The invention discloses an amphoteric heat-resistant and salt-resistant filtrate
reducer for
drilling fluid and a preparation method. The amphoteric heat-resistant and salt-resistant filtrate
reducer is prepared from, by weight parts,
acrylamide, alkenyl sulfoacid or alkenyl sulphonate,
acrylic acid, cationic monomers, rigid monomers,
sodium hydroxide,
potassium hydroxide, dispersant, deionized water, a molecular weight modifier and an initiator. The preparation method includes the steps that
acrylamide,
acrylic acid, alkenyl sulfoacid or alkenyl sulphonate, the cationic monomers, the rigid monomers and the deionized water are added into a reactor, after the materials are dissolved, the pH value of the solution is adjusted, the dispersant is added, the materials are mixed, then the mixture is transferred into a reaction still,
nitrogen is introduced for deoxygenization, the initiator is added for triggering
polymerization, and jelly is taken out after the reaction is completed, dried, smashed and sieved. The molecular weight of the filtrate
reducer for the
drilling fluid is controllable; the filtrate reducer can adapt to complex drilling conditions, and can be used in
horizontal wells, high-temperature deep wells and evaporite beds; fewer residual monomers of the filtrate reducer for the
drilling fluid are generated; the filtrate reducer and other
oil field chemicals are good in compatibility; the preparation method is simple; the cost is low, and popularization is promoted.