CN115519670B - Preparation process of tough elastic cement paste for gas storage well cementation - Google Patents

Preparation process of tough elastic cement paste for gas storage well cementation Download PDF

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CN115519670B
CN115519670B CN202211285061.8A CN202211285061A CN115519670B CN 115519670 B CN115519670 B CN 115519670B CN 202211285061 A CN202211285061 A CN 202211285061A CN 115519670 B CN115519670 B CN 115519670B
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mixture
stirring
control unit
central control
consistency
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CN115519670A (en
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张春龙
马吉龙
朱健军
李洪岩
王玉
刘立超
王志新
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Daqing Changyuan Energy Technology Co ltd
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B28—WORKING CEMENT, CLAY, OR STONE
    • B28C—PREPARING CLAY; PRODUCING MIXTURES CONTAINING CLAY OR CEMENTITIOUS MATERIAL, e.g. PLASTER
    • B28C5/00—Apparatus or methods for producing mixtures of cement with other substances, e.g. slurries, mortars, porous or fibrous compositions
    • B28C5/003—Methods for mixing
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B28—WORKING CEMENT, CLAY, OR STONE
    • B28C—PREPARING CLAY; PRODUCING MIXTURES CONTAINING CLAY OR CEMENTITIOUS MATERIAL, e.g. PLASTER
    • B28C5/00—Apparatus or methods for producing mixtures of cement with other substances, e.g. slurries, mortars, porous or fibrous compositions
    • B28C5/40—Mixing specially adapted for preparing mixtures containing fibres
    • B28C5/402—Methods
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B28—WORKING CEMENT, CLAY, OR STONE
    • B28C—PREPARING CLAY; PRODUCING MIXTURES CONTAINING CLAY OR CEMENTITIOUS MATERIAL, e.g. PLASTER
    • B28C7/00—Controlling the operation of apparatus for producing mixtures of clay or cement with other substances; Supplying or proportioning the ingredients for mixing clay or cement with other substances; Discharging the mixture
    • B28C7/02—Controlling the operation of the mixing
    • B28C7/022—Controlling the operation of the mixing by measuring the consistency or composition of the mixture, e.g. with supply of a missing component
    • B28C7/024—Controlling the operation of the mixing by measuring the consistency or composition of the mixture, e.g. with supply of a missing component by measuring properties of the mixture, e.g. moisture, electrical resistivity, density
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B28/00—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B2111/00—Mortars, concrete or artificial stone or mixtures to prepare them, characterised by specific function, property or use
    • C04B2111/00474—Uses not provided for elsewhere in C04B2111/00
    • C04B2111/00724—Uses not provided for elsewhere in C04B2111/00 in mining operations, e.g. for backfilling; in making tunnels or galleries
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
    • Y02W30/00—Technologies for solid waste management
    • Y02W30/50—Reuse, recycling or recovery technologies
    • Y02W30/91—Use of waste materials as fillers for mortars or concrete

Abstract

The invention relates to a preparation process of tough elastic cement paste for gas storage well cementation, which comprises the following preparation processes of: step S1, acquiring the temperature and pressure of the environment where the target well cementation is located; s2, injecting the cementing material, the additive and water into a stirring device to form a first mixture; step S3, detecting the consistency of the first mixture, and judging whether to adjust each parameter of the stirring device by the central control unit according to a consistency detection result; s4, injecting a cementing material into the first mixture with qualified consistency, and stirring to form a second mixture; s5, injecting fibers into the second mixture, stirring to form a third mixture, injecting fine sand, water, the nano SiO2 suspension after discrete treatment and an additive into the third mixture, and stirring to form ductile elastic cement paste for gas storage well cementation; and S6, detecting the consistency of the ductile elastic cement slurry for the gas storage well cementation, and judging whether to adjust each parameter of the stirring device by the central control unit according to a consistency detection result.

Description

Preparation process of tough elastic cement paste for gas storage well cementation
Technical Field
The invention relates to the field of cement slurry preparation, in particular to a preparation process of tough elastic cement slurry for gas storage well cementation.
Background
Cementing is a major link in well construction and is a construction operation of setting a casing into a drilled wellbore and injecting a cementing slurry into an annular space between the wellbore and the casing. However, because the environmental conditions such as pressure intensity and temperature in the stratum are greatly different from the environmental conditions applied when the common cement slurry is prepared, the consistency of the well cementation cement slurry is affected slightly, the construction is not facilitated, the cement slurry is cured in advance due to heavy weight, the subsequent maintenance is not facilitated, and the well cementation quality is seriously affected.
Chinese patent CN113444504A discloses a crystallization channeling-preventing well cementing slurry, and provides a crystallization channeling-preventing well cementing slurry and a preparation method thereof, which can solve the defects of complex general system, high design difficulty, strong sensitivity, poor stability, difficult control and the like of the particle size distribution well cementing slurry, and the technical problems of slow weight loss and high-speed strength development requirements under high temperature conditions are difficult to be simultaneously solved, but the problem of early strength phenomenon of the slurry in the special environment of well cementing is not solved yet.
Disclosure of Invention
Therefore, the invention provides a preparation process of tough elastic cement paste for gas storage well cementation, which can solve the problem that the consistency of cement paste cannot meet the construction requirement due to early strength of cement paste under special environment conditions of well cementation.
In order to achieve the above purpose, the preparation process of the ductile elastic cement paste for gas storage well cementation of the invention comprises the following steps: the preparation method is secondary stirring, and comprises the following steps:
s1, acquiring the temperature T and the pressure P of an environment where a gas storage well cementation is located, setting the initial temperature of a stirring device as T0 and setting the pressure as P0;
s2, injecting a thickening agent and a cementing material into a stirring device, stirring for a preset time at a first rotation speed omega a, and injecting a water reducing agent, a defoaming agent and water into the stirring device, and stirring the thickening agent and the cementing material to form a first mixture;
step S3, detecting the consistency of the first mixture according to the sinking amount of the first mixture, comparing the sinking amount of the first mixture with a preset sinking amount by a central control unit, judging the consistency of the first mixture, adding the additive into the first mixture in batches when the consistency of the first mixture does not meet the standard, adjusting each parameter of the stirring device according to the variable value of the sinking amount after single additive injection, and judging to implement step S4 when the consistency of the first mixture meets the standard by the central control unit; when the consistency of the first mixture does not meet the standard, the additive is required to be injected into the first mixture in a divided mode, the types of the additive are selected according to the sinking amount h, meanwhile, the central control unit adjusts all parameters of the stirring device according to the variable value of the sinking amount after the additive is injected once, and when the consistency of the first mixture meets the standard, the central control unit judges to implement the step S4;
S4, injecting a cementing material into the first mixture with qualified consistency, and stirring the first mixture and the cementing material at a second rotating speed omega b to form a second mixture;
s5, injecting fibers into the second mixture, stirring for a preset time at the adjusted first rotating speed, adjusting the rotating speed to the adjusted second rotating speed to form a third mixture, injecting fine sand, water, a defoaming agent, a nano SiO2 suspension after discrete treatment and a water reducing agent into the third mixture, and stirring at the adjusted second rotating speed to form a tough elastic cement paste for gas storage well cementation;
and S6, performing consistency detection on the ductile elastic cement paste for gas storage well cementation, taking the sinking amount of the ductile elastic cement paste for gas storage well cementation as a parameter for judging the consistency of the ductile elastic cement paste for gas storage well cementation, judging that the consistency of the ductile elastic cement paste for gas storage well cementation is qualified by the central control unit, finishing the preparation of the cement paste, judging that the consistency of the cement paste is unqualified by the central control unit, and adjusting each parameter of a stirring device until the consistency of the ductile elastic cement paste for gas storage well cementation is qualified.
