Water-blocking damage blocking remover, using method thereof and water-blocking damage acidizing fluid

Abstract

The invention relates to a water-blocking damage blocking remover, a using method thereof and a water-blocking damage acidizing fluid, and belongs to the field of oilfield chemistry application. The water-blocking damage blocking remover comprises prepad acid, main treatment fluid and postpad fluid, and the prepad acid is composed of the following components, by mass: 10-15% of retarded acid, 0.3-1% of a corrosion inhibitor, 0.3-0.7% of a complexing agent, 0.3-1.7% of a clay stabilizer, 0.4-1% of a retarder, 0.2-0.8% of a cleanup additive and the balance of water; the main treatment fluid is prepared from the following components, by mass: 20 to 50 percent of ethanol, 0.2 to 1 percent of nonionic surfactant, 0.5 to 1.5 percent of mutual solvent and the balance of water; and the postpad fluid is composed of a cationic surfactant, ammonium chloride and water. According to the blocking remover disclosed by the invention, blocking is removed through the combination of the prepad acid, themain treatment liquid and the postpad liquid, so that the action range of acidifying blocking removal is wider, and the action time is longer.

Description

technical field [0001] The invention relates to a water-lock damage plugging remover, a method for using the same, and a water-lock damage acidizing fluid, which belong to the field of oil field chemical applications. Background technique [0002] By the end of 2000, the proven geological reserves of low-permeability oilfields in my country were 52.14×10 8 tons, accounting for 26.1% of all proven geological reserves. The geological reserves of low-permeability oilfields that have been produced in my country are 26.66×10 8 tons, accounting for 25.5% of all used reserves. With the deepening of exploration, low-permeability oil fields have become one of the important fields of crude oil production. Therefore, the development of low-permeability oil fields is of great significance to the future development of my country's petroleum industry. [0003] Due to tight lithology and high seepage resistance in low-permeability reservoirs, the natural productivity of oil wells is lo...

AI Technical Summary

Problems solved by technology

However, due to relying solely on the active agent system to unplug low-permeability reservoirs, the reaction speed is slow, and the well generally needs to be shut down for 2-3 days to react after construction, and the operation and construction take up a long time in production, which increases the construction cost; and the commonly used surface The temperature resistance of the active agent is poor, generally lower than 80°C, which affects the scope of use

In response to the above problems, the Chinese invention patent application with the application publication number CN104449619A discloses a water lock damage plugging agent for downhole operations, which consists of the following components in parts by weight: 30-50 parts by weight of hydrochloric acid, erucic acid amidopropyl sulfo 10-20 parts of betaine, 15-35 parts of ethanol, 5-20 parts of potassium chloride, 10-35 parts of dodecylalanine, 2-7 parts of sodium tripolyphosphate; the downhole operation uses water to lock and unblock The agent uses a large amount of hydrochloric acid, which can speed up the reaction, and at the same time shows certain advantages in clay stability and temperature resistance (not greater than 100°C). However, in general, the formation damage of low-permeability reservoirs is not caused by a single factor. The causes and types of clogging are complex, while the common active agent system has a single purpose of unblocking, which can only relieve water lock damage, so the effect of increasing oil after use is not obvious

Another example is that the Chinese invention patent application with the application publication number CN105733543A discloses a water-dissolving lock agent for low water-cut oil wells. The water-blocking agent can eliminate the interface between oil and water in a short period of time, but it is only suitable for low water-cut oil wells when it is used to release water-blocking damage. The unit price of silicon and ethylene glycol monobutyl ether is expensive, and the cost is high, while the amount of water-blocking agent is large, and the construction cost is greatly increased

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