A plugging-removing agent suitable for acidizing complex lithology reservoirs and an acidizing plugging-removing method

Abstract

The invention discloses a blocking remover suitable for acidification of complex lithologic reservoirs. The blocking remover is prepared by mixing the following raw materials in percentage by weight: 10%-25% of hydrazine hydrochloride, 2%-6% of fluorine-containing compound, 0.3%-3% of acidification corrosion inhibitor, 0.3%-3% of demulsification cleanup agent, 0.3-3% of iron ion stabilizer for acidification, 0.3%-3% of clay stabilizer and the balance of water. According to the blocking remover disclosed by the invention, the powder-like hydrazine hydrochloride and the fluorine-containing compound are mixed to slowly generate HF (hydrogen fluoride) for blocking removing in the reservoir. The blocking remover has the characteristics that raw materials are conveniently transported, and safe and environment-friendly property are achieved in use; and since the HF is slowly generated in the reservoir through the hydrazine hydrochloride and the fluorine-containing compound, the purpose of slowing down can be reached, and the performances on the aspects of improving the permeability and the penetration depth of the reservoir are obviously better than those of conventional mud acid. The blocking remover has the advantages of low cost and great penetration depth and can well control the acidic rock reaction speed, improve the acidification blocking removing efficiency, reduce the corrosion of an acid solution to a metal pipeline and equipment and prevent the pollution to stratum.

Description

technical field [0001] The invention belongs to the technical field of oil and gas field development, and in particular relates to a plug-removing agent suitable for acidizing complex lithology reservoirs. Background technique [0002] In the process of drilling, perforating, oil production and workover operations, the intrusion of foreign liquid or solid, the expansion and migration of clay particles in the oil layer, the precipitation of long-chain paraffins, colloids, asphaltene, etc. in the oil layer and The mixing of incompatible water in the near-well zone of the oil layer can cause blockage of the oil layer, reduce the production capacity of the oil well, and affect the normal production of the oil well and the effective utilization of the oil well. [0003] Acidizing plugging removal measure is an effective oil well stimulation measure, which can effectively remove formation plugging and increase crude oil production. Generally, the plugging agent uses a combination...

AI Technical Summary

Problems solved by technology

[0005] The classic SHF process working fluids are HCl and NH 4 F, the disadvantage is that the process is more complicated, the solubility is low, and the liquid hydrochloric acid is volatile and seriously polluted

The SGMA process takes a long time to take effect, so it is difficult to select additives; in addition, improper process operation can easily cause secondary pollution, so it should be selected carefully

A disadvantage of the BRMA process is that when it is used to treat sandstone formations, it is easy to generate alkali metal precipitates of fluorosilicate and block the formations; the organic earth acid process is not strong in dissolving clay; the fluoroboric acid acidification process only generates slight damage to the formation Potassium fluoroborate precipitation; Phosphoric acid retarded acid acidification process has a high pH value, and there is also the possibility of generating fluorosilicate precipitation to block the formation

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