Method for determining fluid saturations in petroleum reservoirs

Claim 1

A METHOD FOR MEASURING THE RELATIVE SATURATION OF IMMISCIBLE FLUIDS PRESENT IN A SUBTERRANEAN FORMATION PENETRATED BY A WELL IN COMMUNICATION THEREWITH AND WHEREIN AT LEAST ONE OF SAID FLUIDS IS MOBILE, WHICH COMPRISES: INJECTING A CARRIER FLUID INTO SAID FORMATION, SAID CARRIER FLUID BEING MISCIBLE WITH ONE OF SAID MOBILE FLUIDS AND IMMISCIBLE WITH AT LEAST ONE OF THE OTHER FLUIDS AND CONTAINING LOW CONCENTRATIONS OF (1) A PRECURSOR THAT PARTITIONS BETWEEN THE CARRIER FLUID AND THE IMMISCIBLE FLUID AND THAT REACTS IN THE FORMATION TO FORM A FIRST TRACER MATERIAL THAT PARTITIONS BETWEEN THE CARRIER FLUID AND THE IMMISCIBLE FLUID DIFFERENTLY THAN THE PRECURSOR AND (2) A SECOND SUBSTANTIALLY NON-REACTIVE TRACER MATERIAL THAT PARTITIONS BETWEEN THE CARRIER FLUID AND THE IMMISCIBLE FLUID TO ABOUT THE SAME DEGREE AS SAID PERCURSOR; DISPLACING SAID CARRIER FLUID INTO SAID FORMATION; ANALYZING SAID RECOVERED FLUIDS TO DETERMINE THE CONCENTRATIONS OF SAID FIRST AND SECOND TRACER MATERIALS IN SAID FLUIDS AS A FUNCTION OF THE VOLUME OF SAID FLUIDS PRODUCED FROM SAID FORMATION; AND APPLYING CHROMATOGRAPHIC PRINCIPLES TO DETERMINE THE RELATIVE SATURATION OF THE IMMISCIBLE FLUIDS PRESENT IN SAID FORMATION.

Claim 2

A METHOD FOR MEASURING THE RELATIVE SATURATION OF IMMISCIBLE FLUIDS PRESENT IN A SUBTERRANEAN FORMATION PENETRATED BY A WELL IN COMMUNICATION THEREWITH AND WHEREIN AT LEAST ONE OF SAID FLUIDS IS MOBILE, WHICH COMPRISES: INJECTING A CARRIER FLUID INTO SAID FORMATION, SAID CARRIER FLUID BEING MISCIBLE WITH ONE OF SAID MOBILE FLUIDS AND IMMISCIBLE WITH AT LEAST ONE OF THE OTHER FLUIDS AND CONTAINING LOW CONCENTRATIONS OF (1) A PRECURSOR THAT PARTITIONS BETWEEN THE CARRIER FLUID AND THE IMMISCIBLE FLUID AND THAT REACTS IN THE FORMATION TO FORM A FIRST TRACER MATERIAL THAT PARTITIONS BETWEEN THE CARRIER FLUID AND THE IMMISCIBLE FLUID DIFFERENTLY THAN THE PRECURSOR AND (2) A SECOND SUBSTANTIALLY NON-REACTIVE TRACER MATERIAL THAT PARTITIONS BETWEEN THE CARRIER FLUID AND THE IMMISCIBLE FLUID TO ABOUT THE SAME DEGREE AS SAID PERCURSOR; DISPLACING SAID CARRIER FLUID INTO SAID FORMATION; ANALYZING SAID RECOVERED FLUIDS TO DETERMINE THE CONCENTRATIONS OF SAID FIRST AND SECOND TRACER MATERIALS IN SAID FLUIDS AS A FUNCTION OF THE VOLUME OF SAID FLUIDS PRODUCED FROM SAID FORMATION; AND APPLYING CHROMATOGRAPHIC PRINCIPLES TO DETERMINE THE RELATIVE SATURATION OF THE IMMISCIBLE FLUIDS PRESENT IN SAID FORMATION.

Claim 7

A method for measuring the relative saturation of oil and water present in a subterranean formation penetrated by a well in communication therewith and wherein at least one of said fluids is mobile, which comprises: injecting a liquid carrier fluid through said well and into said formation, said carrier fluid being miscible with one of said mobile fluids and immiscible with the other fluid and having dissolved therein low concentrations of (1) a precursor that partitions between the carrier fluid and the immscible fluid and that reacts in the formation to form a first tracer material that partitions between the carrier fluid and the immiscible fluid differently than the precursor and (2) a second nonreactive tracer material that partitions between the carrier fluid and the immiscible fluid to about the same degree as said precursor; displacing said carrier fluid into said formation away from the well; shutting in said well for a time period sufficient to permit the precursor to react to form detectable quantities of said first tracer material; producing said well to recover fluids from said formation; analyzing said recovered fluids to determine the concentrations of said first and second tracer materials in said fluids as a function of the volume of said fluids recovered from said formation; and applying chromatographic principles to determine the relative saturation of oil and water present in said formation.

