Elastic-toughness well cementation cement slurry suitable for coal bed gas and preparation method thereof
阅读说明：本技术 一种适用于煤层气的弹韧性固井水泥浆及其制备方法 (Elastic-toughness well cementation cement slurry suitable for coal bed gas and preparation method thereof ) 是由 孙晗森 马腾飞 程璐 李丹琼 印薇薇 侯岩波 王德桂 杨刚 王成文 于 2020-12-02 设计创作，主要内容包括：本发明提供了一种适用于煤层气的弹韧性固井水泥浆,包括：油井水泥100重量份；水溶性树脂12～15重量份；纤维0.8～4重量份；纳米颗粒7～9重量份；水35～48重量份。与现有技术相比,本发明利用纳米颗粒调控水泥浆水化反应；同时填充水泥石中的微孔隙,提高水泥石致密性,优化强度；同时加入纤维不仅可在裂缝中起到架桥作用,还可在水泥石中形成致密网状结构,吸收外力冲击,提高水泥的抗拉强度；再者加入水溶性树脂作为胶结材料可提高封堵材料之间及封堵材料与裂缝表面的胶结,进一步提高封堵结构的稳定性,并且由于树脂材料具有较好的弹韧性,可提高水泥浆的弹韧性。(The invention provides elastic toughness well cementation cement slurry suitable for coal bed gas, which comprises the following components: 100 parts of oil well cement; 12-15 parts by weight of a water-soluble resin; 0.8-4 parts by weight of fiber; 7-9 parts of nanoparticles; 35-48 parts of water. Compared with the prior art, the invention utilizes the nano particles to regulate and control the hydration reaction of the cement paste; simultaneously, micropores in the set cement are filled, so that the compactness of the set cement is improved, and the strength is optimized; meanwhile, the added fibers not only can play a bridging role in cracks, but also can form a compact network structure in the set cement to absorb external force impact and improve the tensile strength of the cement; and moreover, the water-soluble resin is added as a cementing material, so that the cementation between the plugging materials and the surfaces of cracks can be improved, the stability of the plugging structure is further improved, and the elastic toughness of the cement paste can be improved due to the fact that the resin material has better elastic toughness.)
1. The utility model provides a bullet toughness well cementation cement thick liquid suitable for coal bed gas which characterized in that includes:
2. the elastic-toughness well cementation cement slurry as claimed in claim 1, wherein the length of the fiber is 2-8 mm; the particle size of the nanoparticles is 50-200 nm.
3. The elasto-tough cementing slurry of claim 2, wherein the tensile strength of the fibers is greater than 0.9 GPa; the density of the nano particles is 1.15-1.3 g/cm3。
4. The elasto-tough cementing slurry of claim 1, wherein the water-soluble resin is selected from phenolic and/or epoxy resins;
the fibers are organic fibers and/or inorganic fibers; the organic fiber is selected from one or more of polypropylene fiber, polyethylene fiber and lignin fiber; the inorganic fiber is selected from one or more of basalt fiber, carbon fiber and glass fiber;
the nano-particles are magnesium oxide and/or silicon oxide.
5. The elastic-tough well cementation cement slurry according to claim 4, wherein the fiber is a mixture of organic fiber and inorganic fiber; the mass ratio of the organic fibers to the inorganic fibers is (2-2.5): 1.
6. the elastic and flexible well cementation cement slurry as claimed in claim 1, wherein the fiber is a mixture of basalt fiber and lignin fiber; the mass ratio of the basalt fibers to the lignin fibers is 1: (2-2.5).
7. The elastic toughness well cementation cement slurry as claimed in claim 1, characterized by further comprising:
0.1-1 part by weight of a defoaming agent;
2.1-4.7 parts by weight of a fluid loss agent;
0.7 to 1.4 parts by weight of a dispersant.
8. The elastic-tough cementing slurry of claim 7, wherein the oil well cement is an API oil well G-grade high sulfur-resistant cement;
the fluid loss agent is a 2-acrylamide-2-methylpropanesulfonic acid polymer and/or a polyvinyl alcohol crosslinking fluid loss agent; the weight average molecular weight of the fluid loss agent is 75-90 ten thousand;
the dispersant is one or more of lignosulfonate, sulfonated aldehyde ketone condensate and sulfonic acid formaldehyde condensate;
the defoaming agent is one or more of a silicon ether copolymerization defoaming agent, an organic siloxane defoaming agent and a polyether defoaming agent;
the water is fresh water and/or mineralization water.
