CN109485788B - Oil well cement sedimentation stabilizer suitable for well cementation of oil-gas well, preparation method thereof and well cement slurry - Google Patents
Oil well cement sedimentation stabilizer suitable for well cementation of oil-gas well, preparation method thereof and well cement slurry Download PDFInfo
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- C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
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- C09K8/46—Compositions for cementing, e.g. for cementing casings into boreholes; Compositions for plugging, e.g. for killing wells containing inorganic binders, e.g. Portland cement
- C09K8/467—Compositions for cementing, e.g. for cementing casings into boreholes; Compositions for plugging, e.g. for killing wells containing inorganic binders, e.g. Portland cement containing additives for specific purposes
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Abstract
The invention belongs to the field of petroleum and natural gas well cementation engineering, and in particular relates to an oil well cement sedimentation stabilizer suitable for oil and gas well cementation, a preparation method thereof and well cementation cement slurry. The oil well cement sedimentation stabilizer comprises a structural unit A of a formula (I), a structural unit B of a formula (II) and a structural unit C of a formula (III); the molar ratio of structural units A, B and C is x: y: z=1: (0.07-0.22): (0.03-0.11); r is R 1 、R 2 And R is 3 Each is H, or C 1 ‑C 4 Substituted or unsubstituted alkyl of (a); m is 15, 17, 19 or 21; the oil well cement sedimentation stabilizer can realize the aim of low-temperature non-thickening and high-temperature thickening, and effectively solve the problem of sedimentation instability of well cementing cement slurry.
Description
Technical Field
The invention belongs to the field of petroleum and natural gas well cementation engineering, and particularly relates to an oil well cement sedimentation stabilizer suitable for oil and gas well cementation, a preparation method of the oil well cement sedimentation stabilizer suitable for oil and gas well cementation, and well cementation cement paste comprising the oil well cement sedimentation stabilizer.
Background
In recent years, with the increase of the demand of oil gas resources in China, the contradiction between oil gas supply and demand is increasingly prominent, so that the exploration and development of the oil gas resources in China are developed towards the directions of deep water, deep stratum and unconventional oil gas while the import amount of oil is properly increased, and large-displacement wells and horizontal wells are increasingly utilized, which provides more challenges for the design of well cementation engineering, in particular well cementation cement paste.
In a high-pressure complex environment, in order to maintain the balance of the wellbore and the ground pressure in the well cementation operation, a high-density cement slurry system is needed, and the slurry is unevenly distributed in the slurry up and down due to the large solid phase density difference in the high-density cement slurry system, so that the sedimentation instability of the cement slurry is easily caused. For the well cementation construction of low-pressure easy-leakage stratum and fractured carbonate stratum, in order to prevent cement slurry leakage and ensure cement slurry to return to high, low-density and ultra-low-density well cementation cement slurry is needed, the density difference between the lightening material in the low-density cement slurry and cement particles is large, free floating and aggregation are easy to occur, and the cement slurry is unstable. Meanwhile, free liquid and solid phase sedimentation generated by unstable cement slurry has great influence on the well cementation quality of the high-inclination section and the horizontal section. In addition, if the downhole temperature is higher (more than or equal to 120 ℃), insufficient slurry suspension capacity can be caused due to the decomposition failure of the high polymer, sedimentation and free liquid are generated, and the cementing quality of the later cement slurry is affected. Therefore, good cement paste sedimentation stability is very important.
Once the cement slurry is settled and unstably, the following effects are brought to well cementation construction: the sedimentation of cement paste can lead to the generation of free liquid, when the free liquid is more, a water ring or a water band can be formed in a cement column to provide a channel for fluid channeling, and especially in a horizontal well and a highly-inclined well, adverse conditions such as loose structure, low strength and the like of a shaft cement stone can be caused to influence the interval packing quality; in the annulus, the compactness and the cementing strength of the cement sheath are continuously reduced from bottom to top, and the sealing quality of the cement sheath is adversely affected; the sedimentation instability of cement slurry can lead the density and rheological property of the cement slurry to be dynamically changed in the cement injection process, and the rheological design of cement slurry is difficult; when the slurry sedimentation instability is serious, the weighting agent particles are easy to be deposited and aggregated rapidly, so that bridge blockage is caused, cement injection displacement pressure is increased, and even pump blocking, pressure leakage, well cementation suspension, failure and the like are caused, thereby seriously endangering the well cementation construction safety.
At present, various solutions are proposed for the problem of sedimentation instability of oil well cement paste at home and abroad. The water-cement ratio of the oil well cement paste, the particle deep processing treatment of the additive, the optimization grading of cement particles, and the addition of inorganic material suspending agents (superfine materials, nanometer materials, micro-silicon, bentonite, sepiolite and the like) or polymer suspending agents (xanthan gum, guar gum, AMPS polymers and the like) are properly reduced. The cement slurry sedimentation stability can be improved to a certain extent by properly reducing the water-cement ratio of the oil well cement slurry, carrying out the particle deep processing treatment of the additive and optimizing the grading of the cement particles, but the effect is not ideal, the processing cost is high, and the process is complex. Inorganic material suspending agents form a net structure through hydration to play a role in sedimentation stabilization, but the addition of excessive inorganic material stabilizing agents can have adverse effects on the development of the strength of cement stones, so that the preference of suitable inorganic material sedimentation stabilizing agents is still a problem. The polymer sedimentation stabilizer can increase the viscosity of the system, establish new association among solid phase particles and improve sedimentation stability. However, under the high temperature condition, the polymer can undergo degradation reactions of depolymerization, random chain breakage and radical removal in 3 forms, so that the molecular weight of the polymer is reduced, the viscosity of the system is reduced, the structural force and the suspending capability are lost, and in addition, the high molecular weight polymer can cause the poor flow property of cement paste to influence normal pumping.
Zhang Hao, li Houming et al (Zhang Hao. Research application of stabilizer for well cementation SS-10L [ J ]. Scientific technology and engineering, 2014.) developed a suspension stabilizer for well cementation in oil field, which consists of Wen Lunjiao as an organic suspension component, mineral B as an inorganic suspension component and surfactant C, and experimental results and field application show that the addition amount of the suspension stabilizer is extremely low, the compatibility with additives is good, the cost performance is high, but the temperature resistance is poor, so that cement slurry is thickened at low temperature and becomes thin at high temperature. Xia Chun et al (Xia Chun, xaichun. ACS novel grouting stabilizer action mechanism research [ J ]. Civil engineering report, 2005,38 (6): 89-91.), developed an ACS cement slurry stabilizer compounded by various components such as polyacrylamide and acrylic acid graft copolymer and inorganic chemical materials, belonging to high molecular surfactant, the result shows that ACS cement slurry stabilizer can obviously improve cement stone strength, the enhancement effect is particularly obvious at low water-cement ratio, but the effect is not obvious at high water-cement ratio.
CN107162512a discloses an ultra-deep well high-temperature-resistant cement slurry system, which comprises cement, a high-temperature fluid loss agent, silica sand, a high-temperature retarder, a high-temperature stabilizer and a dispersing agent, and solves the problem of unstable performance of cement slurry at high temperature by adding an additive for resisting high temperature, but the difficulty of slurry pumping is increased due to overlarge initial consistency of slurry.