Further, the first rotational speed ωa in the step S2 and the second rotational speed ωb in the step S4 are determined according to the target cement paste design compressive strength, wherein,
ωa=1.4 m/s× ((n+) - Δ) × (N- Δ)/R, and ωa is less than or equal to 2.8m/s;
ωb=2m/s× ((n+) - Δ) × (N- Δ)/R, and ωb is less than or equal to 2.8m/s;
the central control unit presets the standard value of the 28 d-age compressive strength of the cement paste as R, and delta is the allowable error range of the actual compressive strength of the cement paste.
Further, the central control unit acquires the sinking amount h1 of the first mixture to judge whether the consistency of the first mixture is qualified, wherein,
when H1 is more than or equal to H1 and less than or equal to H2, judging that the consistency of the primary stirring mixture is qualified, and implementing the step S4;
when H1 is less than H1 or H1 is more than H2, judging that the consistency of the primary stirring mixture is unqualified, and adjusting the mixing proportion of the primary stirring mixture additive and each parameter of the stirring device;
the central control unit presets a first sunk-in threshold value H1 and a second sunk-in threshold value H2.
Further, when H1 < H1, the central control unit increases the injection amount of the water reducer into the first mixture according to the immersion amount of the first mixture, wherein the water reducer is injected for several times, the single injection amount is ma, ma=0.01% ×m× (1+ (H1-H1)/H1), the central control unit determines whether to adjust the first rotation speed ωa and the stirring time t in step S3 according to the variation value Δh of the immersion amount of the first mixture after the water reducer is injected, Δh=h1 (i+1) -h1i, i=1, 2 … … n-1, n is the preset total injection times of the water reducer, H1 (i+1) is the immersion amount after the i+1th injection of the water reducer, and H1i is the immersion amount after the i th injection of the water reducer.
The central control unit judges whether to adjust the first rotation speed omega a and the stirring time t in the step S3 according to the sinking amount change value delta h of the first mixture, wherein,
when Δh is more than or equal to 3+delta, the central control unit judges that the first rotation speed ωa is not regulated, meanwhile, the stirring time t is prolonged to t1, and t1=t+10+5i is set;
when Δh < 3+δ, the central control unit determines to adjust the first rotation speeds ωa to ω1 in step S3 such that ω1=ωa× (1+ (H1-H1)/H1), and stir the mixture at the adjusted first rotation speed ω1 after adding 0.01% of the water reducing agent each time, and set t2=t+10+5i, to extend the stirring time t to t 2;
wherein delta is an allowable error range, and the total amount of the first water reducer is not more than 0.3% of the first cementing material.
Further, when the total amount of the first water reducer reaches 0.3% of the first cementing material, the first mixture sinking amount H1 is smaller than H1, the central control unit judges and adjusts the internal pressures P0 to P1 of the stirring device according to the first rotation speed regulated by the stirring device, adjusts the internal temperatures T0 to T1, prolongs the stirring time tp to tp1, sets t1=tp+20s, and p=1, 2,
T1=T0×（1+（20/t total (S) ）×（ω1×（ω1＋ωa））/（ωa×（ω1－ωa）））；P1=（T1/T0）×P0；
Wherein t is Total (S) The time duration is the whole time duration used in the steps S1-S3.
Further, the central control unit judges whether to adjust the stirring parameters of secondary stirring according to the final sinking amount h01 of the first mixture obtained in the step S3, wherein,
when H01 is more than or equal to H2, the central control unit judges that stirring parameters are not adjusted;
when limh01=h2, the central control unit determines to adjust the second rotation speeds ωb to ω2, increase the temperatures T1 to T2 in the cavity, increase the pressures P1 to P2 in the cavity, and limh01=h2 represents an infinite approach to the second threshold H2 of the sinking amount;
where ω2=1.05×ωb, t2=1.05×t1, p2=1.05×p1.
Further, when H1 > H2, according to the consistency of the first mixture, adding the injection amount of the thickener to the first mixture, wherein the thickener is injected in a plurality of times, the single injection amount is mb, mb=0.005% ×m× (1+ (H1-H2)/H1), the central control unit determines whether to adjust the first rotation speed ωa and the stirring time t in step S3 according to the variation value Δh of the immersion amount of the first mixture after the thickener is injected, wherein Δh=h1 (j+1) -hj, j=1, 2 … … b-1, b is the preset total injection number of the thickener, H1 (j+1) is the immersion amount after the first mixture is injected with the water reducing agent for the j+1th time, and H1j is the immersion amount after the first mixture is injected with the thickener for the j th time.
The central control unit judges whether to adjust the first rotation speed omega a and the stirring time t in the step S3 according to the sinking amount change value delta h of the first mixture, wherein,
when Δh is more than or equal to 3+delta, the central control unit judges that the stirring device ωa is not regulated, the central control unit prolongs the stirring time t to t1, and t1=t+10+5j is set;
when Δh < 3+δ, the central control unit determines to adjust ωa to ω1 such that ω1=ωa× (1+ (H1-H2)/H1), stirring at rotation speed ω1 after adding 0.005% of thickener each time, and the central control unit extends stirring time t to t1, setting t1=t+10+5j;
wherein delta is the allowable error range, and the total amount of the thickening agent is not more than 0.2% of the total cementing material.
Further, when the total amount of the thickener has reached 0.3% of the first batch of the cement, the first mixture is sunk by an amount H1 > H2, the central control unit adjusts the internal pressures P0 to P12, sets P12= (T0/T1) x P0, adjusts the temperatures T0 to T12, T12=T0 x (1- (20/T) Total (S) ）×（ω1×（ω1+ωa））/（ωa×（ω1-ωa））），t Total (S) For the whole duration used in steps S1-S3, the stirring time tk to tk2 is prolonged, and the stirring time of tk2=tk+20s and k=1, 2 is set; the central control unit judges whether to adjust the stirring parameters of secondary stirring according to the final sinking amount h02 of the first mixture obtained in the step S3, wherein,
When H02 is more than or equal to H2, the central control unit does not adjust stirring parameters;
when limh02=h2, the central control unit determines to adjust the second rotation speeds ωb to ω2, reduce the temperatures T1 to T2 in the cavity, reduce the pressures P1 to P2 in the cavity, and limh02=h2 represents that H02 approaches the second critical value H2 of the sinking amount infinitely;
where ω2=0.95×ωb, t2=0.95×t1, p2=0.95×p1.
Further, the central control unit sets an initial feeding angle theta a DEG of the fiber, judges whether to adjust the feeding angle of the fiber according to the adjusted first rotating speed omega',
when the m/s is less than or equal to omega' < 1.5m/s, the central control unit judges that the feeding angle of the fiber is not adjusted;
when omega ' < 1.35m/s, the central control unit judges and adjusts the feeding angles theta a to theta 1 of the fibers so that theta 1 = 45 degrees +R× (1.35-omega ')/omega ';
when omega ' > 1.5m/s, the central control unit judges and adjusts the feeding angles theta a to theta 2 of the fibers to ensure that theta 2 = 45-R× (omega ' -1.5)/omega ';
wherein, the central control unit sets R as the maximum radius in the cavity of the stirring device, and θa=45°.
Further, when the fiber injection in step S5 is completed, a third mixture is obtained, and the central control unit determines whether to adjust the adjusted first rotation speed ω1 and the adjusted second rotation speed ω2 of the stirring device according to the fiber dispersion effect of the third mixture, wherein,
When the stirred fibers do not have aggregation, the central control unit judges that the stirring rate is not regulated;
when the stirred fibers are agglomerated, the central control unit judges to adjust the first rotating speeds omega 'to omega 1', so that omega 1 '=1.05×omega a, adjust omega 2 to omega 2', so that omega 2 '=1.2×omega 2, and stir the stirring device at the rotating speed of omega 2' until the fiber dispersing effect meets the requirement.
