Methods for identifying compounds useful for producing heavy oils from underground reservoirs

Abstract

Described herein are methods for identifying compounds useful for producing heavy oil from an underground reservoir. The methods facilitate the development of chemicals with improved physicochemical features. The methods generally involve first identifying a physicochemical property of a compound that needs to be improved in order to increase the efficiency of heavy oil removal from underground reservoirs. Next, the physicochemical property is calculated by molecular modeling using semi-empirical or ab-initio calculations. By modifying the molecular model of the compound, the targeted physicochemical property can be optimized. After a suitable compound has been identified, the compound can be synthesized and evaluated.

1 . A method for identifying a chemical compound useful for producing heavy oil from an underground reservoir comprising:
 (a) selecting a starting compound useful in producing heavy oil from an underground reservoir and a physicochemical property of the starting compound to be improved;   (b) constructing a molecular model of the starting compound;   (c) constructing a combined property associated with the physicochemical property of the starting compound using one or more sub-properties of a sub-property set of the starting compound;   (d) calculating the combined property of the molecular model of the starting compound;   (e) altering the molecular model of the starling compound to produce a modified molecular model;   (f) calculating the combined property of the modified molecular model;   (g) comparing the combined property of the modified molecular model with the combined property of the molecular model of the starting compound; and   (h) determining if the combined property of the modified molecular model is improved relative to the combined property of the molecular model of the starting compound.   
   
   
       2 . The method of  claim 1 , wherein the combined property of the modified molecular model is improved relative to the combined property of the molecular model of the starting compound, and further comprising determining if synthesis of a new chemical compound according to the modified molecular model is feasible and economic. 
   
   
       3 . The method of  claim 2 , wherein synthesis of a new chemical compound according to the modified molecular model is feasible and economic, and further comprising synthesizing a new chemical compound according to the modified molecular model. 
   
   
       4 . The method of  claim 3 , further comprising determining if the physicochemical property of the new chemical compound is improved relative to that of the starting compound. 
   
   
       5 . The method of  claim 4 , wherein determining if the physicochemical property of the new chemical compound is improved relative to that of the starting compound comprises experimental measurement of the physicochemical properties of the starting compound and the new compound. 
   
   
       6 . The method of  claim 1 , wherein the combined property of the modified molecular model is not improved relative to the combined property of the molecular model of the starting compound, and further comprising repeating steps (e)-(h) of  claim 1 . 
   
   
       7 . The method of  claim 2 , wherein synthesis of a new chemical compound according to the modified molecular model is not feasible or economic, and further comprising repeating steps (e)-(h) of  claim 1 . 
   
   
       8 . The method of  claim 4 , wherein the physicochemical property of the new chemical compound is not improved relative to that of the starting compound, and further comprising repeating steps (c)-(h) of  claim 1 . 
   
   
       9 . The method of  claim 1 , wherein the physicochemical property comprises thermal stability, coke formation, ability of the compound to improve oil recovery, solubility, dielectric permittivity, interfacial activity, oil solubilization capability, emulsion breaking capability, corrosion inhibition capability, adsorption of molecules on solid/liquid, liquid/liquid, or liquid gas interfaces, prevention of gas hydrate formation or deposition, prevention of asphaltene association, precipitation, or deposition, thermal stability and/or foam stability of steam or noncondensable gas foams, viscosity of foams, oil-water interfacial tension, microemulsion formation, wetting angle that water forms in contact with the reservoir rock surface when the incorporating liquid is crude oil, or any combination thereof. 
   
   
       10 . The method of  claim 1 , wherein the compound comprises a surfactant, a polymer, an emulsifier, a demulsifier, an asphaltene inhibitor, a gas hydrate inhibitor, a corrosion inhibitor, or a foam forming compound. 
   
   
       11 . The method of  claim 1 , wherein the physicochemical property comprises thermal stability, and the sub-property set comprises decomposition energy, decomposition rate, enthalpy of formation, enthalpy of decomposition, flash point, bond dissociation energy of the bond having the smallest bond order, hydrolysis energy of the bond having the smallest bond order, hydrolysis energy in the presence of silica of the bond having the smallest bond order, hydrolysis energy in the presence of clays of the bond having the smallest bond order, or any combination thereof. 
   
   
       12 . The method of  claim 1 , wherein the physicochemical property comprises solubility, and the sub-property set comprises the solute-solute interaction energy (E UU ), solvent-solvent interaction energy (E VV ), and the solvent-solute interaction energy (E VU ). 
   
   
       13 . The method of  claim 1 , wherein the physicochemical property comprises dielectric permittivity, and the sub-property set comprises the molar volume, dipole moment, and the rotational diffusion coefficient. 
   
   
       14 . The method of  claim 1 , wherein the physicochemical property comprises interfacial activity of a surfactant, and the sub-property set comprises the HLB number, adsorption enthalpy, CMC value, or any combination thereof. 
   
   
       15 . The method of  claim 1 , wherein the physicochemical property comprises thermal stability, and the sub-property set comprises the reaction rate and/or the activation energy of the decomposition reaction. 
   
   
       16 . The method of  claim 1 , wherein the compound is an asphaltene inhibitor, the physicochemical property comprises prevention of asphaltene association, precipitation, or deposition, and the sub-property set comprises the association energy between asphaltene molecules and the association energy between the asphaltene inhibitor and asphaltene molecules.