| abstract |
Disintegrative particles having a disintegrative coating surrounding a disintegrative core may be pumped within an aqueous treatment fluid downhole to a subterranean formation. With time and/or change in wellbore or environmental condition, these particles will either disintegrate partially or completely, in non-limiting examples, by contact with downhole wellbore fluid, formation water, or a stimulation fluid (e.g. acid or brine). Once disintegrated, metals or compounds are released which raises the fluid pH and forms a structure that selectively inhibits or shuts-off the production of water from water-producing zones. The disintegrative particles may be made by compacting and/or sintering metal powder particles, for instance magnesium or other reactive metal or their alloys. Alternatively, particles coated with nanometer-sized or micrometer sized coatings may be designed where the coatings disintegrate faster or slower than the core in a changed downhole environment. |