Composite oxidation blocking remover

Abstract

The invention discloses a composite oxidation blocking remover. The composite oxidation blocking remover comprises, by mass, 50-70% of calcium peroxide solid powder, 15-30% of polyvinylidene chloride coated organic acid microspheres, 10-18% of an oxidant assistant and 1-2% of an additive. The composite oxidation blocking remover solves the disadvantages of single main agent, limited comprehensive performances, large active release control difficulty, hidden safety troubles in storage and transportation and high construction requirements of present oxidation systems in present Bohai Sea oilfields, becomes a stable solid powder particle at normal temperature, and is safe and convenient to store and transport; and when the composite oxidation blocking remover is used in field, the composite oxidation blocking remover is directly dissolved in normal temperature according to above formula proportions, the obtained solution is extruded to stratum, the stratum is heated to rupture the polyvinylidene chloride coated organic acid microspheres, release the organic acid and activate an oxidant, and the oxidant activity is extensively released to degrade organic blocking materials. The composite oxidation blocking remover has the advantages of simplicity in construction operation, and controllable oxidation activity release.

Description

technical field [0001] The invention relates to a composite oxidation plug-removing agent. Background technique [0002] During the development of polymer flooding in Bohai Oilfield, the problem of under-injection under high pressure in polymer injection wells gradually emerged. For the polymer injection oilfields in the Bohai Sea, although the polymers used are different, they are all polyacrylamide polymers. Polymer injection well blockage mainly includes conventional inorganic blockage and polymer organic blockage. Uneven dilution of dry powder to form fish eyes, traces of water-insoluble matter in dry polymer powder, polymer and high-valent metal cations to form cross-linked polymers, polymers and inorganic particles such as clay and carbonate to form composite plugs, etc. . [0003] Most of the early Bohai Sea polymer injection wells used conventional acidification plugging removal technology, and achieved a certain effect of reducing pressure and increasing injectio...

AI Technical Summary

Problems solved by technology

The depolymerization systems that have been used in Bohai Oilfield include calcium peroxide system, organic benzoyl peroxide system, chlorine dioxide stabilization / generation liquid system and biological acid system, but these systems have certain defects, such as oxidant and activator Problems of coexistence and active release control, weak oxidative properties of organic peroxides, too strong oxidative properties of chlorine dioxide stabilized solution / generated solution, poor degradation of cross-linked polymers and aging cross-linked polymers, etc. Problems such as long blockage time and relatively limited degradation effect

In terms of on-site construction, during the on-site application of the currently used depolymerization system, the oxidizing agent and the activator must be separated during storage and transportation, and must be prepared separately during on-site preparation. The double-liquid extrusion method must be used for extrusion injection. The two agents are mixed at the wellhead. The activity starts to be released immediately, the construction process is difficult and demanding, and the activity release is difficult to control after the plugging solution is mixed at the wellhead, and there are certain safety hazards

[0005] As an efficient degradable polymer organic plugging system, the performance of the oxidation system is gradually recognized by people, but its storage and transportation safety hazards, control of activity release, high requirements for construction and comprehensive performance of chemicals limit its application in offshore oilfields. application