9. The preparation method of the elastic toughness well cementation cement slurry suitable for coal bed gas in claim 1 is characterized by comprising the following steps:
s1) mixing the nano particles, the fibers, the water-soluble resin and water to obtain a liquid phase;
s2) mixing the oil well cement with the liquid phase to obtain the elastic toughness well cementation cement paste suitable for the coal bed gas.
10. The preparation method according to claim 9, wherein the step S1) is specifically: mixing the nano particles with water, carrying out ultrasonic dispersion, and then adding fibers and water-soluble resin to obtain a liquid phase.
Technical Field
The invention belongs to the technical field of coal bed gas exploitation, and particularly relates to elastic and flexible well cementation cement slurry suitable for coal bed gas and a preparation method thereof.
Background
In the existing coal bed gas mining process, cement slurry must be injected in a perforation mode because of a plurality of coal bed blocks and small intervals among coal beds. In the perforation process, the perforating bullet can generate high-speed energy-gathered jet at the moment of detonation to act on the packing structure of the sleeve, the cement sheath and the surrounding rock, and certain damage is caused to the cement sheath. In particular, the casing, the cement sheath and the formation rock have different elastic toughness and strength, and under the condition of external force impact, different deformations are easy to occur, so that the cement sheath body is damaged, and the cementing separation, micro-annular gaps and the like of the first interface (sheath-cement sheath interface) and the second interface (cement sheath-surrounding rock interface) are caused.
In order to ensure the integrity of the cement sheath and the well cementation interface in the perforation process, the elastic toughness and the strength of the set cement need to be improved. In general, elastic toughness of cement paste is modified by adding materials such as rubber, resin, nano material, fiber, latex, and high molecular polymer into the cement paste. For example, Soltanian et al utilize the modified terpolymer rubber of carboxylated monomers to improve the elastic toughness of the cement stone and increase the elasticity of the cement stone (reduce Young modulus and increase Poisson ratio), but the strength of the cement stone is reduced due to the change of the internal structure of the cement stone; wang et al utilize modified multi-walled carbon nanotubes to improve the toughness of the set cement, and research shows that the addition of a small amount of modified multi-walled carbon nanotubes can improve the fracture energy of cement paste by 5 times, improve the compactness of the set cement, show better strength development of the set cement, but the modified multi-walled carbon nanotubes have higher cost and cannot be popularized in a large area under the current engineering situation; the method is characterized in that an early strength and toughness cement slurry system is prepared by using superfine metal oxide or silicon oxide particles subjected to surface modification and graft modification as a main reinforcing agent and matching with a related performance regulating agent, the thickening time is adjustable, the transition time is short, and the elastic modulus is less than 6.6 GPa; wuxuepin et al utilize a latex system and a latex stabilizer, and cooperate with a reinforcing toughening agent and a fiber material, thereby greatly improving the impact resistance of the cement stone and reducing the elastic modulus; cheng Xiao Wei et al in patent CN101857800A "a leak stoppage cement slurry for well cementation and its preparation method" propose, adopt fibrilia material, utilize the change of the surface chemical group of fiber to lead to the change of surface energy and the enhancement of chemical bonding effect, and the increase of surface roughness leads to the enhancement of mechanical locking effect, promote the compactness of the interface, strengthen the bonding strength of the interface, improve the leak stoppage performance and the toughness of the set cement; in the patent CN104946219A of "a low-density high-strength cement paste", Vancaochen et al, liquid silicon dioxide and hollow glass beads are used as lightening agents, and simultaneously, a fiber material is adopted for bridging, so that the strength and better rheological property of the set cement are ensured on the premise of effectively reducing the density.