Because the conventional oil well cement sedimentation stabilizer used at present has common defects, the conventional oil well cement sedimentation stabilizer is excessively thickened at low temperature, so that pumping is difficult, high-temperature hydrolysis becomes thin, sedimentation stability is rapidly reduced, and cementing quality is poor or even fails. Therefore, aiming at the problems of sedimentation instability of cement paste, no better solution exists at present, especially along with the increase of complex structure wells such as deep wells, horizontal wells, large displacement wells and the like, the sedimentation instability problem of the oil well cement paste becomes more prominent, in the prior art, the sedimentation prevention of the cement paste is still a technical bottleneck for current domestic and foreign research, and therefore, the synthesis of a novel oil well cement sedimentation stabilizer is still in need of further research and development.
Disclosure of Invention
The invention aims to solve the problem of sedimentation instability of well cementation cement paste in the prior art, and provides an oil well cement sedimentation stabilizer suitable for well cementation of oil and gas wells, a preparation method thereof and well cementation cement paste. The oil well cement sedimentation stabilizer provided by the invention can realize the aims of low-temperature non-thickening and high-temperature thickening, thereby effectively solving the problem of sedimentation instability of well cementing cement paste, ensuring oil gas safety development and improving well cementing quality.
In order to achieve the above object, a first aspect of the present invention provides a sedimentation stabilizer suitable for oil well cement, wherein the oil well cement sedimentation stabilizer contains a structural unit a represented by formula (I), a structural unit B represented by formula (II), and a structural unit C represented by formula (III);
wherein the molar ratio of the structural unit A, the structural unit B and the structural unit C is x: y: z=1: (0.07-0.22): (0.03-0.11);
wherein R is 1 、R 2 And R is 3 Identical or different, each independently H, or C 1 -C 4 Substituted or unsubstituted alkyl of (a);
wherein m is 15, 17, 19 or 21.
The second aspect of the invention provides a preparation method of the oil well cement sedimentation stabilizer, wherein the method comprises the steps of mixing a monomer A, a monomer B, a monomer C and deionized water in the presence of an initiator, and then carrying out copolymerization reaction;
wherein the monomer A has a structure shown in a formula (IV), the monomer B has a structure shown in a formula (V), and the monomer C has a structure shown in a formula (VI);
wherein R is 4 、R 5 And R is 6 Identical or different, each independently H, or C 1 -C 4 Substituted or unsubstituted alkyl of (a);
wherein m is 15, 17, 19 or 21;
wherein, the weight ratio of the dosage of the monomer A, the monomer B and the monomer C is (1-10): (0.5-5): 1, a step of; preferably (1-5): (0.5-3): 1.
The third aspect of the invention provides a well cementing slurry, wherein the well cementing slurry comprises the oil well cement sedimentation stabilizer or the oil well cement sedimentation stabilizer prepared by the method; preferably, the oil well cement sedimentation stabilizer may be used in an amount of 0.5 to 1.0 wt% based on the total weight of the well cement slurry.
According to the technical scheme, the rigid hydrophobic monomer is introduced into the conventional copolymer, so that cement paste is not thickened at low temperature and thickened at high temperature by utilizing the thermal tackifying effect of the oil well cement sedimentation stabilizer, the sedimentation stability of the cement paste is improved, a novel method for regulating and controlling the sedimentation stability of the well cementing cement paste is formed, the problem of sedimentation instability of the well cementing cement paste is effectively solved, and the oil gas safety development and the well cementing quality are ensured.
Drawings
The accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification, illustrate the invention and together with the description serve to explain, without limitation, the invention. In the drawings:
FIG. 1 is a rheological profile of a well cement settlement stabilizer of varying concentrations according to example 1 of the present invention;
FIG. 2 is a graph of the rheology of a 0.6 wt% oil well cement sedimentation stabilizer of the present invention after addition of NaOH at various concentrations as described in example 1;
FIG. 3 is a graph of the rheology of a 0.6 wt% oil well cement sedimentation stabilizer of example 1 of the present invention after addition of different concentrations of NaCl;
FIG. 4 is a plot of consistency of cement slurries incorporating varying amounts of oil well cement sedimentation stabilizers over time;
FIG. 5 is a graph of the rheology of the same content of different types of cement sedimentation stabilizers.
Description of the reference numerals
1. 0.4 wt% oil well cement sedimentation stabilizer
2. 0.2 wt% oil well cement sedimentation stabilizer
3. 0 wt% NaOH 4, 0.01 wt% NaOH
5. 0.1% by weight NaOH 6, 1% by weight NaOH
7. 4 wt% NaOH8, 0 wt% NaCl
9. 0.05% by weight of NaCl10, 0.2% by weight of NaCl
11. 0.65% by weight of NaCl12, 3% by weight of NaCl
13. Cement raw slurry
14. Adding 0.025 wt% oil well cement sedimentation stabilizer
15. Adding 0.05 wt% oil well cement sedimentation stabilizer
16. Adding 0.10 wt% oil well cement sedimentation stabilizer
17. 0.6 wt% oil well cement sedimentation stabilizer
18. 0.6 wt% hydroxyethyl cellulose
19. 0.6 wt% xanthan gum
20. 0.6 wt% AM/AMPS copolymer
Detailed Description
The endpoints and any values of the ranges disclosed herein are not limited to the precise range or value, and are understood to encompass values approaching those ranges or values. For numerical ranges, one or more new numerical ranges may be found between the endpoints of each range, between the endpoint of each range and the individual point value, and between the individual point value, in combination with each other, and are to be considered as specifically disclosed herein.
The invention provides an oil well cement sedimentation stabilizer suitable for cementing an oil and gas well, wherein the oil well cement sedimentation stabilizer comprises a structural unit A shown in a formula (I), a structural unit B shown in a formula (II) and a structural unit C shown in a formula (III);
wherein the molar ratio of the structural unit A, the structural unit B and the structural unit C is x: y: z=1: (0.07-0.22): (0.03-0.11);
wherein R is 1 、R 2 And R is 3 Identical or different, each independently H, or C 1 -C 4 Substituted or unsubstituted alkyl of (a);
wherein m is 15, 17, 19 or 21.
In the present invention, it is to be noted that: the molar ratio of the structural unit A, the structural unit B and the structural unit C is x: y: z=1: (0.07-0.22): (0.03-0.11), wherein x is the number of moles of the structural unit A, y is the number of moles of the structural unit B, and z is the number of moles of the structural unit C.
According to the invention, R is preferably 1 、R 2 And R is 3 The same or different are each independently H, methyl, ethyl, n-propyl, isopropyl or butyl, more preferably H; m is 17, 19 or 21. In addition, in the present invention, when R 1 、R 2 And R is 3 When each is independently H, the structural unit A is an acrylamide group, the structural unit B is a 2-propenyl amide-2-methylpropanesulfonic acid group, and the structural unit C is the rigid hydrophobic monomer group.
According to the invention, the weight average molecular weight of the oil well cement sedimentation stabilizer is 300 ten thousand to 500 ten thousand, preferably 350 ten thousand to 500 ten thousand. In the invention, the oil well cement sedimentation stabilizer is limited to have the structural units shown in the formulas (I) to (III) and have the weight average molecular weight, so that the sedimentation stability of cement paste can be improved, the problem of sedimentation instability of well cementing cement paste is effectively solved, the oil gas safety development is ensured, and the well cementing quality is improved.
