CN109555512A - Method and device for calculating stress borne by casing - Google Patents
Method and device for calculating stress borne by casing Download PDFInfo
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- CN109555512A CN109555512A CN201710882651.1A CN201710882651A CN109555512A CN 109555512 A CN109555512 A CN 109555512A CN 201710882651 A CN201710882651 A CN 201710882651A CN 109555512 A CN109555512 A CN 109555512A
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- 238000000034 method Methods 0.000 title claims abstract description 31
- 239000004568 cement Substances 0.000 claims abstract description 50
- 238000005553 drilling Methods 0.000 claims abstract description 37
- 239000011435 rock Substances 0.000 claims abstract description 36
- 238000004364 calculation method Methods 0.000 claims abstract description 34
- 238000012545 processing Methods 0.000 claims abstract description 9
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 claims description 32
- 239000011780 sodium chloride Substances 0.000 claims description 32
- 239000007788 liquid Substances 0.000 claims description 14
- 230000015572 biosynthetic process Effects 0.000 claims description 13
- 239000011148 porous material Substances 0.000 claims description 12
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- 238000004519 manufacturing process Methods 0.000 abstract description 9
- 239000012530 fluid Substances 0.000 abstract description 8
- 229910052602 gypsum Inorganic materials 0.000 abstract 1
- 239000010440 gypsum Substances 0.000 abstract 1
- 238000010586 diagram Methods 0.000 description 15
- 239000010410 layer Substances 0.000 description 7
- 238000002474 experimental method Methods 0.000 description 6
- 238000012360 testing method Methods 0.000 description 6
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 4
- 239000000470 constituent Substances 0.000 description 2
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- 150000003839 salts Chemical class 0.000 description 2
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- 235000005035 Panax pseudoginseng ssp. pseudoginseng Nutrition 0.000 description 1
- 235000003140 Panax quinquefolius Nutrition 0.000 description 1
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- 239000012141 concentrate Substances 0.000 description 1
- 239000006071 cream Substances 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 235000008434 ginseng Nutrition 0.000 description 1
- 229930195733 hydrocarbon Natural products 0.000 description 1
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- 239000011229 interlayer Substances 0.000 description 1
- 238000003825 pressing Methods 0.000 description 1
- 238000011084 recovery Methods 0.000 description 1
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- 239000004576 sand Substances 0.000 description 1
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- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B47/00—Survey of boreholes or wells
- E21B47/007—Measuring stresses in a pipe string or casing
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- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F17/00—Digital computing or data processing equipment or methods, specially adapted for specific functions
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Abstract
The invention provides a method and a device for calculating stress borne by a casing. The calculation method of the stress borne by the casing comprises the following steps: performing rock mechanical parameter processing on a plurality of core samples, and determining a creep equation and a ground stress equation set of a stratum, wherein each core sample is a core prepared from a salt-gypsum layer core at different coring angles; establishing a casing-cement sheath-stratum model according to the casing parameters, the cement sheath parameters and a creep equation; and calculating a plurality of equivalent stresses born by each point on the casing according to the drilling fluid pressure, the yield stress of the casing, the ground stress equation set and the casing-cement sheath-stratum model. The invention can accurately obtain the equivalent stress born by each point of the casing, and provides reliable basis for selecting the casing in the drilling or production process.
Description
Technical field
The present invention relates to a kind of calculation methods of stress suffered by oil-gas reservoir drilling well and production technique field more particularly to casing
And device.
Background technique
Horizontal well pair oil-gas reservoir drilling well and exploitation are a kind of effective modes.For basin in tower, most of oil gas
Hiding reservoir concentrates on saline bed hereinafter, the bottom surface of saline bed is smaller away from the vertical range of Gas Reservoir, and therefore, horizontal well needs
Deflecting is carried out in saline bed, i.e., casing is bent in saline bed and is arranged.
Casing can support the borehole wall in oil-gas reservoir drilling well and recovery process, and can as the channel of production of hydrocarbons, because
This, selects to be suitble to the casing of formation characteristics most important.However, the casing that selection is placed in saline bed can not only be bent and set
Set, also suffer from the creep effect on stratum, to change the stress being applied on casing so that casing be easily more than casing from
The bearing capacity of body, leads to casing unstable failure, brings economic loss to production.Therefore, stress suffered by a kind of casing is now needed
Calculation method.
Summary of the invention
The present invention provides the calculation method and device of stress suffered by a kind of casing, with the compacted of the stratum in the prior art of solution
The problem of being changed into causing casing to be easily destroyed having an impact for stress suffered by casing.
The present invention provides a kind of calculation method of stress suffered by casing, comprising:
Multiple core samples are heated with scheduled rate, rise to preset temperature in the temperature of each core sample
When, confining pressure is added to each core sample, when the confining pressure of each core sample rises to default confining pressure, by the default confining pressure
The first preset time is kept, wherein each core sample is the rock core produced from saline bed rock core with different coring angles;
It presets axis pressure using at least one each core sample to be carried out adding axis pressure respectively, in each default axis pressure
After keeping the second preset time, the creep parameters and parameters and earth stress of each core sample are obtained, then to each core sample
Product unload axis pressure, until the default axis buckling is original axis pressure, and the original axis are pressed and keeps third preset time;
According to each corresponding multiple creep parameters of core sample, the Creep Equation formula is determined;
According to each corresponding multiple parameters and earth stress of core sample, the crustal stress equation group is determined;
According to sleeve parameters, cement sheath parameter and the Creep Equation formula, casing-cement sheath-stratigraphic model is established;
According to drilling liquid pressure, the yield stress of casing, the crustal stress equation group and described sleeve pipe-cement sheath-ground
Layer model calculates multiple equivalent stress that each point is born in described sleeve pipe.
Optionally, in the yield stress, the crustal stress equation group and described sleeve pipe-according to drilling liquid pressure, casing
Cement sheath-stratigraphic model calculates in described sleeve pipe after multiple equivalent stress for being born of each point, further includes:
It determines the maximum value in the multiple equivalent stress, the maximum equivalent that the maximum value is determined as described sleeve pipe is answered
Power;
According to the safe bearing capacity of described sleeve pipe and the maximum equivalent of described sleeve pipe, determine whether described sleeve pipe occurs
Surrender;
When the maximum equivalent of described sleeve pipe is less than the safe bearing capacity of described sleeve pipe, determine that described sleeve pipe will not be sent out
Raw surrender;
When the maximum equivalent of described sleeve pipe is equal to or more than the safe bearing capacity of described sleeve pipe, described sleeve pipe is determined
It can surrender.