Further, when the fiber dispersion effect meets the requirement, the central control unit calls back the second rotating speed omega 2' to omega 2 until the step S5 is completed, and the central control unit judges whether the consistency final value of the ductile elastic cement slurry for gas storage well cementation is qualified according to the sinking amount h2 of the ductile elastic cement slurry for gas storage well cementation obtained in the step S5, wherein,
when H3 is more than or equal to H2 and less than or equal to H4, the central control unit judges that the consistency of the cement paste is qualified;
when H2 is less than H3, the central control unit judges that the consistency of the cement paste is unqualified, the temperature in the cavity of the stirring device is increased, the pressure in the cavity is increased, wherein,
when H2 < H1, the central control unit judges that the temperature T2 to T21 in the cavity is increased, and the pressure P2 to P21 in the cavity is increased, so that T21= (1+ (H1-H2)/H1) multiplied by T2, and P21=P2 multiplied by T21/T2;
When H1 is less than H2 and less than H3, the central control unit judges that the temperatures T2 to T21 in the cavity are increased, and the pressures P2 to P21 in the cavity are increased, so that t21= (1+ (H3-H2)/H3) multiplied by T2, and P21=P2 multiplied by T21/T2;
when H2 is more than H4, the central control unit judges that the consistency of the cement paste is unqualified, reduces the temperature in the cavity of the stirring device, reduces the pressure in the cavity, wherein,
when H2 > H2, the central control unit judges to reduce the temperature T2 to T22 in the cavity, and reduces the pressure P2 to P22 in the cavity, so that T22= (1- (H2-H2)/H2) x T2, and P22=P2 x T22/T2;
when H4 < H2, the central control unit determines to decrease the intra-cavity temperatures T2 to T22, and decreases the intra-cavity pressures P2 to P22 such that t22= (1- (H2-H4)/H4) ×t2, p22=p2×t2'/T2.
Further, when the central control unit increases the temperature in the cavity of the stirring device to T21 and increases the pressure to P21, the central control unit judges that the second rotating speed omega 2 of the stirring device is reduced, the stirring time tg to tg1 is prolonged, tg1=tg+30s is set,
when T21/T2 < 1.15, the central control unit determines to decrease the adjusted second rotation speed ω2 to ω21 such that ω21= (T2/T21) ×ω2;
when T21/T2 is not less than 1.15, the central control unit determines to decrease the adjusted second rotation speed ω2 to ω21 such that ω21=1.5 m/s.
Further, when the central control unit reduces the temperature in the cavity of the stirring device to T22 and reduces the pressure to P22, the central control unit judges that the second rotating speed omega 2 of the stirring device is increased, the stirring time tq to tq1 is prolonged, tq1=tq+30s is set, wherein,
when T22/T2 < 0.9, the central control unit determines to increase the second rotation speed ω2 to ω22 such that ω22=2.4 m/s;
when T22/T2 is more than or equal to 0.9, the central control unit judges to increase the second rotation speed omega 2 to omega 21 so that omega 22= (T2/T22) multiplied by omega 2.
Compared with the prior art, the invention has the beneficial effects that the problem that the special temperature and pressure in the well cementation affect the application consistency of the cement is solved; the cement paste preparation process selects a secondary stirring method, and the process regulation and control on the final consistency of the cement paste are realized through the regulation and control on the consistency of the mixture obtained in the process; according to the invention, the mixing amount of the external additive, the mixing speed and the temperature and pressure in the cavity of the stirring device are regulated according to the sinking amount of the first mixture obtained by primary stirring, and each parameter of the stirring device in the secondary stirring process is regulated according to the final value of the sinking amount of the first mixture, so that the consistency of the target cement paste meets the construction requirement.
Particularly, the central control unit judges whether the consistency accords with the standard according to the sinking amount of the mixture obtained in the preparation process, can timely adjust each stirring parameter in the process, including stirring speed, pressure in a stirring device cavity and temperature in the cavity, prolongs stirring time, and carries out supplementary treatment on the mixture so as to ensure that the quality of the produced ductile elastic cement paste for gas storage well cementation accords with the standard, especially when the consistency does not accord with the construction standard in the process of casting the gas storage well cementation, early strength of cement is easy to be caused, and the design strength cannot be achieved when the cement is finally set; according to the invention, secondary stirring is adopted as a preparation method, and the water-gel ratio of the first mixture is larger than 0.3, so that slow stirring is adopted, the consistency change condition of the first mixture is convenient to observe and timely adjust, and the consistency of the first mixture can meet the requirement in a short time; in the secondary stirring process, in order to ensure that the cementing material is not thrown out by the matrix when the fibers are added, the dispersion effect of the fibers is ensured, so that the fibers are stirred at a low speed and then stirred at a high speed; under the condition that the matrix is not thrown out in the process of adding the cementing material in the secondary stirring process, the quick stirring is used, the time required by thickening the matrix can be obviously shortened, the whole stirring process is relatively short, and the engineering application is more facilitated.
Particularly, the first rotating speed and the second rotating speed are preset according to the design compressive strength of the target cement paste, and the initial rotating speed of the stirring device is controlled within a reasonable range, so that the consistency of a first mixture obtained by primary stirring can be controlled, and the first mixture is easier to meet the requirements; when the central control unit judges that the consistency of the first mixture is not in accordance with the requirement, and the stirring time is required to be prolonged and the first rotating speed is required to be regulated, the first rotating speed set according to the design compressive strength of the target cement slurry can meet the regulation value in a smaller range, so that the energy consumption is reduced and the stirring efficiency is improved.
Particularly, the central control unit is provided with the first critical value and the second critical value of the sinking amount, so that whether the first mixture meets the consistency requirement or not is facilitated, further, how to adjust each parameter of the stirring device is judged according to the sinking amount of the first mixture, the consistency requirement range of the cement slurry is enlarged by the first critical value and the second critical value, an adjustable space is reserved for consistency change caused by mixture and mixture proportion change in secondary stirring, and the consistency process of the cement slurry is facilitated to be controlled.
Particularly, when the consistency of the first mixture is larger, the central control unit of the invention preferably selects the content of the water reducer as a first factor influencing the consistency, and judges the optimal content of the water reducer according to the variation value of the sinking amount of the single-injection water reducer; when the variation value of the sinking amount of the single-injection water reducing agent is not changed obviously, the central control unit selects the stirring rate as a second factor influencing the consistency, so that energy conservation and emission reduction can be realized, and the stirring time is prolonged by reducing the stirring rate, so that the consistency of the first mixture is reduced.
In particular, after the content of the water reducer in the first mixture is optimized and the first rotating speed of the stirring device is regulated, the first mixture still does not meet the consistency requirement, and the temperature and the pressure are properly increased, so that the rate of hydration reaction of the mixture is reduced; the invention takes the temperature and pressure regulation as alternative supplementary measures, expands the range of adjustable factors influencing the consistency, and is beneficial to regulating the consistency of the first mixture. After the content of the water reducer and all adjustable parameters in the stirring device are adjusted by the central control unit, the first mixture still does not meet the consistency requirement, but is infinitely close to a first critical value, and the central control unit judges and adjusts all parameters of the stirring device in the secondary stirring process, so that cement paste obtained after secondary stirring meets the target consistency requirement; the central control unit takes the stirring rate in secondary stirring as a first adjusting parameter, which is a first influencing factor influencing the consistency of cement paste in the secondary stirring process, and simultaneously, pressure and temperature are regulated back so that the inner environment of the cavity of the stirring device is closer to the target well cementation.
