CN109931048A

CN109931048A - Oil/gas well tubing and casing integrality detection method and evaluation system

Info

Publication number: CN109931048A
Application number: CN201910237027.5A
Authority: CN
Inventors: 黄有为
Original assignee: Nan Zhi (chongqing) Energy Technology Co Ltd
Current assignee: Nan Zhi (chongqing) Energy Technology Co Ltd
Priority date: 2019-03-27
Filing date: 2019-03-27
Publication date: 2019-06-25

Abstract

The present invention provides a kind of oil/gas well tubing and casing integrality detection method and evaluation systems, comprising: complex hole condition horizontal well track processing module；Complex hole condition horizontal well completion tubular pile tripping in force analysis and strength check module；Complex hole condition horizontal well working string tripping in force analysis and strength check module；Force analysis and strength check module during more packer complex hole condition horizontal well completion working string fracture acidizings；Calculated result visualizes and automatically generates reporting modules；Casing string loading analysis and optimization module；Detection method includes: to establish mechanical model；Establish evaluation system；Implement operation to calculate；Casing strength design；Establish casing string loading analysis and optimization module；The Data Analysis Services such as oil pipe, casing cement sheath, stratum.The invention has the advantages that: comprehensively, system, scientific Comprehensive Evaluation solves the problems, such as that present analysis wellbore integrity method only considers single factors.

Description

Oil/gas well tubing and casing integrality detection method and evaluation system

Technical field

The present invention relates to oil/gas well tubing and casing detection technique fields, in particular to oil/gas well tubing and casing integrity detection side Method and evaluation system.

Background technique

Petroleum gas played in national economy it is particularly significant important, to the high quality of China's oil gas industry More stringent requirements are proposed for security developments, contains CO₂, H₂S, CL^-Etc. a variety of corrosive mediums high temperature and pressure oil/gas well in succession at Function exploration and development comes out, and etching problem also more attracts people's attention.Corrosion is easy that tube and casing in downhole tubing string is made to perforate Even phenomenon of rupture not only influences the normal production of oil/gas well, increases workover cost, can also shorten the production life of well of gas well, It results in significant economic losses, and corrodes more serious gas well for tubing and casing, often there is some potential safety problems, It is easy to cause safety accident.Therefore, the corrosion of tube and casing in downhole tubing string and safety problem have become domestic and international gas field at present and grind One of hot issue studied carefully, technical bottleneck are our technical staff will be clear that whether down-hole oil tube casing is intact.

Tubing and casing etc. is the primary structure and component part of oil/gas well, for high temperature, high pressure, acid oil gas pit shaft, Oil/gas well tubing string is in complicated stress (such as tensile stress, shearing force, bending stress and torque) and corrosive environment In, stress corrosion cracking (Stress Corrosion Cracking), hydrogen embrittlement or hydrogen induced cracking (HIC) will be present The risks such as (HydregenInduced Cracking), fatigue corrosion fracture (Corrosion Fatigue Cracking) and Hidden danger.Since the local corrosions such as spot corrosion, galvanic corrosion cause the stress of privileged site to be concentrically formed micro-crack, corrosiveness Persistently carry out causing the growth and extension of crackle, final to cause perforation, leakage and brittle fracture, oil gas well casing occurs above rotten Erosion phenomenon is referred to as environmental cracking (Environment Induced Craclcing).

Environmental cracking will lead to the decaying of oil/gas well tubing string comprehensive performance, and reliability reduces, and cause oil/gas well tubing string The air-tightness and decline of screw connection point cannot reach design sealing effect and service life, or even oil jacket occur Pipe fracture, perforation, leakage, annular space is with pressure or even the major accidents such as blowout.Oil/gas well column tube fracture accident once occurs, gently then It stops production, heavy then full well is scrapped, and not only seriously endangers the construction of pit shaft safety and wellbore integrity, or even cause ecological environment Destruction, personnel casualty accidents and huge economic losses.

China's gas reservoir geological type, which determines that down-hole string such as oil pipe, casing are difficult to avoid that, will receive CO₂Corrosion, CO₂ Corrosion will be the corrosion type that must be faced in China's oil gas industry. CO₂After being dissolved in water, in same pH due to Its total acidity is higher than hydrochloric acid, even more serious than hydrochloric acid to the corrosion of down-hole string.When certain gas wells enter the exploitation intermediary and later stages, Often there is also the output water of high salinity, work as CO₂When dissolving in, corrosivity will become more severe, CO₂Etching problem value It must pay attention to.

In the past to the research of tubing and casing etching problem, more focuses of attention are often CO₂Corrosion mechanism and each In the research of influence factor, to O₂And CO₂Etching problem under coexisted environment lacks enough research and understanding.Therefore, underground Tubing and casing is containing O₂CO₂Corrosion product film component, structure and its spy of corrosion regularity, formation in high temperature pressure corrosion environment Sign needs further to be inquired into, and corrosion mechanism and the further further investigation of assessment technique needs in such circumstances.Research As a result to O₂And CO₂Corrosion prevention scheme design under coexisted environment can provide foundation, selection, drop of adopting an effective measure to casing string Low corrosion harm is of great significance, to seek the CO that oil gas field safety in production encounters₂The solution for corroding this problem is established Fixed basis.In the practical recovery process of oil gas field, needed according to well stimulation to underground re-injection CO₂Gas, re-injection recovered water, note Enter corrosion inhibiter and down-hole string is carried out the operation such as to overhaul, inevitably brings a certain amount of O into underground₂, so that The production equipments such as tube and casing in downhole column are in O₂And CO₂In the environment coexisted.Due to O₂It is a kind of strong oxidizer, O₂Presence must So the corrosion process of tubing and casing is had an impact.

Tubing and casing corrosive environment it is widely different, while corrode influence factor it is more so that tube and casing in downhole column occur A plurality of types of corrosion.The most common corrosion type has: homogeneous corrosion, local corrosion, spot corrosion, crevice corrosion, galvanic corrosion, SSC and HIC etc., additionally there may be microbiologic(al) corrosion (SRB).

For oil/gas well well letter, not only shaft bottom is nearby easy to happen more serious corrosion in high temperature and pressure position, in reality In the production process of border, the moisture in shaft bottom can as water vapor with natural gas output, with gas in the wellbore on It rises, temperature in wellbore can be gradually reduced, and when being lower than the condensing temperature of vapor, will largely be condensed into corresponding shaft location Water provides media environment for corrosion behavior, causes the corrosion of oil casing, influence oil casing residual intensity and Remaining life threatens production safety.