The rubber material, the latex material, the fiber material, the nano material and the like are adopted, although the internal structure of the cement stone can be modified to a certain degree, the mechanical property of the cement stone can be modified, and the problem that the cement stone is easy to damage and deform under the action of perforation impact can be solved to a certain degree, the following defects still exist: (1) the rubber material can improve the mechanical property, but the temperature resistance is poor, the system is easy to deform under the high-temperature condition, the original characteristics are lost, and the strength of the set cement is even influenced; (2) the latex material can improve the microstructure and the mechanical property of cement, but the latex material contains a large amount of oleophilic groups and is easy to influence the hydration of the cement, so that the related addition needs to be strictly controlled when the latex material is adopted, and the latex can possibly influence the environment to a certain extent; (3) the nano material can play roles of filling cement stone pores, participating in hydration reaction and the like, and improves the microstructure of the cement stone, but the regulation and control rule of the nano material is not fully researched at present, so that the nano material can not be effectively guided to be optimized, and part of the nano material has higher cost and is not suitable for large-area popularization in engineering application; (4) fiber materials and the like have higher mechanical property modification effects, but reasonable surface modification is often needed, and the modification capability of the fiber materials on the elastic modulus of the set cement is limited, so that the elastic modulus of the set cement cannot be effectively improved.
Disclosure of Invention
In view of the above, the technical problem to be solved by the present invention is to provide a high-strength elastic-tough well cementation cement slurry suitable for coal bed gas and a preparation method thereof.
The invention provides elastic toughness well cementation cement slurry suitable for coal bed gas, which comprises the following components:
preferably, the length of the fiber is 2-8 mm; the particle size of the nanoparticles is 50-200 nm.
Preferably, the tensile strength of the fibers is greater than 0.9 GPa; the density of the nano particles is 1.15-1.3 g/cm3。
Preferably, the water-soluble resin is selected from phenolic resin and/or epoxy resin;
the fibers are organic fibers and/or inorganic fibers; the organic fiber is selected from one or more of polypropylene fiber, polyethylene fiber and lignin fiber; the inorganic fiber is selected from one or more of basalt fiber, carbon fiber and glass fiber;
the nano-particles are magnesium oxide and/or silicon oxide.
Preferably, the fibers are a mixture of organic fibers and inorganic fibers; the mass ratio of the organic fibers to the inorganic fibers is (2-2.5): 1.
preferably, the fiber is a mixture of basalt fiber and lignin fiber; the mass ratio of the basalt fibers to the lignin fibers is 1: (2-2.5).
Preferably, the method further comprises the following steps:
0.1-1 part by weight of a defoaming agent;
2.1-4.7 parts by weight of a fluid loss agent;
0.7 to 1.4 parts by weight of a dispersant.
Preferably, the oil well cement is API oil well G-grade high-sulfur-resistant cement;
the fluid loss agent is a 2-acrylamide-2-methylpropanesulfonic acid polymer and/or a polyvinyl alcohol crosslinking fluid loss agent; the weight average molecular weight of the fluid loss agent is 75-90 ten thousand;
the dispersant is one or more of lignosulfonate, sulfonated aldehyde ketone condensate and sulfonic acid formaldehyde condensate;
the defoaming agent is one or more of a silicon ether copolymerization defoaming agent, an organic siloxane defoaming agent and a polyether defoaming agent;
the water is fresh water and/or mineralization water.
The invention also provides a preparation method of the elastic toughness well cementation cement slurry suitable for coal bed gas, which comprises the following steps:
s1) mixing the nano particles, the fibers, the water-soluble resin and water to obtain a liquid phase;
s2) mixing the oil well cement with the liquid phase to obtain the elastic toughness well cementation cement paste suitable for the coal bed gas.
Preferably, the step S1) is specifically: mixing the nano particles with water, carrying out ultrasonic dispersion, and then adding fibers and water-soluble resin to obtain a liquid phase.
The invention provides elastic toughness well cementation cement slurry suitable for coal bed gas, which comprises the following components: 100 parts of oil well cement; 12-15 parts by weight of a water-soluble resin; 0.8-4 parts by weight of fiber; 7-9 parts of nanoparticles; 35-48 parts of water. Compared with the prior art, the invention utilizes the nano particles to regulate and control the hydration reaction of the cement paste; simultaneously, micropores in the set cement are filled, so that the compactness of the set cement is improved, and the strength is optimized; meanwhile, the added fibers not only can play a bridging role in cracks, but also can form a compact network structure in the set cement to absorb external force impact and improve the tensile strength of the cement; and moreover, the water-soluble resin is added as a cementing material, so that the cementation between the plugging materials and the surfaces of cracks can be improved, the stability of the plugging structure is further improved, and the elastic toughness of the cement paste can be improved due to the fact that the resin material has better elastic toughness.
