Method for treating backflow fracturing fluid reclaimed from exploitation of shale gas

Abstract

The invention discloses a method for treating the backflow fracturing fluid reclaimed from exploitation of shale gas. The method comprises the following steps: (S1) detecting the content of ions in the backflow fracturing fluid, and filling the backflow fracturing fluid which is up to the standard in a container for later use, wherein if the content of K<+> is controlled to be less than or equal to 1,500mg / L, the content of Ca<2+> is controlled to be less than or equal to 600mg / L, the content of Na<+> is controlled to be less than or equal to 2,000mg / L, the content of Mg<2+> is controlled to be less than or equal to 1,000mg / L, the content of NH<4+> is controlled to be less than or equal to 600mg / L, the content of total Fe is controlled to be less than or equal to 25mg / L, the content of Cl<-> is controlled to be less than or equal to 3,000mg / L, the content of Al<3+> is controlled to be less than or equal to 30mg / L, the content of SO4<2-> is controlled to be less than or equal to 200mg / L, and the content of COD is controlled to be less than or equal to 300mg / L, the backflow fracturing fluid is deemed to be up to the standard; and (S2) carrying out comparison test on the backflow fracturing fluid which is up to the standard and is filled in a container for later use with two formulas before the backflow fracturing fluid is injected underground to be used for fracturing, and evaluating the kinematic viscosity of slippery water. The method disclosed by the invention is particularly suitable for treating the backflow fracturing fluid immediately after the backflow fracturing fluid is reclaimed or without exceeding 10 days after the backflow fracturing fluid is reclaimed and stored. By adopting the method, various mechanical impurities, ions and bacteria affecting the reclamation of the backflow fracturing fluid can be removed, the treated backflow fracturing fluid can meet the reuse requirement, the water consumed for exploiting the shale gas can be reduced greatly, and the win-win goal of reducing cost and protecting environment can be realized.

Description

technical field [0001] The invention relates to the technical field of oil and gas shale storage fracturing and exploitation, and more precisely relates to a treatment method for shale gas reuse and fracturing flowback fluid, which is suitable for immediate use or storage after recovery of formation fracturing flowback fluid The processing time does not exceed 10 days. Background technique [0002] In the process of oil and gas exploitation, fracturing is one of the main measures for increasing the production of oil and gas wells and increasing the injection of water wells, and is an indispensable and important technical means for the exploration and development of oil and gas fields. Whether it is the sand fracturing stimulation measures used in conventional storage, or the large-scale shale gas exploitation technology in China in the past two years, it is necessary to prepare a large amount of construction liquid. Therefore, large-scale hydraulic fracturing not only puts ...

AI Technical Summary

Problems solved by technology

Existing related patented technologies are mainly aimed at oil and gas field water treatment and flowback fluid treatment technologies (including devices and treatment methods) of conventional oil and gas reservoir sanding fracturing fluid (i.e. vegetable gum fracturing fluid), and do not involve shale gas reservoirs Under development, technology for the reuse, detection, treatment and reuse of slick water plus sand fracturing flowback fluid