In particular, when the consistency of the first mixture is small, the central control unit of the invention preferably uses the content of the thickener as a first factor affecting the consistency, and the central control unit judges the optimal content of the thickener according to the variation value of the sinking amount of the thickener injected once; when the variation value of the sinking amount of the single-time injected thickener is not changed obviously, the central control unit selects the stirring rate as a second factor influencing the consistency, so that energy conservation and emission reduction can be realized, and the consistency of the first mixture can be increased by improving the stirring rate and prolonging the stirring time.
In particular, after the content of the water reducer in the first mixture is optimized and the first rotating speed of the stirring device is regulated, the first mixture still does not meet the consistency requirement, and the temperature and the pressure are properly reduced, so that the rate of hydration reaction of the mixture is improved; the invention takes the temperature and pressure regulation as alternative supplementary measures, expands the range of adjustable factors influencing the consistency, and is beneficial to regulating the consistency of the first mixture; after the central control unit adjusts the content of the thickening agent and all adjustable parameters in the stirring device, the first mixture still does not meet the consistency requirement, but is infinitely close to a first critical value, and the central control unit judges and adjusts all parameters of the stirring device in the secondary stirring process, so that cement paste obtained after secondary stirring meets the target consistency requirement; the central control unit takes the stirring rate in secondary stirring as a first adjusting parameter, which is a first influencing factor influencing the consistency of cement paste in the secondary stirring process, and simultaneously, pressure and temperature are regulated back so that the inner environment of the cavity of the stirring device is closer to the target well cementation.
Particularly, the central control unit presets an initial feeding angle of the fibers, in order to meet the requirement of the dispersion effect of the fibers, the central control unit adjusts the feeding angle according to the rotating speed of the stirring device when the fibers are fed, and when the rotating speed is smaller, the centrifugal force on the outer side of the stirring device is larger, and the fibers are distributed on the outer side of the stirring device by increasing the feeding angle, so that the dispersion effect is achieved to the greatest extent; when the rotating speed is high, fibers are distributed on the inner side of the stirring device when fed by reducing the feeding angle, so that the matrix is prevented from being separated from the stirring device due to overlarge centrifugal force on the outer side of the stirring device.
Especially, if the aggregation phenomenon exists in the fiber, the central control unit judges that the fiber dispersing effect does not meet the dispersing requirement, and then judges to improve the speed of the stirring device, so that the stirring time is prolonged, the centrifugal force of the stirring device can be improved, the fiber dispersing is facilitated, the fiber dispersing effect can influence the toughness and the elasticity of cement paste, the cement paste performance is improved, and the construction quality is further improved.
In particular, the central control unit sets the third critical value and the fourth critical value of the sinking amount as parameters for judging whether the target cement paste meets the consistency requirement or not, and further judges how to adjust each parameter of the stirring device according to the sinking amount of the cement paste.
Especially, when the sinking amount of the target cement paste is smaller, the central control unit increases the stirring rate according to the regulated pressure and temperature in the cavity of the stirring device; after secondary stirring, the central control unit increases the pressure and the temperature, which is favorable for reducing the hydration reaction of the cement consistency, thereby improving the cement paste consistency more efficiently; according to the invention, the stirring speed is regulated according to the pressure and the temperature, so that the process of improving the consistency of the cement slurry is more efficient and energy-saving.
In particular, the central control unit adjusts the stirring speed again according to the adjusted pressure and temperature in the stirring device cavity; after secondary stirring, the central control unit adjusts the pressure and the temperature, so that the speed of improving the consistency is improved, and the consistency of cement paste can be improved more efficiently by improving the stirring speed; according to the invention, the stirring speed is regulated according to the pressure and the temperature, so that the process of improving the consistency of the cement slurry is more efficient and energy-saving.
Drawings
FIG. 1 is a schematic view of a stirring device according to an embodiment of the invention;
FIG. 2 is an exploded view of the chassis mechanism of the stirring device according to the embodiment of the invention;
fig. 3 is a flow chart of a preparation process of ductile elastic cement slurry for gas storage well cementation in an embodiment of the invention.
Detailed Description
In order that the objects and advantages of the invention will become more apparent, the invention will be further described with reference to the following examples; it should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the invention.
Preferred embodiments of the present invention are described below with reference to the accompanying drawings. It should be understood by those skilled in the art that these embodiments are merely for explaining the technical principles of the present invention, and are not intended to limit the scope of the present invention.
It should be noted that, in the description of the present invention, terms such as "upper," "lower," "left," "right," "inner," "outer," and the like indicate directions or positional relationships based on the directions or positional relationships shown in the drawings, which are merely for convenience of description, and do not indicate or imply that the apparatus or elements must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as limiting the present invention.
Furthermore, it should be noted that, in the description of the present invention, unless explicitly specified and limited otherwise, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be either fixedly connected, detachably connected, or integrally connected, for example; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communication between two elements. The specific meaning of the above terms in the present invention can be understood by those skilled in the art according to the specific circumstances.
Referring to fig. 1, a schematic structural diagram of a stirring device according to an embodiment of the invention includes: the double-layer stirring barrel 1 is vacuum in an interlayer and is used for changing the pressure intensity in a cavity of the stirring device by adjusting the gas containing amount; an air inlet 5 arranged at the upper edge of the double-layer stirring barrel and used for conveying air into the interlayer of the double-layer stirring barrel, and an air inlet hopper 6 arranged at the top of the barrel body of the double-layer stirring barrel and used for feeding materials into the stirring barrel, wherein the air inlet can rotate by taking the diameter of the top of the double-layer stirring barrel as an axis so as to change the feeding angle; a stirring cavity 2 forming the inner space of the double-layer stirring barrel is used for accommodating stirring materials; the chassis mechanism 3 is positioned at the bottom of the stirring cavity, and when the gas pressure of the interlayer of the double-layer stirring barrel is changed, the chassis can vertically move under the action of the gas pressure so as to change the pressure in the stirring cavity; the rotating shaft 7 is connected with the chassis mechanism and is used for driving the rotating impeller to rotate; the rotating impeller 4 is dispersed on the rotating shaft and is used for dispersing the stirred materials in the stirring cavity; a central control unit (not shown) for adjusting the stirring rate, the pressure in the cavity and the temperature in the cavity according to the consistency of the mixture in the stirring cavity.
Referring to fig. 2, which is a schematic diagram of an exploded structure of a chassis mechanism according to an embodiment of the present invention, the chassis mechanism includes a rotating disc 32 embedded in the center of the chassis and connected to a rotating shaft 7, a motor is disposed in the rotating disc, and a central control unit changes the rotation speed by adjusting the power of the motor, so as to adjust the stirring rate of the stirring device; the temperature control device 31 is arranged in the chassis and is used for adjusting the temperature in the stirring cavity; the stirring device also comprises a spring 33 which is positioned in the center of the lower part of the chassis and connected with the bottom of the double-layer stirring barrel 1 and is used for controlling the pressure threshold value and avoiding the risk of overlarge pressure in the stirring cavity.
