Produced water treatment in oil recovery
AssigneeE. I. Du Pont de Nemours and Company
InventorsSIMON FRISK, Hyun Sung Lim, Lisa C. Bates, Peter Andrin, Basil El-Borno
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Abstract
An oil recovery process that utilizes one or more filtration medium comprises a filter cake and a second filtration medium being nonwovens sheet to remove silica and/or oil and/or dissolved organics and/or dissolved solids from produced water which includes separating oil from the produced water and precipitating silica into particles and wherein the produced water having the precipitated silica is directed to a filtration medium which operates in a direct flow filtration mode and removes the precipitated silica from the produced water to form a filtrate stream.
Claims26
A method for recovering oil from a subterranean well, comprising the steps of;
- i) recovering a water mixture from the well, where the water mixture comprises water, oil, and silica as either dissolved or particulate silica or any combination thereof;
- ii) separating oil from the water mixture to produce a stream of water comprising dissolved and particulate silica and a residual level of oil;
- iii) adding an effective amount of a silica precipitating agent to the water, precipitating at least a portion of the dissolved silica, and leaving a water phase containing a residual level of dissolved silica;
- iv) directing the water phase containing dissolved, precipitated, and particulate silica, the precipitating agent, and residual oil to a first filtration medium to produce a filtrate stream;
- wherein the first filtration medium comprises a filter cake and a second filtration medium that is located downstream of and adjacent to the filter cake over at least a portion of the filter cake surface, the filter cake comprises precipitated silica and precipitating agent, and the second filtration medium comprises pores having a tortuous path therethrough.
A filtration medium comprising a filter cake and a filtration medium located along at least a portion of one surface of the filter cake, wherein the filter cake comprises precipitated silica and silica precipitating agent, and the filtration medium comprises pores having a tortuous path therethrough.
A system for removing oil from a subterranean well, comprising;
- i) a means for separating oil from the water mixture to produce a stream of water having dissolved and particulate silica
- ii) a means for precipitating the silica
- iii) a filtration medium through which essentially all of the water passes
- wherein the medium has an efficiency of 30% or greater for particles of 1 micrometer size or greater at a flow rate of 2 milliliters per minute per centimeter square of media per unit pressure of the liquid (ml/min/cm2/kPa), and filtering the produced water with the medium produces a filter cake upstream of, and in contact with, the medium and concentrated with the precipitated silica and wherein the filter cake is allowed to build to a pre-determined level until being replaced by a cake-free membrane.
Dependencies are inferred from the claim text.