An apparatus to simulate biocide performance in crude oil pipeline conditions is disclosed. The apparatus includes: a reactor to simulate a two-phase crude oil pipeline which includes a crude oil phase above a water phase. The reactor has an agitator to control a flow of the water phase in the reactor in response to a motor that drives an agitation rate of the agitator. A crude oil inlet supplies crude oil to the reactor for the crude oil phase. A water inlet supplies water to the reactor for the water phase. A control circuit is configured by code to control a proportion of the water to the crude oil supplied to the reactor and to control the motor to drive a desired agitation rate of the agitator. A biocide inlet supplies biocide to the reactor. A water sample outlet enables sampling of the water phase of the reactor.

A paraffin inhibitor composition that exhibits stable properties at low temperature is provided. The composition may contain, for instance, an alkylphenol copolymer having the following repeating units (A) and (B): ##STR00001##
wherein, x is an integer from 1 to 200; y is an integer from 2 to 200; R.sub.1 is a straight or branched C.sub.1-C.sub.15 alkyl; and R.sub.2 is a straight or branched C.sub.16-C.sub.40 alkyl.

A paraffin inhibitor composition that exhibits stable properties at low temperature is provided. The composition may contain, for instance, an alkylphenol copolymer having the following repeating units (A) and (B): ##STR00001##
wherein, x is an integer from 1 to 200; y is an integer from 2 to 200; R.sub.1 is a straight or branched C.sub.1-C.sub.15 alkyl; and R.sub.2 is a straight or branched C.sub.16-C.sub.40 alkyl.

An asphaltene dispersant composition is provided. The composition may contain an alkylphenol copolymer having the following repeating units (A) and (B): ##STR00001##
wherein, x is an integer from 1 to 200; y is an integer from 2 to 200; R.sub.1 is a straight or branched C.sub.1-C.sub.15 alkyl; and R.sub.2 is a straight or branched C.sub.2-C.sub.40 alkyl, wherein R.sub.2 is different than R.sub.1.

An asphaltene dispersant composition is provided. The composition may contain an alkylphenol copolymer having the following repeating units (A) and (B): ##STR00001##
wherein, x is an integer from 1 to 200; y is an integer from 2 to 200; R.sub.1 is a straight or branched C.sub.1-C.sub.15 alkyl; and R.sub.2 is a straight or branched C.sub.2-C.sub.40 alkyl, wherein R.sub.2 is different than R.sub.1.

An alkylphenol copolymer, such as for use in a petroleum composition, is provided. The alkylphenol copolymer has the following repeating units (A) and (B): ##STR00001##
wherein, x is an integer from 1 to 200; y is an integer from 2 to 200; R.sub.1 is a straight or branched C.sub.1-C.sub.15 alkyl; and R.sub.2 is a straight or branched C.sub.2-C.sub.40 alkyl, wherein R.sub.2 is different than R.sub.1.

An alkylphenol copolymer, such as for use in a petroleum composition, is provided. The alkylphenol copolymer has the following repeating units (A) and (B): ##STR00001##
wherein, x is an integer from 1 to 200; y is an integer from 2 to 200; R.sub.1 is a straight or branched C.sub.1-C.sub.15 alkyl; and R.sub.2 is a straight or branched C.sub.2-C.sub.40 alkyl, wherein R.sub.2 is different than R.sub.1.

Disclosed are molybdenum-containing complexes used in compositions and methods for inhibiting or reducing the deposition of foulant on equipment.

Disclosed are molybdenum-containing complexes used in compositions and methods for inhibiting or reducing high temperature corrosion in petroleum refineries.

Polymers are provided for use in inhibiting gas hydrate formation and/or corrosion in hydrocarbon-containing fluids. The polymer comprises repeat units derived from a first monomer comprising N-[3-(dibutylamino)propyl]methacrylamide (DBAPAMA) or an alkyl, acetyl, acryloyl or benzyl quaternary salt thereof, N-[3-(diisobutyl)propyl]methacrylamide or an alkyl, acetyl, acryloyl or benzyl quaternary salt thereof, N-[3-(diisopentyl)propyl]methacrylamide or an alkyl, acetyl, acryloyl or benzyl quaternary salt thereof, or a combination thereof; and repeat units derived from a second monomer comprising acrylamide, N-alkylacrylamide, N-alkyl (alkyl)acrylamide, ((dialkylamino)alkyl)acrylamide or an alkyl or benzyl quaternary salt thereof, ((dialkylamino)alkyl)alkylacrylamide or an alkyl or benzyl quaternary salt thereof, acrylic acid, alkyl acrylate, N,N-(dialkylamino)alkyl acrylate or an alkyl or benzyl quaternary salt thereof, N,N-(dialkylamino)alkyl (alkyl)acrylate or an alkyl or benzyl quaternary salt thereof, hydroxyalkyl acrylate, hydroxyalkyl (alkyl)acrylate, acrylamido alkyl sulfonic acid or a salt thereof, a diallyl dialkyl quaternary ammonium salt, or a combination thereof. The second monomer does not comprise the first monomer.