Referring to fig. 3, a process flow diagram of preparation of a ductile elastic cement slurry for gas storage well cementation according to an embodiment of the present invention is shown, wherein the preparation method is secondary stirring, and includes the following steps:
s1, acquiring the temperature T and the pressure P of an environment where a gas storage well cementation is located, setting the initial temperature of a stirring device as T0 and setting the pressure as P0;
s2, injecting a thickening agent and a cementing material into a stirring device, stirring for a preset time at a first rotation speed omega a, and injecting a water reducing agent, a defoaming agent and water into the stirring device, and stirring the thickening agent and the cementing material to form a first mixture;
Step S3, detecting the consistency of the first mixture according to the sinking amount of the first mixture, comparing the sinking amount of the first mixture with a preset sinking amount by a central control unit, judging the consistency of the first mixture, adding the additive into the first mixture in batches when the consistency of the first mixture does not meet the standard, adjusting each parameter of the stirring device according to the variable value of the sinking amount after single additive injection, and judging to implement step S4 when the consistency of the first mixture meets the standard by the central control unit; when the consistency of the first mixture does not meet the standard, the additive is required to be injected into the first mixture in a divided mode, the types of the additive are selected according to the sinking amount h, meanwhile, the central control unit adjusts all parameters of the stirring device according to the variable value of the sinking amount after the additive is injected once, and when the consistency of the first mixture meets the standard, the central control unit judges to implement the step S4;
s4, injecting a cementing material into the first mixture with qualified consistency, and stirring the first mixture and the cementing material at a second rotating speed omega b to form a second mixture;
s5, injecting fibers into the second mixture, stirring for a preset time at the adjusted first rotating speed, adjusting the rotating speed to the adjusted second rotating speed to form a third mixture, injecting fine sand, water, a defoaming agent, a nano SiO2 suspension after discrete treatment and a water reducing agent into the third mixture, and stirring at the adjusted second rotating speed to form a tough elastic cement paste for gas storage well cementation;
And S6, performing consistency detection on the ductile elastic cement paste for gas storage well cementation, taking the sinking amount of the ductile elastic cement paste for gas storage well cementation as a parameter for judging the consistency of the ductile elastic cement paste for gas storage well cementation, judging that the consistency of the ductile elastic cement paste for gas storage well cementation is qualified by the central control unit, finishing the preparation of the cement paste, judging that the consistency of the cement paste is unqualified by the central control unit, and adjusting each parameter of a stirring device until the consistency of the ductile elastic cement paste for gas storage well cementation is qualified.
Specifically, the central control unit judges whether the consistency accords with the standard according to the sinking amount of the mixture obtained in the preparation process, can timely adjust each stirring parameter in the process, including stirring speed, pressure in a stirring device cavity and temperature in the cavity, prolongs stirring time, and carries out supplementary treatment on the mixture so as to ensure that the quality of the produced ductile elastic cement paste for gas storage well cementation accords with the standard, especially when the consistency does not accord with the construction standard in the process of casting the gas storage well cementation, early strength of cement is easy to be caused, and the design strength cannot be achieved when the cement is finally set; according to the invention, secondary stirring is adopted as a preparation method, and the water-gel ratio of the first mixture is larger than 0.3, so that slow stirring is adopted, the consistency change condition of the first mixture is convenient to observe and timely adjust, and the consistency of the first mixture can meet the requirement in a short time; in the secondary stirring process, in order to ensure that the cementing material is not thrown out by the matrix when the fibers are added, the dispersion effect of the fibers is ensured, so that the fibers are stirred at a low speed and then stirred at a high speed; under the condition that the matrix is not thrown out in the process of adding the cementing material in the secondary stirring process, the quick stirring is used, the time required by thickening the matrix can be obviously shortened, the whole stirring process is relatively short, and the engineering application is more facilitated.
The first rotational speed ωa in the step S2 and the second rotational speed ωb in the step S4 are determined according to the target cement paste design compressive strength, wherein,
ωa=1.4 m/s× ((n+) - Δ) × (N- Δ)/R, and ωa is less than or equal to 2.8m/s;
ωb=2m/s× ((n+) - Δ) × (N- Δ)/R, and ωb is less than or equal to 2.8m/s;
the central control unit presets the standard value of the 28 d-age compressive strength of the cement paste as R, and delta is the allowable error range of the actual compressive strength of the cement paste.
Specifically, in this embodiment, the water-gel ratio of the weight of water to the weight of all the cementing materials in the step S2 is 0.2-0.3:1, the cementing materials in the step S2 are 50% -60% of all the cementing materials, and the standard value of the 28d age compressive strength of the cement slurry is 25MPa.
Specifically, the method presets the first rotating speed and the second rotating speed according to the design compressive strength of the target cement paste, controls the initial rotating speed of the stirring device within a reasonable range, can enable the consistency of the first mixture obtained by one-time stirring to be controllable, and enables the first mixture to meet the requirements more easily; when the central control unit judges that the consistency of the first mixture is not in accordance with the requirement, and the stirring time is required to be prolonged and the first rotating speed is required to be regulated, the first rotating speed set according to the design compressive strength of the target cement slurry can meet the regulation value in a smaller range, so that the energy consumption is reduced and the stirring efficiency is improved.
The central control unit acquires the sinking amount h1 of the first mixture to judge whether the consistency of the first mixture is qualified, wherein,
when H1 is more than or equal to H1 and less than or equal to H2, judging that the consistency of the primary stirring mixture is qualified, and implementing the step S4;
when H1 is less than H1 or H1 is more than H2, judging that the consistency of the primary stirring mixture is unqualified, and adjusting the mixing proportion of the primary stirring mixture additive and each parameter of the stirring device;
the central control unit presets a first sunk-in threshold value H1 and a second sunk-in threshold value H2.
Specifically, the method for detecting the sinking amount of the first mixture according to the embodiment of the present invention is not limited as long as the method can obtain the sinking amount of the first mixture, and the embodiment of the present invention provides a preferred implementation method, in which the sinking amount of the first mixture is obtained by using an ISO vicat through the sinking depth of the pilot cone sinking neat paste by a substitution method, wherein the first preset sinking amount is preferably 20mm, and the second preset sinking amount is preferably 35mm.
Specifically, the central control unit is provided with the first critical value and the second critical value of the sinking amount, so that whether the first mixture meets the consistency requirement or not is facilitated, further, how to adjust each parameter of the stirring device is judged according to the sinking amount of the first mixture, the consistency requirement range of the cement slurry is enlarged by the first critical value and the second critical value, an adjustable space is reserved for consistency change caused by mixture and mixture proportion change in secondary stirring, and the consistency process of the cement slurry is facilitated to be controlled.
When H1 < H1, the central control unit increases the injection amount of the water reducer into the first mixture according to the immersion amount of the first mixture, wherein the water reducer is injected for a plurality of times, the single injection amount is ma, ma=0.01% ×m× (1+ (H1-H1)/H1), the central control unit determines whether to adjust the first rotation speed ωa and the stirring time t in step S3 according to the variation value Δh of the immersion amount of the first mixture after the water reducer is injected, wherein Δh=h1 (i+1) -h1i, i=1, 2 … … n-1, n is the preset total injection number of the water reducer, H1 (i+1) is the immersion amount after the first mixture is injected for the i+1th time of the water reducer, and H1i is the immersion amount after the first mixture is injected for the i th time of the water reducer.
The central control unit judges whether to adjust the first rotation speed omega a and the stirring time t in the step S3 according to the sinking amount change value delta h of the first mixture, wherein,
when Δh is more than or equal to 3+delta, the central control unit judges that the first rotation speed ωa is not regulated, meanwhile, the stirring time t is prolonged to t1, and t1=t+10+5i is set;
when Δh < 3+δ, the central control unit determines to adjust the first rotation speeds ωa to ω1 in step S3 such that ω1=ωa× (1+ (H1-H1)/H1), and stir the mixture at the adjusted first rotation speed ω1 after adding 0.01% of the water reducing agent each time, and set t2=t+10+5i, to extend the stirring time t to t 2;
Wherein delta is an allowable error range, and the total amount of the first water reducer is not more than 0.3% of the first cementing material.