Tubing and casing is in high temperature and pressure CO₂Corrosion process in multinomial stream is more complicated, and corrosion mechanism is always to study Hot spot, the past few decades, domestic and foreign scholars were with regard to CO₂Corrosion mechanism carried out a large amount of research work, propose a variety of corrosion Mechanism.Carbon steel CO has been carried out for the first time in nineteen eighty-three₂The system evaluation of corrosion, however, many mechanism problems are not resolved yet, Or there is dispute, need further to be studied.

With the continuous growth of petroleum resources demand, the faced situation of natural petroleum gas field exploitation is increasingly sophisticated, Tubing and casing service condition is more complicated severe, contains H in high temperature, high pressure, highly mineralized formation brines and height₂S,CO₂Corrosivity gas Under the sour corrosion environment of body, the Problem of Failure induced due to corrosion is on the rise, and the exploitation in complex hydrocarbon field is caused to be exploited Task difficulty is increasing, and tubing and casing fracture accident happens occasionally in recovery process.

The materials such as oil/gas well tubing string, surface technology device, conveyance conduit difference, Service Environment thousand during oil-gas mining Become ten thousand to change, suffered load type, corrosion type and extent of corrosion also all have diversity, so to oil/gas well tubing string And the research of assembly corrosion fatigue will face extremely complex problem, and it is multidisciplinary to be related to mechanics, electrochemistry, material science etc. Friendship justice field.Therefore, to the research of corrosion fatigue to the materials ' durability design of engineering field, residual life assessment, ring Maintenance solution formulation of border military service equipment etc. all has important meaning.Meanwhile how complicated problem is simplified simultaneously Exploring its profound mechanism of corrosion fatigue problem is also the hot issue in current corrosion fatigue and its reliability consideration.

Summary of the invention

The present invention in view of the drawbacks of the prior art, provides a kind of oil/gas well tubing and casing integrality detection method and evaluation System can effectively solve the above-mentioned problems of the prior art.

In order to realize the above goal of the invention, the technical solution adopted by the present invention is as follows:

A kind of oil/gas well tubing and casing integrity detection evaluation system, comprising:

(1) complex hole condition horizontal well track processing module；

Complex hole condition horizontal well track processing module uses the two of least square method using well track measurement data Order polynomial is fitted to obtain smooth continuous two-dimentional well track, and discrete measurement point can be significantly reduced to completion tubular column stress Caused by error.It is also possible to reduce the influence of a single point measurement error or mistake to overall calculation result.

Complex hole condition horizontal well track processing module draws the well by selecting the casing programme data of a well Two-dimentional casing programme, and it will be shown on program interface.Meanwhile user can pass through click " main view ", " right view Figure ", " top view " realization quickly navigate to a certain special angle and check to casing programme.In addition, being provided for software The display and drafting function of horizontal segment partial enlargement figure, have more clear convenient for wellbore trajectory smoothness of the user to horizontal segment It is clear and get information about and recognize.

(2) complex hole condition horizontal well completion tubular pile tripping in force analysis and strength check module；

For the Calculation and Analysis of Force of complex hole condition horizontal well completion tubular pile tripping in process, be classified as two sections respectively into Row calculates, i.e., vertical well section, curved portion and net horizontal section.By ten complex hole condition horizontal well completion tubular piles in bending section stress Complexity, in order to guarantee calculate accuracy, four kinds of different theoretical analysis models of proposed adoption, to carry out analysis comparison. Four theoretical analysis models are respectively as follows: two-dimensional rigid model, two-dimensional rigid model, rigidity power model and entire mathematical model. And the safety of completion tubular column is checked using fourth strength theory, it provides corresponding safety coefficient and dangerous point is corresponding Position.

Complex hole condition horizontal well, directional well completion tubular column tripping in Calculation and Analysis of Force module, mainly calculate tripping in process In axial force, well head pulling force, frictional resistance and its corresponding MISES stress, obtain the safety coefficient of tubing string during tripping in, Construction parameter and safety evaluation are provided for completion tubular column tripping in operation.

(3) complex hole condition horizontal well working string (band power tool) tripping in force analysis and strength check module；

When in view of separate stratum fracfturing operation there is the influence to tubing string stress in multiple packers, and different parameters are calculated Stress and the parameters such as stress level and safety coefficient during lower working string tripping in.It calculates under single packer working string Frictional resistance, axial force, well head pulling force and corresponding stress, obtain the safety coefficient during working string tripping in, obtain during entering Influence quantitative relationship of the packer parameter to stress during tripping in out.

(4) force analysis and intensity school during more packer complex hole condition horizontal well completion working string fracture acidizings Core module；

Fracture acidizing tubing string is in lower going-into-well bottom, anchor fluke anchoring, packer setting and later fracture acidizing or produces Cheng Zhong, due to tubing string self weight, fluid column buoyancy, the frictional resistance effect of tubing string internal and external pressure difference, the temperature difference and fluid makes fracture acidizing Tubing string generates following basic effect.The various stress of tubing string and deformation when analyzing single packer working string pressure break are calculated, is obtained In fracturing process under different operating conditions and work layer working string safety coefficient.

(5) calculated result visualizes and automatically generates reporting modules；

After the completion of calculating, the calculation result data and figure being the previously calculated will be automatically write word by software In document, in order to user's use.

Above-mentioned oil/gas well tubing and casing integrity detection evaluation system, further includes: casing string loading analysis and optimization module, The module includes: data input module；Axial load analysis module；Interior pressure analysis module；External pressure analysis module；Casing Database module；Shell material database module；Casing string strength, which is calculated, designs module with casing string optimization；Data export mould Block.

A kind of oil/gas well tubing and casing integrality detection method, comprising the following steps:

Step 1 establishes mechanical model；

1. the axial force suffered by the fracturing string is less than fracturing string bending deformation critical load, it is curved to establish fracturing string The mechanical model of bent deformation analysis is established more packer fracturing strings and is connect with casing wall according to sag curve change limitation condition Touch decision model.

2. the axial force suffered by the fracturing string is greater than fracturing string bending deformation critical load, horizontal well is established respectively Fracturing string vertical section, bending section, horizontal segment bending deformation differential equation equation, and its Sine Buckling and Helical Buckling are become Shape is analyzed, and the calculation of critical model that Sine Buckling and Helical Buckling occur for fractured horizontal well tubing string is established.

3. considering that packer to the effect of contraction of fracturing string bending deformation, establishes the change of packer section fracturing string buckling Conformal analysis mechanical model.Obtain the plane buckling section fracturing string length and contact normal pressure calculation method against packer.

4. analyzing the fracturing string Deformation of helical differential equation, establishes fracturing string and pressure break pipe when helical buckling occurs Column section maximal bending moment computation model, and then obtain fracturing string interface maximum stress in bend computation model.Vertical well section pressure break The moment of flexure and bending stress of tubing string are gradually increased with helical curve variation, and curved portion and net horizontal section change with helical curve In sinusoidal trend, fracturing string moment of flexure and bending stress when contacting with casing wall upper wall obtain maximum value.

