Method of produced water treatment, method of water reuse, and systems for these methods

1. A method of conducting water treatment of water produced from an in-situ recovery of bitumen from oil sand, comprising the steps of:

subjecting a bitumen-mixed fluid to separation in a separator to obtain bitumen and a hot oil-containing water, the bitumen-mixed fluid being produced from an oil sand well; and

filtering the hot oil-containing water at a temperature of from 85-135° C. with a microfiltration membrane made of polytetrafluoroethylene to produce a product water having a lowered oil content

wherein the hot oil-containing water is filtered under an external or internal pressure with the microfiltration membrane having a hollow fiber structure, the microfiltration membrane has an outer diameter of 1-5 mm, an inner diameter of 0.5-4 mm, a porosity of 40-90% and continuous structures having a pore size of 0.01-0.45 μm and the microfiltration member is contained in a cross-flow filter system.

2. The method of produced water treatment as claimed in claim 1 , wherein the hot oil-containing water is filtered to produce product water having an oil concentration of 5 mg/liter or less.

3. The method of produced water treatment as claimed in claim 2 , wherein the product water has an oil concentration of no more than 0.1 mg/L.

4. The method of claim 3 , consisting of the separation and filtering steps.

5. The method of produced water treatment as claimed in claim 1 , wherein the in-situ recovery method is a SAGD process or a CSS process.

6. The method of claim 1 , wherein the oil content of the hot oil-containing water is from 1,000-3,000 mg/L.

7. The method of claim 1 , wherein the oil content of the product water is no more than 10 mg/L.

8. The method of claim 1 , wherein the hot oil-containing water is at a temperature of from 90-120° C. during filtering.

9. The method of claim 1 , wherein the microfiltration membrane has hydrophilic properties.

10. A method of water reuse in an in-situ recovery method of producing bitumen, comprising the steps of:

treating an oil-containing water according to the method of claim 1 to obtain treated water;

distilling the treated water via an evaporator;

generating steam from the distilled water by using a drum-type boiler; and reusing the steam for recovering bitumen from the oil sand wells.

11. A system for conducting water treatment of water produced from an in-situ recovery of bitumen from oil sand, comprising:

a separator for subjecting a bitumen-mixed fluid to separation comprising an inlet for receiving a bitumen-mixed fluid, an outlet for discharging bitumen, and an outlet for discharging an oil-containing water; and

a microfiltration membrane contained in a cross-flow filter system and made of polytetrafluoroethylene, having a hollow fiber structure, an outer diameter of 1-5 mm, an inner diameter of 0.5-4 mm, a porosity of 40-90% and continuous structures having a pore size of 0.01-0.45 μm for filtering the hot oil-containing water at a temperature of from 85-135° C. under an external or internal pressure, the membrane comprising an inlet for receiving the oil-containing water and an outlet for discharging a product water having a lowered oil content.

12. The system of claim 11 , wherein the in-situ recovery method is a SAGD process or a CSS process.

13. The system of claim 11 , further comprising:

an evaporator for distilling treated water to obtain distilled water, the treated water having been treated by the microfiltration membrane, and

a drum-type boiler for generating steam from the distilled water, the steam being capable of using for recovering bitumen from the oil sand wells.

14. The system of claim 11 , wherein the microfiltration membrane has hydrophilic properties.

15. The system of claim 11 , wherein the system comprises a circulating flow filtration unit having a circulating flow line and a separation membrane module containing the microfiltration membrane installed in the circulating flow line.