Optionally, it is described to multiple core samples carry out rock mechanics parameters processing, determine stratum Creep Equation formula and
Crustal stress equation group, comprising:
Each core sample is heated with scheduled rate, rises to preset temperature in the temperature of each core sample
When, confining pressure is added to each core sample, when the confining pressure of each core sample rises to default confining pressure, by the default confining pressure
Keep the first preset time;
It presets axis pressure using at least one each core sample to be carried out adding axis pressure respectively, in each default axis pressure
After keeping the second preset time, the creep parameters and parameters and earth stress of each core sample are obtained, then to each core sample
Product unload axis pressure, until the default axis buckling is original axis pressure, and the original axis are pressed and keeps third preset time;
According to each corresponding multiple creep parameters of core sample, the Creep Equation formula is determined;
According to each corresponding multiple parameters and earth stress of core sample, the crustal stress equation group is determined.
Optionally, the creep parameters include creeping pressure, deformation of creep amount and creep time.
Optionally, the Creep Equation formula is indicated by following formula (1):
Wherein, A is undetermined coefficient, and n is stress exponent, and Q is activation energy, σ*=1M Pa is referring to stress, R0=
8.31441kJ/(mol K-1) it is universal gas constant, T is creep temperature, and σ is creeping pressure, and ε=W/t is creep rate, and W is
Deformation of creep amount, t are creep time.
Optionally, described according to the corresponding multiple parameters and earth stress of each core sample, determine the crustal stress equation
Group, comprising:
According to corresponding multiple parameters and earth stress of each core sample, vertical crustal stress expression formula, horizontal maximum
Crustal stress expression formula and horizontal minimally stress expression formula determine vertical crustal stress, horizontal maximum crustal stress and level minimally
Stress;
According to each corresponding multiple parameters and earth stress of core sample, crustal stress equation group to be corrected is determined;
According to the vertical crustal stress, the horizontal maximum crustal stress and the horizontal minimum crustal stress, to described to school
Normal incidence stress equation group is corrected processing, obtains the crustal stress equation group.
Optionally, the vertical crustal stress expression formula, the horizontal maximally stress expression formula and it is described it is horizontal minimally
Stress expression formula is indicated by following formula (2):
Wherein, σν,σH,σhRespectively vertical crustal stress, horizontal maximum crustal stress and horizontal minimum crustal stress, α is effective
Stress coefficient, P are pore pressure, and φ is interior angle of rubbing, σ⊥For the stress in vertical direction at kayser point, σ0It is for coring angle
0 ° of the core sample stress at Lloyd " Butch " Keaser stress point in the horizontal direction, σ90For coring angle be 90 ° core sample in water
Square upwards stress at Lloyd " Butch " Keaser stress point, σ45The core sample for being 45 ° for coring angle in the horizontal direction answer by Lloyd " Butch " Keaser
Stress at force.
Optionally, the crustal stress equation group to be corrected is indicated by following formula (3):
Wherein, σν,σH,σhRespectively vertical crustal stress, horizontal maximum crustal stress and horizontal minimum crustal stress, ρ is rock
Density, H are depth, PpFor pore pressure, usFor quiet Poisson's ratio, h is formation thickness, and g is acceleration of gravity, and a is effective stress system
Number, str1,str2For structural correction amount.
The present invention also provides a kind of computing devices of stress suffered by casing, comprising:
Determining module, for being heated to multiple core samples with scheduled rate, in the temperature of each core sample
When rising to preset temperature, confining pressure is added to each core sample, it, will when the confining pressure of each core sample rises to default confining pressure
The default confining pressure keeps the first preset time, wherein each core sample be with different coring angles from saline bed rock core
The rock core produced;It presets axis pressure using at least one each core sample to be carried out adding axis pressure respectively, each described default
After axis pressure keeps the second preset time, the creep parameters and parameters and earth stress of each core sample are obtained, then to each rock
Heart sample unloads axis pressure, until the default axis buckling is original axis pressure, and the original axis is pressed and keeps third preset time;Root
According to each corresponding multiple creep parameters of core sample, the Creep Equation formula is determined;
The determining module is also used to determine institute according to each corresponding multiple parameters and earth stress of core sample
State crustal stress equation group;
Model building module, for establishing casing-water according to sleeve parameters, cement sheath parameter and the Creep Equation formula
Mud ring-stratigraphic model;
Module is obtained, for the yield stress, the crustal stress equation group and the set according to drilling liquid pressure, casing
Pipe-cement sheath-stratigraphic model calculates multiple equivalent stress that each point is born in described sleeve pipe.
Optionally, the determining module is also used to determine the maximum value in the multiple equivalent stress, by the maximum value
It is determined as the maximum equivalent of described sleeve pipe;
According to the safe bearing capacity of described sleeve pipe and the maximum equivalent of described sleeve pipe, determine whether described sleeve pipe occurs
Surrender;
When the maximum equivalent of described sleeve pipe is less than the safe bearing capacity of described sleeve pipe, determine that described sleeve pipe will not be sent out
Raw surrender;
When the maximum equivalent of described sleeve pipe is equal to or more than the safe bearing capacity of described sleeve pipe, described sleeve pipe is determined
It can surrender.
Optionally, the creep parameters include creeping pressure, deformation of creep amount and creep time.
Optionally, the Creep Equation formula is indicated by following formula (1):
Wherein, A is undetermined coefficient, and n is stress exponent, and Q is activation energy, σ*=1M Pa is referring to stress, R0=
8.31441kJ/(mol K-1) it is universal gas constant, T is creep temperature, and σ is creeping pressure, and ε=W/t is creep rate, and W is
Deformation of creep amount, t are creep time.
Optionally, the determining module is specifically also used to according to each corresponding multiple crustal stress of core sample
Parameter, vertical crustal stress expression formula, horizontal maximally stress expression formula and horizontal minimally stress expression formula, determine and answer vertically
Power, horizontal maximum crustal stress and horizontal minimum crustal stress;
According to each corresponding multiple parameters and earth stress of core sample, crustal stress equation group to be corrected is determined;
According to the vertical crustal stress, the horizontal maximum crustal stress and the horizontal minimum crustal stress, to described to school
Normal incidence stress equation group is corrected processing, obtains the crustal stress equation group.
Optionally, the vertical crustal stress expression formula, the horizontal maximally stress expression formula and it is described it is horizontal minimally
Stress expression formula is indicated by following formula (2):
Wherein, σν,σH,σhRespectively vertical crustal stress, horizontal maximum crustal stress and horizontal minimum crustal stress, α is effective
Stress coefficient, P are pore pressure, and φ is interior angle of rubbing, σ⊥For the stress in vertical direction at kayser point, σ0It is for coring angle
0 ° of the core sample stress at Lloyd " Butch " Keaser stress point in the horizontal direction, σ90For coring angle be 90 ° core sample in water
Square upwards stress at Lloyd " Butch " Keaser stress point, σ45The core sample for being 45 ° for coring angle in the horizontal direction answer by Lloyd " Butch " Keaser
Stress at force.
