Recyclable pH value responsive reversible emulsifier for oil field drilling fluid

Abstract

The invention relates to a reversible emulsifier for an oil field drilling fluid, and particularly discloses a recyclable pH value responsive reversible emulsifier for the oil field drilling fluid. The technical scheme of the invention is as follows: the emulsion comprises the following raw material components: 10%-90% of a water phase, 10%-90% of an oil phase and 1.0%-2.5% of a recyclable pH value responsive reversible emulsifier, wherein the oil phase is white oil or diesel oil; and the water phase is a CaCl2 water solution with the concentration of 10-40%. The invention has the beneficial effects that the reversible emulsion of the emulsifier is good in stability, and after the reversible emulsifier loses the reversible conversion capacity after being repeatedly used for many times, the modified magnetic nanoparticles losing the reversible conversion capacity can be separated out by constructing a high-strength magnetic field, so the influence of the modified magnetic nanoparticles on the reversible conversion capacity of a reversible emulsion system is avoided, and meanwhile, the stability of the reversible emulsion is improved. The recovered magnetic nanoparticles can be used as a reversible emulsion stabilized by a reversible emulsifier after being subjected to acid contact treatment.

Description

technical field [0001] The invention relates to a reversible emulsifier for oilfield drilling fluid, in particular to a recyclable pH value responsive reversible emulsifier for oilfield drilling fluid. Background technique [0002] The reversible emulsion can realize the reversible transformation between the water-in-oil emulsion and the oil-in-water emulsion by changing the external conditions, and the reversible emulsion with pH control can realize the reversible transformation of the emulsion by changing the pH value of the system. [0003] The Chinese patent document number is CN106833565B, and the patent name is "A Reversible Emulsion with Salinity-Controlled Phase Transition, Its Preparation Method and Phase-Inversion Method", which mentions a reversible emulsion with salinity-controlled phase transition, reversible The emulsifier system is composed of sodium petroleum sulfonate, P(St-co-MAn-co-PVBTEAB), sodium dodecylbenzenesulfonate, potassium salt of perfluoroalkyl ...

AI Technical Summary

Problems solved by technology

[0006] The reversible emulsifier-stabilized reversible emulsion proposed by the above method can effectively realize pH sensitivity, and the main types of reversible emulsifiers involved include surfactant-type reversible emulsifiers and modified nano-SiO 2 Type reversible emulsifiers, surfactant-type reversible emulsifiers, stable reversible emulsions generally have the disadvantages of poor temperature resistance and shear resistance, modified nano-SiO 2 Although the reversible emulsion stabilized by the surfactant-type reversible emulsifier overcomes the above-mentioned shortcomings of the reversible emulsion stabilized by the surfactant-type reversible emulsifier, the number of reversible transformations of the reversible emulsifier is limited. The most important application field of emulsion is to construct a reversible emulsified drilling fluid system) The cost is high, so it is necessary to focus on the treatment and reuse of the reversible emulsion system that has lost its reversible transformation ability, and modified nano-SiO 2 After the stable reversible emulsion of the type reversible emulsifier repeats the reversible phase and loses the reversible phase ability, there are a large number of nanoparticles that have lost the reversible inversion ability in the system, which will affect the reversible inversion performance of the emulsion as an interference factor, even if it is replenished Reversible emulsifiers cannot restore reversible emulsions to reversible inversion properties

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