초록 ▼

Water soluble thickened acid compositions suitable for matrix or fracture acidizing are provided comprising water, an acid, and a water thickening amount of a copolymer of a N-vinyl lactam and an unsaturated amide. This composition can contain in addition a crosslinking agent to give a gelled acid c

Water soluble thickened acid compositions suitable for matrix or fracture acidizing are provided comprising water, an acid, and a water thickening amount of a copolymer of a N-vinyl lactam and an unsaturated amide. This composition can contain in addition a crosslinking agent to give a gelled acid composition. In a preferred embodiment, a lactam-containing copolymer is made in a diluent containing dissolved electrolytes. These compositions are particularly useful in acid or matrix fracturing in subterranean formations exhibiting a hostile environment, as exemplified by high temperatures and/or high concentration of multivalent metal cations.

대표청구항 ▼

A process for acidizing a subterranean formation penetrated by at least one well comprising injecting into said formation, without a crosslinking agent, a water soluble thickened acid composition comprising: (1) water: (2) acid; and (3) a linear copolymer prepared from the monomers consisting of a N

A process for acidizing a subterranean formation penetrated by at least one well comprising injecting into said formation, without a crosslinking agent, a water soluble thickened acid composition comprising: (1) water: (2) acid; and (3) a linear copolymer prepared from the monomers consisting of a N-vinyl lactam monomer and an alpha, beta-unsaturated amide monomer of the formula [Figure] where R′is methyl, ethyl or hydrogen, said copolymer being made in the absence of a crosslinking agent during polymerization of the monomers.