According to the present invention, although the oil well cement sedimentation stabilizer has the structural units represented by the above-defined formulas (I) to (III) and has the weight average molecular weight as described above, it is possible to improve the sedimentation stability of cement paste, but in the present invention, it is preferable that m is 17, 19 or 21, which has a better effect of improving the sedimentation stability of cement paste.
The second aspect of the invention provides a preparation method of the oil well cement sedimentation stabilizer, wherein the method comprises the steps of mixing a monomer A, a monomer B, a monomer C and deionized water in the presence of an initiator, and then carrying out copolymerization reaction;
wherein the monomer A has a structure shown in a formula (IV), the monomer B has a structure shown in a formula (V), and the monomer C has a structure shown in a formula (VI);
wherein R is 4 、R 5 And R is 6 Identical or different, each independently H, or C 1 -C 4 Substituted or unsubstituted alkyl of (a);
wherein m is 15, 17, 19 or 21;
wherein, the weight ratio of the dosage of the monomer A, the monomer B and the monomer C is (1-10): (0.5-5): 1, a step of; preferably (1-5): (0.5-3): 1.
according to the invention, the monomers A, B and C are used in such amounts that the molar ratio of the structural units A, B and C contained in the oil-well cement sedimentation stabilizer is x: y: z=1: (0.07-0.22): (0.03-0.11);
preferably, R 4 、R 5 And R is 6 The same or different are each independently H, methyl, ethyl, n-propyl, isopropyl or butyl, more preferably H; m is 17, 19 or 21;
preferably, the total amount of monomer A, monomer B and monomer C is 30-40 wt% of the deionized water;
Preferably, the pH of the mixed solution of the monomer A, the monomer B, the monomer C and the deionized water is 8-9.
According to the invention, R is preferably 4 、R 5 And R is 6 The same or different are each independently H, methyl, ethyl, n-propyl, isopropyl or butyl, more preferably H; m is 17, 19 or 21. In addition, in the present invention, when R 4 、R 5 And R is 6 When each is independently H, the monomer A is acrylamide, the monomer B is 2-acrylamido-2-methylpropanesulfonic acid, and the monomer C is the rigid hydrophobic monomer.
According to the invention, acrylamide (AM) is taken as one of the reaction monomers, and has the advantages that the acrylamide has excellent water solubility and low price, the main chain structure of the polymer synthesized by taking the acrylamide as a main monomer is C-C, and the polymer has excellent chemical stability, so that the polymer has certain temperature resistance and salt resistance, and in addition, the amide group in the acrylamide has excellent water solubility and cannot have adverse effects on retarder, flash coagulation and the like of cement paste. In the present invention, acrylamide (AM) is commercially available, for example, from the national pharmaceutical group chemical reagent company, inc.
According to the present invention, 2-acrylamido-2-methylpropanesulfonic Acid (AMPS) is one of the reactive monomers, which has the advantages that the steric hindrance in the molecule of 2-acrylamido-2-methylpropanesulfonic acid makes the heat stability of the 2-acrylamido-2-methylpropanesulfonic acid good, the hydrolysis is not easy, and the molecule contains sulfonate groups (-SO) 3 (-) to make it insensitive to the interference of external acid, alkali and salt ions, thereby further improving the temperature and salt resistance of the cement paste sedimentation stabilizer and enabling the cement paste sedimentation stabilizer to be better applied to high-temperature well cementation. In the present invention, 2-acrylamido-2-methylpropanesulfonic Acid (AMPS) is commercially available, for example, from guangdong Weng Jiang chemical company, model number analytically pure.
According to the invention, the rigid hydrophobic monomer can be synthesized by self through experimental means.
In the invention, a rigid hydrophobic monomer is developed by increasing the length of an alkyl chain in the monomer, and the rigid hydrophobic monomer is a rigid hydrophobic long-chain alkyl monomer which can endow the synthesized polymer with thermal tackifying capability, so that the rigid hydrophobic long-chain alkyl quaternary ammonium salt-containing monomer is synthesized by using chloropropene and N, N-dimethyl long-chain alkyl tertiary amine (the number of the long-chain alkyl is an even number of 14-20) as the rigid hydrophobic monomer, and the specific synthesis method comprises the following steps:
(1) Adding fatty alcohol and a proper amount of catalyst into a reaction kettle, heating the reaction kettle, introducing monomethylamine into the reaction kettle for 75-85min at a flow rate of 35-50 kg/h at a temperature of 130 ℃, and finally keeping the reaction temperature at 180-200 ℃ for 5-7h, thereby synthesizing N, N-dimethyl long-chain alkyl tertiary amine (the number of long-chain alkyl is an even number of 14-20);
(2) The quaternization of tertiary amines is carried out by adding a quaternizing agent (C 3 H 5 Cl) is filled with tertiary amine and a little alkali liquor (Na) 2 CO 3 ) A closed container of alcohol solvent (isopropanol) at a reaction temperature of 75-90 ℃ and a reaction pressure of 3.0X19.8X10 4 Pa to 3.5X19.8X10 4 Synthesized under the condition of Pa.
The reaction formula is as follows:
wherein the hydrophobicity of the rigid hydrophobic monomer is enhanced with increasing long chain alkyl chain length (increasing m value), further preferably N, N-dimethyl long chain alkyl tertiary amine with m=15, 17, 19 or 21 to produce the rigid hydrophobic monomer.
In the present invention, both chloropropene and N, N-dimethyl long chain alkyl tertiary amine are commercially available, for example, chloropropene is available from Jinan ren chemical Co., ltd; n, N-dimethyl long chain alkyl tertiary amine is available from Shanghai Ala Biochemical technologies Co., ltd.
In the invention, the rigid hydrophobic monomer, especially, in the preferred condition, the N, N-dimethyl long-chain alkyl quaternary ammonium salt with m=15, 17, 19 or 21 is selected as one of the reaction monomers, and the invention has the advantages that the rigid hydrophobic monomer has strong hydrophobicity at low temperature, has no adverse effect on the consistency of cement paste, and along with the rising of temperature, hydrophobic groups on molecular chains begin to shrink and aggregate, polymer molecules begin to aggregate and precipitate from liquid phase, so that the viscosity of the solution is obviously increased, the high-temperature tackifying capability of the synthesized polymer can be endowed, the defects of 'low-temperature thickening and high-temperature thinning' of the traditional oil well cement sedimentation stabilizer are overcome, the sedimentation stability of the oil well cement sedimentation stabilizer can be fully exerted under the high-temperature environment, and the purposes of 'low-temperature non-thickening and high-temperature thickening' are truly achieved.
In the invention, the traditional AM-AMPS copolymer has good high temperature resistance and salt resistance, simple and convenient synthesis process and low cost, so that the traditional AM-AMPS copolymer is widely applied to cement paste additives and oilfield chemicals, but the traditional AM-AMPS copolymer has poor tackifying effect, so that the rigid hydrophobic monomer is introduced on the basis of the traditional copolymer, and the synthesized polymer has the thermal tackifying capability of increasing viscosity along with the temperature rise.
