A slow-release gel-breaking method for surfactant fracturing fluid

Abstract

The invention relates to a slow release breaking method for surfactant fracturing fluids. The method includes: during the construction process of surfactant fracturing fluid, adding three slow release breakers in different times; adding 3-10kg of capsule slow-release breaker per cubic meter of the fracturing fluid during the whole course; adding 2-5kg of solid-particle slow release breaker per cubic meter of the fracturing fluid during the pre-liquid phase; adding high-viscosity liquid slow-release breaker during the period 5-15 minutes before the completion of sand adding until the completion of sand adding, at the wedge gradually-increasing rate from 1kg per cubic meter of the fracturing fluid to 30-100kg per cubic meter of the fracturing fluid. The method is applicable to reservoir construction with insufficient surfactant fracturing fluid and guarantees fast breaking and returning and discharging of a post-system, so that the protective reservoir is less damaged, trial discharging period is shortened and development cost is reduced.

Description

technical field [0001] The invention relates to the technical field of production stimulation of oil-water wells in oil fields, in particular to rapid flowback of fracturing fluid after fracturing, and is a slow-release gel-breaking method for surfactant fracturing fluid. Background technique [0002] Surfactant fracturing fluid uses surfactants to entangle with each other above the critical concentration and aggregate into worm-like micelles. Under necessary conditions, the micelles are further compressed or extended by inorganic salts and counter ions, thereby thickening to achieve sand-carrying. After pressing, it is diluted with crude oil or formation water to destroy the winding state and achieve the purpose of reducing viscosity and breaking gel. However, for some low-permeability reservoirs with insufficient energy, in order to ensure rapid flowback of the fracturing fluid using the energy accumulated in the fracture after fracturing, reduce permeability damage, and s...

AI Technical Summary

Problems solved by technology

However, for some low-permeability reservoirs with insufficient energy, in order to ensure rapid flowback of the fracturing fluid using the energy accumulated in the fracture after fracturing, reduce permeability damage, and shorten the trial discharge period, it is necessary to quickly release and flow back, and often such Insufficient fluid volume in low-permeability reservoirs, it is difficult to gather enough formation fluid in a short time after fracturing to break the gel of surfactant fracturing fluid, and forced spraying may easily cause sand vomiting

In order to solve the above contradictions, there is a method to add a liquid breaker in the late stage of sand addition. Since the thickening mechanism of the surfactant fracturing fluid is different from that of the polymer fracturing fluid, the gel can be broken instantly after meeting the breaker, resulting in Sand plugging

There is also a process to continue pumping the breaker after the sand addition is completed, but it only works in the near-wellbore area, and it also destroys the distribution of the proppant, and the gain outweighs the gain