Fluid loss agent and preparation method thereof

Abstract

The invention discloses a fluid loss agent and a preparation method thereof, and belongs to the technical field of oil field well cementation. The fluid loss agent provided by the embodiment of the invention comprises the following components in parts by weight: 100 parts of 2-acrylamide-2-methyl propanesulfonic acid, 0.1-0.5 part of a chain monomer, 1-3 parts of a lubricant, 1-3 parts of a surfactant, 3-5 parts of a cyclic monomer, 8-10 parts of an amide monomer, 1-3 parts of a carboxylic acid monomer and 300-400 parts of water. The fluid loss agent provided by the embodiment of the inventionis suitable for salt paste layer well cementation operation, and salt-containing high-density cement paste prepared from the fluid loss agent has excellent stability and rheological property under the condition of low liquid-solid ratio, is rapid in strength development and high in strength under the condition of large temperature difference, and can effectively reduce the flowing resistance of the salt-containing high-density cement paste under the condition of salt paste layer narrow safe density window well cementation, so that the well cementation construction safety is effectively guaranteed, and the well cementation quality is improved.

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. Floor. 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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