Cement paste toughening agent and application of cement paste toughening agent in preparation of cementing flexible cement paste

Abstract

The invention relates to a cement paste toughening agent and application of the cement paste toughening agent in preparation of a cementing flexible cement paste. The toughening agent is prepared by modification of rubber powder; the modification of rubber powder includes the steps of cleaning, activating, etching and grafting; the cementing flexible cement paste prepared by the toughening agent is prepared from the following components in parts by weight: 100 parts of portland cement, 5-50 parts of modified rubber powder, 10-40 parts of a toughing agent, 15-80 parts of a density regulator, 35-65 parts of water, 0.5-2 parts of a dispersing agent, 0.5-3 parts of a fluid loss agent, 1.5-4 parts of a retarder and 0.1-2 parts of a defoamer. The inherent performance of a substrate is not changed by plasma treatment on the rubber powder; no pollution is generated; the cement paste toughening agent is simple in process, convenient to operate, stable in hydrophilism through the grafted rubber powder, small in effect from timeliness, and low in handling expense; the flexible cement paste prepared from the modified rubber is good in sedimentation stability; the mechanical property is obviously improved; the cement construction requirements of the scene can be completely met.

Description

technical field [0001] The invention relates to a toughening agent for oil well cement slurry, which is mainly used in the field of oil and gas well cementing to improve the mechanical properties of cement. Background technique [0002] The oil well cement sheath bears the perforation impact of the high-energy jet downhole and the collision impact of the casing and the drill bit on the cement sheath when running the casing and continuing to drill. Because the cement sheath is brittle, its overall integrity will be destroyed. This leads to the failure of the interlayer sealing performance in the later stage, which has potential safety hazards for the late stimulation measures and development and production of oil and gas wells, especially high acid gas wells, and cannot guarantee the safe production of oil and gas wells, resulting in huge economic losses. Therefore, it is of great significance to ensure the integrity of the oil well cement sheath. [0003] Waste rubber is a ...

AI Technical Summary

Problems solved by technology

However, the simple use of ozone irradiation or plasma to activate rubber powder has timeliness problems. As time goes by, the hydrophilicity of rubber powder after treatment will decrease, and the polar groups on the surface will decrease, so it is not suitable for long-term storage.

At the same time, due to the influence of timeliness, the long-term storage of the treated rubber powder will seriously affect the later mechanical properties of the modified composite material.

The surface of rubber powder is activated and etched by plasma treatment, and then polar groups are specially introduced to the surface of rubber powder through plasma grafting, thereby increasing the interface bonding force between rubber powder and cement stone, and improving the cementing performance. The mechanical properties of cement stone have not been reported in patent or non-patent literature

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