Abstract A method for determining fluid saturations in a subterranean reservoir formation containing one mobile fluid phase and one or two substantially immobile fluid phases. A carrier fluid which is miscible with the mobile fluid and substantially insoluble in the immobile phase or phases is injected into the formation at one location and displaced through the formation to a second location. The carrier fluid contains two or more tracers having different partition coefficients between the carrier fluid and immobile phase or phases. As the carrier fluid moves through the reservoir, one of the tracers is retarded more than the other due to its higher solubility in the immobile phase and the tracers separate. The degree of separation of the tracers is related to the quantities of mobile and immobile fluids in the reservoir. By monitoring formation fluids at the second location to detect the presence of the tracers, the relative fluid saturations can be determined using chromatographic analytical techniques.
A method as defined by claim 1 wherein the carrier fluid is a liquid.
Claim 2
Dependent Claim
13 words
A method as defined by claim 2 wherein the carrier fluid is aqueous.
Claim 3
Dependent Claim
14 words
A method as defined by claim 2 wherein the carrier fluid is an oil.
Claim 4
Dependent Claim
13 words
A method as defined by claim 1 wherein the carrier fluid is gaseous.
Claim 5
Dependent Claim
31 words
A method as defined by claim 1 wherein the partition coefficient of one of the tracers is at least twice as great as the partition coefficienT of another of the tracers.
Claim 6
Dependent Claim
41 words
A method as defined by claim 1 wherein the first location in the formation is at one location in a well and the second location in the formation is in the same well and is vertically spaced from the first location.
Claim 7
Dependent Claim
38 words
A method as defined by claim 1 wherein the first location in the formation is at one well and the second location in the formation is at a second well which is horizontally spaced from the first well.
Claim 8
Independent Claim
155 words
A method for determining the relative amounts of two fluid phases in a subterranean reservoir formation wherein one of the phases is mobile and the other is essentially immobile comprising injecting into the formation at a first location a solution consisting of a carrier fluid which is substantially insoluble in the immobile fluid phase and which is miscible with the mobile fluid phase and a tracer which is soluble in both the carrier fluid and the immobile fluid phase, the quantities of the carrier fluid and the tracer being sufficiently great to enable detection at a second location in the formation, displacing the carrier fluid-tracer solution to the second location in detectable quantities, detecting the carrier fluid and the tracer at the second location and measuring at least one property related to the chromatographic behavior of the carrier fluid and the tracer to determine the relative amounts of the two fluid phases in the formation.
Claim 9
Independent Claim
169 words
A method of determining the relative amounts of oil, gas, and water in a subterranean oil-bearing formation in which a first of the fluids is mobile and the second and the third fluids are essentially immobile which comprises injecting into the formation at a first location a carrier fluid which is substantially insoluble in the immobile second and third fluids and which is miscible with the mobile first fluid, incorporating in the carrier fluid at least three tracers having different three-phase partition coefficients between the carrier fluid and the immobile second fluid and between the carrier fluid and the immobile third fluid, the concentration of the tracers being sufficiently great to enable detection at a second location in the reservoir, displacing the carrier fluid and tracers to the second location in the formation detecting the tracers at the second location and measuring at least one property related to the chromatographic behavior of each of said tracers to determine the relative amounts of oil, gas, and water in the formation.