5. considering influence of the fracturing string stiffness to fracturing string frictional resistance, fractured horizontal well drilling pipe bending is established Section frictional resistance computation model.The buckling frictional resistance generated due to the effect of fracturing string buckling is analyzed, fractured horizontal well tubing string is established Different well section buckling frictional resistances calculate the type that rubs.

6. by analyzing the frictional resistance under the different coefficient of friction resistances, the relationship of coefficient of friction and normal pressure is established simultaneously Non-linear relation is modified traditional conventional horizontal well fracturing string computation model.

7. being analyzed under fracturing string according to frictional resistance computation model during more packer fracturing string tripping in of foundation Enter process, by introducing decision function, analyzes the influence factor that different well section fracturing string tripping in are hampered, be under fracturing string Enter to be hampered and a solution is provided.

8. when fracturing fluid recovery (backflow), acting on the circumocular pressure break hydraulic coupling in well-case perforating hole can be with fracturing fluid recovery (backflow) speed Change and change, establishes the computation model that pressure break hydraulic coupling changes with discharge speed.

9. when fracturing fluid recovery (backflow), discharge speed, which crosses conference, makes casing that plastic deformation or unstable failure occur, and leads to seal more It is above mentioned every device fracturing string and is hampered and can not be taken out from shaft bottom, establish the fracturing fluid for making casing that plastic deformation or unstable failure occur Critical discharge speed computation model, which is that more packer fracturing strings are smoothly upper, proposes well, proposes a kind of pre-judging method.

10. researching and analysing the factor of stress concentration around porous casing hole by Elasticity in conjunction with the theory of complex functions Problem, and application finite element software simulation calculates the variation of porous casing eyelet ambient stress coefficient of concentration, analyzes different perforations Combine the influence to porous casing eyelet ambient stress coefficient of concentration.

Step 2, evaluation system is established；

Step 3, implement operation to calculate；

1. drill string frictional resistance and torque prediction calculate；

2. the prediction of casing job frictional resistance calculates；

3. keeping a grip on coefficient of friction resistance Inversion Calculation；

Step 4, casing strength designs；

1) when starting, segment length is taken as minimum segment length；

2) minimum of this section is obtained effectively from external and internal pressure computing module according to the bottom depth of casing string and top depth External and internal pressure；

3) assume that the maximum axial force that this section of casing string is born is equal to axial force suffered by this section of casing column bottom；

4) according to the optional bound data according to actual requirement setting, (latus rectum, wall thickness, joint categories, grade of steel, minimum permit Perhaps any combination of quantity in stock least cost and minimum weight) and external applied load, it is found from database all qualified Casing；

5) maximum axial of this section of casing string is calculated, and checks the tensile strength, collapsoing strength, anti-internal pressure of casing Intensity and triaxial strength, if the requirements are not met, then rejects this casing, it is assumed that new counted maximum axial is this section 4) maximum axial is gone to, otherwise enter in next step；

6) this section of casing string compared with leading portion casing string, if identical with leading portion casing string, this section of casing string It is incorporated to the last period casing string, and enabling the segment length of back segment is step-size in search；Otherwise the length of back segment casing string is enabled to be equal to minimal segment It is long；

If 7) non-design length is less than minimum the sum of segment length and step-size in search, enables the segment length of back segment be equal to and do not design Length.

If 8) non-design length is zero, the design of this layer of casing string, which calculates, to be completed, and otherwise carries out 2) continuing to design.,

Step 5, casing string loading analysis and optimization module are established；

Step 6, the Data Analysis Services such as oil pipe, casing cement sheath, stratum；

Establish the database of evaluation system, comprising: casing composition data library, oil pipe database, complete well database, stratum Pore pressure data library, formation fracture pressure database, Geothermal data library, production formations fluid property data library, thermal coefficient library, Flowing bottomhole pressure (FBHP) database, crack type production casing defect library, flows warm database, stream pressure data at volume type production casing defect library External and internal pressure library, the additional load library that oil and gas leakage generates, axial force database, high temperature height are added caused by library, warm high pressure The caused safety coefficient library for adding external and internal pressure working condition safety library of factors, oil pipe under stream pressure effect of pressure, oil and gas leakage operating condition Safety coefficient library, drilling fluid coefficient of expansion library, drilling fluid compression library of factors, material impact toughness library, material yield strength library, Elastic properties of materials mould most library, casing coupling sealing evaluation Table storehouse, casing database, oil pipe database.

Preferably, step 4 temperature influences the Intensity Design of casing in terms of two, it is on the one hand to influence casing string On the other hand inner pressuring load distribution is since the variation of physical characteristics of materials influences the intensity of casing, general temperature is higher, set Pipe intensity is lower.Consider temperature influence casing strength method are as follows: according to casing in pit shaft depth from temperature profile analysis The temperature of the position is obtained, material property (yield strength, Young's modulus and pool at temperature corresponding to the material are then analyzed Loose ratio), casing tension, anti-internal pressure and collapsoing strength then are calculated according to these data and casing strength model, then compares this A little intensity values and external applied load, so that it is determined that whether the casing meets intensity requirement.

Compared with prior art the present invention has the advantages that comprehensively, system, scientific Comprehensive Evaluation solves and divides at present Analysis wellbore integrity method only considers the problems of single factors.For scientific management, high sulfur crude gas well tubing and casing, station technique Device, gas transmission line provide science decision foundation, grasp the integrality of tube and casing in downhole at any time, truly accomplish risk Controllably, safe and efficient exploitation petroleum gas makes bigger contribution for national economy.

Detailed description of the invention

Fig. 1 is the function structure chart of evaluation system of the embodiment of the present invention；

Fig. 2 is evaluation system structure function block diagram of the embodiment of the present invention；

Fig. 3 is drill string of embodiment of the present invention frictional resistance and torque prediction calculation procedure flow chart；

Fig. 4 is casing job frictional resistance of embodiment of the present invention prediction calculating program frame chart；

Fig. 5 is string friction coefficient Inversion Calculation program chart of the embodiment of the present invention；

Fig. 6 is design of casing string block diagram of the embodiment of the present invention；

Fig. 7 is the loading analysis of casing string of the embodiment of the present invention and optimizing Design Software structural block diagram.

Specific embodiment

To make the objectives, technical solutions, and advantages of the present invention more comprehensible, below in conjunction with attached drawing and implementation is enumerated Example, is described in further details the present invention.