According to the invention, the weight ratio of the amounts of 2-acrylamido-2-methylpropanesulfonic acid, acrylamide and of the rigid hydrophobic monomer may preferably be (0.5-5): (1-10): 1, a step of; preferably (0.5-3): (1-5): 1, a step of; more preferably (0.5-2): (3-5): 1.
preferably, the total amount of 2-acrylamido-2-methylpropanesulfonic acid, acrylamide and the rigid hydrophobic monomer is 30-40% by weight of the deionized water;
preferably, the pH value of the mixed solution of the 2-acrylamide-2-methylpropanesulfonic acid, the acrylamide, the rigid hydrophobic monomer and the deionized water is 8-9; in the present invention, the reaction system may be adjusted to pH using a NaOH solution having a mass fraction of 10%.
According to the invention, the process is carried out in the presence of an initiator, which may be sodium bisulfite and/or ammonium persulfate; the molar ratio of the sodium bisulphite to the ammonium persulfate is 1: (1.2-1.4), preferably 1:1.2; more preferably, the total amount of the sodium bisulfite and the ammonium persulfate is 0.5 to 1% by weight of the total amount of the monomer A, the monomer B and the monomer C; more preferably, the total amount of the sodium bisulfite and the ammonium persulfate is 0.5 to 1% by weight of the total amount of 2-acrylamido-2-methylpropanesulfonic acid, acrylamide and the rigid hydrophobic monomer.
According to the invention, monomer A, monomer B and monomer C (for example, 2-acrylamido-2-methylpropanesulfonic acid, acrylamide and the rigid hydrophobic monomer) are all dissolved in deionized water, a mixed solution is formed after uniform stirring, the pH value is regulated, then the mixed solution with the regulated pH value is placed in a three-neck flask, oxygen in the three-neck flask is discharged, the three-neck flask is placed in a water bath box with the temperature of 50-60 ℃ and the temperature of preferably 50 ℃ and is stirred at a constant speed of 100-200r/min, preferably 100r/min, when the temperature of the reaction solution is raised to 50-60 ℃, the initiator is dripped into the mixed solution of 2-acrylamido-2-methylpropanesulfonic acid, acrylamide, the rigid hydrophobic monomer and the deionized water at the dripping rate of 0.5-1ml/min, after 30min, the reaction system starts to be thickened and stops stirring, the three-neck flask is kept stand for 10-12h, preferably 10h, thus obtaining the milky polymer after purification and drying, the oil-gas well cement sedimentation stabilizer is obtained.
Wherein, the step of removing the oxygen in the reaction vessel can be to fill nitrogen into the reaction vessel.
Wherein, the purification can be performed 3-6 times by using absolute ethyl alcohol.
The drying may be performed by a constant temperature drying oven, and the drying time is not particularly limited, as long as the drying time is selected, and for example, 10 to 12 hours, preferably 10 hours.
The third aspect of the invention provides a well cementing slurry, wherein the well cementing slurry comprises the oil well cement sedimentation stabilizer or the oil well cement sedimentation stabilizer prepared by the method.
Preferably, the oil well cement sedimentation stabilizer may be used in an amount of 0.5 to 1.0 wt% based on the total weight of the well cement slurry.
In the invention, the formulation of the well cementing cement slurry is not particularly limited and can be selected conventionally by a person skilled in the art, for example, the formulation of the high-temperature high-density well cementing cement slurry used for example is G-grade oil well cement, 33% silica powder, 140% ilmenite, 5% high-temperature filtrate reducer, 0.5% THIX-558 defoamer, 1.1% high-temperature retarder and 68% water, and the cement slurry density is 2.50G/cm 3 。
The fourth aspect of the invention provides an oil well cement sedimentation stabilizer prepared by the method or the application of the oil well cement sedimentation stabilizer or the well cementing slurry in the oil and natural gas well cementing engineering field.
Preferably, the well cementation may be one or more of deep wells, highly deviated wells and horizontal wells.
Through the technical scheme, the invention has the advantages that:
(1) According to the invention, through optimizing the components and the content in the oil well cement sedimentation stabilizer, the components are synergistic, so that the oil well cement sedimentation stabilizer can be successfully applied to well cementation and sedimentation prevention, and meanwhile, other properties of cement paste such as rheological property, initial consistency, thickening time, compressive strength and the like are not adversely affected.
(2) The oil well cement sedimentation stabilizer does not influence the normal hydration reaction of cement, can improve the compressive strength of cement stones and improve the comprehensive performance of a cement slurry system.
(3) The oil well cement sedimentation stabilizer has good operability, can be directly dry-mixed with cement for use, and has good compatibility with other additives and strong adaptability.
(4) The oil well cement sedimentation stabilizer has the effects of low temperature non-thickening and high temperature thickening, ensures normal pumping of cement paste at low temperature, ensures that the cement paste has a certain consistency at high temperature so as to prevent sedimentation instability of the paste, and is suitable for well cementation operation in petroleum and natural gas exploration and development processes.
(5) The oil well cement sedimentation stabilizer of the invention can be suitable for cement slurry systems with different densities, and the use temperature is up to 150 ℃.
(6) The process is simple and convenient to operate, the polymerization reaction is easy to control, the time consumption is short, and the yield is high.
The present invention will be described in detail by examples.
In the following examples and comparative examples:
the performance of the cement slurry system is tested according to the standard GB/T19139-2003 oil well cement test method, and with reference to the standard SY/T6544-2003 oil well cement slurry performance requirement and the SY/T6466-2000 oil well cement stone high temperature resistance evaluation method.
The starting materials used in the examples and comparative examples are conventional commercial products and are well known to those skilled in the art.
Example 1
This example is intended to illustrate an oil well cement sedimentation stabilizer prepared by the method of the present invention.
1 part by weight of 2-acrylamide-2-methylpropanesulfonic acid, 3 parts by weight of acrylamide and 1 part by weight of rigid hydrophobic monomer are weighed according to the weight ratio, all three monomers are dissolved in deionized water, and mixed solution is formed after uniform stirring;
wherein the rigid hydrophobic monomer has a structure represented by formula (VI) and R 6 Is H, m is 21;
adding 10% NaOH solution into the mixed solution to adjust the reaction system to pH 8.5, placing the mixed solution with the adjusted pH value into a three-mouth flask, discharging oxygen in the three-mouth flask, placing the three-mouth flask into a water bath box with the temperature of 50 ℃ to stir at a constant speed of 100r/min, slowly dropwise adding 1.0% initiator solution with the mass fraction of 1.2% when the temperature of the reaction solution rises to 50 ℃, wherein the initiator solution contains 1 part by weight of sodium bisulfate and 1.2 parts by weight of ammonium persulfate, starting to thicken the reaction system after 30min, stopping stirring, standing for reaction for 10h to obtain a milky polymer, purifying for 4 times by absolute ethyl alcohol, drying for 11h by a constant temperature drying box, and grinding to obtain a powdery oil well cement sedimentation stabilizer, wherein the powder oil well cement sedimentation stabilizer is marked as S1;
The oil well cement sedimentation stabilizer S1 comprises the following structure:
[CH 2 CM 1 H] x -[CM 2 HCH 2 ] y -[CH 2 CM 3 HCl - ] z the method comprises the steps of carrying out a first treatment on the surface of the Wherein M is 1 is-CONH 2 ，M 2 is-CONHC (CH) 3 ) 2 CH 2 SO 3 H，M 3 Is- [ NCH 2 (CH 3 ) 2 (CH 2 ) m CH 3 ] + ；
Wherein x: y: z=1: 0.11:0.055; and
the weight average molecular weight of the oil well cement sedimentation stabilizer S1 is 350 ten thousand.
