Processing aids for enhanced hydrocarbon recovery from oil sands, oil shale and other petroleum residues

Abstract

A method of improving hydrocarbon recovery from oil sands, oil shale, and petroleum residues includes adding a polymeric or nonpolymeric processing aid capable of sequestering cations, such as the multivalent calcium, magnesium and iron cations. The hydrocarbons are preferably contacted with the processing aid before a primary separation of the hydrocarbons in order to increase bitumen recovery. A processing aid is provided in an effective amount to increase the liberation of the hydrocarbons from inorganic solids, particularly when the source is a poor processing ore. Preferred processing aids include citric acid or a polymeric acid selected from polyacrylic acid, polymethacrylic acid, salts of these acids, partial salts of these acids, and combinations thereof. The processing aids significantly increase the hydrocarbon recovery typically with concentrations less than 50 ppm and the polymeric processing aids can also provide beneficial flocculation of solids in tailings slurry.

Description

[0001] This application claims priority from U.S. provisional applications 60 / 505,083 filed on Sep. 22, 2003 and 60 / 604,212 filed on Aug. 25, 2004.BACKGROUND OF THE INVENTION [0002] 1. Field of the Invention [0003] The present invention relates to the recovery of hydrocarbons from tar sands, oil shale and other petroleum residues. The invention also relates to the settling of solids from the tailings slurry of a hydrocarbon recovery process. More specifically, the invention relates to compositions and methods for improving the recovery of hydrocarbons and, in some cases, also the settling of solids in the tailings. [0004] 2. Description of the Related Art [0005] The Athasbasca Oil Sands Deposit is, by itself, the largest petroleum resource in the world. These oil sands or tar sands are located in northwestern Alberta, Canada and represent the equivalent of roughly 1.6 to 2.7 trillion barrels of oil. Oil sand is visible on the banks of the Athabasca River, north and south of Fort McM...

AI Technical Summary

Benefits of technology

[0017] Another embodiment of the invention provides a method that includes providing a polymeric processing aid to sequester cations in an aqueous mixture of hydrocarbons and selectively flocculate inorganic solids, and liberating the hydrocarbons from the inorganic material. Preferably, the polymeric processing aid is provided in an amount that is effective to increase the liberation of the hydrocarbons. The hydrocarbons and inorganic solids may optionally be obtained from oil sand, oil shale, petroleum residue, or a combination thereof. The process is especially beneficial for use wherein the hydrocarbons and inorganic solids are obtained from a poor processing ore.

[0019] Preferably, the aqueous mixture is provided with between 1 and 150 ppm of the polymeric processing aid, more preferably between 10 and 100 ppm, and most preferably between 15 and 60 ppm. The addition of the polymeric processing aid has been shown to increase the bitumen recovery by at least 5 percent, or even at least 10 percent.

[0021] Accordingly, the processing aids of this invention should be suitable for sequestering cations selected from calcium, magnesium, iron, alumina, silica, titanium, zirconium, and combinations thereof. Preferably, the method is characterized by a reduction in the cation concentration and allows greater bubble attachment of the hydrocarbons. Optionally, the method includes reducing the concentration of unsequestered multivalent ions in the aqueous mixture to less than 30 ppm. Still, the method may further comprise monitoring the efficiency of the hydrocarbon recovery; and varying the amount of processing aid added to the aqueous mixture to control the efficiency.

Problems solved by technology

However, the process of separating bitumen from sand, clay, and water is complicated by variations in the composition of the oil sand deposits.

In fact, various oil sands have been classified as “problem ores” or “poor processing ores” while others are referred to as “good processing ores.” Problem ores, such as transition ores, oxidized ores, “type-X” ores and those having high fines or clays, bring about reduced bitumen yield or increased bitumen losses to waste streams.

Because of the relative amounts of problem ores and good processing ores, the problem ores reduce the industry average recovery to about 92% of total bitumen content.

Heretofore, there has been no explanation for why these problem ores are difficult to process and there has been no solution that allows these ores to be processed efficiently.

Eventually, the problem ores must be processed.

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