Method of tracing flow of hydrocarbon from a subterranean reservoir

Abstract

A method of tracing flow of hydrocarbon from a subterranean reservoir including forming a dispersion, injecting a hydraulic fracturing fluid containing the dispersion down a well penetrating a hydrocarbon reservoir, thereafter collecting a sample of hydrocarbon fluid flowing from the reservoir, and analysing the sample to determine whether the tracer compound is present in the sample. The dispersion includes a discontinuous condensed phase having a hydrocarbon-soluble tracer compound and a continuous phase which includes an aqueous liquid.

1 . A method of identifying the flow of reservoir fluids between a first well and a second well, the method comprising the steps of:
 a1) forming an emulsion of at least one hydrocarbon-soluble tracer compound in an aqueous liquid and injecting a hydraulic fracture fluid containing the emulsion down a first well, or   a2) forming an emulsion of at least one hydrocarbon-soluble tracer compound in an aqueous liquid by adding the tracer compound or a solution of the tracer compound in a non-water miscible solvent to a hydraulic fracturing fluid and mixing the tracer or said solution of the tracer with hydraulic fracturing fluid during injection of the fracturing fluid down a first well,   b) thereafter collecting a sample of hydrocarbon flowing from the second well,   c) analyzing the sample collected from the first well to determine whether the tracer compound is present in the sample from the second well and   d) determining, from the results of said analysis, whether a flow of hydrocarbon has occurred from the first well to the second well.   
     
     
         2 . The method of  claim 1 , where the emulsion comprises a discontinuous organic liquid phase and a continuous liquid phase, said discontinuous organic liquid phase comprising a hydrocarbon-soluble tracer compound and said continuous liquid phase comprising an aqueous liquid. 
     
     
         3 . The method of  claim 1 , where the tracer compound substantially or fully partitions into a hydrocarbon within a reservoir into which the first well is located when the dispersion comes into contact with oil and/or gas within the well or formation. 
     
     
         4 . A method according to  claim 1  wherein the tracer compound has a solubility in water between 50 and 120° Celsius of less than 0.1 g/liter. 
     
     
         5 . A method according to  claim 1  wherein the partition coefficient of the tracer compound between the hydrocarbon/water is selected to be at least 1,000. 
     
     
         6 . A method according to  claim 1  wherein the discontinuous organic liquid phase of the emulsion comprises a solution of the tracer compound in an organic solvent. 
     
     
         7 . A method according to  claim 1  wherein said emulsion contains an additive selected from the group consisting of emulsifiers, stabilisers and rheology modifiers. 
     
     
         8 . A method according to  claim 1  wherein the tracer compound is selected from the group consisting of a halogenated aromatic compound, a halogenated cycloalkane and a halogenated aliphatic compound, wherein the halogen is selected from the group consisting of Cl, Br and I. 
     
     
         9 . A method according to  claim 8  wherein the tracer compound is selected from the group consisting of 4-iodotoluene, 1,4-dibromobenzene, 1-chloro-4-iodobenzene, 5-iodo-m-xylene, 4-iodo-o-xylene, 3,5-dibromotoluene, 1,4-diiodobenzene, 1,2-diiodobenzene, 2,4-dibromomesitylene, 2,4,6-tribromotoluene, 1-iodonaphthalene, 2-iodobiphenyl, 9-bromophenanthrene, 2-bromonaphthalene, bromocyclohexane, 1,2-dichlorobenzene, 1,3-dichlorobenzene, 1,4-dichlorobenzene, 1-bromododecane, bromooctane, 1-bromo-4-chlorobenzene, bromobenzene, 1,2,3-trichlorobenzene, 4-chlorobenzylchloride and 1-bromo-4-fluorobenzene. 
     
     
         10 . A method according to  claim 1  wherein the discontinuous organic liquid phase of the emulsion contains more than one tracer compound. 
     
     
         11 . An emulsion consisting of a discontinuous organic liquid phase and a continuous liquid phase, said organic liquid phase comprising a hydrocarbon-soluble tracer compound and said continuous liquid phase comprising an aqueous liquid. 
     
     
         12 . An emulsion according to  claim 11 , wherein said emulsion contains an additive selected from the group consisting of emulsifiers, stabilizers and rheology modifiers. 
     
     
         13 . An emulsion according to  claim 11 , wherein the tracer compound is selected from the group consisting of a halogenated aromatic compound, a halogenated cycloalkane or a halogenated aliphatic compound, wherein the halogen is selected from the group consisting of Cl, Br and I. 
     
     
         14 . An emulsion according to  claim 11 , wherein the tracer compound is selected from the group consisting of 4-iodotoluene, 1,4-dibromobenzene, 1-chloro-4-iodobenzene, 5-iodo-m-xylene, 4-iodo-o-xylene, 3,5-dibromotoluene, 1,4-diiodobenzene, 1,2-diiodobenzene, 2,4-dibromomesitylene, 2,4,6-tribromotoluene, 1-iodonaphthalene, 2-iodobiphenyl, 9-bromophenanthrene, 2-bromonaphthalene, bromocyclohexane, 1,2-dichlorobenzene, 1,3-dichlorobenzene, 1,4-dichlorobenzene, 1-bromododecane, bromooctane, 1-bromo-4-chlorobenzene, bromobenzene, 1,2,3-trichlorobenzene, 4-chlorobenzylchloride and 1-bromo-4-fluorobenzene. 
     
     
         15 . An emulsion according to  claim 11 , wherein the at least one hydrocarbon-soluble tracer compound is selected from the group consisting of a halogenated aromatic compound, a halogenated cycloalkane or a halogenated aliphatic compound. 
     
     
         16 . An emulsion according to  claim 11 , wherein the at least one hydrocarbon-soluble tracer compound is selected from the group consisting of a halogenated aromatic compound, a halogenated cycloalkane or a halogenated aliphatic compound. 
     
     
         17 . An emulsion according to  claim 11 , wherein the discontinuous organic liquid phase of the emulsion contains more than one tracer compound.