1. Characteristics of fracturing flowback fluid wastewater

Hydraulic fracturing technology is widely used in oil and gas exploration. Through hydraulic fracturing, the conductivity of oil and gas layers can be improved to achieve the purpose of increasing production, but at the same time, a large amount of fracturing fluid will flow back to the ground. With the continuous development of our country's oilfields, the displacement of fracturing flowback fluids in oil and gas fields continues to increase.

The fracturing flowback fluid contains various chemical additives. At the same time, due to long-term contact with the formation, it also contains suspended organic impurities, phenols, aldehydes and other pollutants. It has high viscosity, high emulsification degree, high chemical oxygen demand, high total content of suspended solids and the characteristics of complex water quality are refractory high-salt wastewater.

2. Difficulties in wastewater treatment

(1) The main pollutants in the separation wastewater of fracturing flowback fluid are oil, salt (chloride and sulfate), hardness (calcium ion, magnesium ion), heavy metal ion (such as arsenic) and some polymers , the organic pollutants contained in this type of wastewater have high stability, are difficult to oxidize and decompose, and have a low B/C value and poor biodegradability.

(2) Due to the scattered distribution of production wells in oil fields, the geological conditions of production wells will be different, resulting in large changes in the water quality and quantity of this type of wastewater, which brings difficulties to the design of wastewater treatment process schemes, and the design of influent water quality must be comprehensively considered In order to ensure the stable and up-to-standard operation of the wastewater treatment system.

(3) Large area, large processing capacity, poor system integration, and high security level requirements.

3. Execution of water discharge standards

At present, the national control standards for oil field fracturing flowback fluid wastewater are becoming more and more stringent. The fracturing flowback fluid wastewater has implemented the "Surface Water Environmental Quality Standard" (GB3838-2002) surface water category III standard and centralized drinking water surface Requirements for standard limit values of supplementary projects in water sources.

4. Technical features

The comprehensive treatment process of "pretreatment + concentrated brine treatment + advanced treatment" is adopted, and the pollutants in the wastewater that need to be removed are treated with a combined process, which ensures the stability and safety of the entire process system operation and ensures that the effluent Discharge. In addition, the company integrates the complete process of advanced process technology, not only realizes zero discharge treatment of wastewater (pretreatment + membrane concentration + evaporation), but also uses our company's drying-pyrolysis integrated equipment (patented technology) to synchronize the solid waste generated Realize recycling and harmless disposal.

5. Technology Roadmap