Specifically, when the consistency of the first mixture is larger, the central control unit of the invention preferably selects the content of the water reducer as a first factor influencing the consistency, and the central control unit judges the optimal content of the water reducer according to the variation value of the sinking amount of the single-injection water reducer; when the variation value of the sinking amount of the single-injection water reducing agent is not changed obviously, the central control unit selects the stirring rate as a second factor influencing the consistency, so that energy conservation and emission reduction can be realized, and the stirring time is prolonged by reducing the stirring rate, so that the consistency of the first mixture is reduced.
When the total amount of the first water reducer reaches 0.3% of the first cementing material, the sinking amount H1 of the first mixture is smaller than H1, the central control unit judges and adjusts the internal pressures P0 to P1 of the stirring device according to the first rotation speed after the stirring device is adjusted, adjusts the internal temperatures T0 to T1, prolongs the stirring time tp to tp1, sets t1=tp+20s, and p=1, 2,
T1=T0×（1+（20/t total (S) ）×（ω1×（ω1＋ωa））/（ωa×（ω1－ωa）））；P1=（T1/T0）×P0；
Wherein t is Total (S) The time duration is the whole time duration used in the steps S1-S3.
Specifically, after the content of the water reducer in the first mixture is optimized and the first rotating speed of the stirring device is regulated, the first mixture still does not meet the consistency requirement, and the temperature and the pressure are properly increased, so that the rate of hydration reaction of the mixture is reduced; the invention takes the temperature and pressure regulation as alternative supplementary measures, expands the range of adjustable factors influencing the consistency, and is beneficial to regulating the consistency of the first mixture.
The central control unit judges whether to adjust the stirring parameters of secondary stirring according to the final sinking amount h01 of the first mixture obtained in the step S3, wherein,
when H01 is more than or equal to H2, the central control unit judges that stirring parameters are not adjusted;
when limh01=h2, the central control unit determines to adjust the second rotation speeds ωb to ω2, increase the temperatures T1 to T2 in the cavity, increase the pressures P1 to P2 in the cavity, and limh01=h2 represents an infinite approach to the second threshold H2 of the sinking amount;
where ω2=1.05×ωb, t2=1.05×t1, p2=1.05×p1.
Specifically, after the content of the water reducer and all adjustable parameters in the stirring device are adjusted by the central control unit, the first mixture still does not meet the consistency requirement, but is infinitely close to a first critical value, and the central control unit judges and adjusts all parameters of the stirring device in the secondary stirring process, so that cement paste obtained after secondary stirring meets the target consistency requirement; the central control unit takes the stirring rate in secondary stirring as a first adjusting parameter, which is a first influencing factor influencing the consistency of cement paste in the secondary stirring process, and simultaneously, pressure and temperature are regulated back so that the inner environment of the cavity of the stirring device is closer to the target well cementation.
When H1 > H2, increasing the injection amount of the thickener into the first mixture according to the consistency of the first mixture, wherein the thickener is injected for a plurality of times, the single injection amount is mb, mb=0.005% x m× (1+ (H1-H2)/H1), the central control unit judges whether to adjust the first rotation speed ωa and the stirring time t in the step S3 according to the variation value Δh of the immersion amount of the first mixture after the thickener is injected, wherein Δh=h1 (j+1) -hj, j=1, 2 … … b-1, b is the preset total injection number of the thickener, H1 (j+1) is the immersion amount after the j+1th injection of the water reducer into the first mixture, and H1j is the immersion amount after the j th injection of the thickener into the first mixture.
The central control unit judges whether to adjust the first rotation speed omega a and the stirring time t in the step S3 according to the sinking amount change value delta h of the first mixture, wherein,
when Δh is more than or equal to 3+delta, the central control unit judges that the stirring device ωa is not regulated, the central control unit prolongs the stirring time t to t1, and t1=t+10+5j is set;
when Δh < 3+δ, the central control unit determines to adjust ωa to ω1 such that ω1=ωa× (1+ (H1-H2)/H1), stirring at rotation speed ω1 after adding 0.005% of thickener each time, and the central control unit extends stirring time t to t1, setting t1=t+10+5j;
wherein delta is the allowable error range, and the total amount of the thickening agent is not more than 0.2% of the total cementing material.
Specifically, when the consistency of the first mixture is smaller, the central control unit of the invention preferably uses the content of the thickener as a first factor influencing the consistency, and the central control unit judges the optimal content of the thickener according to the variation value of the sinking amount of the thickener injected once; when the variation value of the sinking amount of the single-time injected thickener is not changed obviously, the central control unit selects the stirring rate as a second factor influencing the consistency, so that energy conservation and emission reduction can be realized, and the consistency of the first mixture can be increased by improving the stirring rate and prolonging the stirring time.
When the total amount of thickener has reached 0.3% of the first batch of cementitious material, the first mixture is sunk by an amount H1 > H2, the central control unit adjusts the internal pressures P0 to P12, sets P12= (T0/T1) x P0, adjusts the temperatures T0 to T12, T12=T0 x (1- (20/T) Total (S) ）×（ω1×（ω1+ωa））/（ωa×（ω1-ωa））），t Total (S) For the whole duration used in steps S1-S3, the stirring time tk to tk2 is prolonged, and the stirring time of tk2=tk+20s and k=1, 2 is set; the central control unit judges whether to adjust the stirring parameters of secondary stirring according to the final sinking amount h02 of the first mixture obtained in the step S3, wherein,
when H02 is more than or equal to H2, the central control unit does not adjust stirring parameters;
when limh02=h2, the central control unit determines to adjust the second rotation speeds ωb to ω2, reduce the temperatures T1 to T2 in the cavity, reduce the pressures P1 to P2 in the cavity, and limh02=h2 represents that H02 approaches the second critical value H2 of the sinking amount infinitely;
where ω2=0.95×ωb, t2=0.95×t1, p2=0.95×p1.
Specifically, after the content of the water reducer in the first mixture is optimized and the first rotating speed of the stirring device is regulated, the first mixture still does not meet the consistency requirement, and the temperature and the pressure are properly reduced, so that the rate of hydration reaction of the mixture is improved; the invention takes the temperature and pressure regulation as alternative supplementary measures, expands the range of adjustable factors influencing the consistency, and is beneficial to regulating the consistency of the first mixture; after the central control unit adjusts the content of the thickening agent and all adjustable parameters in the stirring device, the first mixture still does not meet the consistency requirement, but is infinitely close to a first critical value, and the central control unit judges and adjusts all parameters of the stirring device in the secondary stirring process, so that cement paste obtained after secondary stirring meets the target consistency requirement; the central control unit takes the stirring rate in secondary stirring as a first adjusting parameter, which is a first influencing factor influencing the consistency of cement paste in the secondary stirring process, and simultaneously, pressure and temperature are regulated back so that the inner environment of the cavity of the stirring device is closer to the target well cementation.
The central control unit sets an initial feeding angle theta a of the fiber, judges whether to adjust the feeding angle of the fiber according to the adjusted first rotating speed omega', wherein,
when the m/s is less than or equal to omega' < 1.5m/s, the central control unit judges that the feeding angle of the fiber is not adjusted;
when omega '< 1.35m/s, the central control unit judges and adjusts the feeding angles theta a to theta 1 of the fibers to ensure that theta 1 = 45 degrees +R× (1.35-omega')/omega 1;
when omega '> 1.5m/s, the central control unit judges and adjusts the feeding angles theta a to theta 2 of the fibers to ensure that theta 2 = 45-R× (omega' -1.5)/omega 1;
wherein θa=45°, and the central control unit sets R as the maximum radius in the cavity of the stirring device.
