US 2026/0308034 A1 · Method for Complete Sulfate and Metal Removal from Produced Water Using a Three-Step Treatment Process for Reinjection

Abstract

A method for treating produced water for reinjection into oil reservoirs by removing sulfates, metals, sulfur compounds, and microbial contaminants. Step one adds barium hydroxide to form barium sulfate. Sodium sulfide and carbon dioxide may be used to remove metals and stabilize excess barium. Step two uses a manganese-doped ceramic contactor and oxidants such as air, oxygen, hydrogen peroxide, or UV light to convert sulfur compounds to elemental sulfur. Step three filters the stream through an organophobic ceramic membrane to remove solids, organics, and bacteria. Hydrazine is added before filtration to remove dissolved oxygen. The process yields clean, scale-free water suitable for reinjection under high salinity. It offers a reliable, compact solution for produced water reuse and protects oilfield infrastructure from scaling and fouling.

Claims7

Dependent claims

A method for treating produced water for reinjection into oil reservoirs, comprising:

(a) introducing barium hydroxide into produced water to precipitate sulfate ions as barium sulfate;
(b) injecting carbon dioxide to convert excess barium ions into barium carbonate;
(c) optionally adding sodium sulfide to precipitate trace heavy metals as metal sulfides;
(d) passing the treated water through a catalytic ceramic contactor impregnated with manganese oxide while introducing an oxidizing agent selected from the group consisting of air, oxygen, hydrogen peroxide, and ultraviolet light, to oxidize sulfur compounds into elemental sulfur or sulfate;
(e) injecting hydrazine into the water stream to remove dissolved oxygen;
(f) filtering the water through an organophobic ceramic membrane to remove all precipitated solids, elemental sulfur, non-polar organics, sulfur-reducing bacteria, and iron-reducing bacteria.

3 more elements

Dependencies are inferred from the claim text.

Method for Complete Sulfate and Metal Removal from Produced Water Using a Three-Step Treatment Process for Reinjection

Life of this patent

Method for Complete Sulfate and Metal Removal from Produced Water Using a Three-Step Treatment Process for Reinjection

Life of this patent

Abstract

Claims7