Experiments show that the cement stone formed by the elastic and tough well cementation cement paste provided by the invention has the 24-hour compressive strength of more than 23MPa and the 72-hour compressive strength of more than 31MPa, and meets the requirements of field engineering; the elastic toughness well cementation cement slurry can reduce the elastic modulus of the set cement by over 25 percent; the density of the elastic toughness well cementation cement paste is 1.60-1.80 g/cm3The cement has better stability and flow property, no free liquid, no water loss amount less than or equal to 45mL/30min, adjustable thickening time and accordance with the requirements of site construction.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
The invention provides elastic toughness well cementation cement slurry suitable for coal bed gas, which comprises the following components:
the present invention is not particularly limited in terms of the source of all raw materials, and may be commercially available.
Aiming at the problems of cement damage caused by impact perforation and micro annular space generation on a well cementation interface in the coal bed gas development process in the prior art, the invention improves the mechanical property of cement stone by combining and compounding water-soluble resin, nano particles and fiber materials, optimizes additives, regulates and controls other engineering properties of cement paste, constructs high-strength elastic toughness well cementation cement paste suitable for coal bed gas well cementation, improves the overall well cementation quality and ensures the requirements of later development.
The oil well cement is preferably API oil well G-grade high-sulfur-resistant cement, and more preferably API oil well G-grade high-sulfur-resistant cement produced from Shandong Lin 384victoria Special Cement Ltd or Jiahua special cement.
The invention realizes the purpose of improving the compactness of the set cement by adding the nano particles and utilizing the principles of particle grading and compact packing, so that the formed set cement has high strength, and the nano particles can influence the hydration of the set cement and improve the early strength of the set cement. The particle size of the nano particles is preferably 50-200 nm; the density of the nano particles is preferably 1.15-1.3 g/cm3(ii) a The nanoparticles are preferably magnesium oxide and/or silicon dioxide; in the invention, the nano particles can also be micro-nano sized crystal nucleus materials; in the present invention, silica is most preferably used as the nanoparticle; compared with nano liquid silicon, the solid phase nano silicon dioxide particles have more appropriate surface groups, and the influence of a large amount of hydroxyl groups on the surface of the nano liquid silicon on the interaction of the nano liquid silicon and cement particles is avoided.
In the invention, the water-soluble resin is preferably phenolic resin and/or epoxy resin, more preferably bisphenol A epoxy resin, and the structure of the water-soluble resin is shown as the formula (I); according to the invention, the microscopic pores are filled with the water-soluble resin, especially the epoxy resin, so that the cementation condition of particles and components in the set cement is improved, the problem that the set cement is easily damaged by external force due to uneven stress distribution caused by the existence of larger pores or abnormal solid particles in the set cement is solved, and the toughness of the set cement is improved. In the present invention, bisphenol a epoxy resin is most preferably included, and the epoxy group of bisphenol a epoxy resin can make the resin phase compatible with the water phase of the cement paste through epoxy ring-opening reaction in the curing stage during the resin crosslinking process. By the method, the resin can generate chemical action with the suspended matters in the cement slurry to form a novel chain skeleton consisting of silicate and polyamine groups in a water phase, and the novel chain skeleton has excellent micron-sized dispersibility between organic resin and cement hydration products, thereby effectively reducing brittleness caused by cement product inhomogeneity and improving early compressive strength.
The length of the fiber is preferably 2-8 mm, more preferably 3-7 mm, further preferably 3-6 mm, and most preferably 3-5 mm; the tensile strength of the fibers is preferably greater than 0.9 GPa; in the present invention, the fibers are preferably organic fibers and/or inorganic fibers, more preferably a mixture of organic fibers and inorganic fibers; the organic fiber is preferably one or more of polypropylene fiber, polyethylene fiber and lignin fiber; the inorganic fiber is preferably one or more of basalt fiber, carbon fiber and glass fiber; the mass ratio of the organic fibers to the inorganic fibers is (2-2.5): 1; in the present invention, the fibers are most preferably a mixture of basalt fibers and lignin fibers; the mass ratio of the basalt fibers to the lignin fibers is 1: (2-2.5). The addition of the mixed fiber can form a compact reticular structure in cement paste, and the fiber has hydrophilicity, so the fiber has better compatibility with cement stone minerals and can effectively bond. When the set cement is impacted by external force, the impact energy can be effectively absorbed and dispersed, and when the set cement is cracked, the fiber lacing wire effect can be formed, so that the stress field at the tip of the crack is shielded, the fracture toughness of the set cement is improved, and the elastic modulus is reduced. In the invention, the fibers do not need to be modified, but depend on proper water solubility and compounding of different fiber lengths, so that the fibers are uniformly and compactly distributed in cement paste to play a role in reducing cost and improving efficiency.