Oil/gas well tube or cased well letter safety evaluation software

Probing with exploitation high temperature and pressure high yield petroleum resources well, referred to as " high temperature and pressure high-yield well " be shaft building engineering and A kind of harsh well of difficulty maximum, risk highest and both expensive in production operation.High temperature and pressure prolific oil and gas field downhole production The leakproofness and security reliability of tubing and casing are the great peaces of probing with overriding concern necessary in exploitation engineering and strict control Full technical problem, slightly careless mistake will lead to serious accident.Therefore, advanced " high temperature and pressure high-yield well oil jacket is researched and developed Pipe well cylinder safety evaluation software " carries out quantitative assessment to flow string, can oil/gas well safety in production and Operation control offer section Learn foundation.

1, Safety Influence Factors

The factor for influencing the pit shaft safety of high temperature and pressure high yield can be attributed to two aspects, that is, act on production tubing and casing Carry He and produce tubing and casing bearing capacity.The load factor of consideration includes: that the load for acting on production tubing and casing has test Fluid pressure during production；The tubing and casing additional load that oil and gas leakage generates；Temperature increases confined space fluid expansion and leads The principal element that the pressure increase of cause influences tubing and casing bearing capacity includes: that the casings such as volume type, crack type and geometric type lack Sunken and reliability of thread connection etc..

2, safety evaluation criterion

Using " method of exhaustion ", safety evaluation is carried out to high temperature and pressure prolific oil and gas field production oil casing, that is, calculate with it is right Than under the conditions of various load and its corresponding tubing and casing intensity (consider that volume moulds defect, crack-type defect, geometric type defect With the influence factors such as thread connection reliability), if tubing and casing intensity is greater than its load born, tubing and casing be it is safe, It otherwise is unsafe.

3, the sequencing of Model for Safety Evaluation

Procedure treatment is carried out to related mathematical model, including testing and the Fluid pressure and temperature computation during production External and internal pressure computation model caused by model and the tubing and casing additional load computation model of oil and gas leakage generation, high temperature and pressure contains Volume flaw casing strength computation model, the computation model of casing strength containing crack-type defect, the casing strength of defect containing geometric type Computation model, thread connection reliability criterion etc..

Software configuration

The model structural design of evaluation software is as shown in Figure 1.

The defeated people's modular program of the data of establishment, including casing programme, casing composition, oil pipe composition, complete well data, stratum Pore pressure, formation fracture pressure, Geothermal data, production formations fluid property, thermal coefficient, flowing bottomhole pressure (FBHP) and gas production relationship, Volume type production casing defect, crack type production casing defect, the drilling fluid coefficient of expansion, the drilling fluid compressed coefficient, material impact The defeated people interfaces such as toughness, material yield strength, elasticity modulus of materials and box cupling leakproofness evaluation table.It has worked out and computing module Connection and output module, main contents include the regularity of distribution, the stream pressure regularity of distribution along well depth, high temperature of the stream temperature along well depth External and internal pressure is added caused by high pressure, the additional load that oil and gas leakage generates

Consider to influence the factor of pit shaft safety first and evaluates principle

The factor for influencing the safety of high temperature and pressure pit shaft can be attributed to two aspects, that is, act on the load He of production casing With the bearing capacity of production casing.The load factor of consideration includes: that the load for acting on production casing has during testing production Fluid pressure；The pipe additional loads that oil and gas leakage generates；Temperature increases pressure increase caused by confined space fluid expansion The principal element for influencing bearing capacity of casing includes: the casing imperfections such as volume type, crack type and geometric type and thread connection Reliability etc..

Using " method of exhaustion ", safety evaluation is carried out to high temperature high pressure oil gas well liquid loading casing string, that is, is calculated various with comparison Under the conditions of load and its corresponding casing strength (consider volume modeling defect, crack-type defect, geometric type defect and screw thread connection Connect the influence factors such as reliability), if casing strength is greater than its load born, otherwise it is dangerous that casing, which is safe, 's.

Establish mechanical model

More smooth lower going-into-well bottoms of packer fracturing string and upper proposition well are the successful necessary conditions of pressing crack construction.We Method is established by carrying out more packer fracturing string bendings and bending deformation mechanical analysis and considers that more packer fracturing strings are rigid The frictional resistance computation model of degree；Fracturing string tripping in process is analyzed, by introducing decision function, analyzes different well section pressure break pipes The influence factor that column tripping in is hampered is hampered for fracturing string tripping in and provides a solution；Consider fracturing fluid recovery (backflow) speed Influence to sleeve stress establishes on fracturing string and proposes the critical discharge speed computation model of fracturing fluid of well, is more packers Fracturing string is smoothly upper to propose well, proposes a kind of pre-judging method.Following goal in research is realized by studying above:

6. this method by analyzing the frictional resistance under the different coefficient of friction resistances, establishes coefficient of friction and normal pressure Relationship and non-linear relation, are modified traditional conventional horizontal well fracturing string computation model.

Software configuration function

The function of software mainly has following 5 aspects:

(1) complex hole condition horizontal well track smoothing processing；

(2) complex hole condition horizontal well completion tubular pile tripping in force analysis and strength check；

(3) complex hole condition horizontal well working string (band power tool) tripping in force analysis and strength check；

(4) during more packer complex hole condition horizontal well completion working string fracture acidizings (hydraulic and machinery is set) Force analysis and strength check；

(5) calculated result visualizes and automatically generates report.

Software basic function module

It is as shown in Figure 2:

(1) complex hole condition horizontal well track processing module

" processing of complex hole condition horizontal well track " module draws this by selecting the casing programme data of a well The two-dimentional casing programme of well, and it will be shown on program interface.Meanwhile user can pass through click " main view ", " right view Figure ", " top view " realization quickly navigate to a certain special angle and check to casing programme.In addition, being provided for software The display and drafting function of horizontal segment partial enlargement figure, have more clear convenient for wellbore trajectory smoothness of the user to horizontal segment It is clear and get information about and recognize.

(2) complex hole condition horizontal well completion tubular pile tripping in force analysis and strength check module

For the Calculation and Analysis of Force of complex hole condition horizontal well completion tubular pile tripping in process, two sections points can be classified as It is not calculated, i.e., vertical well section, curved portion and net horizontal section.By ten complex hole condition horizontal well completion tubular piles in bending section The complexity of stress, in order to guarantee the accuracy calculated, four kinds of different theoretical analysis models of proposed adoption, to be analyzed Comparison.Four theoretical analysis models are respectively as follows: two-dimensional rigid model, two-dimensional rigid model, rigidity power model and overall calculation Model.And the safety of completion tubular column is checked using fourth strength theory, provide corresponding safety coefficient and dangerous point Corresponding position.