Optionally, the crustal stress equation group to be corrected is indicated by following formula (3):
Wherein, σν,σH,σhRespectively vertical crustal stress, horizontal maximum crustal stress and horizontal minimum crustal stress, ρ is rock
Density, H are depth, PpFor pore pressure, usFor quiet Poisson's ratio, h is formation thickness, and g is acceleration of gravity, and a is effective stress system
Number, str1,str2For structural correction amount.
The calculation method and device of stress suffered by casing provided by the invention, by multiple core samples with scheduled rate
It is heated, when the temperature of each core sample rises to preset temperature, confining pressure is added to each core sample, in enclosing for each core sample
When pressure rises to default confining pressure, default confining pressure is kept into the first preset time, then using at least one default axis pressure respectively to each rock
Heart sample carries out plus axis pressure, after each default axis pressure keeps the second preset time, obtain each core sample creep parameters and
Parameters and earth stress, then axis pressure is unloaded to each core sample, until default axis buckling is original axis pressure, and original axis is pressed and keeps third
Preset time determines Creep Equation formula, according to each core sample then according to the corresponding multiple creep parameters of each core sample
The corresponding multiple parameters and earth stress of product, definitely stress equation group, then according to sleeve parameters, cement sheath parameter and creep
Equation establishes casing-cement sheath-stratigraphic model, further according to drilling liquid pressure, the yield stress of casing, crustal stress equation group with
And casing-cement sheath-stratigraphic model calculates multiple equivalent stress that each point is born on casing.The ground of present invention combination saline bed
The characteristic of layer feature, the characteristic of cement sheath and casing itself has fully taken into account creep effect to the shadow of stress suffered by casing
It rings, has been accurately obtained the equivalent stress that each point on casing is born, it can not only be to selecting casing in drilling well or production process
Reliable basis is provided, with the generation for effectivelying prevent casing to damage, and accurate foundation can be provided for the setting of saline bed middle sleeve.
Detailed description of the invention
Fig. 1 is the flow chart one of the calculation method of stress suffered by casing provided by the invention;
Fig. 2 is the schematic diagram one of creep test parameter in the calculation method of stress suffered by casing provided by the invention;
Fig. 3 is the schematic diagram one of creep experiments in the calculation method of stress suffered by casing provided by the invention;
Fig. 4 is the schematic diagram two of creep test parameter in the calculation method of stress suffered by casing provided by the invention;
Fig. 5 is the schematic diagram two of creep experiments in the calculation method of stress suffered by casing provided by the invention;
Fig. 6 is the flowchart 2 of the calculation method of stress suffered by casing provided by the invention;
Fig. 7 is calculation method middle sleeve-cement sheath-stratigraphic model signal of stress suffered by casing provided by the invention
Figure;
Fig. 8 is the equivalent stress of the casing of different wall thickness and side in the calculation method of stress suffered by casing provided by the invention
The changing rule schematic diagram of parallactic angle degree;
Fig. 9 is the equivalent stress of the casing of different curvature and side in the calculation method of stress suffered by casing provided by the invention
The changing rule schematic diagram of parallactic angle degree;
Figure 10 is the flow chart 3 of the calculation method of stress suffered by casing provided by the invention;
Figure 11 is the structural schematic diagram of the computing device of stress suffered by casing provided by the invention.
Specific embodiment
Fig. 1 is the flow chart one of the calculation method of stress suffered by casing provided by the invention, and Fig. 2 is set provided by the invention
The schematic diagram one of creep test parameter in the calculation method of suffered stress is managed, Fig. 3 is stress suffered by casing provided by the invention
The schematic diagram one of creep experiments in calculation method, Fig. 4 are compacted in the calculation method of stress suffered by casing provided by the invention
Become the schematic diagram two of test parameters, Fig. 5 is creep experiments in the calculation method of stress suffered by casing provided by the invention
Schematic diagram two, Fig. 6 are the flowchart 2 of the calculation method of stress suffered by casing provided by the invention, and Fig. 7 is provided by the invention
Calculation method middle sleeve-cement sheath-stratigraphic model schematic diagram of stress suffered by casing, Fig. 8 are casing institute provided by the invention
By the changing rule schematic diagram of the equivalent stress and orientation angles of the casing of different wall thickness in the calculation method of stress, Fig. 9 is this
The variation for inventing the equivalent stress and orientation angles of the casing of different curvature in the calculation method of stress suffered by the casing provided is advised
Restrain schematic diagram.When carrying out actual well drilled operation or production operation using horizontal well, the bottom surface of saline bed is stored up away from oil-gas reservoir
The lesser situation of vertical range of layer, casing can be bent setting in saline bed, and therefore, casing itself can generate yield stress,
Power suffered by casing is had an impact.Again since the crustal stress that stratum generates can be passed to casing by cement sheath, and saline bed has
There is wriggling, stratum can change the cement bad crustal stress transmitted to casing when wriggling.Therefore, the formation characteristics and cement of saline bed
The characteristic of ring can have an impact the pressure suffered by casing.Those skilled in the art is appreciated that the bearing capacity of casing itself
Most important for drillng operation or production operation, the maximum bearing capacity of casing needs to be greater than the stress that casing is subject to.Therefore,
In order to accurately calculate pressure suffered by casing, to the specific implementation process of calculation of pressure method suffered by the present embodiment middle sleeve
It is described in detail.As shown in Figure 1, calculation of pressure method suffered by the casing of the present embodiment includes:
S101, multiple core samples are heated with scheduled rate, rises to preset temperature in the temperature of each core sample
When, confining pressure is added to each core sample, when the confining pressure of each core sample rises to default confining pressure, default confining pressure holding first is preset
Time, wherein each core sample is the rock core produced from saline bed rock core with different coring angles.
Specifically, saline bed rock core can be obtained in positive drilling well and containing coring in the compound salt constituent of interlayer in the present embodiment.Again
According to International Rock mechanics standard, the dry rock followed the example of and saline bed rock core is prepared into same size with different coring angles is used
Heart sample, wherein coring angle is angle formed by the axial direction of two core samples.Wherein, the range of coring angle can be
0°-180°。
Further, since the meeting difference of drilling well angle makes orientation locating for casing different, specifically can with ground surface at 0 °-
180 ° of angle, therefore, in order to really restore casing in the true bearing on stratum, the present embodiment can utilize different coring angles
Core sample carrys out true environment locating for analog casing.Casing in all directions is arrived in order to balance, core sample in the present embodiment
Number can be four, and creep properties and the calculating process that can more accurately obtain stratum are simple, it is easy to accomplish.Four
Core sample be in saline bed rock core, from vertical direction on take a core sample, from horizontal direction on take three core samples
Product, wherein the coring angle of these three core samples differs 45 ° two-by-two.That is a core sample takes with other core samples
Heart angle is 90 °, and using a core sample as benchmark in remaining three, and its coring angle is if 0 °, and remaining two
The coring angle of core sample therewith is respectively 45 ° and 90 °.To the acquisition modes of core sample and core sample in the present embodiment
Number without limitation, need to only meet each core sample can really reflect the physical location and orientation of casing.