In the present invention, the water is preferably fresh water and/or mineralized water; wherein the mineralization water can also be seawater.
According to the invention, the coating also preferably comprises 0.1-1 part by weight of a defoaming agent, and more preferably also comprises 0.4-1 part by weight of a defoaming agent; the defoaming agent is preferably one or more of a silicon ether copolymerization defoaming agent, an organic siloxane defoaming agent and a polyether defoaming agent.
According to the invention, the water loss agent also comprises 2.1-4.7 parts by weight of water loss agent; the fluid loss agent is preferably a 2-acrylamide-2-methylpropanesulfonic acid polymer and/or a polyvinyl alcohol crosslinking fluid loss agent; the weight average molecular weight of the fluid loss agent is preferably 75-90 ten thousand; the applicable temperature of the fluid loss agent is preferably 10-110 ℃.
According to the invention, the paint also preferably comprises 0.7-1.4 parts by weight of a dispersant; the dispersant is preferably one or more of a lignosulfonate, a sulfonated aldehyde ketone condensate and a sulfonic acid formaldehyde condensate.
The density of the elastic-toughness well cementation cement slurry provided by the invention is preferably 1.6-1.8 g/cm3The product has good stability and fluidity without free liquid; the water loss amount of the elastic and flexible well cementation cement slurry is preferably less than or equal to 45mL/30min, the thickening time is adjustable, and the requirements of site construction are met.
The invention utilizes the nano particles to regulate and control the hydration reaction of the cement paste; simultaneously, micropores in the set cement are filled, so that the compactness of the set cement is improved, and the strength is optimized; meanwhile, the added fibers not only can play a bridging role in cracks, but also can form a compact network structure in the set cement to absorb external force impact and improve the tensile strength of the cement; and moreover, the water-soluble resin is added as a cementing material, so that the cementation between the plugging materials and the surfaces of cracks can be improved, the stability of the plugging structure is further improved, and the elastic toughness of the cement paste can be improved due to the fact that the resin material has better elastic toughness.
The invention also provides a preparation method of the elastic toughness well cementation cement slurry, which comprises the following steps: s1) mixing the nano particles, the fibers, the water-soluble resin and water to obtain a liquid phase; s2) mixing the oil well cement with the liquid phase to obtain the elastic toughness well cementation cement paste suitable for the coal bed gas.
The invention has no special limitation to the types of all raw materials, and the raw materials are available on the market; wherein, the nano particles, the fibers, the water-soluble resin, the water and the oil well cement are the same as the above, and are not repeated herein.
In the invention, preferably, the nanoparticles are mixed with water, ultrasonically dispersed, and then the fibers and the water-soluble resin are added, more preferably, the antifoaming agent, the fluid loss agent and the dispersing agent are also added to obtain a liquid phase; the defoaming agent, the fluid loss agent and the dispersing agent are the same as those described above, and are not described again; the power of the ultrasonic dispersion is preferably 800 w-1500 w; the ultrasonic dispersion time is preferably 30-50 min, and more preferably 40 min; in the preparation process, the nano-particles are firstly dispersed in the water phase by adopting an ultrasonic dispersion means, so that the agglomerated nano-particles are favorably smashed, the agglomerated particle size is further reduced, the specific surface area is increased, the nano-particles are favorably dispersed better and are favorably interacted with the cement particles fully, and simultaneously, the nano-particles are favorably and more fully filled in various pores.
And mixing the oil well cement with the liquid phase to obtain the elastic toughness well cementation cement slurry suitable for the coal bed gas.
The preparation method provided by the invention is multiple, the used materials are wide in source and low in price, and the cost of a cement paste system is maintained at a lower level.
