Gelled acid used for acid fracturing of high-temperature fractured-vuggy type carbonate reservoir

Abstract

The invention relates to gelled acid used for acid fracturing of a high-temperature fractured-vuggy type carbonate reservoir. The gelled acid comprises components in percentage by weight as follows: 20% of hydrochloric acid (HCl), 3% of a gelling agent (TP-1), 2% of a corrosion inhibitor (MC50), 1.5% of a ferric ion stabilizer (FL4-7), 0.05% of a demulsifying agent (PRJ), 1.5% of a discharge aiding agent (AD12) and the balance of water. The gelled acid can resist a temperature of 130 DEG C, and has an excellent rheological property and shearing resistance, good compatibility and filtration reduction performance and low frictional resistance; compared with common acid (20% of HCl), the acid-rock reaction speed can be reduced by 52%; under the condition of high temperature, the processing depth of the gelled acid to the stratum is enlarged, acidulating efficiency and success rate are increased, and pipe column corrosion and formation damage can be effectively reduced simultaneously, the gelled acid is prone to flowback and has a capacity of carrying solid-phase particles, the acid dissolution time of the gelling agent is short, so that field preparation is facilitated, and the gelled acid is very suitable for acid fracturing improvement of the high-temperature fractured-vuggy type carbonate reservoir.

Description

technical field [0001] The invention relates to the acid fracturing stimulation technology for carbonate rock reservoirs, in particular to the thickening acid technology for acid fracturing of high-temperature fracture-cavity carbonate rock reservoirs. Background technique [0002] Acid fracturing is the most effective stimulation measure for the development of carbonate reservoirs, and its success depends on the effective length of acid-etched fractures and the conductivity of acid-etched fractures after acid fracturing. For high-temperature deep wells, in addition to being controlled by rock properties and in-situ stress fields, the effective acid-etched fracture length is mainly controlled by the acid-rock reaction rate and the fluid loss characteristics of acid fluid. The conductivity of acid-etched fractures depends on the closure stress of the formation, the compressive strength of the rock, the amount of acid-dissolved rock, and the irregularity of the acid-etched sha...

AI Technical Summary

Problems solved by technology

[0015] At present, domestic thickener products used in acid fracturing of high-temperature carbonate rock reservoirs above 120 °C mostly show shortcomings such as being greatly affected by shearing, weak acid viscosity-increasing ability, and long preparation time on site. It can overcome the above shortcomings, but it does not comprehensively consider the severe corrosion of the pipe string and the damage of the reservoir, the size of friction resistance, and the effect of flowback under the high temperature condition of deep well, and the formula is incomplete and perfect

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