Clastic sandstone gas reservoir acidizing fluid

Abstract

The invention relates to a clastic sandstone reservoir acidizing fluid, which comprises, by weight, 0.5-1.0% of hydrochloric acid, 3.0-6.0% of HEDP, 2.0-4.5% of ammonium bifluoride, 3.0-5.0% of acetic acid, 0.25-0.5% of an organic acid corrosion inhibitor Lan-926, 0.5-1.0% of nitilotriacetic acid or iso ascorbic acid, 0.5-1.0% of a polyquaternary anti-swelling agent, 0.3-0.6% of a hydrocarbon chain surfactant peregal O-15 or O-20, 0.3-0.6% of a fluorocarbon chain surfactant FSO-100 or FSN-100 and the balance of water. The acidizing fluid has little corrosion and good cleanup effect, hardly produces secondary precipitation, and has little damage to reservoir.

Description

technical field [0001] The invention relates to a liquid system for acidizing high-temperature clastic sandstone gas reservoirs. Background technique [0002] Sandstone matrix acidizing technology is an important technology for oil and gas well plugging removal and production stimulation. Soil acid is the earliest and most commonly used acid system for sandstone acidification. Patent USP 5529125 introduces the application of organic phosphonates in HCl and HF, which can play a good retarding effect; patent CN 101089118 introduces an acidifying agent composition, which can relieve low permeability and high Plugging problem in salinity scale-prone sandstone reservoirs. The acidification of high-temperature sandstone reservoirs faces the following problems: First, the reaction speed between conventional soil acid and formation minerals is extremely fast at high temperature, the effective action distance of acid liquid is short, and the active acid cannot reach deep formations;...

AI Technical Summary

Problems solved by technology

The acidification of high-temperature sandstone reservoirs faces the following problems: First, the reaction speed between conventional soil acid and formation minerals is extremely fast at high temperature, the effective action distance of acid liquid is short, and the active acid cannot reach deep formations; secondly, the chemical reaction between HF and sandstone is not a simple one-time process. reaction, the by-products of fluorosilicide and fluoroaluminide can also undergo secondary and tertiary reactions with aluminosilicate to form a series of insoluble precipitates, causing serious damage to the reservoir; Downhole pipe strings and tools are highly corrosive, requiring high performance of corrosion inhibitors

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