# US 10,767,458 B2 · Characterization of crude oil-water interfacial film rigidity to enhance oil recovery > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,767,458 B2 - Document ID: US10767458B2 - Status: Granted - Kind: B2 - Application number: 15/912,065 - Filed: 2018-03-05 - Published: 2018-10-11 - Granted: 2020-09-08 - Earliest claimed: 2017-03-08 - Assignees: Saudi Arabian Oil Company - Applicants: Saudi Arabian Oil Company - Inventors: Subhash Chandrabose Ayirala; Ali Abdallah Al-Yousef - Web page: https://patentgrep.com/patent/US10767458B2 ## CPC - E21B 43/20: Displacing by water - E21B 49/08: Obtaining fluid samples or testing fluids, in boreholes or wells - G01N 11/10: by moving a body within the material - G01N 13/00: Investigating surface or boundary effects, e.g. wetting power; Investigating diffusion effects; Analysing materials by determining surface, boundary, or diffusion effects (scanning-probe techniques or apparatus G01Q) - G01N 13/02: Investigating surface tension of liquids - G01N 33/1833: {Oil in water} - E21B: EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS - G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q) ## Abstract Assessing a rigidity of an interface between a crude oil and a brine includes at least one of: assessing a compression energy for the interface between the crude oil and the brine; assessing a time at which an elastic modulus and a viscous modulus of the interface between the crude oil and the brine are equal; assessing a crumpling behavior or a crumpling ratio of a droplet of the crude oil in the brine; and assessing a coalescence time of droplets of the crude oil in the brine. ## Claims ### Claim 1 A method of assessing a rigidity of an interface between a crude oil and a brine, the method comprising at least one of: assessing a compression energy for the interface between the crude oil and the brine; assessing a time at which an elastic modulus and a viscous modulus of the interface between the crude oil and the brine are equal; assessing a crumpling behavior or a crumpling ratio of a droplet of the crude oil, wherein the droplet of the crude oil is in the brine; and assessing a coalescence time of a plurality of droplets of the crude oil, wherein the plurality of droplets of the crude oil is in the brine. ### Claim 2 (depends on 1) The method of claim 1, wherein assessing a compression energy for the interface between the crude oil and the brine comprises: assessing interfacial pressure versus area isotherms for the interface between the crude oil and the brine; and integrating the interfacial pressure over a change in surface area to yield the compression energy. ### Claim 3 (depends on 2) The method of claim 2, wherein assessing interfacial pressure versus area isotherms for the interface between the crude oil and the brine is achieved with a Langmuir trough. ### Claim 4 (depends on 1) The method of claim 1, wherein assessing a time at which an elastic modulus and a viscous modulus of the interface between the crude oil and the brine are equal comprises: assessing elastic moduli and viscous moduli of the interface between the crude oil and the brine as a function of time; and identifying a time at which the elastic modulus is equal to the viscous modulus. ### Claim 5 (depends on 4) The method of claim 4, further comprising assessing a dynamic interfacial viscosity using the elastic moduli and the viscous moduli. ### Claim 6 (depends on 4) The method of claim 4, wherein assessing elastic moduli and viscous moduli of the interface between the crude oil and the brine as a function of time is achieved with an interfacial shear rheometer. ### Claim 7 (depends on 1) The method of claim 1, wherein assessing the crumpling ratio of the droplet of the crude oil comprises: assessing an initial size of the droplet of the crude oil before initiating a contraction of the droplet of the crude oil; and assessing a size of the droplet of the crude oil at the time at which crumpling begins. ### Claim 8 (depends on 1) The method of claim 1, wherein the crumpling ratio is a projected area of the droplet of the crude oil just before the droplet of the crude oil crumples divided by an initial projected area of the droplet of the crude oil. ### Claim 9 (depends on 1) The method of claim 1, wherein the brine comprises ions of at least one of sodium, calcium, magnesium, chloride, bicarbonate, and sulfate. ### Claim 10 (depends on 1) The method of claim 1, wherein the brine is substantially free of sulfate. ### Claim 11 (depends on 1) The method of claim 1, wherein assessing the