Amphoteric heat-resistant and salt-resistant filtrate reducer for drilling fluid and preparation method

Abstract

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.

Description

technical field

[0001] The invention relates to an amphoteric anti-temperature and anti-salt anti-fluid loss additive for drilling fluid and a preparation method thereof, belonging to the field of chemical drilling fluid treatment agents for oilfields. Background technique

[0002] During the drilling process, the drilling fluid will infiltrate when it flows through the permeable formation under pressure, causing the filtrate of the drilling fluid to invade the formation. This process is commonly known as "water loss". If the water loss is not controlled, the decrease of the liquid volume will increase the density of the cement slurry, and the thickening time and rheological properties will deviate from the original design requirements. A large amount of liquid will flow into the formation, making the cement slurry difficult to pump, and causing different degrees of damage to the formation. Injury, the filtrate intrusion into the formation will not only cause shale hydration...

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