Salt-resistant filtrate-loss reducer for drilling fluid and preparation method of salt-resistant filtrate-loss reducer

Abstract

The invention discloses a salt-resistant filtrate-loss reducer for a drilling fluid. The salt-resistant filtrate-loss reducer comprises the following raw materials: 2400-3600kg of acrylamide, 180-350kg of sodium carbonate, 0-200kg of 2-acrylamide-2-methyl propane sulfonic acid, 100-300kg of hydroxide calcium and 5-10kg of N,N-methylenebisacrylamide. The preparation method of the salt-resistant filtrate-loss reducer comprises the steps of polymerizing the raw materials, modifying and the like. The salt-resistant filtrate-loss reducer has the advantages of proper viscosity, very strong water solubility, good compatibility, low filtrate loss and strong salt resistance and can be used in combination with different drilling fluids, also can be used in various freshwater and saltwater drilling fluids and can inhibit the hydration dispersion of shale; the addition amount of the salt-resistant filtrate-loss reducer in freshwater is 0.2%-0.5% and the addition amount of the salt-resistant filtrate-loss reducer in saltwater is 1.0%-2.0%.

Description

technical field [0001] The invention relates to the field of petrochemicals, in particular to a salt-resistant fluid loss reducer for drilling fluid and a preparation method thereof. Background technique [0002] During the drilling process, due to the pressure difference, the water in the drilling fluid will inevitably leak into the formation through the wellbore wall, causing the drilling fluid to lose water. As the water enters the formation, the clay particles in the drilling fluid adhere to the well wall to form a "filter cake", forming a filter cake well wall. Since the well wall of the filter cake is much denser than the original well wall, on the one hand, it prevents the drilling fluid from further dehydration, and on the other hand, it plays a role in protecting the well wall. However, during the formation of the filter cake wall, too much water is lost by filtration, the filter cake is too thick, and fine clay particles enter the formation with water, which will ...

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Problems solved by technology

[0003] The Chinese patent with the patent number ZL 201010172409.3 discloses a preparation method of a high-temperature and salt-resistant fluid loss reducer for drilling fluids. It adopts a single reaction device and copolymerizes two or more functional monomers. During the reaction process, the reaction concentration is too high , the reaction is violent, and there is a safety hazard to the equipment and operators

In addition, due to sudden polymerization, the reaction temperature is high and the reaction time is short, resulting in low molecular weight and low viscosity of the polymer, which cannot effectively adjust the flow pattern, shale cuttings are dispersed, and in severe cases, it will lead to formation slurry and hole diameter shrinkage , well wall collapse, etc.

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