Filtrate loss reducer for drilling fluid and preparation method thereof

Abstract

The invention provides a filtrate loss reducer for a drilling fluid and a preparation method thereof. The filtrate loss reducer is an inverse emulsion polymer prepared from a water phase and an oil phase through emulsification. The water phase comprises, by weight, 45-56 parts of a sulfonic monomer, 25-38 parts of an amide group monomer, 5-10 parts of a rigid structure monomer and 100-120 parts of water. The water phase also comprises a cross-linking agent and an initiator, a mass ratio of the cross-linking agent to the sulfonic monomer, the amide group monomer and the rigid structure monomer is 0.008-0.015%, and a mass ratio of the initiator to the sulfonic monomer, the amide group monomer and the rigid structure monomer is 0.05-0.15%. The oil phase comprises 80-110 parts by weight of base oil and 4-10% by mass of an emulsifier. The preparation method has simple processes, a fast dissolution rate and excellent filtrate loss reduction performances.

Description

technical field [0001] The invention belongs to the technical field of drilling fluid treatment agents, in particular to a fluid loss control agent for drilling fluid and a preparation method thereof. Background technique [0002] In oil exploration or drilling operations, the drill bit is easily damaged under the action of huge pressure and friction, so drilling fluid is used to protect the drill bit during drilling operations, but the drilling fluid will seep into the formation soil under pressure and cause loss , this process is commonly referred to as "dehydration". A large amount of water loss entering the soil will not only induce wellbore instability, but also cause damage to oil and gas layers. The current solution to this problem is to add fluid loss control agents to the drilling fluid, which can block all directions The capillary channels in the mud cake formed by the drilling fluid and the soil make it smooth and dense; increase the negative charge density of th...

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Problems solved by technology

[0003] Currently widely used fluid loss control agents are supplied and used in powdered polymer products. Practice has shown that powdered polymers have many disadvantages when used, such as: slow dissolution rate, slow dissolution rate in the process of compounding the glue solution in field application, resulting in Increased working hours and even some polymers form gel blocks, resulting in unstable performance and easy to be screened out by vibrating sieves, resulting in waste; in addition, powdery polymers generally have a drying and crushing process, and the production cycle is long, and due to degradation, crosslinking, etc. The reaction will cause adverse effects and affect its performance, and it cannot be directly added to the drilling fluid during use, the dispersion speed is slow, the workload of the mud workers on site is heavy, and the cost of drilling fluid treatment is high

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