(3) complex hole condition horizontal well working string (band power tool) tripping in force analysis and strength check module

During fracturing work, various downhole tools can be had on working string, especially the presence of packer is to operation Stress and intensity effect during tubing string tripping in is all very big, needs to consider emphatically.When this software consideration arrives separate stratum fracfturing operation There is influence to tubing string stress in multiple packers, be calculated the stress under different parameters during working string tripping in and The parameters such as stress level and safety coefficient.Frictional resistance, axial force, well head are drawn during the single packer working string tripping in of calculating Power and corresponding stress, obtain the safety coefficient during working string tripping in, obtain packer parameter to stress during tripping in Influence quantitative relationship.

(4) force analysis and intensity school during more packer complex hole condition horizontal well completion working string fracture acidizings Core module

(5) calculated result visualizes and automatically generates reporting modules

Implement operation to calculate

As shown in figure 3,1, drill string frictional resistance and torque predict calculation procedure

Drill string frictional resistance and torque arithmetic program circuit under various handling situations is as shown in Figure 1.The numerical simulation that can be carried out Operating condition includes: the put-on and delegated of drill string, zero frictional resistance, torsion and sliding etc..In addition to common data, rubbing for each well section must also be known Hinder coefficient.For drill string rotating and slipping drilling, it is also necessary to provide bit pressure and torque-on-bit.Drill string axial load (frictional resistance) edge The relationship of well depth (depth measurement) changing rule and hook load and lower depth (depth measurement of tubing string lower end during tripping in), is various works The results of prediction and calculation shared under condition.For rotary drilling operation, results of prediction and calculation further includes torque along well depth changing rule And torque and the relationship of drilling depth etc..

2, casing job frictional resistance predicts calculation procedure

As shown in figure 4, there are many different operators in the casing jobs such as directional well, horizontal well and extended reach well Formula is available.The predictive analysis results of casing tripping in frictional resistance are that preferred orientation well, horizontal well and extended reach well setting of casing are made The scientific basis of industry mode.Casing tripping in frictional resistance predicts calculation procedure such as Fig. 4, and the setting of casing mode of analog includes under routine Casing routinely empties setting of casing, empties four kinds of floating coupling setting of casing of setting of casing and use entirely.Other than common data, also The coefficient of friction resistance between casing and wellbore need to be given；Setting of casing is emptied for conventional, also to give and empty position (complete set under i.e. The well depth of drilling well liquid level position in Guan Houguan)；For using the setting of casing mode of floating coupling, also to give floating and connect Binding round position, (floating coupling position (well depth of floating coupling position after complete casing under i.e.) or filling aggravate after complete casing under i.e. The position (well depth of the position under i.e. where complete casing latter two fluid interface) of drilling fluid and the density of weighted drilling fluid. The analog result of above-mentioned difference setting of casing mode are as follows: the pass of hook load and lower depth (depth of tubing string lower end during tripping in) System and casing string axial load along well depth changing rule etc..

3, coefficient of friction resistance Inversion Calculation program is kept a grip on

The coefficient of friction resistance between tubing string and wellbore is how reasonably determined, is to carry out string friction and torque value analysis One of key problem in technology and a more complicated theory and method problem.It was verified that anti-using field measurement data The string friction coefficient calculated under different operating conditions is drilled, is a kind of solution of practicable, but need to establish corresponding inverting Computation model and software for calculation.For this purpose, we have developed string friction coefficient Inversion Calculation program, block diagram is as shown in Fig. 5. The tubing string working condition of its analog includes: put-on and delegated, rotary drilling and slipping drilling of down-hole string etc..In addition to public Outside data, hook load is also given；For rotary drilling and slipping drilling, there are also given bit pressure, torque-on-bit and turntables to turn round Square etc..Calculated result is the coefficient of friction resistance between tubing string and wellbore.

Casing strength design cycle

Since external and internal pressure calculates, select casing before first determining external and internal pressure unrelated with specific casing string Along the data of well depth distribution.The design process of any position casing is as shown in Figure 6:

Process description:

When beginning, segment length is taken as minimum segment length；

The minimum for obtaining this section from external and internal pressure computing module according to the bottom depth of casing string and top depth is effectively interior External pressure；

Assuming that the maximum axial force that this section of casing string is born is equal to axial force suffered by this section of casing column bottom；

According to optional bound data (latus rectum, wall thickness, joint categories, grade of steel, the minimum allowable set according to actual requirement Any combination of quantity in stock least cost and minimum weight) and external applied load, all qualified sets are found from database Pipe；

The maximum axial of this section of casing string is calculated, and checks the tensile strength, collapsoing strength, anti-interior pressure of casing Degree and triaxial strength, if the requirements are not met, then rejects this casing, it is assumed that new counted maximum axial be this section most 4) big axial load is gone to, otherwise enter in next step；

This section of casing string compared with leading portion casing string, if identical with leading portion casing string, simultaneously this section of casing string Enter the last period casing string, and enabling the segment length of back segment is step-size in search；Otherwise the length of back segment casing string is enabled to be equal to minimum segment length；

If non-design length is less than minimum the sum of segment length and step-size in search, enables the segment length of back segment be equal to and do not design length Degree.

If non-design length is zero, the design of this layer of casing string, which calculates, to be completed, and otherwise carries out 2) continuing to design.

Temperature influences the Intensity Design of casing in terms of two, is on the one hand the inner pressuring load distribution for influencing casing string, separately It on the one hand is since the variation of physical characteristics of materials influences the intensity of casing, general temperature is higher, and casing strength is lower.Consider The method of temperature influence casing strength are as follows: depth obtains the temperature of the position from temperature profile analysis in pit shaft according to casing Degree, then analyzes the material property (yield strength, Young's modulus and Poisson's ratio) at temperature corresponding to the material, then basis These data and casing strength model calculate casing tension, anti-internal pressure and collapsoing strength, then compare these intensity values and outer load Lotus, so that it is determined that whether the casing meets intensity requirement.

If given one layer of casing string wall thickness, joint categories and grade of steel and enable design ratio be a lesser number (such as 0.001), then design of casing string process is actually check process, the reason is that casing is by its outer diameter, wall thickness, joint categories and steel Grade uniquely determines.

This software main modular

The comprising modules of software and data flow between them are as shown in Figure 7.The main modular of composition software has:

(1) data input module；

(2) axial load analysis module；

(3) interior pressure analysis module；

(4) external pressure analysis module；

(5) casing database module；

(6) shell material database module；

(7) casing string strength, which is calculated, designs module with casing string optimization

(8) data outputting module.