Specifically, the central control unit presets an initial feeding angle of the fibers, and in order to meet the requirement of the dispersion effect of the fibers, the central control unit adjusts the feeding angle according to the rotating speed of the stirring device when the fibers are fed, and when the rotating speed is smaller, the centrifugal force on the outer side of the stirring device is larger, and the fibers are distributed on the outer side of the stirring device by increasing the feeding angle, so that the dispersion effect is achieved to the greatest extent; when the rotating speed is high, fibers are distributed on the inner side of the stirring device when fed by reducing the feeding angle, so that the matrix is prevented from being separated from the stirring device due to overlarge centrifugal force on the outer side of the stirring device.
When the fiber injection in the step S5 is completed, a third mixture is obtained, and the central control unit determines whether to adjust the adjusted first rotation speed ω' and the adjusted second rotation speed ω2 of the stirring device according to the fiber dispersion effect of the third mixture, wherein,
when the stirred fibers do not have aggregation, the central control unit judges that the stirring rate is not regulated;
when the stirred fibers are agglomerated, the central control unit judges to adjust the first rotating speeds omega 'to omega 1', so that omega 1 '=1.05×omega a, adjust omega 2 to omega 2', so that omega 2 '=1.2×omega 2, and stir the stirring device at the rotating speed of omega 2' until the fiber dispersing effect meets the requirement.
Specifically, if the aggregation phenomenon exists in the fibers, the central control unit judges that the fiber dispersing effect does not meet the dispersing requirement, and then judges to increase the speed of the stirring device, so that the stirring time is prolonged, the centrifugal force of the stirring device can be increased, the fiber dispersing is facilitated, the fiber dispersing effect can influence the toughness and the elasticity of cement paste, the cement paste performance is improved, and the construction quality is further improved.
When the fiber dispersion effect meets the requirement, the central control unit calls back the second rotating speeds omega 2' to omega 2 until the step S5 is completed, and the central control unit judges whether the final consistency value of the ductile elastic cement slurry for gas storage well cementation is qualified according to the sinking amount h2 of the ductile elastic cement slurry for gas storage well cementation obtained in the step S5, wherein,
When H3 is more than or equal to H2 and less than or equal to H4, the central control unit judges that the consistency of the cement paste is qualified;
when H2 is less than H3, the central control unit judges that the consistency of the cement paste is unqualified, the temperature in the cavity of the stirring device is increased, the pressure in the cavity is increased, wherein,
when H2 < H1, the central control unit judges that the temperature T2 to T21 in the cavity is increased, and the pressure P2 to P21 in the cavity is increased, so that T21= (1+ (H1-H2)/H1) multiplied by T2, and P21=P2 multiplied by T21/T2;
when H1 is less than H2 and less than H3, the central control unit judges that the temperatures T2 to T21 in the cavity are increased, and the pressures P2 to P21 in the cavity are increased, so that t21= (1+ (H3-H2)/H3) multiplied by T2, and P21=P2 multiplied by T21/T2;
when H2 is more than H4, the central control unit judges that the consistency of the cement paste is unqualified, reduces the temperature in the cavity of the stirring device, reduces the pressure in the cavity, wherein,
when H2 > H2, the central control unit judges to reduce the temperature T2 to T22 in the cavity, and reduces the pressure P2 to P22 in the cavity, so that T22= (1- (H2-H2)/H2) x T2, and P22=P2 x T22/T2;
when H4 < H2, the central control unit determines to decrease the intra-cavity temperatures T2 to T22, and decreases the intra-cavity pressures P2 to P22 such that t22= (1- (H2-H4)/H4) ×t2, p22=p2×t2'/T2.
Specifically, the method for detecting the sinking amount of the ductile elastic cement paste for the gas storage well cementation is not limited, as long as the method can obtain the sinking amount of the cement paste, and the embodiment of the invention provides a preferred implementation method, wherein the sinking amount of the cement paste is obtained through the sinking depth of the pilot cone sinking neat paste in a substitution method by adopting an ISO type Vicat instrument, wherein the third preset sinking amount is preferably 26mm, and the second preset sinking amount is preferably 30mm.
Specifically, the central control unit sets the third critical value and the fourth critical value of the sinking amount as parameters for judging whether the target cement paste meets the consistency requirement or not, and further judges how to adjust each parameter of the stirring device according to the sinking amount of the cement paste.
When the central control unit increases the temperature in the cavity of the stirring device to T21 and increases the pressure to P21, the central control unit judges that the second rotating speed omega 2 of the stirring device is reduced, the stirring time tg to tg1 is prolonged, the tg1 = tg+30s is set, wherein,
when T21/T2 < 1.15, the central control unit determines to decrease the adjusted second rotation speed ω2 to ω21 such that ω21= (T2/T21) ×ω2;
when T21/T2 is not less than 1.15, the central control unit determines to decrease the adjusted second rotation speed ω2 to ω21 such that ω21=1.5 m/s.
Specifically, when the sinking amount of the target cement paste is smaller, the central control unit increases the stirring rate according to the regulated pressure and temperature in the cavity of the stirring device; after secondary stirring, the central control unit increases the pressure and the temperature, which is favorable for reducing the hydration reaction of the cement consistency, thereby improving the cement paste consistency more efficiently; according to the invention, the stirring speed is regulated according to the pressure and the temperature, so that the process of improving the consistency of the cement slurry is more efficient and energy-saving.
When the central control unit reduces the temperature in the cavity of the stirring device to T22 and reduces the pressure to P22, the central control unit judges that the second rotating speed omega 2 of the stirring device is increased, the stirring time tq is prolonged to tq1, tq1=tq+30s is set, wherein,
when T22/T2 < 0.9, the central control unit determines to increase the second rotation speed ω2 to ω22 such that ω22=2.4 m/s;
when T22/T2 is more than or equal to 0.9, the central control unit judges to increase the second rotation speed omega 2 to omega 21 so that omega 22= (T2/T22) multiplied by omega 2.
Specifically, the central control unit adjusts the stirring speed again according to the adjusted pressure and temperature in the stirring device cavity; after secondary stirring, the central control unit adjusts the pressure and the temperature, so that the speed of improving the consistency is improved, and the consistency of cement paste can be improved more efficiently by improving the stirring speed; according to the invention, the stirring speed is regulated according to the pressure and the temperature, so that the process of improving the consistency of the cement slurry is more efficient and energy-saving.
Thus far, the technical solution of the present invention has been described in connection with the preferred embodiments shown in the drawings, but it is easily understood by those skilled in the art that the scope of protection of the present invention is not limited to these specific embodiments. Equivalent modifications and substitutions for related technical features may be made by those skilled in the art without departing from the principles of the present invention, and such modifications and substitutions will be within the scope of the present invention.