Rock mechanics parameters processing is carried out to each core sample further, in this embodiment different modes can be used, from
And determine Creep Equation formula and crustal stress equation group.Wherein Creep Equation can reflect that the rule of creep effect occurs for saline bed,
Creep Equation can be determined by creep parameters.Crustal stress equation is able to reflect out the rule of the crustal stress of saline bed generation,
Crustal stress equation can be determined by parameters and earth stress.
Further, due to creep long action time and precision prescribed is high, in order to accurately determine Creep Equation formula and answer
Power equation group, the present embodiment availability data acquire equipment and carry out rock mechanics parameters processing, the equipment for each core sample
Based on rock mechanics integrated test system, can by parameters such as control temperature and pressures, continuously strain can be measured and
Record.Core sample can be sealed and be placed in hyperbaric chamber in the present embodiment, it can be equipped with strain axially and radially on sealing shroud
Sensor, strain signal can reach data acquisition equipment by data line.
Specifically, for any core sample, original confining pressure and original axis pressure can be applied to core sample in the present embodiment,
To fix core sample in confined chamber.Wherein original confining pressure and original axis pressure are smaller, generally less than 0.1Mpa.It connects
, the present embodiment can carry out securing core sample with scheduled rate to continue heating, until temperature is raised to preset temperature.
Wherein, scheduled rate can be set as 1 ° -2 ° per minute, and preset temperature can be set according to stratum actual temperature situation, this implementation
Example does not limit this.When temperature obtains preset temperature, to core sample plus confining pressure, adding to the confining pressure that core sample is subject to is
Default confining pressure.Confining pressure is preset in the present embodiment to be set according to the practical confining pressure situation in stratum, and the present embodiment does not limit this
It is fixed.And core sample is persistently preset to the first preset time in the state of confining pressure, wherein the first preset time is 1 hour desirable, by
It can reach uniformly in the internal temperature of rock sample at this time, and this state can simulate the reset condition in actual formation,
Therefore, the present embodiment can obtain creep parameters and parameters and earth stress, and can improve and determine Creep Equation formula and crustal stress equation group
Precision.
S102, axis pressure is preset using at least one each core sample is carried out plus axis pressure respectively, protect in each default axis pressure
After holding the second preset time, the creep parameters and parameters and earth stress of each core sample are obtained, then axis pressure is unloaded to each core sample, directly
It is original axis pressure to default axis buckling, and original axis is pressed and keeps third preset time.
Specifically, a default axis pressure can be used in the present embodiment and carry out the process for adding axis pressure to each core sample, it can also
Using the process for carrying out adding axis pressure to reddendo signula singulis core sample respectively to a default axis pressure.No matter which kind of above-mentioned mode, for every
A core sample carries out each core sample in a default axis pressure plus the process of axis pressure is similar.Detailed process are as follows: when to rock core
When sample applies the axis pressure of a certain default axis pressure size, need to keep the second preset time, then obtain core sample under current state
The creep parameters and parameters and earth stress of product.Then, axis pressure is unloaded to core sample, and pressing up to axis is original axis pressure, just completely will
The axis pressure being applied on core sample is laid down, wherein original axis pressure is the axis pressure of the fixation applied in S101 to core sample,
It can be set according to the actual situation.And core sample is kept into third preset time under original axis pressure condition, so that next
Secondary plus axis presses through the creep parameters of journey acquisition and parameters and earth stress not will receive the influence that last plus axis presses through journey, acquisition it is compacted
Variable element and parameters and earth stress also can be more accurate.Wherein, creep parameters may include creep temperature, creeping pressure, the deformation of creep
Amount and creep time etc..Parameters and earth stress may include the Poisson's ratio of stress on core sample at Lloyd " Butch " Keaser stress point, salt constituent
With elasticity modulus etc..The present embodiment without limitation, need to only meet creep ginseng to the particular contents of creep parameters and parameters and earth stress
Several and parameters and earth stress can determine Creep Equation formula and crustal stress equation group respectively.
A kind of feasible implementation, the present embodiment can apply multiple default axis pressures to core sample, above-mentioned side can be used
Formula applies each default axis pressure to core sample, and the process for applying each default axis pressure is similar.Wherein, the size of each default axis pressure
Need the gradient for keeping being gradually increased.In the present embodiment without limitation to the number of default axis pressure.And it is applied to core sample
Add the process of each default axis pressure, the second lasting preset time can be identical during each, can not also be identical, the present embodiment to this not
It limits.In the process for unloading axis straightening to original axis pressure from default axis pressure to core sample, when the lasting third of each process is preset
Between can be identical, can not also be identical, the present embodiment does not limit this.
It in a specific embodiment, can be first to core sample as shown in Fig. 2, being kept for 130 DEG C of temperature, confining pressure 20MPa
Product apply 32MPa axis and press 600min, measure the deformation of creep amount in creep parameters, then unload axis straightening to unloading completely to core sample
Continue several hours again after complete.Then 40MPa axis is applied to core sample and presses 1000min, the creep measured in creep parameters becomes
Shape amount, then to core sample unload axis straightening to after unsnatching completely again continue several hours.Then 48MPa axis is applied to core sample
Press 400min, measure the deformation of creep amount in creep parameters, if then to core sample unload axis straightening to after unsnatching completely again continue
Dry hour.The present embodiment can will measure multiple groups deformation of creep amount and be fitted, and obtain matched curve, as shown in Figure 3, it can be seen that with
Be applied to the increase of axis pressure on core sample, the deformation of creep amount that core sample occurs gradually increases.And it presses and keeps in each axis
When constant, the deformation of creep amount of core sample is held essentially constant.Herein it should be noted that not showing in Fig. 2 to rock core
Sample unloads the process of axis pressure.
Another feasible implementation, the present embodiment can apply a default axis pressure to core sample, can be used above-mentioned
Mode applies default axis pressure to core sample, wherein the second preset time may be set to the long period.The present embodiment does not do this
It limits.