rigidity of the interface between the crude oil and the brine comprises assessing the compression energy for the interface between the crude oil and the brine, and further comprising selecting a composition of an injection fluid for a reservoir from which the crude oil was obtained by increasing or decreasing a concentration of at least one ion in the brine to decrease the rigidity of the interface between the crude oil and the brine. ### Claim 12 (depends on 1) The method of claim 1, wherein assessing the rigidity of the interface between the crude oil and the brine comprises assessing the time at which the elastic modulus and the viscous modulus of the interface between the crude oil and the brine are equal, and further comprising selecting a composition of an injection fluid for a reservoir from which the crude oil was obtained by increasing or decreasing a concentration of at least one ion in the brine to decrease the rigidity of the interface between the crude oil and the brine. ### Claim 13 (depends on 1) The method of claim 1, wherein assessing the rigidity of the interface between the crude oil and the brine comprises assessing the crumpling behavior or the crumpling ratio of the droplet of the crude oil in the brine, and further comprising selecting a composition of an injection fluid for a reservoir from which the crude oil was obtained by increasing or decreasing a concentration of at least one ion in the brine to decrease the rigidity of the interface between the crude oil and the brine. ### Claim 14 (depends on 1) The method of claim 1, wherein assessing the rigidity of the interface between the crude oil and the brine comprises assessing a coalescence time of droplets of the crude oil in the brine, and further comprising selecting a composition of an injection fluid for a reservoir from which the crude oil was obtained by increasing or decreasing a concentration of at least one ion in the brine to decrease the rigidity of the interface between the crude oil and the brine. ### Claim 15 (depends on 1) The method of claim 1, further comprising: obtaining a sample of the crude oil from a reservoir before assessing the rigidity of the interface between the crude oil and the brine; selecting a composition of an injection fluid for the reservoir from which the crude oil was obtained by increasing or decreasing a concentration of at least one ion in the brine to decrease the rigidity of the interface between the crude oil and the brine; and injecting the injection fluid into the reservoir. ### Claim 16 A method of selecting a composition of an injection fluid for an enhanced oil recovery process, the method comprising: assessing a rigidity of an interface between a crude oil and a brine; and selecting the composition of the injection fluid, wherein selecting the composition of the injection fluid comprises altering a composition of the brine to increase or decrease a concentration of one or more ions in the brine to yield the injection fluid, such that a crude oil-injection fluid interfacial film rigidity is less than a crude oil-brine interfacial film rigidity. ### Claim 17 (depends on 16) The method of claim 16, wherein assessing the rigidity of the interface between the crude oil and the brine comprises at least one of: assessing a compression energy for the interface between the crude oil and the brine; assessing a time at which an elastic modulus and a viscous modulus of the interface between the crude oil and the brine are equal; assessing a crumpling behavior or a crumpling ratio of a droplet of the crude oil, wherein the droplet of the crude oil is in the brine; and assessing a coalescence time of a plurality of droplets of the crude oil, wherein the plurality of droplets of the crude oil is in the brine. ### Claim 18 (depends on 16) The method of claim 16, further comprising obtaining a sample of the crude oil from a reservoir before assessing the rigidity of the interface between the crude oil and the brine. ### Claim 19 (depends on 18) The method of claim 18, further comprising injecting the injection fluid into the reservoir. ### Claim 20 (depends on 16) The method of claim 16, comprising increasing a concentration of at least one of sodium ions, calcium ions, magnesium ions, chloride ions, bicarbonate ions, or sulfate ions in the brine to decrease the rigidity of the interface between the crude oil and the brine. ### Claim 21 (depends on 16) The method of claim 16, comprising decreasing a concentration of sulfate ions in the brine to decrease the rigidity of the interface between the crude oil and the brine.