Enzyme seepage agent for improving performance of guar gum fracturing fluid and application of enzyme seepage agent

Abstract

The invention discloses an enzyme seepage agent for improving the performance of a guar gum fracturing fluid and application of the enzyme seepage agent. The enzyme seepage agent comprises the following substances in parts by mass: 5-10 parts of alpha-D-trehalose-6-corynomycolate, 5-7 parts of L-asparagine, 5-10 parts of asparaginic acid, 2-5 parts of sodium diacetate, 2-10 parts of protease, 5-10parts of mannase, 3-5 parts of cellulase and 43-73 parts of water. The substances are mixed and stirred for 30 min to 1 h at normal temperature so as to obtain the enzyme seepage agent. In application, the prepared enzyme seepage agent is added on the basis of a conventional guar gum fracturing fluid; or the prepared enzyme seepage agent is added into the cross-linking tank and mixed with a cross-linking agent to form a mixture, the mixture is swabbed to a fracturing blender truck for uniform stirring and then injected into a stratum; so the efficiency of a fracturing process is improved, oiland gas in a compact oil and gas reservoir are fully released after fracturing, and yield increase is achieved.

Description

technical field [0001] The invention relates to a formula of fracturing fluid for fracturing tight oil and gas layers and its application, in particular to an enzyme seepage agent for improving the performance of guar gum fracturing fluid and its application. Background technique [0002] For the development of low-permeability, ultra-low-permeability and tight oil and gas reservoirs, fracturing is one of the most commonly used and most effective stimulation measures. The fracturing process generally uses natural plant gum guar gum and synthetic polymers to form a viscous solution of water, which is cross-linked into a colloid to carry proppant (ceramsite sand) into the oil reservoir to support each fracture, so that The oil gas trapped inside is released. [0003] After these viscous colloidal substances enter the reservoir with proppant, they need to be broken and thinned according to the requirements, and the viscosity is required to be less than 5mPa.s. However, if the...

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Problems solved by technology

However, this activation method is often an instantaneous response. Since the wedge-shaped addition method is intermittent in the field, it is difficult to accurately control the quantity and activation time. Either adding too little will not break the gel, or adding too much will break the gel instantly, resulting in fracturing fluid. During the process of carrying proppant, the pressure fluctuates up and down, the pump injection fluctuates, and some colloids will remain in the formation due to uneven gel breaking

In addition, the vegetable gum guar gum used for fracturing also has water-insoluble substances in itself, and there will be a lot of residue after the gel is broken.

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