Elastic-tough well cementation cement paste suitable for coalbed methane and preparation method thereof

Abstract

The invention provides elastic-tough well cementation cement paste suitable for coalbed methane. The elastic-tough well cementation cement paste comprises the following components in parts by weight:100 parts of oil well cement; 12 to 15 parts by weight of water-soluble resin; 0.8 to 4 parts by weight of fibers; 7-9 parts by weight of nanoparticles; 35-48 parts by weight of water. Compared with the prior art, the nanoparticles are used for regulating and controlling the hydration reaction of the cement paste; meanwhile, micropores in set cement are filled, the compactness of the set cement isimproved, and the strength is optimized; meanwhile, the added fibers not only can play a bridging role in cracks, but also can form a compact net-shaped structure in set cement to absorb external force impact and improve the tensile strength of the cement; in addition, the water-soluble resin is added as a cementing material, so that the cementation between the plugging materials and between theplugging materials and the surfaces of the cracks can be improved, the stability of the plugging structure is further improved, and the elasticity and toughness of the cement paste can be improved asthe resin material has better elasticity and toughness.

Description

technical field [0001] The invention belongs to the technical field of coalbed gas exploitation, and in particular relates to an elastic-ductile cementing cement slurry suitable for coalbed gas and a preparation method thereof. Background technique [0002] In the existing coalbed methane mining process, because there are many coal seam blocks and the intervals between coal seams are small, the cement slurry must be injected by perforation. During the perforating process, the perforating charge will generate a high-speed energy-gathering jet at the moment of detonation to act on the casing, cement sheath, and the isolation structure of the surrounding rock, causing certain damage to the cement sheath. In particular, the casing, cement sheath, and formation rock have different elastic toughness and strength. Under the condition of external impact, different deformations are prone to occur, leading to the destruction of the cement sheath and the first interface (casing-cement ...

AI Technical Summary

Problems solved by technology

For example, Soltanian and others use the modified terpolymer rubber of carboxylated monomers to improve the elastic toughness of cement stone, which increases the elasticity of cement stone (reduces Young's modulus and increases Poisson's ratio), but due to changing the internal structure of cement stone , leading to a reduction in its strength; Wang et al. used modified multi-walled carbon nanotubes to improve the toughness of cement stone. The study showed that adding a small amount of modified multi-walled carbon nanotubes can increase the fracture energy of cement slurry by 5 times, and cement stone The compactness is improved, showing better cement strength development, but the cost of modified multi-walled carbon nanotubes is high, and it cannot be widely promoted under the current engineering status; Lu Bin et al. Fine metal oxide or silicon oxide particles were used as the main reinforcing agent, combined with related performance regulators, to prepare a cement slurry system with early strength and toughness, with adjustable thickening time, short transition time, and elastic modulus less than 6.6GPa; Wu Xueping and others used latex System and latex stabilizer, combined with reinforcing and toughening agent and fiber material, greatly improved the impact resistance of cement stone and reduced the elastic modulus; Cheng Xiaowei et al. in the patent CN101857800A "a cement slurry for plugging well cementing and its preparation method" It is proposed that the use of hemp fiber material, the change of surface energy and the enhancement of chemical bonding due to the change of chemical groups on the surface of the fiber, and the increase of surface roughness lead to the enhancement of mechanical locking, which improves the compactness of the interface and strengthens the interface bonding. Strength, improve plugging performance and cement toughness; Fan Jiachen et al. proposed in the patent CN104946219A "a low-density high-strength cement slurry" that liquid silica and hollow glass microspheres are used as lightening agents, and fiber materials are used for bridging. Under the premise of reducing the density, the cement stone strength and better rheology are guaranteed

[0004] The use of rubber materials, latex materials, fiber materials, and nano-materials, etc., can modify the internal structure of cement stones to a certain extent, modify its mechanical properties, and solve the problem of easy damage and deformation of cement stones under the impact of perforation to a certain extent. However, there are still the following deficiencies: (1) Rubber materials can improve mechanical properties, but their temperature resistance is poor. The material itself may also change the internal stress distribution of the cement stone, which has a certain and difficult to control effect on its strength; (2) The use of latex materials can improve the microstructure and mechanical properties of cement, but latex materials contain a large number of lipophilic groups , easy to affect cement hydration, so when using latex materials, it is necessary to strictly control the relevant dosage, and latex may have a certain degree of impact on the environment; (3) nanomaterials can fill the pores of cement stones and participate in hydration reactions and so on, to improve the microstructure of cement stone, but the current research on its regulation is not enough to effectively guide the selection of nanomaterials, and some nanomaterials are expensive and not suitable for large-scale promotion in engineering applications; (4) fiber Materials, etc. have a high effect of modifying mechanical properties, but reasonable surface modification is often required, and the ability of fiber materials to modify the elastic modulus of cement stone is limited, so it cannot effectively improve the elastic modulus of cement stone.

Images