Oil field extracted water deoiling process by using supercritical liquid extraction technique

A technology of supercritical fluid and extraction technology, applied in the direction of extraction water/sewage treatment, etc., can solve the problems of longer time, long residence time, poor adaptability, etc., and achieve the effect of reducing treatment cost, prolonging use time, and proper critical temperature

Inactive Publication Date: 2008-05-28
程海鹰 +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

For light crude oil, gravity sedimentation and hydrocyclone technology based on oil-water density difference are relatively easy to separate alkane crude oil components. In the water produced by polymer flooding, the residual oil forms a more stable dispersion and / or emulsification system in the water. At the same time, they are usually dense, and it takes longer to separate by gravity sedimentation or centrifugation, and the separation effect is poor. Due to the large pollution load, it is difficult to make the effluent meet the requirements of reinjection or discharge by using the current treatment process (flocculation, sedimentation, air flotation, filtration)
Biological treatment requires longer residence time and does not meet oil field needs
Membrane technology is a high-efficiency filtration technology, but the problem of membrane pollution by crude oil has not been effectively solved, which limits its application in the field of oily sewage treatment.
However, for heavy oil produced water and polymer flooding produced water, due to the small oil-water density difference and serious emulsification, it takes longer to settle and separate, and the effect is not good, and the oil removal efficiency of the hydrocyclone is not high, so the current The treatment process has poor adaptability to difficult-to-treat produced water from heavy oil production and polymer flooding, and cannot meet actual needs

Method used

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  • Oil field extracted water deoiling process by using supercritical liquid extraction technique
  • Oil field extracted water deoiling process by using supercritical liquid extraction technique

Examples

Experimental program
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Effect test

Embodiment 1

[0029] Embodiment 1 The deoiling of common produced water

[0030] The produced water of an oilfield (after settling and separation in a large tank) contains 216mg / L of oil in the raw water, and the density of crude oil is 0.8590g / cm3. After being directly deoiled by the hydrocyclone, the oil in the outlet is about 30-50mg / L. Adopt the process of the present invention, the LNG addition amount is 1.5%, after the technological process of Fig. 1 is processed, the hydrocyclone effluent oil content is less than 15mg / L; If adopt two-stage hydrocyclone process (Fig. 2), the LNG addition amount is 1.0% , the oil content of the final effluent can be reduced to below 5mg / L.

Embodiment 2

[0031] Example Dimer Flooding Produced Water Removal of Oil

[0032] The quality of the raw water produced by polymer flooding in an oilfield is: oil content 1800mg / L, polymer content 680mg / L, crude oil density 0.8920g / cm3, after direct oil removal by hydrocyclone, the outlet oil content is about 140-250mg / L.

[0033] Using the process shown in Figure 1, the amount of LNG added is 2.5%, and the oil content in the hydrocyclone effluent is about 50mg / L; The oil content can be reduced to below 15-30mg / L, and after fine filtration (walnut shell and fiber ball), the final oil content of the effluent can be reduced to below 5mg / L.

Embodiment 3

[0034] Example 3 Deoiling of Heavy Oil Produced Water

[0035] The raw water quality of heavy oil produced in an oilfield is (after demulsification and settlement): oil content 1100mg / L, crude oil density 0.9770g / cm3, the oil content after direct oil removal by hydrocyclone is about 120-180mg / L, oil removal less efficient.

[0036] Using the process shown in Figure 1, the amount of LNG added is 2.5%, and the oil content in the effluent of the hydrocyclone can be reduced to about 20-40mg / L; The oil content of the hydrocyclone effluent can be reduced to below 10mg / L, and after fine filtration (walnut shells and fiber balls), the final oil content of the effluent can be reduced to below 2mg / L.

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Abstract

The invention relates to a new technique of the oil removal of oilfield-produced water, which utilizes a solvent extraction technology. The novel technique is invented to quickly condense the micro oil drop of dispersed oil, emulsible oil and soluble oil in the water into the oil drop with a larger dimension, thus realizing quick and high-effective oil removing from the oilfield-produced water. The novel technique relates to the application of supercritical fluid extraction technology which adopts liquefied natural gas (LNG) as the solvent. The whole technique process mainly comprises units of a primary separator, a natural gas purification and liquefaction system, a second stage separator, an extraction reactor, a hydrocyclone, etc. The invention has the advantages that: the oil removal effect is good, the detention time of each unit is short, the solvent can be recycled and repeatedly used and the floor area of the device is small, which is especially applicable to ocean or sea beach oil-production platform. The technique is applicable to the oil removal of effluent from heavy oil produced water and polymer flooding produced water.

Description

technical field [0001] The invention relates to a new process of using liquefied natural gas as a solvent to remove oil from oil field development and production water under supercritical conditions through solvent extraction technology, and belongs to the field of oil production sewage treatment. Background technique [0002] In China, the general oil field development method is mainly through water injection. At present, the comprehensive water cut of my country's old oilfields (especially the eastern oilfields) is basically above 90%. With the extraction of crude oil, a large amount of oily sewage is also produced. Most of the produced water after treatment will be used for reinjection, and a small part will be discharged or used for boiler water. Usually, the oil well production fluid passes through the three-phase separator to separate oil and gas, and produces a large amount of oily sewage (or called produced water). Oilfield produced water has the following characte...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C02F1/26
Inventor 程海鹰邱鹏
Owner 程海鹰
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