It in a specific embodiment, can be first to core sample as shown in figure 4, being kept for 130 DEG C of temperature, confining pressure 20MPa
Product apply 42MPa axis and press 3600min, measure the deformation of creep amount in creep parameters, then unload axis straightening to complete to core sample
Continue several hours again after unsnatching.The present embodiment can will measure multiple groups deformation of creep amount and be fitted, and obtain matched curve, such as scheme
Shown in 5, it can be seen that when axis pressure remains unchanged, the deformation of creep amount of core sample is slightly increased.
Further, in this embodiment each core sample is handled by rock mechanics parameters can be obtained multiple creeps
Parameter and multiple parameters and earth stress.Therefore, for each core sample of different coring angles can be obtained multiple creep parameters and
Multiple parameters and earth stress, the data volume the big more can really, accurately reflect the formation characteristics of saline bed, can be true by S103
Creep Equation formula is determined, by S104 definitely stress equation group.
S103, according to the corresponding multiple creep parameters of each core sample, determine Creep Equation formula.
Specifically, Creep Equation has many various forms of expression formulas in the present embodiment, specifically can be according to actual salt cream
The strata condition of layer is selected, and the present embodiment does not limit this.Optionally, Creep Equation formula passes through following formula (1) table
Show:
Wherein, A is undetermined coefficient, and n is stress exponent, and Q is activation energy, σ*=1M Pa is referring to stress, R0=
8.31441kJ/(mol K-1) it is universal gas constant, T is temperature, and σ is creeping pressure, and ε=W/t is deformation of creep rate, and W is
Deformation of creep amount, t are the deformation of creep time.
Further, in this embodiment can substitute into multiple creep parameters to formula one, multiple groups parameter A, n undetermined can be obtained
And Q, such as table 1.Four groups of parameters A, n and Q are shown in table 1, the average value that can use each parameter A, n and Q in the present embodiment is made respectively
For the end value of parameter A, n and Q, so that it is determined that Creep Equation formula, enables Creep Equation more accurately to reflect saline bed
Formation characteristics.
The determination of 1 creep parameters of table
S104, according to the corresponding multiple parameters and earth stress of each core sample, definitely stress equation group.
Wherein, S103 can be executed prior to S104, and S104 can also be executed prior to S103, and S103 and S104 can be also performed simultaneously,
The present embodiment to the execution of S103 and S104 sequence without limitation.
Crustal stress equation group has many various forms of expression formulas in the present embodiment, can be according to fault pattern or other realities
The strata condition of border saline bed is selected, and the present embodiment does not limit this.In order to which crustal stress equation is determined more accurately
Group, the present embodiment are detailed to being carried out according to the specific implementation process of each parameters and earth stress of each core sample definitely stress equation group
It describes in detail bright.As shown in fig. 6, this method further include:
S1041, according to the corresponding multiple parameters and earth stress of each core sample, vertical crustal stress expression formula, it is horizontal most
Ground Stress expression formula and horizontal minimally stress expression formula determine that vertical crustal stress, horizontal maximum crustal stress and level are minimum
Crustal stress.
Specifically, the equivalent stress that the present embodiment middle sleeve is subject to can according to vertical crustal stress, horizontal maximum crustal stress and
Horizontal these three component of minimum crustal stress are indicated, and multiple parameters and earth stress of each core sample be able to reflect casing by
Equivalent stress.Therefore, the present embodiment can be used various ways according to the multiple groups parameters and earth stress of each core sample, vertical answer
Power expression formula, horizontal maximally stress expression formula and horizontal minimally stress expression formula, so that it is determined that vertical crustal stress, level are most
Ground Stress and horizontal minimum crustal stress.Optionally, vertical crustal stress expression formula, horizontal maximally stress expression formula and it is horizontal most
Small crustal stress expression formula is indicated by following formula (2):
Wherein, σν,σH,σhRespectively vertical crustal stress, horizontal maximum crustal stress and horizontal minimum crustal stress, α is effective
Stress coefficient, P are pore pressure, and φ is interior angle of rubbing, σ⊥For the stress in vertical direction at Lloyd " Butch " Keaser stress point, σ0For coring
The core sample that angle the is 0 ° stress at Lloyd " Butch " Keaser stress point in the horizontal direction, σ90The core sample for being 90 ° for coring angle
The product stress at Lloyd " Butch " Keaser stress point in the horizontal direction, σ45The core sample for being 45 ° for coring angle is triumphant in the horizontal direction
Stress at Sai Er stress point.
Specifically, the reality in the area can be obtained according to the geological structure and seismic interpretation data of drilling area in the present embodiment
Border geological structure and tomography distribution situation, so that it is determined that the pore pressure P of saline bed, the interior angle φ that rubs, and pass through each core sample
Multiple parameters and earth stress of product determine σ⊥、σ0、σ45And σ90, such as table 2.
2 Kai Seer effect crustal stress experimental result of table
Further, in table 2 core sample be from well-name be DB1, well depth be 5880 meters place acquisition.Pass through horizontal direction
On coring angle be 0 °, 45 ° and 90 ° of three core samples, in the case where confining pressure remains unchanged, pass through setting Lloyd " Butch " Keaser
The poor stress of point changes the axis pressure of core sample, so that it is determined that vertical crustal stress, horizontal maximum crustal stress and it is horizontal minimally
Stress.It can use its average value in the present embodiment minimally to answer respectively as vertical crustal stress, horizontal maximum crustal stress and level
Power, specially σv=2.6Mpa/100m, σH=2.7Mpa/100m, σh=2.0Mpa/100m.
S1042, according to the corresponding multiple parameters and earth stress of each core sample, determine crustal stress equation group to be corrected.
Specifically, in the present embodiment can by assuming undetermined parameter, further according to each parameters and earth stress of each core sample, from
And obtain crustal stress equation group to be corrected.Optionally, crustal stress equation group to be corrected is indicated by following formula (3):
Wherein, σν,σH,σhRespectively vertical crustal stress, horizontal maximum crustal stress and horizontal minimum crustal stress, ρ is rock
Density, H are depth, PpFor pore pressure, usFor quiet Poisson's ratio, h is formation thickness, and g is acceleration of gravity, and a is effective stress system
Number, str1,str2For structural correction amount.
Specifically, the drilling area can be obtained according to the geological structure and seismic interpretation data of drilling area in the present embodiment
With the rock density ρ of change in depth, depth H, pore pressure P in domainp, quiet Poisson's ratio usAnd formation thickness h.The present embodiment is again
By assuming parameter a and parameter str1,str2, to obtain crustal stress equation group to be corrected.
S1043, according to vertical crustal stress, horizontal maximum crustal stress and horizontal minimum crustal stress, to crustal stress side to be corrected
Journey group is corrected processing, obtains crustal stress equation group.
