Preparation and evaluation of microencapsulated gel-breaking agents with high-temperature resistance and a high encapsulation rate

As one of the important additives in the oil and gas recovery process, the delayed release gel breaker plays an important role in reservoir protection. In this study, we adopted a novel, environmentally friendly method to induce the condensation of ethyl cellulose (EC) and acrylonitrile-butadiene-styrene copolymer (ABS) to form a mixed shell by polydimethylsiloxane (PDMS), and successfully achieved the encapsulation of ammonium persulfate (APS). A novel high temperature resistant and high encapsulation rate microcapsule gel breaker (HE-MGB) was prepared. The formation and release mechanism of the microencapsulated gel breaker was investigated, and its embedding rate, morphology, structure, release property and gel breaking property were tested in detail. The results show that the APS microcapsules coated with mixed shells have a porous surface and core-shell structure, and have the characteristics of micron particles. It is worth noting that HE-MGB showed significant advantages over reported microcapsule gel breakers, with an encapsulation rate of 90%. Therefore, the microcapsule with excellent comprehensive properties has the potential for application in high temperature deep oil and gas reservoirs.