The Data Analysis Services such as oil pipe, casing cement sheath, stratum

In programmed process, the tissue of defeated people's output data is necessarily involved.In the software that we research and develop, use Number saw library file carries out tissue to defeated people's output data.The various data structure informations used in the software are set forth below.Table 1 The data structure of the input data of the production tubing and casing safety evaluation of each well, the data record of each well are specific to table 12 It is uniquely determined by pound sign, therefore insult number table to have a data item " pound sign ".Table 13 to table 20 is various calculated numbers According to the output data record of each well is also to be uniquely determined by pound sign, therefore every number table also has a data item " pound sign ". Table 21 is the data structure of Universal Database to table 25, since such data are general, so not having well in each tables of data Number item.For the data of character type, only number of characters, it is without unit, such as data type of data item " pound sign " Character string, the length of value is no more than 30 byte or 15 Chinese characters.For carrying out, according to the meaning of different data item, There is corresponding unit, if the data type of data item " sleeve outer " is full mold, unit is " mm ", in order to general, here not Define the width of such data.

1 casing programme data (JSJG.DBF) of table

2 casing composition data (YJTGSJ.DBF) of table

Each layer of casing string can be made of a variety of different types of casings, be indicated in tables of data by a plurality of record, every Record represents a kind of casing, and every layer of casing is by " borehole diameter " unique identification.

It is assumed that each well only has a string of tubing strings, and tubing string must be suspended from well head, and the lower depth of tubing string is each Segmentation cumulative and.A record for forming each section of variety classes oil pipe all corresponding data tables of tubing string, by single kind The tubing string of oil pipe composition only has data record.

3 oil pipe data of table (YG SL.DBF)

In practical projects, complete well data far listed these data item not only in table 4, this software only provides high temperature The useful data item of the stable evaluation of high-pressure gas well.For each well, only data record.

The complete well data (WJSJ.DBF) of table 4

Formation pore pressure (table 5) and fracture pressure (table 6) are all the functions of vertical depth, for specific a well, vertical depth Different stratum may have different barometric gradients, for such data of every mouth well, need with multiple data points (vertical depth, Barometric gradient) description, it is indicated in tables of data by a plurality of record.

5 formation pore pressure data (KXYL.DBF) of table

6 formation fracture pressure data (PLYL.DBF) of table

Geothermal gradient is not constant, but actually it changes less.Furthermore scene can only often provide following three number According to item: room temperature layer depth, normal temperature layer temperature and geothermal gradient (table 7).Therefore, the present invention calculates different wells with this three item data The prime stratum temperature of depths.For every mouth well, data record is only needed in tables of data.

7 Geothermal data of table (WDSJ.DBF)

The data item for describing production formations fluid property is as shown in table 8, for gas well, often also output a small amount of water and oil.Often One record of the production formations fluid property corresponding data table of mouth well.

8 production formations fluid property data (CCLTXZ.DBF) of table

Calculate gas well at HTHP production when temperature in wellbore along well depth be distributed when, need to know composition pit shaft tubing, The thermal coefficient of annular fluid and stratum.Each well only needs a data record description.

9 thermal coefficient of table (DRXS.DBF)

Flowing bottomhole pressure (FBHP) is the starting point for calculating stream pressure distribution in tubing string.In production or test process, flowing bottomhole pressure (FBHP) is not one At constant.In general, yield is bigger, flowing bottomhole pressure (FBHP) is lower.The flowing bottomhole pressure (FBHP) curve of each well all may be different.

10 flowing bottomhole pressure (FBHP) data (JDLY.DBF) of table

According to volume type production casing defect it is assumed that describing such defect (table 11) with minimum wall thickness (MINI W.).Borehole diameter is used In the level (specifying specific casing string with wear column) of specified casing string with wear, well depth is for given defect in casing axis of a cylinder Upward position.Casing may be indicated in tables of data with a plurality of record in many places containing defective.For the side of data management Just, although collapsoing strength corresponding with defect, internal pressure strength and tensile strength are calculated result, also it is stored in same table In lattice.

11 volume type production casing defect (TJX TGQX.DBF) of table

According to crack type production casing defect it is assumed that with crack length, crack depth, direction of check and crack position Such defect (table 12) is described.Borehole diameter is for specifying the level of casing string with wear (to specify specific casing string with wear Column), well depth is used for axial position of the given defect on casing string.Casing may be used in tables of data in many places containing defective A plurality of record indicates.For the convenience of data management, although collapsoing strength corresponding with defect, internal pressure strength and tension are strong Degree is calculated result, but is also stored in same table.

12 crack type production casing defect (LWX_QX.DBF) of table

Flowing warm data is calculated result, is the function (table 13) of well depth.The stream temperature (temperature) of different well depths is by different notes Record indicates.Therefore, in tables of data, same pound sign has a plurality of data record, and by the ascending sequence arrangement of well depth.

Table 13 flows warm data (LW.DBF)

Stream pressure data are calculated result, are the functions (table 14) of well depth.The stream pressure (pressure) of different well depths is by different notes Record indicates.Therefore, in tables of data, same pound sign has a plurality of data record, and by the ascending sequence arrangement of well depth.

The stream pressure of table 14 data (LY.DBF)

High temperature makes the pressure rise of constrained liquid in oil jacket annulus and other level casing annulus.For a well, need Pressure after calculating and saving the raising of different levels annular space, therefore, different levels annular space need to be marked with borehole diameter Note, it is assumed that marked by forming borehole diameter locating for the outer layer jacket tubing string of annular space.Such as surface pipe and protective casing Between annular space is corresponding by surface pipe and eye diameter marks, the annular space between production casing and oil pipe is by production casing Corresponding borehole diameter marks.Pressure of the identical annular space at different depth is distinguished by well depth, and presses the ascending row of well depth Column.Realize that the data list structure of above-mentioned requirements is as shown in Table 15.

External and internal pressure (HTHP_AP.DBF) is added caused by 15 high temperature and pressure of table

When tubing leak, oil gas causes annular pressure to increase into the annular space between people's oil pipe and production casing.Annular space Pressure value is the function of well depth, and every mouth well corresponds to multiple pressure datas, and being recorded in tables of data by identical data indicates, pressure Force data presses the ascending arrangement of well depth.It calculates and saves data structure used by the additional load that oil and gas leakage generates such as Shown in table 16.

The additional load (TL-AP.DBF) that 16 oil and gas leakage of table generates

Tubing string and each layer casing string will bear the effect of axial force as casing data, each layer of every mouth well The axial force data of casing string will be marked by the corresponding borehole diameter of each layer casing, and tubing string is then by being worth for the wellbore of " 0 " Diameter mark.The axial force of tubing string and each layer casing string is all the function of well depth, and tubing string and each layer casing string have multiple Axial force data and different wells are corresponding, are indicated in tables of data by equal number of data record, and by well depth by it is small to Longer spread.It is as shown in table 17 to calculate and save data structure employed in axial force data.

