Preparation method of self-healing agent for oil well cement, well cementation self-healing cement slurry and application

Abstract

The invention discloses a preparation method of a self-healing agent for oil well cement. The preparation method comprises the following steps: i) mixing substituted or unsubstituted styrene, acrylates, 2-acrylamide-2-methyl propane sulfonic acid, divinyl benzene, acrylamide and derivatives thereof, mono polyethylene glycol maleate, an emulsifier and a chain transfer agent with water and pre-emulsifying to obtain a pre-emulsion A; ii) preparing an initiator solution B by water and an initiator; iii) heating a part amount of the pre-emulsion A to 70-90 DEG C and then adding a part amount of the initiator solution B; then, further adding the residual amount of the pre-emulsion A and the initiator solution B; and iv) after reaction, adjusting the pH value to 7-9 to obtain the self-healing agent for oil well cement. The invention further relates to well cementation self-healing cement slurry which contains the self-healing agent prepared by the method as well as an application of the self-healing agent or the well cementation self-healing cement slurry in oil gas well cementing operation.

Description

technical field [0001] The present invention relates to the field of petroleum exploration, in particular to a preparation of an oil well cement self-healing agent and an oil well self-healing cement slurry containing the self-healing agent prepared by the method, more specifically, it relates to a cementing cement for deep wells A preparation method of an oil well cement self-healing agent, well cementing self-healing cement slurry containing the self-healing agent prepared by the method and application thereof. Background technique [0002] After the cement slurry is solidified in the oil and gas well, due to the characteristics of the cement itself or the influence of the later operation, defects such as cracks are easily formed in the cement stone, and oil and gas channeling due to the damage of the cement sheath causes the annulus to be pressurized. Squeeze cement overhaul and chemical plugging repair methods, but the success rate is low, some repair operations need to ...

AI Technical Summary

Problems solved by technology

[0002] After the cement slurry is solidified in the oil and gas well, due to the characteristics of the cement itself or the influence of the later operation, defects such as cracks are easily formed in the cement stone, and oil and gas channeling due to the damage of the cement sheath causes the annulus to be pressurized. Squeeze cement overhaul and chemical plugging repair methods, but the success rate is low, some repair operations need to be carried out many times, and the repaired oil and gas wells often have problems in a short period of time, and need to be repaired again, often causing A large number of economic losses and the extension of the drilling cycle. At present, major oil companies and scientific research institutes at home and abroad are also working on the research on solving the damage and self-repair of cement stones, but there is no public information on the preparation of self-healing agents.

The research on self-healing of micro-cracks in cement-based materials in the domestic construction industry started earlier, but self-healing agents in the construction industry are difficult to apply to oil well cement due to their low operating temperature.

Foreign countries have made some progress in the research and application of cement sheath self-repair. Schlumberger and Halliburton have made research on cement sheath damage and cement sheath micro-expansion, but the research and development of repairing agents has not yet been disclosed.

[0003] The styrene-acrylic emulsions disclosed in Chinese patents CN201010531412.X, CN201210587842.2, CN201110375710.9, CN201010530012.7, etc. are only suitable for the construction industry, coating industry, etc., and are difficult to apply in high-temperature and high-pressure oil wells with a temperature higher than 100 ° C, and When added to oil well cement, the oil well cement has no fluidity and is difficult to pump into the well

[0004] The self-healing agents invented by Chinese patents CN201010617895.5 and CN201310031979.4 are only suitable for construction cement at normal temperature, and cannot work for oil well cement at high temperature

[0005] Chinese patent CN201110326575.9 uses modified resin as a self-healing material, but the use temperature of the material is around 70°C; Chinese patent CN201210264282.7 does not give a preparation method for the self-healing material

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