Self-repairing material for oil and gas well cementation and preparation method

Abstract

The invention discloses a self-repairing material for oil and gas well cementation and a preparation method. The self-repairing material is prepared from the following raw materials: 100 parts by weight of polyisoprene; 0.5 to 100 parts by weight of a precursor; 1-50 parts by weight of a coupling agent; 0.5 to 100 parts by weight of water; 100 to 1000 parts by weight of a solvent; and 0.1-0.5 partby weight of a catalyst. A nano SiO2 shell layer is generated on the surface of the polyisoprene by a sol-gel method; the coupling agent is introduced so that the polyisoprene and the nano SiO2 shelllayer are effectively linked, and the mechanical property and the heat resistance of the whole core-shell structure material are improved, so that the compatibility of the modified self-repairing nano composite material and a cement matrix is improved, and the modified self-repairing nano composite material has better comprehensive mechanical property and heat resistance in the cement matrix.

Description

technical field [0001] The invention relates to the technical field of petroleum drilling, in particular to a self-repairing material used in oil and gas well cementing and a preparation method. Adding cement stone can endow cement stone with self-healing ability when it encounters natural gas, and can reduce the elastic modulus of cement stone, which can meet the cementing requirements of high temperature and high pressure gas wells and staged fracturing wells, and is suitable for current high-yield gas wells, shale oil and gas, and tight oil and gas Application in wells and gas storage wells. Background technique [0002] As the gas well annulus under pressure becomes more and more common, the sealing quality and durability of the cement sheath are getting more and more attention in the industry. However, conventional cement stone is a brittle material. During the long-term production or operation of oil wells, the cement sheath is prone to cracks or micro-annulus, result...

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Problems solved by technology

[0006] The self-healing cement slurry system disclosed in US patents US7607482 and US7530396 is Selfhealing Cement, a product of a foreign company. The self-healing material is mainly ethylene / butadiene / carboxyl modified rubber, which has achieved good application results at home and abroad, but the price is extremely expensive

[0007] Due to poor cementing quality or poor mechanical properties of cement (hard and brittle), the annulus is under pressure, causing serious safety hazards and reducing the production life of the oil well

At the same time, in order to stabilize and increase production, various oilfields have successively carried out production increase measures such as water injection, fracturing, and acidification. Different operating processes will inevitably cause changes in the stress state of the downhole casing and cement sheath. The use of conventional cement slurry systems may easily lead to damage to the cement sheath. The cement sheath loses its sealing ability, which affects the later production. Therefore, it is necessary to develop a self-repairing material with excellent performance and economical feasibility, which can repair the damage of the cement sheath and improve the long-term sealing performance of the cement sheath.

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