Furthermore, the nano particles are dispersed in water, so that on one hand, the nano particles are ensured to be fully dispersed in a system by overcoming higher surface energy without modifying the surfaces of the nano particles, thereby reducing the cost, and on the other hand, hydrophilic surface functional groups of the nano particles can better react with cement particles, thereby improving hydration products and improving the mechanical property of the cement.
In order to further illustrate the invention, the following describes in detail an elastic toughness well cementation cement slurry suitable for coal bed methane and a preparation method thereof, which are provided by the invention, with reference to the examples.
The reagents used in the following examples are all commercially available;
the experimental method comprises the following steps: preparing elastic toughness well cementation cement paste and oil well G-grade cement paste according to a standard GB/T19139-.
The "parts" described in the examples and test examples are "parts by mass".
In the present invention, the formulation of the elastomeric cement slurry system is not particularly limited and may be routinely selected by those skilled in the art.
The raw materials used in the following examples and comparative examples are all conventional commercial products, as follows:
g-grade oil well cement: g-grade oil well cement purchased from Shandong Linji384vici Special Cement Ltd;
water-soluble resin material: bisphenol a epoxy resins available from seiko faith laboratory supplies, huang dao;
lignin fiber and basalt fiber: the length of basalt fiber purchased from Taian concrete companion fiber company Limited is 3-5 mm, and the length of lignin fiber is 3-5 mm;
nano-particles: the silicon dioxide is purchased from Jiangsu Tianxing New Material Co Ltd, and the density is 1.15-1.30 g/cm3The particle size is 50-200 nm, and the particles are spherical;
high-temperature fluid loss agent: the polyvinyl alcohol cross-linking fluid loss agent is self-synthesized and numbered as BD-L; synthetic methods refer to the article "Design and performance evaluation of a unique drainage strategy" (SPE Drilling & Completion);
high-temperature retarder: purchased from Onek Petroleum science, Inc., Chengdu, Inc., HX-36L brand;
dispersing agent: purchased from Onek Petroleum science, Inc., Youmek, Inc., under the FS-13L designation.
The defoaming agent is a polyether ester defoaming agent ST-61 produced by field chemistry.
Example 1
35 parts by mass of clear water, then adding 7 parts by mass of nano particles into water, and dispersing for 40min by adopting ultrasonic waves (with the power of 1000W); then, 0.8 part by mass of a mixed fiber material (basalt fiber and lignin fiber in a mass ratio of 1: 2.5), 12 parts by mass of a resin material, 0.7 part by mass of a dispersant, 2.1 parts by mass of a fluid loss additive, and 0.4 part by mass of a defoaming agent are sequentially dissolved in water; next, 100 parts by mass of cement paste was poured into the liquid phase and stirred uniformly to form an elastic and flexible cement paste system, which is denoted by S1.
Example 2
The cement paste system was prepared in the same procedure as in example 1, except that the clear water was 48 parts by weight, the resin material was 15 parts by weight, the mixed fiber was 4 parts by weight (basalt fiber and lignin fiber in a mass ratio of 1: 2), the nanoparticles were 9 parts by weight, the dispersant was 1.4 parts by weight, the fluid loss additive was 4.7 parts by weight, and the defoaming agent was 1 part by weight.
This step forms a resiliently flexible cement slurry system, designated S2.
Comparative example 1
The same procedure as in example 1 was followed to prepare a flexible cement slurry system, except that: the nanoparticles were not ultrasonically dispersed and labeled DS 1.
Comparative example 2
The same procedure as in example 1 was followed to prepare a flexible cement slurry system, except that: the mass fraction of the resin material is 8, the nanoparticle addition is 5, and the label is DS 2.
Comparative example 3
The same procedure as in example 1 was followed to prepare a flexible cement slurry system, except that: no fibrous material was added, labeled as DS 3.
Test example 1: compressive strength testing of elasto-tough cement slurry systems
The elastic and tough cement slurry prepared in the examples 1, 2, 1, 2 and 3 is taken as a test object, then the slurry is prepared according to the GB/T19139-. The test results are shown in Table 1.
