Asphaltene-dispersing/inhibiting additive based on oxazolidines derived from polyalkyl or polyalkenyl N-hydroxyalkyl succinimides

A composition comprising:

• (1) an asphaltene dispersant-inhibitor additive formulation, said additive formulation including a compound having the formula
• Zone Name:
• wherein R is a polyalkyl or polyalkenyl group having an average molecular weight within the range from 450 to 5000 Daltons;
• m is an integer having values between 1 and 5;
• n is an integer between 0 and 1;
• and R1, R2, R3 and R4 are independent radicals represented by the groups —H, —CH2(CH2)AB, —C6H3DE or —C10H4FG;
• wherein:
• A is an integer between 0 and 8,
• B is a group selected among —H, —NH2, —OH, —COOH;
• and D, E, F and G are independent radicals, selected from the groups:
• —H, —CH3, —CH2CH3, —CH2CH2CH3, —CH2(CH2)2CH3, —(CH3)3, C6H5, —NH2, —OH, —OCH3, OCH2CH2OH, OCH(CH3)CH2OH, OC6H5—COOH, —SO3;
• dispersed in an organic solvent in a ratio of 1:9 to 9:1;
• and
• (2) crude oil, where said additive and crude oil are mixed in a weight ratio sufficient to disperse, inhibit precipitation and deposition of asphaltenes in said crude oil at reservoir conditions.

A method of inhibiting the precipitation and deposition of asphaltenes in crude oil comprising:

• adding additive formulation to crude oil in an amount effective to inhibit precipitation of asphaltenes from said crude oil at reservoir conditions where crude oil is considered as live, and at pressures below its onset point, and to inhibit deposition of asphaltenes on surfaces carrying said crude oil at atmospheric conditions where crude oil is considered dead oil, wherein said additive formulation comprises an oxazolidine derived from polyalkyl or polyalkylene N-hydroxyalkyl succinimides wherein said oxazolidine has the general formula
• wherein R is a polyalkyl or polyalkenyl group having an average molecular weight within the range from 450 to 5000 Daltons;
• m is an integer having values between 1 and 5;
• n is an integer between 0 and 1;
• and R1, R2, R3 and R4 are independent radicals represented by the groups —H, —CH2(CH2)AB, —C6H3DE or —C10H4FG;
• wherein:
• A is an integer between 0 and 8,
• B is a group selected among —H, —NH2, —OH, —COOH;
• and D, E, F and G are independent radicals, selected from the groups:
• —H, —CH3, —CH2CH3, —CH2CH2CH3, —CH2(CH2)2CH3, —(CH3)3, C6H5, —NH2, —OH, —OCH3, OCH2CH2OH, OCH(CH3)CH2OH, OC6H5—COOH, —SO3, wherein said additive formulation is dispersed in an organic solvent in a weight ratio of 1:9 to 9:1.