Tide type sand laying fracturing method

Abstract

The invention provides a tide type sand laying fracturing method. The method includes the steps that S1) prepad fluid is pumped into a reservoir so as to fracture a stratum; S2) sand carrying fluid formed by air and sand mixing fluid is pumped into an artificial fracture formed in the step S1 so that a geometric shape of a fracture is supported; and S3) displacement fluid is pumped into the reservoir. Compared with the prior art, according to the method, discontinuity of fluid and gas volume fracture in the sand carrying fluid and into-well fluid collaboratively strengthens fluid fluctuating amplitude and fluctuating frequency, and fluid fluctuating in the fracture is utilized to propel a support agent to the deep of the fracture in a tide mode so that the sand carrying capacity of effective fracture volume and fracturing fluid can be effectively improved. At the same time, fluctuating impact of the fluid under the discontinuous flow state can facilitate the forming of branch fractures, and the complexity of the fracture is improved so that the effective fracture volume can be effectively increased. Moreover, a fluctuating condition has good for improving the filling effect of thesupport agent in the fracture, and the fracture fluid guide capacity can be improved and the period of validity can be prolonged.

Description

technical field [0001] The invention belongs to the technical field of petroleum drilling engineering, and in particular relates to a tidal sand-laying fracturing method. Background technique [0002] Hydraulic fracturing is a necessary stimulation method for low-porosity and low-permeability reservoirs such as coal seams and shale. Under a certain displacement and pressure, hydraulic fracturing is performed by pumping liquid into the formation to form fractures, and then filled with proppant Prevents cracks from closing. [0003] According to the tasks of the fracturing fluid injected into the well during the fracturing process, it can be divided into: (1) Prefluid: Its function is to break the bottom layer and form cracks of a certain geometric size for subsequent sand-carrying fluid to enter. In the formation with higher temperature, it can also play a certain role in cooling. Sometimes in order to improve the working efficiency of the pre-flush, a certain amount of fin...

AI Technical Summary

Problems solved by technology

Viscous fracturing fluid has good sand-carrying ability and can carry proppant to the deep part of the fracture, but after the gel is broken, there are many residues and the large particle size of the residue is easy to block the pores of the reservoir

In order to protect the reservoir, active water (1%-5% KCl solution) is often used as the fracturing fluid for low-permeability reservoirs. As a non-viscous liquid, the sand-carrying capacity of the active water fracturing fluid (viscosity 1mPa·s) is far worse than that of Viscous liquid causes proppant to deposit rapidly near the wellbore in the fracture, preventing the fracturing fluid and proppant from flowing further into the fracture, shortening the effective fracture length and easily causing dangerous accidents such as sand plugging, which seriously reduces the success of fracturing operations. Fracturing rate and fracturing effect are one of the key problems in the field of fracturing stimulation.

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