Specifically, due to that can determine actual vertical crustal stress, horizontal maximum in S1041 according to test parameters and earth stress
Crustal stress and horizontal minimum crustal stress therefore can be by actual vertical crustal stress, horizontal maximum crustal stress and levels minimally
Stress carrys out vertical crustal stress, horizontal maximum crustal stress and the horizontal minimum crustal stress that updating formula three is calculated, so as to adjust
The parameter a and parameter str assumed in crustal stress equation group to be corrected1,str2, finally determine accurate crustal stress equation group.
S105, according to sleeve parameters, cement sheath parameter and Creep Equation formula, establish casing-cement sheath-stratigraphic model.
Specifically, for actual single casing oil/gas well, it is followed successively by stratum, cement sheath and casing, and casing from outside to inside
Parameter can reflect that casing characteristic, cement sheath parameter can reflect that cement ring property, Creep Equation are able to reflect out the ground of saline bed
Layer characteristic.Therefore, the present embodiment can establish casing-cement sheath-ground by sleeve parameters, cement sheath parameter and Creep Equation formula
Layer model constructs actual drillng operation or the condition of production, to reflect the actual influence factor to stress suffered by casing.
Finite difference software specifically can be used in the present embodiment, is established by known sleeve parameters, cement sheath parameter and Creep Equation formula
Casing-cement sheath-the stratigraphic model being consistent with practical geological condition, as shown in Figure 7.In Fig. 7, x-axis represents level maximally
Stress direction, y-axis represent horizontal minimum crustal stress direction, and z-axis represents vertical crustal stress direction.
Further, in this embodiment sleeve parameters can be obtained according to the geological structure and seismic interpretation data of drilling area
With cement sheath parameter.In a specific embodiment, sleeve parameters, cement sheath parameter and parameters and earth stress can be as shown in table 3.
The determination of table 3 sleeve parameters and cement sheath parameter
S106, according to drilling liquid pressure, the yield stress of casing, crustal stress equation group and casing-cement sheath-stratum mould
Type calculates multiple equivalent stress that each point is born on casing.
Specifically, since casing will receive the drilling liquid pressure that drilling fluid applies it, the yield stress and ground of casing
The crustal stress that layer generates it, and in view of practical geological structure locating for casing, therefore, the present embodiment can pass through drilling hydraulic
Power, the yield stress of casing, crustal stress equation group and casing-cement sheath-stratigraphic model obtain casing each point born it is more
A equivalent stress.Wherein, the present embodiment can be answered according to known sleeve parameters and parameters and earth stress, the surrender for obtaining casing
Power, can also be according to casing-cement sheath-stratigraphic model come the actual configuration of simulated formation.
Further, the present embodiment can carry out formation fracture pressure experiment in positive drilling well saline bed section or leakage experiment comes really
Fixed reasonable drilling fluid density, to obtain drilling liquid pressure.Detailed process are as follows: by being gradually increased drilling fluid density, until
There is the phenomenon that leakage, record drilling fluid density at this time, the value of this density will be slightly less than as drilling fluid density, to pass through
Drilling fluid density calculates drilling fluid to the drilling liquid pressure of casing.Drilling hydraulic can be obtained in the present embodiment in several ways
Power, the present embodiment do not limit this.Different wall thickness can be depicted using the calculation method of stress suffered by the present embodiment casing
Casing, equivalent stress with orientation angles changing rule, as shown in Figure 8.Using the meter of stress suffered by the present embodiment casing
Calculation method also depicts the casing of different curvature, equivalent stress with orientation angles changing rule, as shown in Figure 9.
The calculation method of stress suffered by casing provided in this embodiment, by being carried out to multiple core samples with scheduled rate
Heating, when the temperature of each core sample rises to preset temperature, adds confining pressure to each core sample, in the confining pressure liter of each core sample
To when presetting confining pressure, default confining pressure is kept into the first preset time, then using at least one default axis pressure respectively to each core sample
Product carry out plus axis pressure, after each default axis pressure keeps the second preset time, obtain each core sample creep parameters and answer
Force parameter, then axis pressure is unloaded to each core sample, until default axis buckling is original axis pressure, and original axis is pressed, third is kept to preset
Time determines Creep Equation formula then according to the corresponding multiple creep parameters of each core sample, each according to each core sample
Self-corresponding multiple parameters and earth stress, definitely stress equation group, then according to sleeve parameters, cement sheath parameter and Creep Equation
Formula establishes casing-cement sheath-stratigraphic model, further according to drilling liquid pressure, the yield stress of casing, crustal stress equation group and set
Pipe-cement sheath-stratigraphic model calculates multiple equivalent stress that each point is born on casing.The stratum of the present embodiment combination saline bed
The characteristic of feature, the characteristic of cement sheath and casing itself has fully taken into account influence of the creep effect to stress suffered by casing,
It has been accurately obtained the equivalent stress that each point on casing is born, casing can not only have been selected to provide in drilling well or production process
Reliable basis with the generation for effectivelying prevent casing to damage, and can provide accurate foundation for the setting of saline bed middle sleeve.
Figure 10 is the flow chart 3 of the calculation method of stress suffered by casing provided by the invention.On the basis of above-described embodiment
On, the equivalent stress of casing has been calculated in the calculation method of stress suffered by casing through this embodiment.Those skilled in the art
Would generally be by comparing the yield strength of casing and the size for the maximum equivalent being subject to, whether the casing to determine selection is full
Sufficient safety requirements.As shown in Figure 10, the method for the present embodiment includes:
S201, each core sample is heated with scheduled rate, when the temperature of each core sample rises to preset temperature,
Confining pressure is added to each core sample, when the confining pressure of each core sample rises to default confining pressure, when default confining pressure holding first is default
Between, wherein each core sample is the rock core produced from saline bed rock core with different coring angles.
S202, axis pressure is preset using at least one each core sample is carried out plus axis pressure respectively, protect in each default axis pressure
After holding the second preset time, the creep parameters and parameters and earth stress of each core sample are obtained, then axis pressure is unloaded to each core sample, directly
It is original axis pressure to default axis buckling, and original axis is pressed and keeps third preset time.
S203, according to the corresponding multiple creep parameters of each core sample, determine Creep Equation formula.
S204, according to the corresponding multiple parameters and earth stress of each core sample, definitely stress equation group.
S205, according to sleeve parameters, cement sheath parameter and Creep Equation formula, establish casing-cement sheath-stratigraphic model.
S206, according to drilling liquid pressure, the yield stress of casing, crustal stress equation group and casing-cement sheath-stratum mould
Type calculates multiple equivalent stress that each point is born on casing.
Wherein, S201-S206 is similar with S101-S106 in Fig. 1 embodiment and other implementations, and the present embodiment is herein no longer
It repeats.
