Fluid loss reducer and preparation method thereof

Abstract

The invention discloses a fluid loss reducer and a preparation method thereof, belonging to the technical field of oil field cementing. The fluid loss reducer provided by the embodiment of the present invention includes: 100 parts by weight of 2-acrylamide-2-methylpropanesulfonic acid, 0.1-0.5 parts by weight of chain monomers, 1-3 parts by weight of lubricant, 1-3 parts by weight of surfactant, 3-5 parts by weight of cyclic monomer, 8-10 parts by weight of amide monomer, 1-3 parts by weight of carboxylic acid monomer and 300-400 parts by weight of water. The fluid loss reducer provided by the embodiment of the present invention is suitable for well cementing operations in salt-gypsum layers. The salt-containing high-density cement slurry prepared with it has excellent stability and rheological properties under the condition of low liquid-solid ratio. Under the condition of temperature difference, the strength develops rapidly and the strength is high. Under the condition of narrow safe density window cementing in salt-gypsum layer, it can effectively reduce the flow resistance of high-density cement slurry containing salt, so as to effectively ensure the safety of cementing construction and improve the quality of cementing.

Description

technical field [0001] The invention relates to the technical field of oil field cementing. In particular, it relates to a fluid loss reducing agent and a preparation method thereof. Background technique [0002] There are salt-gypsum layers in many oilfield blocks in my country, and the salt-gypsum layers are formations containing sodium chloride and other water-soluble inorganic salts. The salt-gypsum layer is generally buried deep and the pressure is high. There is a high-pressure brine layer in the salt-gypsum layer, which is prone to accidents such as well kick and blowout. Therefore, high-density cement slurry is required to stabilize the salt-gypsum during cementing operations. layer. At the same time, there are weak layers between the salt-gypsum layers. During cementing, when the dynamic equivalent density of the cement slurry is too high, it is easy to leak the salt-gypsum layer, and the cement slurry leaks into the salt-gypsum layer and other layers except the s...

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Problems solved by technology

[0004] However, polyvinyl alcohol fluid loss reducers are mainly used in medium and low temperature conditions, and the salt paste layer is generally buried deep and the temperature is high, and polyvinyl alcohol type fluid loss reducers are not resistant to salt, so they are not suitable for the preparation of salt paste layer. Cement slurry for well operations

However, the dispersion of AMPS polymer fluid loss reducer in cement slurry is poor. Adding it to salt-containing high-density cement slurry will cause the rheological properties of salt-containing high-density cement slurry to deteriorate, and the flow resistance will become larger. When the equivalent density increases, the pressure on the salt-gypsum layer increases. During the cementing operation, the salt-gypsum layer may be leaked, resulting in low safety of cementing construction and poor cementing quality.

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