Comprehensive treatment method of shale gas extraction water

Abstract

The invention discloses a comprehensive treatment method of shale gas extraction water. The method is characterized by comprising: (1) adjusting the pH value of shale gas extraction water to 2.5-5; (2) performing contacting of the pH value-adjusted material, a catalyst and an oxidant under microwave irradiation, and carrying out a microwave catalysis oxidation reaction; (3) adjusting the pH value of the material obtained through the microwave catalysis oxidation to 7.5-12 so as to obtain a suspension; (4) carrying out solid-liquid separation on the suspension to obtain a supernatant and a solid; and (5) carrying out a microwave pressure reducing treatment on the obtained supernatant, and carrying out a harmless treatment on the solid and the remaining residue obtained through the microwave pressure reducing treatment. With the technical scheme of the present invention, the shale gas extraction water can be efficiently treated, the contents of the chlorine ions and other impurities in the treated extraction water are substantially reduced, the treated extraction water can meet the discharge standard or can be recovered and utilized, and the treatment process is simple and effective.

Description

technical field [0001] The invention relates to the field of wastewater treatment, in particular to a treatment method for stratum produced water brought out during shale gas exploitation. Background technique [0002] Shale gas is an unconventional natural gas resource, which occurs in organic-rich shale and its interlayers, and exists mainly in the state of adsorption or free. In recent years, due to breakthroughs in shale gas exploration and development technology in the United States and rapid growth in production, it has had a major impact on the international natural gas market and the world's energy structure. The world's major oil and gas resource countries have increased their efforts in shale gas exploration and development. As the country with the largest shale gas reserves in the world, China is undoubtedly the next main battlefield of the global shale gas revolution. At the same time, the environmental problems brought about by shale gas development, especially...

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Problems solved by technology

Among them, the first treatment method - reinjection is commonly used, but the reinjection treatment method has certain limitations, not all areas of shale gas produced water are suitable for this method, such as Sichuan, the main shale gas producing area in China Basin, due to the tight formation and complex hydrogeological conditions, the reinjection of produced water is greatly restricted

However, the related research and application of the second and third treatment methods are still in their infancy.

[0005] CN103304104A discloses a method for splitting the sewage in the gas field during the pretreatment of natural gas water, wherein the process of the method is relatively complicated, and the inclined plate oil separation is carried out first, then coagulation and sedimentation are carried out, and finally air flotation and aeration are carried out. Pressure filtration treatment, the treatment process involves a lot of equipment, and the evaporation treatment process uses a four-effect evaporation processor, which has the disadvantages of large equipment, high energy consumption, large heat loss, and difficulty in starting and stopping at any time. It is mainly suitable for large-scale wastewater treatment. Evaporation treatment, not suitable for single well small water volume wastewater treatment

CN 1579968A discloses a "coagulation + air flotation + anaerobic + aerobic + two-stage biological aerated filter" treatment process, but this process can only treat wastewater with low chloride content, for chlorides in the 10000mg / Shale gas produced water above L is not suitable, because it is difficult for organisms to survive in high-chlorinated wastewater, and the process has disadvantages such as numerous devices and slow processing speed.

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