CN106599472B - A kind of annular space trapped pressure prediction technique - Google Patents
A kind of annular space trapped pressure prediction technique Download PDFInfo
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- CN106599472B CN106599472B CN201611161173.7A CN201611161173A CN106599472B CN 106599472 B CN106599472 B CN 106599472B CN 201611161173 A CN201611161173 A CN 201611161173A CN 106599472 B CN106599472 B CN 106599472B
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Abstract
The invention discloses a kind of annular space trapped pressure prediction techniques, comprising the following steps: 1) establishes annular space temperature profile according to production status；2) annular fluid thermal physical property parameter is calculated；3) casing deformation model is established using casing deformation formula；4) annular volume variation is calculated；5) annular space trapped pressure computation model is established using annular space trapped pressure accounting equation and solve.
Description
Technical field
The present invention relates to a kind of prediction technique, in particular to a kind of annular space trapped pressure prediction technique.
Background technique
Annular space trapped pressure refers to during oil gas well mining, due to flowing in the closed annular space of high temperature fluid heating in oil pipe
Body makes fluid in closed annular space expand caused pressure.Fluid thermophysical property, fluid temperature in annular space trapped pressure value and annular space
Degree variation, annular volume variation etc. are related, and excessively high annular space trapped pressure will cause casing collapse, and 1999, the Gulf of Mexico BP
After a few hours of going into operation, production casing is squeezed to be ruined the oil field Marlin A-2 well.On land and shallow well, annular space trap can be in well
Mouth release, and in deep well, other than the annular space between oil pipe and production string, other casing annulus trapped pressures can not pass through
Well head release.
Accurately calculate annular space trapped pressure can reasonably preferred casing size, formulate suitable annular space trapped pressure prevention and treatment
Scheme guarantees oil/gas well production safety to control trapped pressure.Currently, annular space trapped pressure prediction technique mainly considers to flow
Body expansion pinch effect and the deformation of casing free segment are calculated, and representative business software is the Wellcat mould of Landmark
Block, the factors such as the thermal physical property parameter of fluid expansion pinch effect chooses there are error, the deformation that does not consider casing interval isolation make
The trapped pressure that this method and software calculate is 10-30% higher than field measurement value, can not accurate instruction oil gas casing type selecting
With the formulation of the control prece of trapped pressure.
Summary of the invention
In view of the above-mentioned problems, the object of the present invention is to provide a kind of accurate annular space trapped pressure prediction technique of prediction, it should
Prediction technique can provide support for offshore oil and gas casing post design and the formulation of trapped pressure control prece.
To achieve the above object, the invention adopts the following technical scheme: a kind of annular space trapped pressure prediction technique, including with
Lower step: 1) annular space temperature profile is established according to production status；2) annular fluid thermal physical property parameter is calculated；3) casing deformation is utilized
Formula establishes casing deformation model；4) annular volume variation is calculated；5) annular space circle is established using annular space trapped pressure accounting equation
It closes calculation of pressure model and solves.
In the step 2), the annular fluid thermal physical property parameter is measured by experiment, and process includes:
1. measuring the Experimental Flowing Object volume change under different annular space temperature profiles and under different pressures；
2. the equation of Experimental Flowing Object volume change Yu the fluid thermophysical property parameter can be obtained according to annular fluid state equation
Formula, equation are as follows:
ΔV1=α V0ΔT1
ΔV1=ktV0ΔP1
Δ V in formula1For Experimental Flowing Object volume change, m3；α is the coefficient of expansion, DEG C-1；ΔT1For Experimental Flowing Object temperature change,
℃；V0For Experimental Flowing Object volume, m3；ktFor the compressed coefficient, MPa-1；ΔP1For Experimental Flowing Object pressure change, MPa；
3. according to step 2. in two equations export the fluid thermal under different annular space temperature profiles and different pressures
Physical parameter calculation formula is as follows:
In the step 2), the annular fluid thermal physical property parameter is measured by density anti-inference method, and process includes:
1. the fluid density under known different temperatures pressure；
2. it is as follows to obtain mass-conservation equation according to fluid mass conserva-tion principle before and after fluid expansion:
ρT,P(V2+ΔV2)=ρ0V2
It is exported by above formula
Δ V in formula2For annular fluid volume change, m3；V2For annular fluid volume, ρ0For initial annular fluid density, g/
cm3；ρT,PFor fluid density, g/cm under different temperatures pressure3；
3. the equation of annular fluid volume change and the fluid thermophysical property parameter can be obtained according to annular fluid state equation
Formula, equation are as follows:
ΔV2=α V2ΔT2
ΔV2=ktV2ΔP2
Δ V in formula2For annular fluid volume change, m3；α is the coefficient of expansion, DEG C-1；ΔT2For annular fluid temperature change,
℃；V2For annular fluid volume, m3；ktFor the compressed coefficient, MPa-1；ΔP2For annular fluid pressure change, MPa；
4. in conjunction with step 2. 3. in equation obtain the fluid thermal under different annular space temperature profiles and different pressures
The equation of physical parameter, equation are as follows:
In the step 3), described sleeve pipe distorted pattern includes casing free segment and interval isolation distorted pattern.
