Treatment device and treatment process of oilfield produced water as reinjection water

Abstract

The invention relates to a treatment device and a treatment process of oilfield produced water as reinjection water. The treatment device comprises a buffer tank, a phase separator and a ceramic membrane separation system, wherein the oilfield produced water enters the buffer tank through a produced water pipeline, the buffer tank is connected with the phase separator by virtue of a pipeline, the phase separator is connected with the ceramic membrane separation system by virtue of a pipeline, a produced water pump is mounted on the produced water pipeline and a phase inlet separator pump is mounted on the pipeline between the buffer tank and the phase separator. The process flow comprises the following steps of pumping the produced water into the buffer tank by virtue of the produced water pump and then pumping into the phase separator by virtue of the produced water pump, separating produced water to obtain oil and water, discharging partial solid particles through a sand discharge hopper arranged on the device, conveying the produced water subjected to oil and solid removal to the ceramic membrane separation device, reinjecting clean liquid which is subjected to membrane separation and meets the reinjection indexes of the oilfield reinjection water and returning concentrated liquid side sewage containing greasy dirt to the buffer tank. The treatment device is fully enclosed and has the advantages that the separation effect is good, the system operation is simple and the process flow is short.

Description

Technical field [0001] The invention relates to the technical field of environmental protection, in particular to a treatment device and a treatment process for reinjecting oil field produced water with stable effluent water quality, simple system operation, short process flow, high degree of automation and good separation effect. Background technique [0002] At present, most of my country's oilfields are exploited by water injection. As the oilfield enters the late stage of high water cut, the produced water volume of some oilfields has increased significantly, and the produced water composition is complex, except for natural substances such as suspended emulsified oil droplets, solid particles, and soluble salts. , It also contains various agents such as chemical additives and lubricants, which cause serious emulsification of the produced water, stable structure and difficult to handle. [0003] But for low-permeability layers and extra-low-permeability oil layers, A1 grade water...

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Problems solved by technology

[0002] At present, most oilfields in my country are exploited by water flooding. As the oilfields enter the late stage of high water cut, the water produced by some oilfields has increased significantly, and the composition of the produced water is complex. In addition to natural substances such as suspended emulsified oil droplets, solid particles, and soluble salts, etc. , also contains chemical additives, lubricants and other agents, resulting in serious emulsification of produced water, stable structure and difficult handling

[0003] However, for low-permeability layers and ultra-low-permeability oil layers, A1 grade water quality requires the median particle size of suspended solids to be ≤ 1 μm, suspended solids ≤ 1 mg / L, crude oil ≤ 5 mg / L, and average corrosion rate < 0.076 mm / a. Conventional water treatment methods (such as gravity sedimentation, cyclone centrifugal separation, air flotation and fine filtration, etc.) are difficult to meet this requirement

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