S207, it determines maximum value in multiple equivalent stress, maximum value is determined as to the maximum equivalent of casing.
S208, according to the safe bearing capacity of casing and the maximum equivalent of casing, determine whether casing is surrendered.
Specifically, those skilled in the art be appreciated that casing need there are certain safe clearances, in order to guarantee casing
It can satisfy safety requirements, therefore, the present embodiment can be calculated according to known casing yield strength and safety coefficient (such as taking 1.5)
Obtain the safe bearing capacity of casing.By comparing the maximum equivalent of casing and the size of safe bearing capacity, set can be evaluated
Whether pipe can be used in suitable for saline bed.
Optionally, when the maximum equivalent of casing is less than the safe bearing capacity of casing, determine that casing will not be bent
Clothes;When the maximum equivalent of casing is equal to or more than the safe bearing capacity of casing, determine that casing can be surrendered.
Specifically, if the maximum equivalent of casing is less than the safe bearing capacity of casing, it is determined that the casing of selection will not
It surrenders, specifications parameter meets safety requirements.If the maximum equivalent of casing is equal to or more than the safe pressure-bearing of casing
Power, it is determined that the casing of selection can be surrendered, and specifications parameter is unsatisfactory for safety requirements, so that the present embodiment can be to pit shaft
Safety evaluatio firm foundation is provided.
Figure 11 is the structural schematic diagram of the computing device of stress suffered by casing provided by the invention.As shown in figure 11, this reality
The device for applying example may include:
Determining module 10, for being heated to multiple core samples with scheduled rate, in the temperature of each core sample
When degree rises to preset temperature, confining pressure is added to each core sample, when the confining pressure of each core sample rises to default confining pressure,
The default confining pressure is kept into the first preset time, wherein each core sample is with different coring angles from saline bed rock core
In the rock core produced;It presets axis pressure using at least one each core sample to be carried out adding axis pressure respectively, each described pre-
If obtaining the creep parameters and parameters and earth stress of each core sample, then to each described after axis pressure keeps the second preset time
Core sample unloads axis pressure, until the default axis buckling is original axis pressure, and the original axis is pressed and keeps third preset time;
According to each corresponding multiple creep parameters of core sample, the Creep Equation formula is determined;
The determining module 10 is also used to be determined according to each corresponding multiple parameters and earth stress of core sample
The crustal stress equation group;
Model building module 20, for establishing casing-according to sleeve parameters, cement sheath parameter and the Creep Equation formula
Cement sheath-stratigraphic model;
Module 30 is obtained, for according to the yield stress of drilling liquid pressure, casing, the crustal stress equation group and described
Casing-cement sheath-stratigraphic model calculates multiple equivalent stress that each point is born in described sleeve pipe.
Optionally, the determining module 10, is also used to determine the maximum value in the multiple equivalent stress, by the maximum
Value is determined as the maximum equivalent of described sleeve pipe;
According to the safe bearing capacity of described sleeve pipe and the maximum equivalent of described sleeve pipe, determine whether described sleeve pipe occurs
Surrender;
When the maximum equivalent of described sleeve pipe is less than the safe bearing capacity of described sleeve pipe, determine that described sleeve pipe will not be sent out
Raw surrender;
When the maximum equivalent of described sleeve pipe is equal to or more than the safe bearing capacity of described sleeve pipe, described sleeve pipe is determined
It can surrender.
Optionally, the creep parameters include creeping pressure, deformation of creep amount and creep time.
Optionally, the Creep Equation formula is indicated by following formula (1):
Wherein, A is undetermined coefficient, and n is stress exponent, and Q is activation energy, σ*=1M Pa is referring to stress, R0=
8.31441kJ/(mol K-1) it is universal gas constant, T is creep temperature, and σ is creeping pressure, and ε=W/t is creep rate, and W is
Deformation of creep amount, t are creep time.
Optionally, the determining module 10 is specifically also used to answer multiplely according to each core sample is corresponding
Force parameter, vertical crustal stress expression formula, horizontal maximally stress expression formula and horizontal minimally stress expression formula, determine vertically
Stress, horizontal maximum crustal stress and horizontal minimum crustal stress;
According to each corresponding multiple parameters and earth stress of core sample, crustal stress equation group to be corrected is determined;
According to the vertical crustal stress, the horizontal maximum crustal stress and the horizontal minimum crustal stress, to described to school
Normal incidence stress equation group is corrected processing, obtains the crustal stress equation group.
Optionally, the vertical crustal stress expression formula, the horizontal maximally stress expression formula and it is described it is horizontal minimally
Stress expression formula is indicated by following formula (2):
Wherein, σν,σH,σhRespectively vertical crustal stress, horizontal maximum crustal stress and horizontal minimum crustal stress, α is effective
Stress coefficient, P are pore pressure, and φ is interior angle of rubbing, σ⊥For the stress in vertical direction at kayser point, σ0It is for coring angle
0 ° of the core sample stress at Lloyd " Butch " Keaser stress point in the horizontal direction, σ90For coring angle be 90 ° core sample in water
Square upwards stress at Lloyd " Butch " Keaser stress point, σ45The core sample for being 45 ° for coring angle in the horizontal direction answer by Lloyd " Butch " Keaser
Stress at force.
Optionally, the crustal stress equation group to be corrected is indicated by following formula (3):
Wherein, σν,σH,σhRespectively vertical crustal stress, horizontal maximum crustal stress and horizontal minimum crustal stress, ρ is rock
Density, H are depth, PpFor pore pressure, usFor quiet Poisson's ratio, h is formation thickness, and g is acceleration of gravity, and a is effective stress system
Number, str1,str2For structural correction amount.
Above method embodiment can be performed in the computing device of stress suffered by casing provided in an embodiment of the present invention, specific
Implementing principle and technical effect, reference can be made to above method embodiment, details are not described herein again for the present embodiment.
Those of ordinary skill in the art will appreciate that: realize that all or part of the steps of above-mentioned each method embodiment can lead to
The relevant hardware of program instruction is crossed to complete.Program above-mentioned can be stored in a computer readable storage medium.The journey
When being executed, execution includes the steps that above-mentioned each method embodiment to sequence;And storage medium above-mentioned include: ROM, RAM, magnetic disk or
The various media that can store program code such as person's CD.
Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention., rather than its limitations;To the greatest extent
Pipe present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that: its according to
So be possible to modify the technical solutions described in the foregoing embodiments, or to some or all of the technical features into
Row equivalent replacement;And these are modified or replaceed, various embodiments of the present invention technology that it does not separate the essence of the corresponding technical solution
The range of scheme.
