# US 2014/0151040 A1 · In-situ method and system for removing heavy metals from produced fluids > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0151040 A1 - Document ID: US20140151040A1 - Status: Published application - Kind: A1 - Application number: 13/896,255 - Filed: 2013-05-16 - Published: 2014-06-05 - Earliest claimed: 2012-05-16 - Assignees: Chevron U.S.A. Inc. - Inventors: Sujin Yean; Darrell Lynn Gallup; Lyman Arnold Young; Russell Evan Cooper; Matthew Bernard Zielinski; Mark Anthony Emanuele; Brian Christopher Llewellyn; Dennis John O'Rear - Web page: https://patentgrep.com/patent/US20140151040A1 ## CPC - E21B 43/38: in the well - C09K 8/52: Compositions for preventing, limiting or eliminating depositions, e.g. for cleaning - E21B 43/16: Enhanced recovery methods for obtaining hydrocarbons - E21B 43/26: by forming crevices or fractures - E21B 43/40: Separation associated with re-injection of separated materials {(E21B43/385 takes precedence)} - E21B: EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS - C09K: MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE ## Abstract Methods and systems relate to the in-situ removal of heavy metals such as mercury, arsenic, etc., from produced fluids such as gases and crudes from a subterranean hydrocarbon-bearing formation. A sufficient amount of a fixing agent is injected into formation with a dilution fluid. The fixing agent reacts with the heavy metals forming precipitate, or is extracted heavy metals into the dilution fluid as soluble complexes. In one embodiment, the heavy metal precipitates remain in the formation. After the recovery of the produced fluid, the dilution fluid containing the heavy metal complexes is separated from the produced fluid, generating a treated produced fluid having a reduced concentration of heavy metals. In one embodiment, the dilution fluid is water, and the wastewater containing the heavy metal complexes after recovery can be recycled by injection into a reservoir. ## Claims ### Claim 1 A method for recovering hydrocarbons from a subterranean hydrocarbon-bearing formation while simultaneously removing heavy metals from the hydrocarbons, comprising: exposing the heavy metals in the hydrocarbons to a fixing agent in a dilution fluid for the fixing agent to react with the heavy metals forming heavy metal complexes in the dilution fluid; and recovering the hydrocarbons having a reduced concentration of heavy metals and the dilution fluid containing the heavy metal complexes as a mixture from the formation via a production well. ### Claim 2 (depends on 1) The method of claim 1, further comprising: separating the dilution fluid containing the heavy metal complexes from the hydrocarbons for treated hydrocarbons having a reduced concentration of heavy metals. ### Claim 3 (depends on 2) The method of claim 2, further comprising recovering the dilution fluid after the separating step for injection into an oil or gas reservoir. ### Claim 4 (depends on 1) The method of claim 1, wherein at least a portion of the heavy metal complexes comprises insoluble heavy metal complexes, which precipitate out of the mixture of hydrocarbons and dilution fluid. ### Claim 5 (depends on 4) The method of claim 4, wherein at least a portion of the insoluble heavy metal complexes remain in the formation. ### Claim 6 (depends on 1) The method of claim 1, wherein the heavy metal complexes comprises soluble mercury compounds. ### Claim 7 (depends on 1) The method of claim 1, wherein the heavy metals in the hydrocarbons are exposed to the fixing agent at a molar ratio of fixing agent to heavy metals ranging from 1:1 to 20,000:1. ### Claim 8 (depends on 7) The method of claim 7, wherein the heavy metals in the hydrocarbons are exposed to the fixing agent at a molar ratio of fixing agent to heavy metals ranging from 5:1 to 10,000:1. ### Claim 9 (depends on 1) The method of claim 1, wherein the heavy metals contain mercury, the dilution fluid is water, the fixing agent is selected from organic polysulfides, alkali sulfides, alkali hydrosulfides, ammonium sulfides and mixtures thereof, and wherein the fixing agent reacts with mercury forming soluble mercury compounds in water. ### Claim 10 (depends on 1) The method of claim 1, wherein the heavy metals contain mercury, the dilution fluid is water, the fixing agent is selected from sodium polysulfide, ammonium polysulfide, sulfide-containing polymer, alkali sulfides, alkali hydrosulfides, ammonium sulfides and mixtures thereof, and wherein the fixing agent reacts with mercury forming insoluble mercury complexes that precipitate in the reservoir to effect in-situ removal of mercury from produced hydrocarbons. ### Claim 11 (depends on 1) The method of claim 1, wherein the heavy metals contain mercury and the treated hydrocarbons has a mercury concentration of less than 100 ppbw. ### Claim 12 A method for recovering hydrocarbons from a subterranean hydrocarbon-bearing formation while simultaneously removing heavy metals from the hydrocarbons, comprising: fracturing the formation to generate fractures; providing a dilution fluid containing a fixing agent to flow through the fractures in the formation for the fixing agent to react with at least a portion of the heavy metals in the formation forming heavy metal complexes soluble in the dilution fluid; recovering the dilution fluid containing the soluble heavy metal complexes and hydrocarbons having a reduced concentration of heavy metals from the formation via a production well. ### Claim 13 (depends on 12) The method of claim 12, wherein at least of a portion of the fixing agent is adsorbed into the fractures. ### Claim 14 (depends on 12) The method of claim 12, wherein at least a portion of the heavy metal complexes remains in the formation as insoluble heavy metal complexes. ### Claim 15 (depends on 12) The method of claim 12, wherein at least a portion of the fixing agent diffuses into the fractures in the formation and react with the heavy metals for a period of at least 2 hours. ### Claim 16 (depends on 12) The method of claim 12, wherein the heavy metals contain mercury, the dilution fluid is water, the fixing agent is selected from sodium polysulfide, ammonium polysulfide, sulfide-containing polymer, alkali sulfides, alkali hydrosulfides, ammonium sulfides and mixtures thereof, and wherein the fixing agent reacts with mercury forming insoluble mercury complexes that precipitate in the reservoir to effect in-situ removal of mercury from produced hydrocarbons. ### Claim 17 (depends on 12) The method of claim 12, further comprising separating the dilution fluid from the hydrocarbons to recover treated hydrocarbons having a reduced concentration of heavy metals. ### Claim 18 (depends on 17) The method of claim 17, further comprising recovering the dilution fluid after the separating step for injection into an oil or gas reservoir. ### Claim 19 (depends on 12) The method of claim 12, wherein the dilution fluid comprises produced water and the heavy metals comprise mercury. ### Claim 20 A method for recovering hydrocarbons from a subterranean hydrocarbon-bearing formation while simultaneously removing heavy metals from the hydrocarbons, comprising: exposing the heavy metals in the hydrocarbons to a fixing agent in a dilution fluid for the fixing agent to react with at least a portion of the heavy metals forming heavy metal compounds that remain in the formation; and recovering the hydrocarbons and the dilution fluid from the formation via a production well as a mixture; wherein the recovered hydrocarbons have a concentration of heavy metals less than the concentration of heavy metals in the hydrocarbons in the formation. ### Claim 21 (depends on 20) The method of claim 20, wherein the heavy metals in the hydrocarbons are exposed to the fixing agent at a molar ratio of fixing agent to heavy metals ranging from 1:1 to 20,000:1.