Acid for erosion of sandstone

Abstract

The present invention discloses a sandstone acid, and its composition is formed from (wt%) phosphonobutanedioic acid 10-20%, ammonium bifluoride 5-15%, Mannich base 1.5-2.5%, hydrochloric acid 5-10%, dodecyl dimethyl benzyl ammonium chloride or dodecyl trimethyl ammonium chloride 1%, and the rest is water. The use of said sandstone acid can effectively raise well permeability to obtain the effect of raising oil production.

Description

Technical field: [0001] The invention relates to a chemical agent for oil field exploitation. Background technique: [0002] At present, in order to increase the production of oil wells with low permeability, the method of injecting acid into the oil well is generally used to make the acid react with the sandstone at the bottom of the oil well, corrode the sandstone, increase the permeability of the oil well, and achieve the purpose of increasing production. The acids used include hydrochloric acid, Hydrofluoric acid, phosphoric acid, sulfuric acid, etc., also include some potential acids such as esters, halogen salts, etc., and also include some compound acids, such as earth acid, capsule acid, etc., but there are two main disadvantages in using these acids: one is that these acids are different from Clay, silicate and other matrix non-consolidated substances in the near-wellbore react very quickly. Before the acid falls and corrodes the sandstone at the bottom of the oil w...

AI Technical Summary

Problems solved by technology

[0002] At present, in order to increase the production of oil wells with low permeability, the method of injecting acid into the oil well is generally used to make the acid react with the sandstone at the bottom of the oil well, corrode the sandstone, increase the permeability of the oil well, and achieve the purpose of increasing production. The acids used include hydrochloric acid, Hydrofluoric acid, phosphoric acid, sulfuric acid, etc., also include some potential acids such as esters, halogen salts, etc., and also include some compound acids, such as soil acid, capsule acid, etc., but there are two main disadvantages in using these acids: one is that these acids are different from Clay, silicate and other matrix non-consolidated substances in the near-wellbore react very quickly. Before the acid falls and the eroded sandstone at the bottom of the oil well, it fails or partially fails halfway, which greatly affects the stimulation effect of the oil well.

The second is that these acids react with the matrix non-consolidated matter near the wellbore to produce by-product precipitation, which also reduces the stimulation effect of the oil well