age hardening of seclected time.For example, as mentioned above, use in the oil field equipment through Q﹠amp; The foundry goods of ST, forging and rolled-up stock can be gone through the final tempering of seclected time then not having to carry out fine finishining and selective reinforcement under the situation of complete tempering under chosen temperature.Then, the oil field parts of the final tempering of warp can plant at the chosen temperature branch and replenish age hardening, do not make the further tempering of base material with further reinforcement clad material, and then produce the clad material with selected intensity gradient.

Oil field parts through conventional quenching and final tempering also can plant the additional age hardening of going through seclected time at the chosen temperature branch.Can carry out complete heat treatment to foundry goods, forging and the rolled-up stock that the oil field parts use by normalizing, austenitizing, solution annealing, tempering, age hardening, heat treatment and other method known in the art, with embedded or outside reach required final substrate performance before covering the CRA material.Then, the oil field parts of process conventional quenching and final tempering can replenish age hardening, do not make " final tempering " further tempering of base material with further reinforcement clad material, and then produce the clad material with selected intensity gradient.

Selected intensity gradient can comprise the minimum strength at certain depth place.For example, in some embodiments, clad material can reach the yield strength of 125ksi at least in its surface.In some embodiments, clad material can reach the yield strength of 130ksi at least in its surface, in some other embodiment, clad material can reach the yield strength of 135ksi at least in its surface, in some embodiments again, clad material can reach the yield strength of 140ksi at least in its surface.

In some embodiments, clad material can reach the yield strength of 115ksi at least at about 0.375 inch degree of depth place.In some embodiments, clad material can reach the yield strength of 120ksi at least at about 0.375 inch degree of depth place, in some other embodiment, clad material can reach the yield strength of 125ksi at least at about 0.375 inch degree of depth place, in some embodiments again, clad material can reach the yield strength of 135ksi at least at about 0.375 inch degree of depth place.In some embodiments, clad material can reach the yield strength of 120ksi at least at about 0.4375 inch degree of depth place, in some other embodiment, clad material can reach the yield strength of 120ksi at least at about 0.500 inch degree of depth place, in some embodiments again, clad material can reach the yield strength of 120ksi at least at about 0.5625 inch degree of depth place.Thereby SMYS and certain depth can change according to the design standard that is adopted (for example regulation).

Figure 10 shows the producible intensity gradient of age hardening of going through seclected time at chosen temperature distribution under-clad layer material.In order to simplify accompanying drawing, suppose thick 12 inches of the cylinder that base material that final tempering SMYS is 85ksi makes, internal diameter is 19 inches, and this cylinder internal diameter on used 0.75 inch homogeneous cladding.

For generating the selected temperature distribution map, adopt initiatively cooling so that outside wall temperature remains on 75 °F, selectivity heating covering makes surface temperature reach 1350 °F.Plant the clad material that the heat aging of going through seclected time can form intensity distributions shown in the generation at the chosen temperature branch.The surface of clad material can reach the SMYS of 135ksi at least, and clad material can reach the SMYS of 120ksi at least.Base material on its whole thickness (be on the curve corresponding to distance base material and clad material between 0.75 inch at interface sentence right part) all keep below 1100 temperature, this temperature is lower than the temperature of base material, thereby does not cause the additional age hardening of base material.

The sketch of Figure 10 shows the example of intensity distributions, and this intensity distributions may be caused by the selected temperature gradient of nonspecific covering clad can metal.The actual intensity gradient that produces may depend on metal, the thickness of covering that covering selects for use, chosen temperature distributes and plant the seclected time of going through at the chosen temperature branch.Can control these variablees to produce selected clad material intensity gradient according to the instruction of this paper.

Embodiment that the application discloses and method can advantageously generate and analyze the oil field partial model by FEA, adopt stress and/or analysis of fatigue, to determine the response in the fatigue loading condition lower member that is characterised in that a large amount of stress.Can utilize resulting analysis result to improve the parts design, improve the performance of parts under the fatigue loading condition then.

Advantageously, the present invention can provide based on ASME Section-VIII Div-3 or similar high-voltage high-temperature equipment design principles and set up the method for whole oil filed parts design.Parts can satisfy NACE peak stress and cycle life requirement.The oil field parts that method that the application discloses and embodiment can provide working life to prolong.For example, but the oil field parts under the simulation fatigue loading conditions such as modelling is compressed repeatedly, bending, to determine the prolonging design feature of oil field parts working life.

