Re-injection method for produced-water desorption oxygen-removal mixing polymer for improving petroleum recovery efficiency

A technology for preparing polymers and desorption, applied in drilling compositions, chemical instruments and methods, and production fluids, etc., can solve the problems of long process flow, expensive filters, and repeated cleaning.

Inactive Publication Date: 2007-07-11
NANKAI UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

For the treatment of produced water in low-permeability oilfields, because low-permeability oilfields have stricter water quality requirements, usually only the use of fine filtration and membrane separation technology can meet the requirements, thus making the process longer
Moreover, because the filter is expensive, has a short life, and needs to be cleaned repeatedly, it is difficult to popularize and apply

Method used

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  • Re-injection method for produced-water desorption oxygen-removal mixing polymer for improving petroleum recovery efficiency
  • Re-injection method for produced-water desorption oxygen-removal mixing polymer for improving petroleum recovery efficiency

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0028] Deoxygenation test after reinjection of water for oxygenation

[0029] In order to test the deoxygenation capacity of the reinjection water desorption deoxygenation device, the reinjection water from the oilfield was taken to carry out the deoxygenation experiment after oxygenation. Under the normal operating conditions of the oxygen removal system, multiple samples of tests and inspections were carried out. The results are shown in Table 1.

[0030] Table 1 Results of desorption and deoxygenation experiments

[0031] sewage index

[0032] The test results show that the DO content in the effluent after low-temperature desorption and oxygen removal treatment of the reinjected water is 0.03-0.10 mg / L, which meets the requirements for DO in sewage polymer injection. The DO content in the effluent water after the reinjection water is deoxidized by the aeration desorption cycle is lower, and generally DO≤0.01mg / L.

Embodiment 2

[0034] Operation test of re-injection water desorption and oxygen removal project

[0035] Under the normal operating conditions of the desorption deoxygenation system, a one-year field test of the deaeration engineering of different reinjection water in the oilfield was carried out, and the results are shown in Table 2.

[0036] Table 2 Statistical results of desorption and oxygen removal treatment with different reinjection water quality (mg / l)

[0037] Water quality project

[0038] It can be seen from Table 2 that the reinjection water has been treated by the low-temperature desorption and oxygen removal process system. The water quality of the reinjection water is 5-10mg / l of suspended solids, pH=7.8-8.9, water temperature of 30-45°C, and oil content of 3-8mg / l. l, COD cr =310~950mg / l, DO=2.8~5.9mg / l, DO<0.1mg / l in the effluent of the deaerator system, and DO meets the requirements of oilfield reinjection water quality indicators.

Embodiment 3

[0040] Effect of Injection Time on Viscosity of Polymer Solution Prepared from Sewage

[0041] 1500mg / L PAM was added to the raw water and the sewage after desorption and deoxygenation treatment to prepare the polymer solution, and the viscosity of the injected liquid was detected at different preparation injection times. The results are listed in Table 3.

[0042] Table 3 The effect of injection time on the viscosity of polymer solution prepared from sewage

[0043] It can be known from Table 3 that the viscosity of the polymer solution prepared by reinjection water without desorption and oxygen removal treatment decreased rapidly with time, and the viscosity of the solution decreased to 76.5 after 1 day, and decreased rapidly with time, and dropped to 12.7 after 10 days, and 12.7 after 20 days. After 30 days, it dropped to 9.1 and 4.6 respectively, and there was almost no effect after reinjection; the viscosity of the polymer solution prepared by reinjection water after deso...

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Abstract

The invention relates to a sewage deoxidizing process and polymer injection method for enhancing tertiary oil recovery effect and improving the viscosity of polymer solution made up by oil sewage. Low-temperature desorptive deoxygenization process is adopted in reinjection deoxygenization, which comprises cycling deoxygenization water tank, deoxygenization water pump and desorptive deoxygenization in turn. The polymer injection process for improving the polymer solution made up by oil rejecting water comprises sewage deoxygenization process, polymer dissolution, mixed preparing sewage and injecting process of high-pressure water pump. PAM is applied in polymer solution made up by sewage. PAM is added from drug solution tank by metering pump. After mixed the polymer reinjecting solution is prepared, which is injected into stratum for oil recovery by high-pressure water pump. The test result shows that the desorptive deoxygenization technology treat the oil water, the serious degradation of polymer generated by oxygen active substance in sewage is eliminated, the viscosity of jetting solution is improved and the oil recovery effect of polymer is enhanced. The method is provided with simple operation and big practical applicable value. It is especially suitable for reinjection after the treatment for waste water with high oxygen content in oil. The running cost is low and the equipment is simple. There is no secondary pollution.

Description

technical field [0001] The invention relates to oil recovery after oilfield produced water treatment, in particular to a sewage injection, polymerisation, desorption, deoxygenation and reinjection method for enhancing the effect of tertiary oil recovery in oilfields and increasing the viscosity of polymer solutions prepared by reinjection water in oilfields. Background technique [0002] With the deepening of oilfield development, the water content of oilfield produced water gradually increases. Considering economic benefits and environmental protection, how to treat and reinject a large amount of oilfield produced water economically and efficiently is of great significance to the economic development of oilfields. The presence of dissolved oxygen in the reinjection water accelerates the corrosion of metal pipes and equipment, and the water injection pipes transporting highly oxygenated water often have to be replaced after 10 years of use. Due to long-term corrosion and de...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): E21B43/22C09K8/58
Inventor 肖羽堂
Owner NANKAI UNIV
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