Oilfield injection friction-reducing agent and application thereof

Abstract

The invention relates to an injection friction-reducing agent for improving the injection capacity of a water injection well of an extra-low permeability reservoir of an oilfield, and application thereof. The injection friction-reducing agent comprises the following compositions by weight percent: (a) 0.8 to 8 weight percent of amine compounds; (b) 1.2 to 12 weight percent of composite carboxylate; (c) 1.7 to 17 weight percent of composite quaternary ammonium salt cationic surfactant; (d) 0.4 to 4 weight percent of combined surfactant containing alkyl polyhydric alcohol ether; and the balance of water. The invention is used for the oilfield injection friction-reducing agent, wherein the dosage of a single well is between 8 and 10 tons; the working concentration is between 2,000 and 5,000 mg / L; the injection pressure is reduced to be between 2 and 5 MPa; the effective period of stable injection capacity is more than 12 months; and the interfacial tension of the oilfield injection friction-reducing agent and crude oil under the condition of stratum can reach 10 mN / m magnitude order.

Description

Technical field: [0001] The invention relates to a water injection resistance reducing agent for improving the water injection capacity of a water injection well in an ultra-low permeability reservoir in an oil field and an application thereof. Background technique [0002] The water injection pressure is too high, the water injection volume is difficult to meet the injection-production balance requirements, the fluid production rate of the oil well is reduced, and the production declines rapidly, which have become the main problems restricting the development of ultra-low permeability oilfields by water injection. [0003] In recent years, some low-permeability oilfields in China have successively carried out experimental studies on depressurization and injection enhancement with low content of surfactants. According to literature reports, the use of the ZP-1918 system composed of multi-component polymer surfactants can reduce the oil-water interfacial tension to 10 -2 On ...

AI Technical Summary

Problems solved by technology

However, for ultra-low permeability reservoirs, it is more obvious to improve the efficiency of water flooding. Due to the small pore throats of ultra-low permeability reservoirs, reaching 0.4-1um, and the content of interstitial materials in the pores increased significantly, the single surfactant system It is not applicable to reduce the injection pressure of water flooding, and the injection pressure is very high at the initial stage of water flooding in ultra-low permeability reservoirs