Oil-based polyamide assistant emulsifier for drilling fluids, and preparation method thereof

Abstract

The invention discloses an oil-based polyamide assistant emulsifier for drilling fluids, and a preparation method thereof. The oil-based polyamide assistant emulsifier is prepared through a dehydration polycondensation reaction of diacid anhydrides, polyalkenepolyamine and aliphatic acid, wherein a molar ratio of the diacid anhydrides to polyalkenepolyamine to aliphatic acid is 1:1:1.4-4. The emulsifier is a macromolecular polymer surfactant, per unit mass of the emulsifier contains more lipophilic and hydrophilic groups, and the emulsifying efficiency is high; hydrophilic groups in the molecular structure is an amido structure, so the emulsifier has good high-temperature resistance; and the emulsifier and a wetting agent have synergism, so the wetting reversal of solid phase surface is facilitated.

Description

technical field [0001] The invention relates to the technical field of oil and gas drilling, in particular to an auxiliary emulsifier for oil-based drilling fluid and a preparation method of the auxiliary emulsifier. Background technique [0002] As one of the most important treatment agents for water-in-oil emulsified drilling fluid, the auxiliary emulsifier mainly has two functions: together with the main emulsifier, it can reduce the interfacial tension of oil and water to form a stable water-in-oil emulsion; as a kind of oil with a high HLB value The water-in-oil emulsifier has a certain wetting reversal effect, which can reverse the surface of solid phase particles from hydrophilic wetting to lipophilic wetting, making it easier to disperse evenly in the oil phase. At present, commonly used co-emulsifiers are mainly two types of sorbitan fatty acid esters and alkylphenol polyoxyethylene ethers, as the publication number is CN1215075, and the Chinese patent literature pu...

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Problems solved by technology

[0003] However, the co-emulsifier represented by the above-mentioned patent documents has an unsatisfactory practical effect, mainly in the following aspects: no matter it is a sorbitan fatty acid ester co-emulsifier or an alkylphenol polyoxyethylene ether co-emulsifier, both Both of them belong to small molecule emulsifiers with poor emulsifying effect, and the emulsification stability of the emulsion configured by them is poor, and they are prone to demulsification; the high temperature resistance of the two is poor, and the main functional groups of sorbitan fatty acid esters are esters, alkyl The main functional group of phenol polyoxyethylene ether is ether, and these two functional groups are prone to chain scission decomposition under high temperature conditions, thus making the emulsifier invalid