Claims (10)
1. a kind of calculation method of stress suffered by casing characterized by comprising
Multiple core samples are heated with scheduled rate, it is right when the temperature of each core sample rises to preset temperature
Each core sample adds confining pressure, and when the confining pressure of each core sample rises to default confining pressure, the default confining pressure is kept
First preset time, wherein each core sample is the rock core produced from saline bed rock core with different coring angles;
Axis pressure is preset using at least one each core sample to be carried out adding axis pressure respectively, is kept in each default axis pressure
After second preset time, the creep parameters and parameters and earth stress of each core sample are obtained, then each core sample is unloaded
Axis pressure until the default axis buckling is original axis pressure, and the original axis is pressed and keeps third preset time;
According to each corresponding multiple creep parameters of core sample, the Creep Equation formula is determined;
According to each corresponding multiple parameters and earth stress of core sample, the crustal stress equation group is determined;
According to sleeve parameters, cement sheath parameter and the Creep Equation formula, casing-cement sheath-stratigraphic model is established;
According to drilling liquid pressure, the yield stress of casing, the crustal stress equation group and described sleeve pipe-cement sheath-stratum mould
Type calculates multiple equivalent stress that each point is born in described sleeve pipe.
2. the method according to claim 1, wherein according to the yield stress of drilling liquid pressure, casing, described
Crustal stress equation group and described sleeve pipe-cement sheath-stratigraphic model calculate the effects such as multiple that each point in described sleeve pipe is born
After power, further includes:
It determines the maximum value in the multiple equivalent stress, the maximum value is determined as to the maximum equivalent of described sleeve pipe;
According to the safe bearing capacity of described sleeve pipe and the maximum equivalent of described sleeve pipe, determine whether described sleeve pipe bends
Clothes;
When the maximum equivalent of described sleeve pipe is less than the safe bearing capacity of described sleeve pipe, determine that described sleeve pipe will not be bent
Clothes;
When the maximum equivalent of described sleeve pipe is equal to or more than the safe bearing capacity of described sleeve pipe, determine that described sleeve pipe can be sent out
Raw surrender.
3. the method according to claim 1, wherein the creep parameters include creeping pressure, deformation of creep amount
And creep time.
4. according to the method described in claim 3, it is characterized in that, the Creep Equation formula is indicated by following formula (1):
Wherein, A is undetermined coefficient, and n is stress exponent, and Q is activation energy, σ*=1MPa is referring to stress, R0=8.31441kJ/
(mol K-1) it is universal gas constant, T is creep temperature, and σ is creeping pressure, and ε=W/t is creep rate, and W is the deformation of creep
Amount, t is creep time.
5. the method according to claim 1, wherein described answer according to each core sample is corresponding multiplely
Force parameter determines the crustal stress equation group, comprising:
According to the corresponding multiple parameters and earth stress of each core sample, vertical crustal stress expression formula, horizontal maximally answer
Power expression formula and horizontal minimally stress expression formula determine vertical crustal stress, horizontal maximum crustal stress and horizontal minimum crustal stress;
According to each corresponding multiple parameters and earth stress of core sample, crustal stress equation group to be corrected is determined;
According to the vertical crustal stress, the horizontal maximum crustal stress and the horizontal minimum crustal stress, to it is described to be correctedly
Stress equation group is corrected processing, obtains the crustal stress equation group.
6. according to the method described in claim 5, it is characterized in that, the vertical crustal stress expression formula, it is described it is horizontal maximally
Stress expression formula and the horizontal minimally stress expression formula are indicated by following formula (2):
Wherein, σν,σH,σhRespectively vertical crustal stress, horizontal maximum crustal stress and horizontal minimum crustal stress, α is effective stress
Coefficient, P are pore pressure, and φ is interior angle of rubbing, σ⊥For the stress in vertical direction at kayser point, σ0It is 0 ° for coring angle
The core sample stress at Lloyd " Butch " Keaser stress point in the horizontal direction, σ90For coring angle be 90 ° core sample in level side
Stress at upward Lloyd " Butch " Keaser stress point, σ45The core sample Lloyd " Butch " Keaser stress point in the horizontal direction for being 45 ° for coring angle
The stress at place.
7. according to the method described in claim 5, it is characterized in that, the crustal stress equation group to be corrected passes through following formula
(3) it indicates:
Wherein, σν,σH,σhRespectively vertical crustal stress, horizontal maximum crustal stress and horizontal minimum crustal stress, ρ are that rock is close
Degree, H is depth, PpFor pore pressure, usFor quiet Poisson's ratio, h is formation thickness, and g is acceleration of gravity, and a is effective stress system
Number, str1,str2For structural correction amount.
8. a kind of computing device of stress suffered by casing characterized by comprising
Determining module rises to for being heated to multiple core samples with scheduled rate in the temperature of each core sample
When preset temperature, confining pressure is added to each core sample, it, will be described when the confining pressure of each core sample rises to default confining pressure
Default confining pressure keeps the first preset time, wherein each core sample is to be produced from saline bed rock core with different coring angles
Rock core;It presets axis pressure using at least one each core sample to be carried out adding axis pressure respectively, in each default axis pressure
After keeping the second preset time, the creep parameters and parameters and earth stress of each core sample are obtained, then to each core sample
Product unload axis pressure, until the default axis buckling is original axis pressure, and the original axis are pressed and keeps third preset time;According to each
The corresponding multiple creep parameters of core sample, determine the Creep Equation formula;
The determining module is also used to be determined describedly according to each corresponding multiple parameters and earth stress of core sample
Stress equation group;
Module is established, for establishing casing-cement sheath-stratum according to sleeve parameters, cement sheath parameter and the Creep Equation formula
Model;
Module is obtained, for the yield stress, the crustal stress equation group and described sleeve pipe-according to drilling liquid pressure, casing
Cement sheath-stratigraphic model calculates multiple equivalent stress that each point is born in described sleeve pipe.
9. device according to claim 8, which is characterized in that the determining module is also used to determine the effects such as the multiple
The maximum value is determined as the maximum equivalent of described sleeve pipe by the maximum value in power;According to the safe pressure-bearing of described sleeve pipe
The maximum equivalent of power and described sleeve pipe, determines whether described sleeve pipe surrenders;When the maximum equivalent of described sleeve pipe
Less than described sleeve pipe safe bearing capacity when, determine that described sleeve pipe will not surrender;When the maximum equivalent of described sleeve pipe
Equal to or more than described sleeve pipe safe bearing capacity when, determine that described sleeve pipe can surrender.
10. device according to claim 8, which is characterized in that the creep parameters include creeping pressure, deformation of creep amount
And creep time.
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CN110457807A (en) * | 2019-08-02 | 2019-11-15 | 中国石油天然气集团有限公司 | A kind of combustion in situ displacement of reservoir oil gas injection well casing string military service safe evaluation method |
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