In the step 3), it is as follows that described sleeve pipe distorted pattern process is established using described sleeve pipe deformation formula:
1. establishing described sleeve pipe free segment distorted pattern
The adjacent annular space of casing and casing temperature distortion factor are taken into account into amendment casing deformation formula, obtain described sleeve pipe
The distorted pattern formula of free segment is as follows:
u1=c1p1+c2p2+uT
U in formula1For casing free segment deflection, m；c1, c2For coefficient；p1、p2The respectively pressure of the adjacent annular space of casing,
MPa；uTFor thermally-induced casing deformation amount, m；
2. establishing described sleeve pipe interval isolation distorted pattern
The deformation of casing interval isolation is only related with annular pressure, therefore obtains the deformation of described sleeve pipe interval isolation by casing deformation formula
Model formation is as follows:
u2=Ap+B
U in formula2For casing interval isolation deflection, m；A, B is coefficient；P is annular pressure.
In the step 4), the annular volume variation is calculated using cylindrical volume equation or finite element software.
The equation changed using the cylindrical volume equation calculation annular volume is as follows:
ΔVan=π [(r+u)2-r2]h
Δ V in formulaanFor annular volume variation, m3；R is casing radius, m；U is casing deformation amount, m；H is casing height,
m。
Annular space trapped pressure accounting equation in the step 5) is as follows:
P is annular space trapped pressure, MPa in formula；ΔVanIt is annular volume variation, m3；α is the coefficient of expansion, DEG C-1；ktFor pressure
Contracting coefficient, MPa-1；Δ T is fluid temperature variations, VanAnnular volume.
The invention adopts the above technical scheme, has the advantages that the present invention is calculated by experimental method and density inverse
The deformation of casing free segment and interval isolation is taken into account and calculates annular space trapped pressure, can be improved prediction loop by thermal physical property parameter
The accuracy of barren trap pressure provides support for offshore oil and gas casing post design and the formulation of trapped pressure control prece.
Detailed description of the invention
Fig. 1 is overall flow schematic diagram of the invention.
Specific embodiment
The present invention is described in detail below with reference to the accompanying drawings and embodiments.
As shown in Figure 1, the present invention provides a kind of annular space trapped pressure prediction techniques comprising following steps:
1) annular space temperature profile is established according to production status
In oil/gas well production, hydrocarbon stratum is to heating annular fluid during moving uphole.When pit shaft different output,
Annular fluid temperature is different, therefore, mineshaft annulus can be established according to heat transfer equation by thermal model, obtains pit shaft different location, no
The temperature of annular fluid in the same time forms mineshaft annulus temperature profile.It is above-mentioned to be passed through wellflo, wellcat etc. by thermal model
Software is established and is calculated.
2) annular fluid thermal physical property parameter is calculated
Fluid thermophysical property parameter includes the coefficient of expansion and the compressed coefficient.Annular fluid thermal physical property parameter is by temperature, pressure, close
The parameters such as degree influence, and should calculate separately fluid thermal physical parameter under different conditions.Two methods of experiment or density inverse can be passed through
It obtains.
It is as follows that experiment measures fluid thermophysical property parametric procedure:
1. measuring the Experimental Flowing Object volume change under different annular space temperature profiles and under different pressures.
2. the equation of Experimental Flowing Object volume change Yu fluid thermophysical property parameter can be obtained according to annular fluid state equation, side
Formula is as follows:
ΔV1=α V0ΔT1 (1)
ΔV1=ktV0ΔP1 (2)
Δ V in formula1For Experimental Flowing Object volume change, m3；α is the coefficient of expansion, DEG C-1；ΔT1For Experimental Flowing Object temperature change,
℃；V0For Experimental Flowing Object volume, m3；ktFor the compressed coefficient, MPa-1；ΔP1For Experimental Flowing Object pressure change, MPa.
3. exporting the fluid thermophysical property parameter meter under different annular space temperature profiles and different pressures according to equation (1) (2)
It is as follows to calculate formula:
It is as follows that density anti-inference method calculates fluid thermophysical property parameter step:
1. the fluid density under known different temperatures pressure.
