Preparation method of temperature-resistant composite scale inhibitor and application thereof

Abstract

The invention discloses a preparation method of a temperature-resistant composite scale inhibitor and application thereof. The composite scale inhibitor comprises phosphonocarboxylic acid copolymer, polyamino polyether methylene phosphonate, diethylene triaminepentamethyl phosphate, isopropanol, hydrochloric acid and ammonium chloride as raw materials. The composite scale inhibitor has a good scale inhibition effect at high temperatures (higher than 120 DEG C), and can be used in high temperature injection wells and strata in oil fields to prevent calcium carbonate scales; the scale inhibitorhas a pH value of 5.5-6.5, and is environmentally-friendly; compared with the conventional agent, the temperature-resistant composite scale inhibitor is wide in raw material sources, easy to prepare and good in injection property, has a scale inhibition rate more than 85% at high temperatures (higher than 120 DEG C), can reduce the damage to the strata, and is suitable for large-scale applicationin high-temperature oil fields.

Description

technical field [0001] The patent of the invention relates to a preparation method and application of a temperature-resistant composite scale inhibitor in the technical field of oil and gas field development. Background technique [0002] In the process of oilfield water injection development, due to downhole temperature, pressure, formation water compatibility and other problems, scaling occurs in the wellbore and formation of the water injection well. Oilfield scaling is divided into two types. The first type of scale is suspended scale, which has a small particle size and will not be adsorbed on the wellbore wall, but will enter the formation with the injected water to block and adsorb on the rock pores and throats. The interfacial tension of oil and water increases on the rock surface, which reduces the effect of water flooding. The second type of scale is sedimentary scale, which will adhere to the wall of the wellbore and will not enter the formation with the injected...

AI Technical Summary

Problems solved by technology

Oilfield scaling is divided into two types. The first type of scale is suspended scale, which has a small particle size and will not be adsorbed on the wellbore wall, but will enter the formation with the injected water to block and adsorb on the rock pores and throats. Increased oil-water interfacial tension on the rock surface, resulting in reduced water flooding effect

The second type of scale is sedimentary scale, which will adhere to the wall of the wellbore and will not enter the formation with the injected water, causing blockage of the water injection section, increased water injection pressure, and affecting the distribution of water injection wells; sedimentation of water injection wells will also cause The downhole test and deployment encountered obstacles and stuck and could not be carried out normally

At present, there are many types of scale inhibitors used in oilfields, including polycarboxylic acid scale inhibitors, inorganic phosphorus scale inhibitors, organic phosphoric acid scale inhibitors, copolymer scale inhibitors, environmental protection scale inhibitors, etc., but the commonly used scale inhibitors The general use temperature of the agent is below 100°C, and the anti-scaling effect drops sharply above 100°C, not only the scaling is not inhibited, but also by-products will be produced, which will cause more serious damage to the wellbore and reservoir

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