The present disclosure relates to delivery and release systems, such as core-shell particles. An exemplary composition according to the disclosure can include a degradable polymeric shell surrounding a core that includes a crosslinker, which can encompass a metal, such as chromium. The core-shell particles can be provided with a gel-forming polymer, such as a polyacrylamide, into a subterranean reservoir having conditions such that the shell of the core-shell polymer degrades, and the so-released metal is effective to at least partially crosslink the gel-forming polymer to form a gel. The so-formed gel can be effective to control water flow through the subterranean reservoir, such as in relation to a waterflood of the reservoir.
Methods and materials for controlled release of materials in a subterranean reservoir
Johnson, L., Rothrock, G. D., Norton, C. A., Huffman, N. D., & Mecham, J. B. (2019). Methods and materials for controlled release of materials in a subterranean reservoir. (U.S. Patent No. 10,421,894).