The axial force data (ZXL.DBF) of table 17

In order to guarantee the safety of oil well, various Strength co-mputations and check will be made to tubing string and each layer casing string, these It calculates and check result is all indicated with safety coefficient.In order to mark the calculated result of different tubing strings, need by each layer casing string pair The borehole diameter answered marks, and tubing string does not have corresponding borehole diameter, since every mouth well all only has unique tubing string, For convenience's sake, this book assumes that its corresponding borehole diameter is " 0 ".To any string tubing string, in different location, it is safely Number may be different, it is therefore desirable to which the specific location that safety coefficient is marked with well depth is saved in tables of data by a plurality of record. The data structure of these safety coefficients use is calculated and saved as shown in table 18 to 19.

External and internal pressure working condition safety coefficient (AQXS_AP.DBF) is added caused by 18 high temperature and pressure of table

Safety coefficient (AQXS_LY.DBF) of 19 oil pipe of table under stream pressure effect

20 oil and gas leakage working condition safety coefficient (AQXS_TL.DBF) of table

When the temperature varies, the volume of drilling fluid can change, and the complexity of variation is by coefficient of expansion table Show.At that the same temperature and pressure, the coefficient of expansion of different types of drilling fluid may be different, therefore specific expansion system Number needs to be distinguished with drilling fluid types.Meanwhile the coefficient of expansion is the function of temperature and pressure again, i.e., in different temperatures and pressure Under power, the coefficient of expansion may have different numerical value.Therefore, the coefficient of expansion is uniquely true by drilling fluid types, temperature and pressure It is fixed.It is as shown in table 21 to save data structure used by the drilling fluid coefficient of expansion.

The 21 drilling fluid coefficient of expansion (PZXS.DBF) of table

When pressure changes, the volume of drilling fluid can change, and the complexity of variation is by compressed coefficient table Show.At that the same temperature and pressure, the compressed coefficient of different types of drilling fluid may be different, so specific compression system Number needs to be distinguished with drilling fluid types.Meanwhile the compressed coefficient is the function of temperature and pressure again, i.e., in different temperatures and pressure Under power, the compressed coefficient may have different numerical value.Therefore, the compressed coefficient is uniquely true by drilling fluid types, temperature and pressure It is fixed.It is as shown in table 22 to save data structure used by the drilling fluid compressed coefficient.

The 22 drilling fluid compressed coefficient (YSXS.DBF) of table

At different temperatures, the engineering properties (impact toughness, yield strength and elasticity modulus) of specific shell material Numerical value is different, i.e. their functions for being temperature.The changing rule of the engineering properties of different materials is different, thus needs to indicate tool The material type (grade of steel) of body.As it can be seen that the engineering properties of material is uniquely determined by grade of steel and temperature in data access.In order to Allow various engineering properties to be distributed with different temperatures, is saved using different data table, data structure such as table 23,24 Shown in 25.

23 material impact toughness (CJRD.DBF) of table

24 material yield strength of table (QFQD.DBF)

25 elastic properties of materials mould of table most (TXML.DBF)

For different thread types, in the case where guaranteed conditions all obtain satisfaction, different well's conditions (oil well, water are adapted to Well, gas well, air-fuel mixture well, thermal production well and condensate gas well), interior pressure limit (upper and lower limit) and temperature range (upper and lower limit). Casing coupling sealing evaluation data are described by data structure as shown in table 26.

26 casing coupling of table seals evaluation table (JGMF.DBF)

Specific casing is uniquely determined by sleeve outer, wall thickness, grade of steel and form of thread.Save the tables of data of casing data Structure is as shown in table 27.

27 casing database (TGSJK.DBF) of table

Specific oil pipe is uniquely determined by oil pipe outer diameter, pipe aperture (or wall thickness) and grade of steel.Save the data of oil pipe data Table structure is as shown in table 28.

28 oil pipe database of table (YGSJ K.DBF)

It is data structure part above

Evaluation conclusion

Natural gas well oil pipe, casing, cement sheath mechanical analysis test and analyze, and software evaluation analysis obtains its safe shape State；It whether controllable specifies unsafe status, controllably shows that pit shaft is complete.Exploitation tool safe and efficient to petroleum gas There is great directive significance.

Those of ordinary skill in the art will understand that the embodiments described herein, which is to help reader, understands this The implementation method of invention, it should be understood that protection scope of the present invention is not limited to such specific embodiments and embodiments.This The those of ordinary skill in field disclosed the technical disclosures can make according to the present invention and various not depart from essence of the invention Various other specific variations and combinations, these variations and combinations are still within the scope of the present invention.

Claims

1. a kind of oil/gas well tubing and casing integrity detection evaluation system characterized by comprising

(1) complex hole condition horizontal well track processing module；

Complex hole condition horizontal well track processing module is using well track measurement data using the secondary more of least square method Item formula is fitted to obtain smooth continuous two-dimentional well track, and discrete measurement point can be significantly reduced caused by completion tubular column stress Error；It is also possible to reduce the influence of a single point measurement error or mistake to overall calculation result；

Complex hole condition horizontal well track processing module draws the two of the well by selecting the casing programme data of a well Casing programme is tieed up, and it will be shown on program interface；Meanwhile user can by click " main view ", " right view ", " bow View " realization quickly navigates to a certain special angle and checks to casing programme；In addition, providing horizontal segment office for software Portion amplifies the display of figure and draws function, has convenient for wellbore trajectory smoothness of the user to horizontal segment apparent and intuitive Understand and recognizes；

For the Calculation and Analysis of Force of complex hole condition horizontal well completion tubular pile tripping in process, it is classified as two sections and is counted respectively It calculates, i.e., vertical well section, curved portion and net horizontal section；By ten complex hole condition horizontal well completion tubular piles bending section stress complexity Property, in order to guarantee the accuracy calculated, four kinds of different theoretical analysis models of proposed adoption, to carry out analysis comparison；Four reasons It is respectively as follows: two-dimensional rigid model, two-dimensional rigid model, rigidity power model and entire mathematical model by analysis model；And using the Four strength theories check the safety of completion tubular column, provide the corresponding position of corresponding safety coefficient and dangerous point；

Complex hole condition horizontal well, directional well completion tubular column tripping in Calculation and Analysis of Force module, during mainly calculating tripping in Axial force, well head pulling force, frictional resistance and its corresponding MISES stress, obtain the safety coefficient of tubing string during tripping in, have been well Tubing string tripping in operation provides construction parameter and safety evaluation；

When in view of separate stratum fracfturing operation there is the influence to tubing string stress in multiple packers, and operation under different parameters is calculated The parameters such as stress and stress level and safety coefficient during tubing string tripping in；During the single packer working string tripping in of calculating Frictional resistance, axial force, well head pulling force and corresponding stress, obtain the safety coefficient during working string tripping in, obtain packer Influence quantitative relationship of the parameter to stress during tripping in；

(4) force analysis and strength check mould during more packer complex hole condition horizontal well completion working string fracture acidizings Block；

Fracture acidizing tubing string is anchored, in packer setting and later fracture acidizing or production process in lower going-into-well bottom, anchor fluke, Due to tubing string self weight, fluid column buoyancy, the frictional resistance effect of tubing string internal and external pressure difference, the temperature difference and fluid produces fracture acidizing tubing string Raw following basic effect；The various stress of tubing string and deformation when analyzing single packer working string pressure break are calculated, obtains pressure break mistake In journey under different operating conditions and work layer working string safety coefficient；

After the completion of calculating, the calculation result data and figure being the previously calculated will be automatically write word document by software In, in order to user's use.