Example 2
This example is intended to illustrate an oil well cement sedimentation stabilizer prepared by the method of the present invention.
An oil well cement sedimentation stabilizer was prepared in the same manner as in example 1 except that: 2 parts by weight of 2-acrylamido-2-methylpropanesulfonic acid, 3 parts by weight of acrylamide and 1 part by weight of rigid hydrophobic monomer are weighed according to the weight ratio.
The oil well cement sedimentation stabilizer prepared by the result is marked as S2;
the oil well cement sedimentation stabilizer S2 comprises the following structure:
[CH 2 CM 1 H] x -[CM 2 HCH 2 ] y -[CH 2 CM 3 HCl - ] z the method comprises the steps of carrying out a first treatment on the surface of the Wherein M is 1 is-CONH 2 ，M 2 is-CONHC (CH) 3 ) 2 CH 2 SO 3 H，M 3 Is- [ NCH 2 (CH 3 ) 2 (CH 2 ) m CH 3 ] + ；
Wherein x: y: z=1: 0.22:0.055; and
the weight average molecular weight of the oil well cement sedimentation stabilizer S2 is 500 ten thousand.
Example 3
This example is intended to illustrate an oil well cement sedimentation stabilizer prepared by the method of the present invention.
An oil well cement sedimentation stabilizer was prepared in the same manner as in example 1 except that: 1 part by weight of 2-acrylamide-2-methylpropanesulfonic acid, 3 parts by weight of acrylamide and 2 parts by weight of rigid hydrophobic monomer are weighed according to the weight ratio.
The oil well cement sedimentation stabilizer prepared by the result is marked as S3;
wherein, this oil well cement sedimentation stabilizer S3 contains the structure:
[CH 2 CM 1 H] x -[CM 2 HCH 2 ] y -[CH 2 CM 3 HCl - ] z the method comprises the steps of carrying out a first treatment on the surface of the Wherein M is 1 is-CONH 2 ，M 2 is-CONHC (CH) 3 ) 2 CH 2 SO 3 H，M 3 Is- [ NCH 2 (CH 3 ) 2 (CH 2 ) m CH 3 ] + ；
Wherein x: y: z=1: 0.11:0.11; and
the weight average molecular weight of the oil well cement sedimentation stabilizer S3 is 450 ten thousand.
Example 4
This example is intended to illustrate an oil well cement sedimentation stabilizer prepared by the method of the present invention.
An oil well cement sedimentation stabilizer was prepared in the same manner as in example 1 except that: 1 part by weight of 2-acrylamide-2-methylpropanesulfonic acid, 5 parts by weight of acrylamide and 1 part by weight of rigid hydrophobic monomer are weighed according to the weight ratio.
The oil well cement sedimentation stabilizer prepared by the result is marked as S4;
wherein, this oil well cement sedimentation stabilizer S4 contains the structure:
[CH 2 CM 1 H] x -[CM 2 HCH 2 ] y -[CH 2 CM 3 HCl - ] z the method comprises the steps of carrying out a first treatment on the surface of the Wherein M is 1 is-CONH 2 ，M 2 is-CONHC (CH) 3 ) 2 CH 2 SO 3 H，M 3 Is- [ NCH 2 (CH 3 ) 2 (CH 2 ) m CH 3 ] + ；
Wherein x: y: z=1: 0.07:0.03; and
the weight average molecular weight of the oil well cement sedimentation stabilizer S4 is 422 ten thousand
Example 5
This example is intended to illustrate an oil well cement sedimentation stabilizer prepared by the method of the present invention.
An oil well cement sedimentation stabilizer was prepared in the same manner as in example 1 except that: the rigid hydrophobic monomer has a structure shown in formula (VI), and R 6 H and m is 15.
The oil well cement sedimentation stabilizer prepared by the result is marked as S5;
wherein, this oil well cement sedimentation stabilizer S5 contains the structure:
[CH 2 CM 1 H] x -[CM 2 HCH 2 ] y -[CH 2 CM 3 HCl - ] z the method comprises the steps of carrying out a first treatment on the surface of the Wherein M is 1 is-CONH 2 ，M 2 is-CONHC (CH) 3 ) 2 CH 2 SO 3 H，M 3 Is- [ NCH 2 (CH 3 ) 2 (CH 2 ) m CH 3 ] + ；
Wherein x: y: z=1: 0.11:0.07; and
the weight average molecular weight of the oil well cement sedimentation stabilizer S5 is 363 ten thousand.
Example 6
This example is intended to illustrate an oil well cement sedimentation stabilizer prepared by the method of the present invention.
An oil well cement sedimentation stabilizer was prepared in the same manner as in example 1 except that: the rigid hydrophobic monomer has a structure shown in formula (VI), and R 6 H and m is 17.
The oil well cement sedimentation stabilizer prepared by the result is marked as S6;
wherein, this oil well cement sedimentation stabilizer S6 contains the structure:
[CH 2 CM 1 H] x -[CM 2 HCH 2 ] y -[CH 2 CM 3 HCl - ] z the method comprises the steps of carrying out a first treatment on the surface of the Wherein M is 1 is-CONH 2 ，M 2 is-CONHC (CH) 3 ) 2 CH 2 SO 3 H，M 3 Is- [ NCH 2 (CH 3 ) 2 (CH 2 ) m CH 3 ] + ；
Wherein x: y: z=1: 0.11:0.064; and
the weight average molecular weight of the oil well cement sedimentation stabilizer S6 is 378 ten thousand.
Example 7
This example is intended to illustrate an oil well cement sedimentation stabilizer prepared by the method of the present invention.
An oil well cement sedimentation stabilizer was prepared in the same manner as in example 1 except that: the rigid hydrophobic monomer has a structure shown in formula (VI) and ，R 6 H and m is 19.
The oil well cement sedimentation stabilizer prepared by the result is marked as S7;
the oil well cement sedimentation stabilizer S7 comprises the following structure:
[CH 2 CM 1 H] x -[CM 2 HCH 2 ] y -[CH 2 CM 3 HCl - ] z the method comprises the steps of carrying out a first treatment on the surface of the Wherein M is 1 is-CONH 2 ，M 2 is-CONHC (CH) 3 ) 2 CH 2 SO 3 H，M 3 Is- [ NCH 2 (CH 3 ) 2 (CH 2 ) m CH 3 ] + ；
Wherein x: y: z=1: 0.11:0.059; and
the weight average molecular weight of the oil well cement sedimentation stabilizer S7 is 403 ten thousand.
Example 8
This example is intended to illustrate an oil well cement sedimentation stabilizer prepared by the method of the present invention.
An oil well cement sedimentation stabilizer was prepared in the same manner as in example 1 except that: the pH was 9 and the amounts of the respective monomers 2-acrylamido-2-methylpropanesulfonic acid, acrylamide and rigid hydrophobic monomer were adjusted accordingly.
