Environment-friendly multifunctional scale inhibitor and preparation method and application thereof

Abstract

The invention provides an environment-friendly multifunctional scale inhibitor. The environment-friendly multifunctional scale inhibitor is prepared from, by weight, 45-70% of phosphorus-free chelating agent, 3-10% of natural polymer, 5-15% of scaling inhibitor, 0.3-1% of dodecyl dimethyl glycine betaine, 0.1-0.5% of polyhexamethylene guanidine hydrochloride and the balance water, wherein the scaling inhibitor is at least one of a sulfonic acid copolymer and a maleic anhydride copolymer. In addition, the invention also provides a preparation method and application of the scale inhibitor. A trace amount of dodecyl dimethyl glycine betaine and a trace amount of polyhexamethylene guanidine hydrochloride are added into the scale inhibitor and play the cooperative synergistic effect on scale inhibition, the finally prepared scale inhibitor has the remarkable scale inhibiting effect on three types of scale calcium carbonate, calcium phosphate and barium sulfate and is free of phosphorus andpollution to the environment and is environmentally friendly, and the problems of oil field water scaling and blockage can be effectively solved.

Description

technical field [0001] The invention belongs to the technical field of water treatment, and in particular relates to an environment-friendly multifunctional scale inhibitor and its preparation method and application. Background technique [0002] In the oil field development and secondary oil recovery process, the energy of the oil layer itself will be continuously consumed, resulting in a continuous drop in oil layer pressure, a large amount of degassing of underground crude oil, an increase in viscosity, and a great reduction in oil well production. In order to maintain or increase oil layer pressure, obtain higher Oilfield water must be injected to improve oil recovery. In order to save water resources, oilfield water reinjection is usually used. In addition, in the process of oilfield exploitation, fracturing of oil and gas wells is a measure to increase production. By improving the conductivity of oil layers, the purpose of increasing production and injection can be ach...

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Problems solved by technology

[0003] However, oilfield reinjection water, fracturing water, and formation water all contain different scaling ions such as calcium, magnesium, strontium, and barium. Due to the thermodynamic instability and chemical incompatibility of water, the interaction of scaling ions will produce Unstable, easily precipitated substances, such as barium (strontium) sulfate, calcium carbonate, calcium sulfate, etc.

These sediments accumulate on the surface of the oil casing and various equipment and will scale, often causing the oil pump to be stuck, the annulus between the well pipe and the sucker rod to be blocked, and the inner diameter of the gathering and transportation pipeline to decrease sharply. It may even cause problems such as severe blockage of equipment and formations, which greatly affects the normal production of oil fields, and even causes oil and gas wells to stop production in severe cases

[0004] The current scale mainly includes carbonate scale and sulfate scale. Carbonate scale is easy to be removed by acidification, but sulfate scale, especially barium sulfate scale, is difficult to remove by general methods

At present, the scale inhibitors used in oil fields generally have a narrow trial range. Most scale inhibitors are only for a single type of scale, and there are very few researches on scale inhibitors that can effectively inhibit calcium carbonate scale, calcium sulfate scale, and barium sulfate scale at the same time. However, these antiscalants also have the problems of weak antiscaling ability, poor antiscaling effect and environmental pollution.

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