A kind of preparation method of surfactant for oil recovery of low permeability reservoir

Abstract

The present invention discloses a preparation method of a surfactant for oil recovery in a low-permeability reservoir. The preparation method is characterized by comprising: adding 3-260 parts of liquid paraffin, 0.2-45 parts of emulsifier, 0.5-10 parts of surface-active macromer and 0.03-3 parts of fluoromonomer into a three-neck reaction bottle and stirring the mixture for 30 minutes to obtain an oil phase; weighing 10 parts of acrylamide, 1.5-20 parts of anionic monomer, and 20-400 parts of deionized water, adjusting the solution PH to 5-9 and stirring the solution to obtain an aqueous phase; slowly adding the aqueous phase dropwise into the oil phase, and after N2 is directed into the reaction bottle for 60 minutes, adding 0.01-1.3 parts of initiator potassium persulfate or ammonium persulfate and 0.002-1.0 parts of sodium sulfite into the reaction bottle at a temperature of 40-70 DEG C, and performing an inverse emulsion polymerization reaction for 8-16 hours to produce PAFB emulsion; performing a demulsification by using anhydrous ethanol, washing the demulsified PAFB emulsion 3 times and drying the washed thing in vacuum to obtain a PAFB product. A trace amount of PAFB is capable of obviously increasing the contact angle of water on the rock surface, improving the relative permeability of the aqueous phase, and reducing pressure and increasing injection.

Description

technical field [0001] The invention relates to a preparation method of a surfactant for oil recovery of low-permeability oil reservoirs. The surfactant can be used as an oil displacement agent in tertiary oil recovery technology, and belongs to the fields of organic chemistry, polymer materials and enhanced oil recovery. Background technique [0002] At present, the contradiction between supply and demand of oil in my country is becoming more and more prominent. The import volume of crude oil is increasing year by year, and the proportion of imported oil to the demand exceeds 60%. There is a large amount of crude oil, but its reservoir properties are poor, it is difficult to produce, the degree of reserve production is low, the development effect and economic benefit are poor, and the recovery factor is very low. Today, for low-permeability reservoirs, my country mainly adopts secondary oil recovery and water injection technology, but there is a problem that water injection ...

AI Technical Summary

Problems solved by technology

In order to reduce pressure and increase injection in low-permeability reservoirs, surfactant flooding technology is used to enhance oil recovery. Low molecular weight surfactant petroleum sulfonate and its composite surfactants, mainly low molecular weight surfactants of several hundreds, and the interfacial tension between its active water and crude oil is low interfacial tension (10 -2 mN / m order of magnitude), in order to form oil and water ultra-low interfacial tension (10 -3 mN / m order of magnitude) in order to achieve the purpose of enhancing the recovery factor, alkali is often added to the active water, but the addition of alkali will cause new formation damage to low permeability reservoirs

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