Acid solution system capable of relieving damage of mud to low-permeability reservoir

Abstract

The invention discloses an acid solution system capable of relieving damage of mud to a low-permeability reservoir, which is composed of the following components in percentage by weight: 5-10% of methyl sulfonic acid derivative, 2-5% of isoascorbic acid, 0.5-1% of nonionic surfactant, 0.1-0.5% of corrosion inhibitor, 3-5% of hydrofluoric acid, 3-10% of low-polymer alcohol and the balance of water. The methyl sulfonic acid derivative is aminomethane sulfonate, ethyl methanesulfonate, methyl methanesulfonate, methanesulfonic acid or mixture thereof; the nonionic surfactant is fatty alcohol polyethenoxy ether; the corrosion inhibitor is imidazoline quaternary ammonium salt; and the low-polymer alcohol is methanol, ethanol, isopropanol or mixture thereof. The system can effectively relieve damage of clay minerals in drilling mud to the reservoir, and can restore the permeability of the reservoir, so that oil gas can flow into the shaft from the stratum; and thus, the system has important practical meanings.

Description

technical field [0001] The invention relates to an acid liquid system for removing the damage of mud to low-permeability reservoirs in the process of increasing production in the field of oil and gas field development. Background technique [0002] A large amount of clay needs to be added to the drilling fluid to make the drilling fluid into a mud state, so that during the drilling process, the rock side pressure on the well wall can be balanced, a filter cake can be formed on the well wall, the well wall can be sealed and stabilized, and the oil and gas layers can be prevented from being polluted and the well The wall collapsed. The ideal construction process is that the clay in the drilling fluid is only adsorbed on the surface of the well wall. With the subsequent mining, the clay particles adsorbed on the surface of the well wall will completely separate from the well wall, exposing the oil and gas channels, and the oil and gas wells can be produced smoothly. However, d...

AI Technical Summary

Problems solved by technology

Judging from the field effect, the use of soil-acid system has no obvious effect on removing the clogging of clay, and the stable production period of oil and gas wells is shorter after each acidification of soil-acid solution

The main reason is that the secondary damage of the soil-acid system to the reservoir cannot be avoided