Compressive strength properties of 1 elastomer-tough cement slurry system
As can be seen from Table 1, the elastic and flexible cement paste system provided by the invention can effectively increase the early strength of the set cement and optimize the development of the compressive strength of the set cement by adding and reasonably optimizing the water-soluble resin material, the fiber material and the nano material. After the elastic and flexible cement slurry is maintained for 24 hours and 72 hours at the temperature of 60 ℃ and 90 ℃, the strength of the cement paste meets the requirements of on-site well cementation.
Test example 2: flexural strength test of elastic and tough cement slurry system
The elastic and tough cement slurry prepared in the examples 1, 2, 1, 2 and 3 is taken as a test object, then the slurry is prepared according to the standard GB/T19139-. The test results are shown in Table 2.
TABLE 2 flexural Strength Properties of the elasto-tough Cement mortar System
As can be seen from Table 2, the elastic and flexible cement paste system provided by the invention has higher flexural strength, when the use amounts of resin and nano materials are reduced or the nano materials are unevenly dispersed, the flexural strength of the set cement is influenced to a certain extent, and when a fiber material is not adopted, the compressive strength of the set cement is greatly reduced.
Test example 3: triaxial mechanical property test of elastic toughness well cementation cement slurry system
The elastic and tough cement paste prepared in the examples 1, 2, 1, 2 and 3 is taken as a test object, then the paste is prepared according to the GB/T19139-. The test results are shown in Table 3.
TABLE 3 triaxial mechanical Properties of elastically ductile Cement
As can be seen from Table 3, after the water-soluble resin material, the nano material and the fiber material are added, the elastic modulus and the volume modulus of the set cement are further reduced, and the strain is obviously increased, which indicates that the set cement has better elastic-plastic mechanical properties, and the compressive strength of the set cement is higher, thereby meeting the well cementation requirement.
Test example 4: gas permeability testing of elasto-tough well cementation cement slurry systems
The elastic and tough cement slurry prepared in the examples 1, 2, 1, 2 and 3 is taken as a test object, then the slurry is prepared according to the standard GB/T19139-. The test results are shown in Table 4.
Table 4 gas permeability test of elasto-tough set cement
System of
Gas permeability/mD
S1
0.0077
S2
0.0097
DS1
0.1237
DS2
0.1048
DS3
0.0096
According to the test results, after the water-soluble resin material and the nano material are added, the compactness of the cement paste is effectively enhanced, and relatively speaking, the fiber material has small influence on the compactness of the set cement. The purpose of improving the compactness of the set cement is realized by adding the nano material and utilizing the principles of particle gradation and close packing. Meanwhile, microscopic pores are filled with epoxy resin, so that the cementation condition of particles and components in the set cement is improved. The bonding performance of the nano-particle micro-particles and the water-soluble resin effectively fills pores and microcracks generated by cement hydration, so that the permeability is effectively reduced.
Test example 5: rheological property test of elastic toughness cement paste
The elastic and flexible cement slurry prepared in the examples 1, 2, 1, 2 and 3 is taken as a test object, then the slurry is prepared according to the GB/T19139-. The test results are shown in Table 5.
TABLE 5 rheology of elasto-tough cement slurries
The test result shows that the addition of the resin material, the nano material and the fiber material can reduce the flow characteristic index n of the cement paste and increase the consistency coefficient K, so that the paste is obviously thickened, but the engineering requirement is met. The n and K values of the elastic toughness well cementation cement paste are obviously better than those of the first-grade product in the standard SY/T5406-1999 (n is more than or equal to 0.60, and K is less than or equal to 0.35).
Test example 6: slurry property test of elastic toughness cement slurry
The elastic toughness cement slurry prepared in the embodiments 1, 2, 1, 2 and 3 is taken as a test object, then the slurry is prepared according to the GB/T19139-. The test results are shown in Table 6.
TABLE 6 slurry Properties of elasto-tough Cement slurries
Sample numbering
Fluidity/cm
API Water loss/mL
Amount of free liquid/mL
S1
21
19.5
0
S2
20.5
19.7
0
DS1
18.5
25.5
1
DS2
22
26.7
2
DS3
22
33.4
4
As is clear from table 6, the addition of the resin material, the nanomaterial, and the fiber material slightly reduced the fluidity of the cement paste, and the water loss was small. The water loss, the fluidity and the free liquid amount of the elastic and flexible cement paste system meet the field requirements.
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