The oil well cement sedimentation stabilizer prepared by the result is marked as S8;
wherein, this oil well cement sedimentation stabilizer S8 contains the structure:
[CH 2 CM 1 H] x -[CM 2 HCH 2 ] y -[CH 2 CM 3 HCl - ] z the method comprises the steps of carrying out a first treatment on the surface of the Wherein M is 1 is-CONH 2 ，M 2 is-CONHC (CH) 3 ) 2 CH 2 SO 3 H，M 3 Is- [ NCH 2 (CH 3 ) 2 (CH 2 ) m CH 3 ] + ；
Wherein x: y: z=1: 0.08:0.048; and
the weight average molecular weight of the oil well cement sedimentation stabilizer S8 is 383 ten thousand.
Comparative example 1
An oil well cement sedimentation stabilizer was prepared in the same manner as in example 1 except that: hydroxyethyl cellulose is used as an oil well cement sedimentation stabilizer. The oil well cement sedimentation stabilizer prepared as a result is marked as DS1.
Comparative example 2
An oil well cement sedimentation stabilizer was prepared in the same manner as in example 1 except that: AM/AMPS copolymer is used as the oil well cement sedimentation stabilizer. The oil well cement sedimentation stabilizer prepared as a result is marked as DS2.
Comparative example 3
An oil well cement sedimentation stabilizer was prepared in the same manner as in example 1 except that: xanthan gum is used as an oil well cement sedimentation stabilizer. And marking the oil well cement sedimentation stabilizer prepared as a result as DS3.
Comparative example 4
An oil well cement sedimentation stabilizer was prepared in the same manner as in example 1 except that: the weight ratio of the 2-acrylamido-2-methylpropanesulfonic acid, acrylamide and the rigid hydrophobic monomer is 1:5:4.
the oil well cement sedimentation stabilizer prepared as a result is marked as DS4.
Comparative example 5
An oil well cement sedimentation stabilizer was prepared in the same manner as in example 1 except that: the 2-acrylamido-2-methylpropanesulfonic acid, acrylamide and the rigid hydrophobic monomer are used in amounts such that the oil well cement sedimentation stabilizer prepared contains the following structures:
[CH 2 CR 1 H] x -[CR 2 HCH 2 ] y -[CH 2 CR 3 HCl - ] z the method comprises the steps of carrying out a first treatment on the surface of the Wherein R is 1 is-CONH 2 ，R 2 is-CONHC (CH) 3 ) 2 CH 2 SO 3 H，R 3 Is- [ NCH 2 (CH 3 ) 2 (CH 2 ) m CH 3 ] + ；
Wherein x: y: z=1: 0.01:0.01.
the oil well cement sedimentation stabilizer prepared as a result is marked as DS5.
Comparative example 6
An oil well cement sedimentation stabilizer was prepared in the same manner as in example 1 except that: the 2-acrylamido-2-methylpropanesulfonic acid, acrylamide and the rigid hydrophobic monomer are used in amounts such that the weight average molecular weight of the prepared oil well cement sedimentation stabilizer is 155 ten thousand.
The oil well cement sedimentation stabilizer prepared as a result is marked as DS6.
Test example 1
Preparation of oil well Cement sedimentation stabilizers of different concentrations (0.2 wt%, 0.4 wt%) as described in example 1, evaluation of the high temperature rheology of the polymer solutions was carried out using a HAAKE advanced rheometer (Sesameimer technology Co., ltd., germany) with a shear rate of 430s -1 The temperature control mode is water bath temperature control, the temperature range is 25-200 ℃, the temperature rising speed is 1 ℃/min, and the result is shown in figure 1.
As can be seen from fig. 1, the rheological curve of the 0.4 wt% concentration oil well cement sedimentation stabilizer solution gradually increases and then decreases with increasing temperature, which indicates that the oil well cement sedimentation stabilizer exhibits a strong thermal tackifying effect at higher concentrations. The high temperature rheological curve of the 0.2 wt% concentration oil well cement sedimentation stabilizer solution is very smooth, and the apparent viscosity is not changed basically with the temperature rise, which indicates that the oil well cement sedimentation stabilizer can also show certain thermal viscosity increasing property at low concentration, so that the apparent viscosity of the polymer solution is not obviously reduced at high temperature. In addition, as can be seen from fig. 1, the oil well cement sedimentation stabilizer of the invention can resist high temperature up to 150 ℃ and can meet the requirement of high-temperature well cementation.
Test example 2
The oil well sedimentation stabilizer solution of example 1, the hydroxyethylcellulose solution of comparative example 1 and the comparative example 2AM/A were prepared to have a mass fraction of 0.6 wt%, respectivelyThe apparent viscosity of the MPS copolymer solution and the 0.6 wt% xanthan gum solution of comparative example 3 were measured by a six-speed rotational viscometer (Qingdao sea Toyoshida Instrument Co., ltd.) and the shear rate was 732.4s, respectively -1 The temperature control mode is water bath temperature control, the temperature rise is controlled to be 5 ℃, and the result is shown in figure 2.
As can be seen from fig. 2, the oil well cement sedimentation stabilizer solution has a thermal viscosity increasing property, has the lowest apparent viscosity at normal temperature (20-50 ℃), and gradually increases with the increase of temperature after reaching a certain temperature; hydroxyethyl cellulose solution and xanthan gum solution exhibit high viscosity at normal temperature, but their apparent viscosity decreases rapidly with increasing temperature; the apparent viscosity of the AM/AMPS copolymer solution was kept substantially unchanged with temperature and was kept at about 80 mPas. Apparent viscosity at room temperature (25 ℃) was: 6% AM/AMPS copolymer solution <0.6% xanthan gum solution approximately equal to 0.6% oil and gas well cement sedimentation stabilizer solution <0.6% hydroxyethyl cellulose solution; apparent viscosity at high temperature (80 ℃) was: 0.6% hydroxyethylcellulose solution <0.6% xanthan gum solution <6% am/AMPS copolymer solution <0.6% oil well cement sedimentation stabilizer solution.
In conclusion, the hydroxyethyl cellulose and the xanthan gum can effectively improve the apparent viscosity of a liquid phase under normal temperature conditions, and almost have no tackifying effect at high temperature, and the oil well cement sedimentation stabilizer can realize a thermal tackifying effect.
Test example 3
Since oil well cement slurries are weakly alkaline (pH typically 9-13), the alkali resistance of the synthesized oil well cement settlement stabilizers needs to be evaluated to determine whether they can exhibit a thickening effect in the cement slurry. The oil well cement sedimentation stabilizer described in example 1 was first prepared with a mass fraction of 0.6%, then NaOH (NaOH concentration vs. pH shown in table 1) with a mass fraction of 0.01%, 0.1%, 1% and 4% was added to the solution, respectively, and the rheology of each set of polymer solutions was evaluated using a six-speed rotational viscometer (Qingdao sea access instruments limited) and the results are shown in fig. 3.
TABLE 1
As can be seen from fig. 3, at NaOH concentrations of 0.01% and 0.1%, the thickening effect of the oil well cement sedimentation stabilizer was hardly affected, and when the NaOH concentration was increased to 1%, the apparent viscosity of the oil well cement sedimentation stabilizer solution began to decrease, but the decrease was small in magnitude. And when the concentration of NaOH reaches 4%, the apparent viscosity of the oil well cement sedimentation stabilizer solution begins to decrease significantly. When the concentration of NaOH is 1%, the corresponding pH value is 13.4 and is higher than the pH value (9-13) of common oil well cement slurry, so that the oil well cement sedimentation stabilizer synthesized by the invention has enough alkali resistance and is completely suitable for the weak alkaline environment of the oil well cement slurry.
