Low-cost multifunctional acid fluid system

Abstract

The invention discloses a low-cost multifunctional acid fluid system. The low-cost multifunctional acid fluid system is prepared from, by mass, 5-30% of hydrochloric acid, 0.001-2% of discharge aidingagent, 0.05-2% of anti-swelling agent, 0.05-2% of iron ion stabilizer, 0.05-2% of demulsifier, 0.05-5% of corrosion inhibitor, 0.001-2% of anti-acid slag agent, 0.01-0.5% of resistance reducing agentand the balance water, wherein hydrochloric acid is measured according to the mass of pure hydrogen chloride. The low-cost multifunctional acid fluid system is suitable for a carbonic acid rock storage layer, and on the basis of keeping the excellent performance of acid fluid, the cost is lowered by 15% or above; meanwhile the low-cost multifunctional acid fluid system has the advantages of beinglow in cost, high in corrosion rate to carbonate rock, good in fluid resistance reduction performance, good in anti-swelling effect, excellent in corrosion inhibition performance, good in anti-acid slag performance, high in demulsification rate, low in surface tension, capable of easily flowing back fluid, high in stability capacity of iron ions, good in compatibility and excellent in other comprehensive multifunctional performance.

Description

technical field [0001] The invention relates to the field of exploration and development of oil and gas fields, in particular to a low-cost multifunctional acid liquid system. Background technique [0002] Acidizing operation is one of the stimulation measures for carbonate and sandstone reservoirs. At present, the acid liquids used in the acidizing construction of oil, gas and water wells in oilfields at home and abroad are mainly hydrochloric acid (for carbonate reservoirs) and soil acid (for sandstone reservoirs). The principle of acidification is to use the chemical dissolution of acid liquid to strongly react and dissolve rock minerals, external pollutants or blockages in the reservoir, expand or create or clean the pore throat channels of the reservoir, so as to restore or increase the permeability of the reservoir. Greatly reduce the resistance of fluid entering the well, so as to achieve the purpose of increasing production of oil and gas wells or increasing injecti...

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Problems solved by technology

However, this conventional hydrochloric acid liquid system faces the following problems: (1) in the existing conventional acid system, except that the mass percent content of hydrochloric acid is 5%-30%, other acidifying additives are generally added in a relatively high amount, resulting in The cost of squaraine system is high; (2) When acidizing oil and gas wells with high bottom-hole temperature, the high temperature conditions increase the corrosion of downhole pipe strings and equipment by the acid liquid, shortening its service life and reducing maintenance and replacement costs. Adding a high-temperature corrosion inhibitor or synergist to the acid system can slow down the degree of corrosion, prolong the service life, and reduce the cost of maintenance and replacement; (4) When the target layer of acidification contains high clay minerals, clay swelling and migration may occur after acidification, reducing the permeability of the reservoir, thereby affecting the effect of acidification stimulation; (5 ) When the acid fluid enters the well to the target formation, the friction of the acid fluid in the wellbore is relatively high, which weakens the pressure of the acid fluid to the bottom of the well and shortens the formation acidizing depth; , affecting crude oil recovery; (7) The iron ions in the wellbore are easy to form precipitation, which can block the wellbore or near wellbore

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