Claim 8

A method for measuring the relative saturation of oil and water present in a subterranean formation penetrated by a well in communication therewith and wherein at least one of said fluids is mobile, which comprises: injecting a liquid carrier fluid through said well and into said formation, said carrier fluid being miscible with one of said mobile fluids and immiscible with the other fluid and having dissolved therein low concentrations of (1) a precursor that partitions between the carrier fluid and the immscible fluid and that reacts in the formation to form a first tracer material that partitions between the carrier fluid and the immiscible fluid differently than the precursor and (2) a second nonreactive tracer material that partitions between the carrier fluid and the immiscible fluid to about the same degree as said precursor; displacing said carrier fluid into said formation away from the well; shutting in said well for a time period sufficient to permit the precursor to react to form detectable quantities of said first tracer material; producing said well to recover fluids from said formation; analyzing said recovered fluids to determine the concentrations of said first and second tracer materials in said fluids as a function of the volume of said fluids recovered from said formation; and applying chromatographic principles to determine the relative saturation of oil and water present in said formation.

Claim 13

A method for measuring the relative saturation of oil and water present in a subterranean formation penetrated by a well in communication therewith and containing mobile water and immobile oil, which comprises: injecting an aqueous liquid carrier fluid through said well and into said formation, said carrier fluid having dissolved therein low concentrations of (1) a precursor that partitions between the carrier fluid and the immobile oil and that reacts in the formation to form a first tracer material that partitions between the carrier fluid and the immobile oil differently than the percursor and (2) a second nonreactive tracer material that partitions between the carrier fluid and the immobile oil to about the same degree as said percursor; injecting an aqueoous liquid through the well and into the formation to displace said carrier fluid into the formation away from the well; shutting in said well for a time period sufficient to permit the precursor to react to form detectable quantities of said first tracer material; producing said well to recover water from said formation; analyzing said recovered water to detemine the concentrations of said first and second tracer materials in said water as a function of the volume of said water produced from said formation; and applying chromatographic principles to determine the relative saturation of oil and water present in said formation.

Claim 14

A method for measuring the relative saturation of oil and water present in a subterranean formation penetrated by a well in communication therewith and containing mobile water and immobile oil, which comprises: injecting an aqueous liquid carrier fluid through said well and into said formation, said carrier fluid having dissolved therein low concentrations of (1) a precursor that partitions between the carrier fluid and the immobile oil and that reacts in the formation to form a first tracer material that partitions between the carrier fluid and the immobile oil differently than the percursor and (2) a second nonreactive tracer material that partitions between the carrier fluid and the immobile oil to about the same degree as said percursor; injecting an aqueoous liquid through the well and into the formation to displace said carrier fluid into the formation away from the well; shutting in said well for a time period sufficient to permit the precursor to react to form detectable quantities of said first tracer material; producing said well to recover water from said formation; analyzing said recovered water to detemine the concentrations of said first and second tracer materials in said water as a function of the volume of said water produced from said formation; and applying chromatographic principles to determine the relative saturation of oil and water present in said formation.

Claim 15

A method for measuring the relative saturation of immiscible fluids present in a subterranean formation penetrated by a well in communication therewith and wherein at least one of said fluids is mobile, which comprises: injecting a carrier fluid into said formation, said carrier fluid being miscible with one of said mobile fluids and immiscible with at least one of the other fluids and containing (1) about 100 ppm to 10,000 ppm of a precursor that partitions between the carrier fluid and the immiscible fluid and that reacts in the formation to form a first tracer material that partitions between the carrier fluid and the immiscible fluid to a different degree than the precursor and (2) about 100 ppm to 10,000 ppm of a second substantially nonreactive, nonradioactive tracer material or about 0.1 to 2 Curies of a substantially nonreactive, radioactive second tracer material, said precursor and said second tracer material partitioning between the carrier fluid and the immiscible fluid to about the same degree; injecting a displacement fluid through said well and into said formation to displace said carrier fluid into said formation an average distance of about 5 to 50 feet from said well, said displacement fluid being of the type and injected in about the same proportions as the fluids produced from said well; shutting in said well for a period of about 1 to 30 days sufficient to permit the precursor to react to form detectable quantities of said first tracer material; producing said well to recover fluids from said formation; analyzing said recovered fluids to determine the concentrations of said first and second tracer materials in said fluids as a function of the volume of said fluids produced from said formation; and applying chromatographic principles to determine the relative saturation of the immiscible fluids present in the formation.

Claim 16

A method for measuring the relative saturation of immiscible fluids present in a subterranean formation penetrated by a well in communication therewith and wherein at least one of said fluids is mobile, which comprises: injecting a carrier fluid into said formation, said carrier fluid being miscible with one of said mobile fluids and immiscible with at least one of the other fluids and containing (1) about 100 ppm to 10,000 ppm of a precursor that partitions between the carrier fluid and the immiscible fluid and that reacts in the formation to form a first tracer material that partitions between the carrier fluid and the immiscible fluid to a different degree than the precursor and (2) about 100 ppm to 10,000 ppm of a second substantially nonreactive, nonradioactive tracer material or about 0.1 to 2 Curies of a substantially nonreactive, radioactive second tracer material, said precursor and said second tracer material partitioning between the carrier fluid and the immiscible fluid to about the same degree; injecting a displacement fluid through said well and into said formation to displace said carrier fluid into said formation an average distance of about 5 to 50 feet from said well, said displacement fluid being of the type and injected in about the same proportions as the fluids produced from said well; shutting in said well for a period of about 1 to 30 days sufficient to permit the precursor to react to form detectable quantities of said first tracer material; producing said well to recover fluids from said formation; analyzing said recovered fluids to determine the concentrations of said first and second tracer materials in said fluids as a function of the volume of said fluids produced from said formation; and applying chromatographic principles to determine the relative saturation of the immiscible fluids present in the formation.