Test example 4
The oil well cement sedimentation stabilizer described in example 1 was prepared with a mass fraction of 0.6%, and then NaCl (the correspondence between NaCl concentration and mineralization degree is shown in Table 2) with a mass fraction of 0.05%, 0.2%, 0.65% and 3% was added to the solution, respectively, so that the solution corresponded to the median mineralization degree of fresh water, brackish water (weakly mineralized water), salty water (moderately mineralized water) and brine (strongly mineralized water), respectively, and the rheological properties of each group of polymer solutions were evaluated by using a six-speed rotary viscometer (Qingdao sea access special instruments Co., ltd.), and the results are shown in FIG. 4.
TABLE 2
| NaCl concentration/% | Mineralization degree/(g/L) | Water-based products |
| 0.05 | 0.5 | Fresh water |
| 0.2 | 2 | Brackish water |
| 0.65 | 6.5 | Salt water |
| 3 | 30 | Brine |
As can be seen from fig. 4, the apparent viscosity of the oil well cement sedimentation stabilizer solution gradually decreases at various temperatures as the NaCl concentration increases. The viscosity of the oil well cement sedimentation stabilizer solution decreased slightly when the NaCl was less than 0.65%, and when the NaCl concentration reached 3%, the viscosity of the oil well cement sedimentation stabilizer solution began to decrease significantly and the thermal thickening effect was also inhibited. The results show that the oil well cement sedimentation stabilizer has certain salt resistance, can be used cooperatively with inorganic salt additives with certain concentration, and can be prepared by adopting fresh water, brackish water and salty water in a well cementation site.
Test example 5
The oil well cement sedimentation stabilizer described in example 1 was added to a grade G cement slurry at a ratio of 0.025 wt%, 0.05 wt% and 0.1 wt%, the effect of the oil well cement sedimentation stabilizer on the thickening time of the cement slurry was tested using an atmospheric thickener, the thickening temperature was kept at 75 c, the test thickening curve was shown in fig. 5, and the thickening time and the initial consistency were summarized as shown in table 3.
TABLE 3 Table 3
| Cement and its preparation method | Water to ash ratio | Sedimentation stabilizer/% | Initial consistency/Bc | Thickening time/min |
| G-level cement paste | 0.44 | 0 | 18.0 | 83 |
| G-level cement paste | 0.44 | 0.025 | 19.1 | 89 |
| G-level cement paste | 0.44 | 0.05 | 24.4 | 92 |
| G-level cement paste | 0.44 | 0.1 | 21.1 | 100 |
As can be seen from fig. 5 and table 3, the thickening time of the G-stage cement slurry without the oil well cement sedimentation stabilizer is 83min at 75 ℃, and the addition of 0.025%, 0.05% and 0.1% of the oil well cement sedimentation stabilizer can prolong the thickening time of the G-stage cement slurry to 89min, 92min and 100min, respectively, i.e. the thickening time of the cement slurry is prolonged along with the increase of the addition of the oil well cement sedimentation stabilizer, which indicates that the oil well cement sedimentation stabilizer has a certain retarding effect. In addition, by comparing the initial consistencies, the oil well cement sedimentation stabilizer has no adverse effect on the initial consistencies of the cement slurry.
Test example 6
The high-temperature high-density well cementation cement slurry is prepared according to the formula, and the used high-temperature fluid loss agent and high-temperature retarder are provided by medium petrochemical victory well cementation companies. Wherein no sedimentation stabilizer was added and designated as cement slurry A, cement slurries prepared by dry mixing the sedimentation stabilizers described in example 1, comparative examples 1-3 directly with powder materials were designated as cement slurries S1, DS2, DS3, respectively. According to the standard GB/T19139-2003 oil well cement test method, and referring to the standard SY/T6544-2003 oil well cement slurry performance requirement and the standard SY/T6466-2000 oil well cement stone high temperature resistance evaluation method, the consistency, thickening time, compressive strength and upper and lower density differences of cement slurry are tested to evaluate the influence of different sedimentation stabilizers on the cement slurry performance. The evaluation method of the cement paste up-down density difference comprises the following steps: stirring the high-temperature high-density cement paste in a thickener at 30 ℃ for 20min, curing for 2.5h at room temperature, and testing the upper and lower densities to calculate the density difference; stirring the high-temperature high-density cement paste at 100deg.C, 135 deg.C and 150deg.C in a thickener for 20min at 100deg.C, 135 deg.C and 150deg.C respectively, curing at 90deg.C for 2.5 hr, and testing the upper and lower densities to calculate the density difference, when the upper and lower densities difference is less than or equal to 0.03g/cm 3 In this case, the sedimentation stability was good. Results such asTable 4 shows the effect of different oil well cement sedimentation stabilizers on cement slurry properties.
TABLE 4 Table 4
From the experimental results in table 4, it can be seen that:
(1) In terms of consistency, the oil well cement sedimentation stabilizer of the invention does not increase the consistency of cement paste at normal temperature, for example, at 30 ℃, but can have a thickening effect at high temperature, for example, at 100 ℃, 135 ℃ and 150 ℃ so as to keep the consistency of cement paste within a reasonable range. The hydroxyethyl cellulose, the AM/AMPS copolymer and the xanthan gum can increase the consistency of cement paste at normal temperature, for example, at 30 ℃, reduce the rheological property of the cement paste, and are unfavorable for pumping the cement paste, and the consistency can be obviously reduced at high temperature, for example, at 100 ℃, 135 ℃ and 150 ℃, so that the effect of obviously thickening is not achieved, and the ideal effect of improving the sedimentation stability is difficult to achieve.
(2) In the aspect of thickening time, the thickening time of cement added with the oil well cement sedimentation stabilizer and the hydroxyethyl cellulose does not obviously change along with the increase of temperature, and the AM/AMPS copolymer and the xanthan gum obviously prolong the thickening time of cement and influence the normal hydration reaction of the cement. Therefore, the oil well cement sedimentation stabilizer can realize the aims of low-temperature non-thickening and high-temperature thickening, and effectively improve the sedimentation stability of well cementing cement slurry.
(3) In the aspect of compressive strength, no matter whether an oil well cement sedimentation stabilizer is added or not, the compressive strength of the cement stone is reduced along with the increase of the temperature at the temperature of more than 100 ℃. Under the same temperature condition, the oil well cement sedimentation stabilizer can slightly improve the compressive strength of the cement stone, and the hydroxyethyl cellulose, the AM/AMPS copolymer and the xanthan gum can obviously reduce the compressive strength of the cement stone, so that the oil well cement sedimentation stabilizer is not suitable for the environment of deep wells at high temperature and high pressure.
(4) In terms of the upper and lower density differences of cement paste, the four sedimentation stabilizers of the oil well cement sedimentation stabilizer, the hydroxyethyl cellulose, the AM/AMPS copolymer and the xanthan gum can reduce the upper and lower density differences of cement paste under the normal temperature condition, for example, the temperature is 50 ℃, and only the oil well cement sedimentation stabilizer can obviously reduce the upper and lower density differences of cement paste and can achieve good sedimentation stabilizing effect under the high temperature condition, for example, the temperature is 100 ℃, 135 ℃ and 150 ℃. Therefore, the oil well cement sedimentation stabilizer can play a role in sedimentation stabilization at normal temperature and high temperature, has a wide temperature range, has good temperature resistance, and can resist the temperature up to 150 ℃.