Advantageously, the present invention can provide the method for making the oil field parts, compares with solid high strength and corrosion resistant alloy or other metal manufacture component of attempting by satisfying the NACEMR0175 requirement, and this method cost is lower.In view of the mechanical strength apart from the main body at 0.250 to 0.500 inch place of wellbore fluids wetting surface below the covering may be starkly lower than the desired mechanical strength in local stress district that stands fatigue failure, particularly like this.Other embodiment can be strengthened existing parts design, thereby can be applicable to the high strength material selective reinforcement oil field parts of oil and gas environments by use, deals with sulfide-stress cracking or the maximum conditions relevant with corrosion.

The selection of clad alloy can be mainly according to the high mechanical properties of covering and can be according to the metallurgy combination that reaches between covering and the matrix.The additional contribution of covering may be the corrosion resistance that clad alloy is given the oil field parts.Another contribution of covering is that any cut or the cutter mouth of the inner surface of parts are difficult for extending to below the covering degree of depth, thereby makes covering be continued the low-alloy steel matrix of protecting it to deposit.Particularly, covering also will continue guard block in order to avoid the pitting that occurs finding in the oil field parts inner chamber of being everlasting.In addition, repair in the covering the cutter mouth may than repair in the low-alloy steel matrix similar damage easily and cost lower.

On the other hand, the present invention can advantageously provide the method for making selective reinforcement oil field parts.This method can be included in the selected time and temperature is carried out final tempering to the oil field parts, so that base material tempering and be used in the clad material age hardening that forms selective reinforcement oil field parts.This method can advantageously realize the required performance of base material by this way, connect the postweld head treatment of welding line joint of base material and clad material and the age hardening of clad material.

On the other hand, the present invention can advantageously provide the method for making selective reinforcement oil field parts, and wherein this method comprises the additional age hardening of clad material.In some embodiments, can plant the additional age hardening of clad material being carried out seclected time at the chosen temperature branch.This method can advantageously realize the selected intensity of clad material or intensity gradient and not make base material surpass maximum allowing hardness by this way.

Although invention has been described at a limited number of embodiments, benefit from of the present invention one skilled in the art will appreciate that without departing from the present invention and can design other embodiment.Thereby scope of the present invention should only be subject to claims.

Claims (15)

1. method of making the oil field parts, this method comprises:

With age hardening clad material selective reinforcement base material; And

Make described clad material plant the age hardening of going through seclected time at the chosen temperature branch;

Wherein said age hardening produces the clad material with selected intensity gradient.

2. the method for claim 1 also comprises:

Analyze first model of described oil field parts;

Determine the zone of the high stress concentrations of described first model under selected loading condiction;

Make up described oil field parts; And

Wherein said selective reinforcement comprises the determined high stress concentrations zone corresponding to constructed oil field parts of selective reinforcement.

3. the method for claim 2 also comprises the minimum strength requirement of determining the certain depth place.

4. the process of claim 1 wherein that described intensity gradient comprises the minimum strength at certain depth place.

5. the method for claim 1,

Wherein said base material comprises the forging of deep drawing; And

Wherein said age hardening comprises that selectivity heats at least a portion of described clad material, so that described clad material age hardening and make described base material keep below its temperature.

6. the method for claim 1,

Wherein said base material comprises the prompt tempering forging;

This method also comprises makes described oil field parts go through the final tempering of seclected time under chosen temperature, so that described base material tempering and make described clad material age hardening; And

Wherein said age hardening comprises that selectivity heats at least a portion of described clad material, so that described clad material age hardening and make described base material keep below its temperature.

7. the process of claim 1 wherein that described clad material has the yield strength of 135ksi at least on its surface.

8. the method for claim 7, wherein said clad material has the yield strength of 120ksi at least in about 0.375 inch degree of depth.

9. the process of claim 1 wherein that described clad material has the yield strength of 120ksi at least in about 0.375 inch degree of depth.

10. ram blowout preventer that the method for utilizing claim 1 is made.

11. the main body of a ram blowout preventer comprises:

The low-alloy base material;

Pass the upright opening of described main body;

Pass the lateral aperture that described main body and described upright opening intersect;

At least a portion of wherein said main body is optionally strengthened with clad material; And

Wherein make described clad material plant the age hardening of going through seclected time, have the clad material of selected intensity gradient with generation at the chosen temperature branch.

12. the ram blowout preventer of claim 11, wherein said base material have 237 maximum Brinell hardness.

13. the ram blowout preventer of claim 11, wherein said clad material have the yield strength of 135ksi at least on its surface.

14. the ram blowout preventer of claim 12, wherein said clad material has the yield strength of 120ksi at least in about 0.375 inch degree of depth.

15. the ram blowout preventer of claim 11, wherein said clad material has the yield strength of 120ksi at least in about 0.375 inch degree of depth.

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