The foregoing description is only of the preferred embodiments of the invention and is not intended to limit the invention; various modifications and variations of the present invention will be apparent to those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims (2)

1. The preparation process of the tough elastic cement paste for the well cementation of the gas storage is characterized by comprising the following steps of: the preparation method is secondary stirring, and comprises the following steps:
s1, acquiring the temperature T and the pressure P of an environment where a gas storage well cementation is located, setting the initial temperature of a stirring device as T0 and setting the pressure as P0;
s2, injecting a thickening agent and a cementing material into a stirring device, stirring for a preset time at a first rotation speed omega a, and injecting a water reducing agent, a defoaming agent and water into the stirring device, and stirring the thickening agent and the cementing material to form a first mixture;
step S3, detecting the consistency of the first mixture according to the sinking amount of the first mixture, judging the consistency of the first mixture by the central control unit according to the comparison of the sinking amount of the first mixture and the preset sinking amount, and executing the step S4 when the consistency of the first mixture meets the standard; when the consistency of the first mixture does not meet the standard, the additive is required to be injected into the first mixture in a divided manner, the type of the additive is selected according to the sinking amount h, meanwhile, the central control unit adjusts all parameters of the stirring device according to the sinking amount change value after the additive is injected once, and when the consistency of the first mixture meets the standard, the central control unit judges and implements the step S4, wherein all parameters of the stirring device comprise the rotating speed, the stirring time, the pressure in the cavity and the temperature in the cavity;
S4, injecting a cementing material into the first mixture with qualified consistency, and stirring the first mixture and the cementing material at a second rotating speed omega b to form a second mixture;
s5, injecting fibers into the second mixture, stirring for a preset time at the adjusted first rotating speed, adjusting the rotating speed to the adjusted second rotating speed to form a third mixture, injecting fine sand, water, a defoaming agent, a nano SiO2 suspension after discrete treatment and a water reducing agent into the third mixture, and stirring at the adjusted second rotating speed to form a tough elastic cement paste for gas storage well cementation;
s6, performing consistency detection on the ductile elastic cement paste for gas storage well cementation, taking the sinking amount of the ductile elastic cement paste for gas storage well cementation as a parameter for judging the consistency of the ductile elastic cement paste for gas storage well cementation, judging that the consistency of the ductile elastic cement paste for gas storage well cementation is qualified by the central control unit, finishing the preparation of the cement paste, judging that the consistency of the cement paste is unqualified by the central control unit, and adjusting each parameter of a stirring device until the consistency of the ductile elastic cement paste for gas storage well cementation is qualified;
wherein, the first rotation speed ωa in the step S2 and the second rotation speed ωb in the step S4 are determined according to the designed compressive strength of the target cement slurry;
The central control unit acquires the sinking amount H1 of the first mixture, judges whether the consistency of the first mixture is qualified, judges that the consistency of the primary stirring mixture is qualified when H1 is more than or equal to H1 and less than or equal to H2, and executes the step S4; when H1 is less than H1 or H1 is more than H2, judging that the consistency of the primary stirring mixture is unqualified, and adjusting the mixing proportion of the primary stirring mixture additive and each parameter of the stirring device; the central control unit presets a first sunk-in threshold value H1 and a second sunk-in threshold value H2;
when H1 is less than H1, the central control unit increases the injection amount of the water reducer into the first mixture according to the immersion amount of the first mixture, wherein the water reducer is injected for a plurality of times, the central control unit judges whether to adjust the first rotation speed ωa and the stirring time t in the step S3 according to the variation value Δh of the immersion amount of the first mixture after the water reducer is injected, wherein Δh=h1 (i+1) -h1i, i=1, 2 … … n-1, n is the preset total injection number of the water reducer, H1 (i+1) is the immersion amount of the first mixture after the water reducer is injected for the i+1th time, H1i is the immersion amount of the first mixture after the water reducer is injected for the i-th time, the central control unit judges whether to adjust the first rotation speed ωa and the stirring time t in the step S3 according to the variation value Δh is greater than or equal to 3+delta, and when Δh is greater than or equal to 3+delta, the central control unit judges that the first rotation speed ωa is not adjusted, and the stirring time t is set to be equal to 1+t=5t10+t1j; when Δh < 3+δ, the central control unit determines to adjust the first rotation speeds ωa to ω1 in step S3 such that ω1=ωa× (1+ (H1-H1)/H1), and stir the mixture at the adjusted first rotation speed ω1 after adding 0.01% of the water reducing agent each time, and set t2=t+10+5i, to extend the stirring time t to t 2; delta is an allowable error range, and the total amount of the first water reducer is not more than 0.3% of that of the first cementing material;
When the total amount of the first water reducer reaches 0.3% of the first cementing material, the first mixture sinks into the water reducer by an amount hWhen 1 is smaller than H1, the central control unit judges and adjusts the internal pressure P0 to P1 of the stirring device according to the first rotation speed after the stirring device is adjusted, adjusts the internal temperature T0 to T1, prolongs the stirring time tp to tp1, sets tp1 = tp+20s, P = 1,2, and T1 = T0× (1+ (20/T) Total (S) )×(ω1×(ω1+ωa))/(ωa×(ω1－ωa)))，P1＝(T1/T0)×P0，t Total (S) The total duration used in steps S1 to S3;
the central control unit judges whether to adjust stirring parameters of secondary stirring according to the final sinking amount H01 of the first mixture obtained in the step S3, when H01 is more than or equal to H2, the central control unit judges that the stirring parameters are not adjusted, when limh01=H2, the central control unit judges that the second rotating speed ωb to ω2 is adjusted, the temperatures T1 to T2 in the cavity are increased, the pressures P1 to P2 in the cavity are increased, limh01=H2 represents a second critical value H2 which is infinitely close to the sinking amount, ω2=1.05xωb, T2=1.05xT1, and P2=1.05xP1;
when H1 > H2, increasing the injection amount of the thickener into the first mixture according to the consistency of the first mixture, wherein the thickener is injected for a plurality of times, and the central control unit judges whether to adjust the first rotation speed omega a and the stirring time t in the step S3 according to the variation value delta H of the immersion amount of the first mixture after the thickener is injected, wherein delta h=h1 (j+1) -hj, j=1, 2 … … b-1, b is the preset total injection times of the thickener, H1 (j+1) is the immersion amount of the first mixture after the j+1 injection of the water reducing agent, and H1j is the immersion amount of the first mixture after the j injection of the thickener;
The central control unit judges whether to adjust the first rotating speed omega a and the stirring time t in the step S3 according to the variation value delta H of the sinking amount of the first mixture, when delta H is more than or equal to 3+delta, the central control unit judges that the stirring device omega a is not adjusted, the central control unit prolongs the stirring time t to t1, t1=t+10+5j is set, when delta H is less than 3+delta, the central control unit judges that the stirring time t to t1 is adjusted to ensure that omega 1=omega a× (1+ (H1-H2)/H1), the stirring time t to t1 is increased by the central control unit after 0.005% of thickener is added, and the delta is set as an allowable error range, and the total amount of the thickener does not exceed 0.2% of all the gelled materials;
when the total amount of thickener has reached 0.3% of the first batch of cementitious material, firstThe mixture sinking amount H1 > H2, the central control unit adjusts the internal pressures P0 to P12, sets P12= (T0/T1) x P0, adjusts the temperatures T0 to T12, T12=T0 x (1- (20/T) Total (S) )×(ω1×(ω1+ωa))/(ωa×(ω1-ωa)))，t Total (S) For the total duration used in steps S1 to S3, the stirring time tk to tk2 is prolonged, and the stirring time of tk2=tk+20s, k=1, 2 is set; and the central control unit judges whether to adjust stirring parameters of secondary stirring according to the final sinking amount H02 of the first mixture obtained in the step S3, when H02 is more than or equal to H2, the central control unit does not adjust the stirring parameters, when limh02=H2, the central control unit judges to adjust the second rotating speed omega b to omega 2, reduces the temperatures T1 to T2 in the cavity, reduces the pressures P1 to P2 in the cavity, limh02=H2 represents that H02 approaches the sinking amount second critical value H2 infinitely, omega 2=0.95×omega b, T2=0.95×T1, and P2=0.95×P1.
2. The process for preparing a ductile elastic cement slurry for gas storage well cementation according to claim 1, wherein when the fiber injection in step S5 is completed, a third mixture is obtained, the central control unit determines whether to adjust the adjusted first rotation speed ω' and the adjusted second rotation speed ω2 of the stirring device according to the fiber dispersion effect of the third mixture, wherein,
when the stirred fibers do not have aggregation, the central control unit judges that the stirring rate is not regulated;
when the stirred fibers are agglomerated, the central control unit judges to adjust the first rotating speeds omega ' to omega 1', so that omega 1' =1.05×omega ', adjust omega 2 to omega 2', and make omega 2' =1.2×omega 2, and the stirring device stirs at the rotating speeds of omega 2' until the fiber dispersing effect meets the requirement.
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