Preparation method of associated modified xanthan gum

Abstract

The invention discloses a preparation method of an associated modified xanthan gum, which is characterized by adding 20 parts of xanthan gum with a medium or low molecular weight, 10-900 parts of solvents, and 0.01-15 parts of catalysts, on a weight basis, into a three-mouth reaction bottle equipped with a reflux condensation device, stirring and swelling the mixture at room temperature for 24 hours; then increasing the temperature to 30-95 DEG C, slowly adding 0.1-20 parts of phenyl ring-containing chlorinated hydrocarbon modifiers, and reacting for 4-72 hours; precipitating and washing the products by acetone, n-propanol or isopropanol to remove unreacted modifiers and catalysts, and filtering; drying in a vacuum oven at 30-70 DEG C for 4-8 hour so as to obtain the associated modifiedxanthan gum. Compared with unmodified xanthan gums, the associated modified xanthan gum has better tackifying performance, heat resistance, salt resistance, and aging resistance, and has a lower using amount. The associated modified xanthan gum with a medium or low molecular weight can be used as an oil displacement agent for tertiary oil recovery in medium and low-permeability oil reservoir, andcan also be used as a thickening agent in drilling fluid; the associated modified xanthan gum can be crosslinked with an inorganic or organic agent to obtain a weak gel used as an oil displacement agent, a profile control and oil displacement agent, a profile control agent, or a plugging agent.

Description

1. Technical field [0001] The invention relates to a preparation method of associative modified xanthan gum, which 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. 2. Technical background [0002] At present, the polymer oil displacement agents used in the tertiary oil recovery technology of my country's oilfields are mainly ultra-high molecular weight (1.6×10 7 ~3.0×10 7 ) partially hydrolyzed polyacrylamide (HPAM), these copolymers can only be used for permeability higher than 1000 (10 -3 μm), it is difficult to meet the hydraulic permeability of 50-500 (10 -3 μm) for medium and low permeability reservoirs, otherwise structural (non-insoluble) plugging will easily occur in the pore media of medium and low permeability reservoirs. In addition, HPAM has poor heat resistance, salt resistance and shear resistance, and the limit service temperature under ...

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Problems solved by technology

However, the oil displacement agent used in the oil field generally does not exceed 2000mg / L, which shows that the amount of xanthan gum solution is relatively high

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