In conclusion, from the use effect, the oil well cement sedimentation stabilizer S1 has no adverse effect on the comprehensive performance of cement paste, can improve the high-temperature sedimentation stability and the compressive strength of the cement paste, and ensures the well cementation quality. The oil well cement sedimentation stabilizer provided by the invention has good application prospects in special well cementation operations such as high-temperature deep wells, high-inclination wells, horizontal wells and the like.
Test example 7
The test was performed in the same manner as in test example 6 except that cement slurry a was not added with the oil well cement sedimentation stabilizer, except that: the cement slurries prepared by dry blending the oil well cement sedimentation stabilizers described in examples 2 to 8, comparative examples 4 to 6 directly with the powder material were designated as cement slurries S2 to S8, and DS4 to DS6, respectively. The results are shown in Table 5 as the effect of different oil well cement sedimentation stabilizers on cement slurry properties.
TABLE 5
From the experimental results in table 5, it can be seen that:
(1) In terms of consistency, the oil well cement sedimentation stabilizer S2-S8 of the invention does not increase the consistency of cement paste at normal temperature, for example, at 30 ℃, but can have a thickening effect at high temperature, for example, at 100 ℃, 135 ℃ and 150 ℃ so as to keep the consistency of cement paste within a reasonable range. While comparative examples 4 to 6 increase the consistency of the cement paste at normal temperature, for example, at 30 ℃, reduce the rheological property of the cement paste, and are unfavorable for pumping of the cement paste, and at high temperature, for example, at 100 ℃, 135 ℃ and 150 ℃, the consistency is remarkably reduced, and the effect of remarkably thickening is not achieved, so that the effect of improving the sedimentation stability is difficult to achieve.
(2) In the aspect of thickening time, the thickening time of cement added with the oil well cement sedimentation stabilizer S2-S8 does not obviously change along with the increase of temperature, and the comparative examples 4-6 obviously prolong the thickening time of cement and influence the normal hydration reaction of cement. Therefore, the oil well cement sedimentation stabilizer can realize the aims of low-temperature non-thickening and high-temperature thickening, and effectively improve the sedimentation stability of well cementing cement slurry.
(3) In the aspect of compressive strength, no matter whether an oil well cement sedimentation stabilizer is added or not, the compressive strength of the cement stone is reduced along with the increase of the temperature at the temperature of more than 100 ℃. Under the same temperature condition, the oil well cement sedimentation stabilizer S2-S8 can slightly improve the compressive strength of the cement stone, and the comparative examples 4-6 can obviously reduce the compressive strength of the cement stone, and are not suitable for the environment of deep wells at high temperature and high pressure.
(4) In terms of the difference between the upper and lower densities of cement paste, the oil well cement sedimentation stabilizer S2-S8 and the comparative examples 4-6 of the invention can reduce the difference between the upper and lower densities of cement paste under normal temperature conditions, for example, at 30 ℃, and only the oil well cement sedimentation stabilizer S2-S8 of the invention can obviously reduce the difference between the upper and lower densities of cement paste and reach sedimentation stability standards under high temperature conditions, for example, at 100 ℃, 135 ℃ and 150 ℃. Therefore, the oil well cement sedimentation stabilizer S2-S8 can play a role in sedimentation stabilization at normal temperature and high temperature, has a wide temperature range, has good temperature resistance, and can resist the temperature of up to 150 ℃.
In conclusion, from the use effect, the oil well cement sedimentation stabilizer S2-S8 has no adverse effect on the comprehensive performance of cement paste, can improve the high-temperature sedimentation stability and compressive strength of the cement paste, and ensures the well cementation quality. The oil well cement sedimentation stabilizer provided by the invention has good application prospects in special well cementation operations such as high-temperature deep wells, high-inclination wells, horizontal wells and the like.
The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited thereto. Within the scope of the technical idea of the invention, a number of simple variants of the technical solution of the invention are possible, including combinations of the individual technical features in any other suitable way, which simple variants and combinations should likewise be regarded as being disclosed by the invention, all falling within the scope of protection of the invention.
Claims (10)
1. A well cementing slurry, characterized in that the well cementing slurry comprises an oil well cement sedimentation stabilizer, and the content of the oil well cement sedimentation stabilizer is 0.5-1.0 wt% based on the total weight of the well cementing slurry;
wherein the oil well cement sedimentation stabilizer comprises a structural unit A shown in a formula (I), a structural unit B shown in a formula (II) and a structural unit C shown in a formula (III);
Wherein the molar ratio of the structural unit A, the structural unit B and the structural unit C is x: y: z=1: (0.07-0.22): (0.03-0.11);
wherein R is 1 、R 2 And R is 3 Each independently is H;
wherein m is 21;
wherein the weight average molecular weight of the oil well cement sedimentation stabilizer is 350-500 ten thousand.
2. The well cementing slurry of claim 1, wherein the method of preparing the oil well cement sedimentation stabilizer comprises: in the presence of an initiator, mixing a monomer A, a monomer B, a monomer C and deionized water, and then carrying out copolymerization reaction;
wherein the monomer A has a structure shown in a formula (IV), the monomer B has a structure shown in a formula (V), and the monomer C has a structure shown in a formula (VI);
wherein R is 4 、R 5 And R is 6 Each independently is H;
wherein m is 21;
wherein, the weight ratio of the dosage of the monomer A, the monomer B and the monomer C is (1-10): (0.5-5): 1.
3. the well cementing slurry of claim 2, wherein the weight ratio of the amounts of monomer a, monomer B, and monomer C is (1-5): (0.5-3): 1.
4. a well cementing slurry according to claim 2 wherein the total amount of monomer a, monomer B and monomer C is 30-40% by weight of the amount of deionized water.
5. The well cementing slurry of claim 2, wherein the pH of the mixture of monomer a, monomer B, monomer C and deionized water is 8-9.
6. A well cementing slurry according to claim 2, wherein the initiator is sodium bisulphite and/or ammonium persulphate.
7. The cement slurry of claim 6, wherein the molar ratio of sodium bisulfite to the amount of ammonium persulfate is 1: (1.2-1.4).
8. The cement slurry of claim 7, wherein the total amount of sodium bisulfite and ammonium persulfate is from 0.5 to 1 weight percent of the total amount of monomer a, monomer B, and monomer C.
9. A well cementing slurry according to claim 2, wherein the copolymerization conditions comprise: reacting for 10-12h under the condition of standing at 50-60 ℃; the initiator is dropwise added into the mixed solution of the monomer A, the monomer B, the monomer C and the deionized water at the dropwise adding rate of 0.5-1ml/min under the constant-speed stirring with the stirring rate of 100-200 r/min.
10. The well cementing slurry of claim 2, wherein the method further comprises subjecting the reaction product after the copolymerization reaction to a purification and drying process, wherein the purification is performed 3-6 times with absolute ethanol.
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| Title |
|---|
| "热增黏聚合物合成及对水泥浆沉降稳定性的影响研究";陈新;《中国石油大学(华东)硕士论文》;20180501;第15,18,22-24,26-29,46,54页 * |
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| CN109485788A (en) | 2019-03-19 |
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