Preparation and application of microcapsule containing sodium potassium tartrate for self-healing of cement

ABSTRACT

The cement sheath may crack during oil and gas production. Due to the microcrack areas are difficult to locate and reach, the repair of microcrack can be achieved by self-healing materials. Potassium sodium tartrate has a self-healing function, but when directly added to Portland cement, it is easy to cause serious retardation. Therefore, the microencapsulation of potassium sodium tartrate as a self-healing agent in urea-formaldehyde resin microcapsules is proposed. The particle size will significantly affect the particle gradation between microcapsules and cement，so this study aimed to produce microcapsules by optimization of various agitation rates. The microcapsules were synthesized by in-situ polymerization method and characterized by the yield rate, FTIR, particle size analysis, TG and SEM. In addition, the self-healing effect of microcapsules in oil well cement was evaluated. The microcapsules prepared by optimizing the agitation rate provide good uniformity of the cement slurry system, acceptable mechanical properties and excellent particle grading between the cement. The fracture permeability of optimizing microcapsule indicated that the microcapsule has excellent healing performance when the crack width was smaller than 86 μm.

KEYWORDS:

• Microcracks
• self-healing
• sodium potassium tartrate
• microencapsulation
• oil well cement

Additional information

Funding

The financial support of National State Science and Technology Support Plan (2012AA091501-003) is greatly acknowledged. Without their support, this work would not have been possible.

Notes on contributors

Zhigang Peng

Zhigang Peng, Doctor, College of Chemistry and Chemical Engineering, Southwest Petroleum University, Chengdu, Sichuan, China.

Chunyang Yu

Chunyang Yu, Master, College of Chemistry and Chemical Engineering, Southwest Petroleum University, Chengdu, Sichuan, China.

Qian Feng

Qian Feng, Doctor, College of Chemistry and Chemical Engineering, Southwest Petroleum University, Chengdu, Sichuan, China.

Yong Zheng

Yong Zheng, Doctor, College of Chemistry and Chemical Engineering, Southwest Petroleum University, Chengdu, Sichuan, China.

Jinhua Huo

Jinhua Huo, Doctor, College of Chemistry and Chemical Engineering, Southwest Petroleum University, Chengdu, Sichuan, China.

Xinwei Liu

Xinwei Liu, Master, College of Chemistry and Chemical Engineering, Southwest Petroleum University, Chengdu, Sichuan, China.