2. it is as follows to obtain mass-conservation equation according to fluid mass conserva-tion principle before and after fluid expansion:
ρT,P(V2+ΔV2)=ρ0V2 (5)
It can be exported by (5)
Δ V in formula2For annular fluid volume change, m3；V2For annular fluid volume, ρ0For initial annular fluid density, g/
cm3；ρT,PFor fluid density, g/cm under different temperatures pressure3。
3. the equation of annular fluid volume change and fluid thermophysical property parameter can be obtained according to annular fluid state equation, side
Formula is as follows:
ΔV2=α V2ΔT2 (7)
ΔV2=ktV2ΔP2 (8)
Δ V in formula2For annular fluid volume change, m3；α is the coefficient of expansion, DEG C-1；ΔT2For annular fluid temperature change,
℃；V2For annular fluid volume, m3；ktFor the compressed coefficient, MPa-1；ΔP2For annular fluid pressure change, MPa.
4. the fluid thermophysical property parameter under different annular space temperature profiles and different pressures can be obtained in conjunction with equation (6) (7) (8)
Equation, equation is as follows:
3) casing deformation model is established using casing deformation formula
Casing deformation includes the deformation of casing free segment and the deformation of casing interval isolation, then casing deformation model includes casing freedom
Section and interval isolation distorted pattern.
Casing deformation model foundation process is as follows:
1. establishing casing free segment distorted pattern
Casing free segment deforms adjacent with casing annular space and casing temperature distortion is related, by the adjacent annular space of casing and casing by
Cause of deformation takes into account amendment casing deformation formula, and the distorted pattern formula that can obtain casing free segment is as follows:
u1=c1p1+c2p2+uT (11)
U in formula1For casing free segment deflection, m；c1, c2For coefficient；p1、p2The respectively pressure of the adjacent annular space of casing,
MPa；uTFor thermally-induced casing deformation amount, m；
2. establishing casing interval isolation distorted pattern
The deformation of casing interval isolation is only related with annular pressure, therefore can obtain casing interval isolation distorted pattern by casing deformation formula
Formula is as follows:
u2=Ap+B (12)
U in formula2For casing interval isolation deflection, m；A, B is coefficient；P is annular pressure.
4) annular volume variation is calculated
Cylindrical volume equation can be used for annular volume variation or finite element software (ABAQUS, ANSYS) is calculated.
It is as follows using cylindrical volume equation calculation annular volume change procedure:
Casing deformation causes annular volume to change, and the deformation of the free segment of casing and interval isolation is taken into account, amendment circle
It is as follows that column volume equation obtains annular volume equation of change:
ΔVan=π [(r+u)2-r2]h (13)
Δ V in formulaanFor annular volume variation, m3；R is casing radius, m；U is casing deformation amount, m；H is casing height,
m。
5) annular space trapped pressure computation model is established using annular space trapped pressure accounting equation and solve
Wherein, annular space trapped pressure accounting equation is as follows:
P is annular space trapped pressure, MPa in formula；ΔVanIt is annular volume variation, m3；α is the coefficient of expansion, DEG C-1；ktFor pressure
Contracting coefficient, MPa-1；Δ T is fluid temperature variations, VanAnnular volume.
In the specific implementation process, the thought that can use iteration calculates annular space trapped pressure to the present invention: firstly,
By initial mineshaft annulus trapped pressure p1、p2The casing deformation model in step 3) is substituted into, casing deformation amount is calculated, secondly, will
Casing deformation amount substitutes into step 4) and show that annular volume changes, then thermal physical property parameter obtained in step 2) and step 4) are obtained
Annular fluid volume change substitute into step 5) annular space trapped pressure computation model, obtain new annular space trapped pressure value p1'、
p2', comparing with intial value, error is less than 0.001, conditioning ring barren trap pressure, otherwise by p for new annular space trapped pressure1'、p2'
It is recalculated as new initial value, until error is less than 0.001.
The present invention is only illustrated with above-described embodiment, and structure, setting position and its connection of each component are all can have
Changed.Based on the technical solution of the present invention, the improvement or equivalent that all principles according to the present invention carry out individual part
Transformation, should not exclude except protection scope of the present invention.