2. a kind of oil/gas well tubing and casing integrity detection evaluation system according to claim 1, it is characterised in that: institute's commentary Valence system further include: casing string loading analysis and optimization module；The module includes: data input module；Axial load analyzes mould Block；Interior pressure analysis module；External pressure analysis module；Casing database module；Shell material database module；Casing string strength It calculates and designs module with casing string optimization；Data outputting module.

3. a kind of detection method of oil/gas well tubing and casing integrity detection evaluation system according to claim 2, feature Be the following steps are included:

Step 1 establishes mechanical model；

1. the axial force suffered by the fracturing string is less than fracturing string bending deformation critical load, fracturing string bending deformation is established The mechanical model of analysis establishes more packer fracturing strings and contacts judgement with casing wall according to sag curve change limitation condition Model；

2. the axial force suffered by the fracturing string is greater than fracturing string bending deformation critical load, fractured horizontal well pipe is established respectively Column vertical section, bending section, horizontal segment bending deformation differential equation equation, and its Sine Buckling and Helical Buckling deformation are divided The calculation of critical model that Sine Buckling and Helical Buckling occur for fractured horizontal well tubing string is established in analysis；

3. considering that packer to the effect of contraction of fracturing string bending deformation, establishes the analysis of packer section fracturing string bending deformation Mechanical model；Obtain the plane buckling section fracturing string length and contact normal pressure calculation method against packer；

4. analyzing the fracturing string Deformation of helical differential equation, establishes fracturing string and fracturing string section when helical buckling occurs Maximal bending moment computation model, and then obtain fracturing string interface maximum stress in bend computation model；Vertical well section fracturing string Moment of flexure and bending stress are gradually increased with helical curve variation, and curved portion and net horizontal section change to become in sine with helical curve Gesture, fracturing string moment of flexure and bending stress when contacting with casing wall upper wall obtain maximum value；

5. considering influence of the fracturing string stiffness to fracturing string frictional resistance, fractured horizontal well drilling pipe bending section frictional resistance is established Power computation model；The buckling frictional resistance generated due to the effect of fracturing string buckling is analyzed, fractured horizontal well tubing string difference well is established Section buckling frictional resistance calculates the type that rubs；

6. by analyzing the frictional resistance under the different coefficient of friction resistances, the relationship of coefficient of friction and normal pressure and non-linear is established Relationship is modified traditional conventional horizontal well fracturing string computation model；

7. analyzing fracturing string tripping according to frictional resistance computation model during more packer fracturing string tripping in of foundation Journey analyzes the influence factor that different well section fracturing string tripping in are hampered, is hampered for fracturing string tripping in by introducing decision function A solution is provided；

8. when fracturing fluid recovery (backflow), act on the circumocular pressure break hydraulic coupling in well-case perforating hole can with fracturing fluid recovery (backflow) velocity variations and Change, establishes the computation model that pressure break hydraulic coupling changes with discharge speed；

9. when fracturing fluid recovery (backflow), discharge speed, which crosses conference, makes casing that plastic deformation or unstable failure occur, and leads to more packers It is mentioned on fracturing string and is hampered and can not be taken out from shaft bottom, establishing makes the fracturing fluid of casing generation plastic deformation or unstable failure is critical to return Velocity computing model is arranged, being that more packer fracturing strings are smoothly upper proposes well, proposes a kind of pre-judging method；

10. the factor of stress concentration problem around porous casing hole is researched and analysed by Elasticity in conjunction with the theory of complex functions, And application finite element software simulation calculates the variation of porous casing eyelet ambient stress coefficient of concentration, analyzes different perforation combinations pair The influence of porous casing eyelet ambient stress coefficient of concentration；

Step 2, evaluation system is established；

Step 3, implement operation to calculate；

1. drill string frictional resistance and torque prediction calculate；

2. the prediction of casing job frictional resistance calculates；

Step 4, casing strength designs；

1) when starting, segment length is taken as minimum segment length；

2) minimum for obtaining this section from external and internal pressure computing module according to the bottom depth of casing string and top depth is effectively inside and outside Pressure；

4) according to optional bound data (latus rectum, wall thickness, joint categories, grade of steel, the minimum allowable inventory set according to actual requirement Measure any combination of least cost and minimum weight) and external applied load, all qualified casings are found from database；

5) calculate the maximum axial of this section of casing string, and check the tensile strength of casing, collapsoing strength, internal pressure strength and Triaxial strength, if the requirements are not met, then rejects this casing, it is assumed that new counted maximum axial is this section of maximum axial 4) load is gone to, otherwise enter in next step；

6) this section of casing string compared with leading portion casing string, if identical with leading portion casing string, this section of casing string is incorporated to The last period casing string, and enabling the segment length of back segment is step-size in search；Otherwise the length of back segment casing string is enabled to be equal to minimum segment length；

If 7) non-design length is less than minimum the sum of segment length and step-size in search, the segment length of back segment is enabled to be equal to non-design length；

If 8) non-design length is zero, the design of this layer of casing string, which calculates, to be completed, and otherwise carries out 2) continuing to design；,

Establish the database of evaluation system, comprising: casing composition data library, oil pipe database, complete well database, formation pore pressure Force data library, formation fracture pressure database, Geothermal data library, production formations fluid property data library, thermal coefficient library, flowing bottomhole pressure (FBHP) Database, crack type production casing defect library, flows warm database, stream pressure database, warm high pressure at volume type production casing defect library It is added caused by caused additional external and internal pressure library, the additional load library of oil and gas leakage generation, axial force database, high temperature and pressure External and internal pressure working condition safety library of factors, oil pipe stream pressure effect under safety coefficient library, oil and gas leakage working condition safety library of factors, bore Well liquid coefficient of expansion library, drilling fluid compression library of factors, material impact toughness library, material yield strength library, elastic properties of materials mould most library, Casing coupling sealing evaluation Table storehouse, casing database, oil pipe database.