Chevron U.s.a. Inc.

Chevon U.s.a. Inc.

Sujin Yean

Dennis John O'Rear

Darrell Lynn Gallup

Russell Evan Cooper

Lyman Arnold Young

Dennis John O'rear

Brian Christopher Llewellyn

Matthew Bernard Zielinski

Mark Anthony Emanuele

Stephen Roby

Seyi Abiodun Odueyungbo

Wei Wang

Jerry Max Rovner

Hosna Mogaddedi

Manuel Eduardo Quintana

A predictive tool is provided for estimating the mercury content of hydrocarbons to be produced from a wellbore in a newly investigated subterranean hydrocarbon producing formation based on the mercury content of an inorganic sample recovered from the wellbore. The mercaptans content of liquid hydrocarbons and/or the hydrogen sulfide content of natural gas produced from the formation may also be used to enhance the prediction. Based on the predicted value, a mercury mitigation treatment may be provided to mitigate the mercury content of hydrocarbons produced from the formation.

Process for mercury removal

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.

In-situ method and system for removing heavy metals from produced fluids

Trace amount levels of non-volatile mercury in crude oil are reduced by contacting the crude oil with a water stream containing at least a monatomic water-soluble sulfur species such as sulfides and hydrosulfides. The non-volatile mercury is extracted into the water phase forming a mercury rich wastewater, yielding a treated crude oil having at less than 50% of the original non-volatile mercury level. The wastewater can disposed or recycled by injection into a reservoir. In one embodiment, the water stream consists essentially of produced water.

Process, method, and system for removing mercury from fluids

Trace element levels of mercury in crude oil are reduced by first passing the crude oil through a filtration device to generate filtered crude having a reduced concentration of mercury and a reject stream having a concentrated mercury level. In one embodiment, the filtration device is back-flushed to generate the reject stream. In another embodiment, the reject stream comprises a portion of the retentate from a cross-flow filter device. The reject stream is treated with an extractive agent selected from tetrakis(hydroxymethyl)phosphonium sulfate; tetrakis(hydroxymethyl) phosphonium chloride; an oxidizing agent; an organic or inorganic sulfidic compound to extract a portion of the mercury into a water phase for subsequent removal. In one embodiment, the extractive agent is a reductant to convert non-volatile mercury into volatile mercury.

Process, method, and system for removing heavy metals from fluids

Trace levels of mercury in a natural gas are reduced by scrubbing the natural gas in an absorber with an aqueous solution comprising a water-soluble sulfur compound. The water-soluble sulfur compound reacts with a least a portion of the mercury in the natural gas to produce a treated natural gas with a reduced concentration of mercury, and a mercury containing sulfur-depleted solution which can be disposed by injection into a (depleted) underground formation. The produced water extracted with the natural gas from the underground formation can be recycled for use as the scrubbing solution. In one embodiment, a fresh source of water-soluble sulfur compound as feed to the absorber can be generated on-site by reacting an elemental sulfur source with a sulfur reagent in produced water.

Trace amount levels of heavy metals such as mercury in crude oil are reduced by contacting the crude oil with a sufficient amount of a reducing agent to convert at least a portion of the non-volatile mercury into a volatile form of mercury, which can be subsequently removed by any of stripping, scrubbing, adsorption, and combinations thereof. In one embodiment, at least 50% of the mercury is removed. In another embodiment, the removal rate is at least 99%. In one embodiment, the reducing agent is selected from sulfur compounds containing at least one sulfur atom having an oxidation state less than +6; ferrous compounds; stannous compounds; oxalates; cuprous compounds; organic acids which decompose to form COand/or Hupon heating; hydroxylamine compounds; hydrazine compounds; sodium borohydride; diisobutylaluminium hydride; thiourea; transition metal halides; and mixtures thereof.

Trace amount levels of heavy metals such as mercury in crude oil are reduced by contacting the crude oil with an oxidizing agent and then with a reducing agent. In one embodiment, the oxidizing agent is selected from the group of hydroperoxides, organic peroxides, inorganic peracids and salts thereof, organic peracids and salts thereof, halogens such as iodine (I), bromine (Br), and ozone. The treatment converts non-volatile mercury in the crude oil into a volatile form for subsequent mercury removal by any of stripping, scrubbing, adsorption, and combinations thereof. In one embodiment, at least 50% of the mercury is removed. In another embodiment, the removal rate is at least 99%.

Trace element levels of heavy metals in crude oil are reduced by contacting the crude oil with an oxidizing agent, extracting heavy metals into a water phase for subsequent separation from the crude oil. The oxidizing agent is selected from the group of hydroperoxides, organic peroxides, inorganic peracids and salts thereof, organic peracids and salts thereof, and ozone. In one embodiment, the oxidizing agent converts heavy metals into the heavy metal cations in a water-oil emulsion, which can be subsequently separated from the crude oil, for a treated crude oil having reduced levels of heavy metals. In one embodiment, at least a complexing agent can be added to facilitate the removal by forming soluble heavy metal complexes in the water phase.

Trace element levels of heavy metals such as mercury in crude oil are reduced by contacting the crude oil with an iodine source, generating a water soluble heavy metal complex for subsequent removal from the crude oil. In one embodiment, the iodine source is generated in-situ in an oxidation-reduction reaction, by adding the crude oil to an iodine species having a charge and a reductant or an oxidant depending on the charge of the iodine species. In one embodiment with an iodine species having a positive charge and a reducing reagent, a complexing agent is also added to the crude oil to extract the heavy metal complex into the water phase to form water soluble heavy metal complexes which can be separated from the crude oil, for a treated crude oil having reduced levels of heavy metals.

Trace element levels of heavy metals such as mercury in crude oil are reduced by contacting the crude oil with an oxidant such as oxyhalites, converting elemental mercury into heavy metal cations for subsequent separation from the crude oil. In an improved method for the removal of mercury, at least a complexing agent is added to convert the heavy metal cations into soluble heavy metal complexes in a water phase, which can be separated from the crude oil, for a treated crude oil having reduced levels of heavy metals. In one embodiment, the complexing agent is selected from the group of metal halides.

Trace element levels of heavy metals in crude oil are reduced by contacting the crude oil with an oxidizing agent, converting heavy metals into heavy metal cations for subsequent separation from the crude oil. At least a complexing agent is added to convert the heavy metal cations into soluble heavy metal complexes in a water phase, which can be separated from the crude oil, for a treated crude oil having reduced levels of heavy metals. In one embodiment, the complexing agent is selected from the group of metal halides, and the oxidizing agent is selected from the group of organic peracids, inorganic peracids and salts thereof.

Trace levels of heavy metals in fluids such as crude oil are reduced by contacting the crude oil with a composition comprising a compound of Formula (I), wherein X is an anion of valency n, the number of phosphonium cations present. In one embodiment, the composition further comprises a complexing additive comprising an amine or corresponding ammonium derivative. Upon contact with the crude oil, the heavy metals form soluble complexes with the compound of Formula (I) for subsequent removal from the crude oil via phase separation.

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Houston, TX, United States of America

Sujin Yean