Claims (6)
1. a kind of annular space trapped pressure prediction technique, comprising the following steps:
1) annular space temperature profile is established according to production status；
2) annular fluid thermal physical property parameter is calculated, the annular fluid thermal physical property parameter is measured by experiment, and process includes:
1. measuring the Experimental Flowing Object volume change under different annular space temperature profiles and under different pressures；
2. the equation of Experimental Flowing Object volume change Yu the fluid thermophysical property parameter can be obtained according to annular fluid state equation, side
Formula is as follows:
△V1=α V0△T1
△V1=ktV0△P1
△ V in formula1For Experimental Flowing Object volume change, m3；α is the coefficient of expansion, DEG C-1；△T1For Experimental Flowing Object temperature change, DEG C；V0
For Experimental Flowing Object volume, m3；ktFor the compressed coefficient, MPa-1；△P1For Experimental Flowing Object pressure change, MPa；
3. according to step 2. in two equations export the fluid thermophysical property under different annular space temperature profiles and different pressures
Parameter calculation formula is as follows:
Alternatively, the annular fluid thermal physical property parameter is measured by density anti-inference method, process includes:
1. the fluid density under known different temperatures pressure；
2. it is as follows to obtain mass-conservation equation according to fluid mass conserva-tion principle before and after fluid expansion:
ρT,P(V2+△V2)=ρ0V2
It is exported by above formula
△ V in formula2For annular fluid volume change, m3；V2For annular fluid volume, ρ0For initial annular fluid density, g/cm3；
ρT,PFor fluid density, g/cm under different temperatures pressure3；
3. the equation of annular fluid volume change and the fluid thermophysical property parameter can be obtained according to annular fluid state equation, side
Formula is as follows:
△V2=α V2△T2
△V2=ktV2△P2
△ V in formula2For annular fluid volume change, m3；α is the coefficient of expansion, DEG C-1；△T2For annular fluid temperature change, DEG C；V2
For annular fluid volume, m3；ktFor the compressed coefficient, MPa-1；△P2For annular fluid pressure change, MPa；
4. in conjunction with step 2. 3. in equation obtain the fluid thermophysical property under different annular space temperature profiles and different pressures
The equation of parameter, equation are as follows:
3) casing deformation model is established using casing deformation formula；
4) annular volume variation is calculated；
5) annular space trapped pressure computation model is established using annular space trapped pressure accounting equation and solve.
2. a kind of annular space trapped pressure prediction technique as described in claim 1, it is characterised in that: in the step 3), institute
Stating casing deformation model includes casing free segment and interval isolation distorted pattern.
3. a kind of annular space trapped pressure prediction technique as claimed in claim 2, it is characterised in that: in the step 3), benefit
It is as follows that described sleeve pipe distorted pattern process is established with described sleeve pipe deformation formula:
1. establishing described sleeve pipe free segment distorted pattern
The adjacent annular space of casing and casing temperature distortion factor are taken into account into amendment casing deformation formula, obtain described sleeve pipe freedom
The distorted pattern formula of section is as follows:
u1=c1p1+c2p2+uT
U in formula1For casing free segment deflection, m；c1, c2For coefficient；p1、p2The respectively pressure of the adjacent annular space of casing, MPa；uT
For thermally-induced casing deformation amount, m；
2. establishing described sleeve pipe interval isolation distorted pattern
The deformation of casing interval isolation is only related with annular pressure, therefore obtains described sleeve pipe interval isolation distorted pattern by casing deformation formula
Formula is as follows:
u2=Ap+B
U in formula2For casing interval isolation deflection, m；A, B is coefficient；P is annular pressure.
4. a kind of annular space trapped pressure prediction technique as described in claim 1, it is characterised in that: in the step 4), institute
Annular volume variation is stated to be calculated using cylindrical volume equation or finite element software.
5. a kind of annular space trapped pressure prediction technique as claimed in claim 4, it is characterised in that: utilize the cylindrical volume side
The equation that journey calculates annular volume variation is as follows:
△Van=π [(r+u)2-r2]h
△ V in formulaanFor annular volume variation, m3；R is casing radius, m；U is casing deformation amount, m；H is casing height, m.
6. a kind of annular space trapped pressure prediction technique as described in claim 1, it is characterised in that: the annular space in the step 5)
Trapped pressure accounting equation is as follows:
P is annular space trapped pressure, MPa in formula；△VanIt is annular volume variation, m3；α is the coefficient of expansion, DEG C-1；ktFor compression system
Number, MPa-1；△ T is fluid temperature variations, VanAnnular volume.
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| CN108510111A (en) * | 2018-03-14 | 2018-09-07 | 中国石油大学(北京) | A kind of method and device of prediction annular space supercharging |
| CN108643886B (en) * | 2018-04-24 | 2022-02-11 | 中国海洋石油集团有限公司 | Deep well annulus trapping pressure monitoring device and method |
| CN109083635B (en) * | 2018-09-26 | 2020-06-19 | 中国石油大学(北京) | Gas-liquid two-phase annular confinement pressure prediction method and device |
| CN109236281B (en) * | 2018-11-28 | 2023-08-01 | 中国石油天然气集团有限公司 | Device and method for detecting annular pressure of gas storage and natural gas well |
| CN115370322B (en) * | 2022-09-28 | 2023-10-20 | 北京化工大学 | Well-shaft-integrity-based prediction method for annular space pressure |
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