Scale inhibitor formula for intraformational multi-crack fracturing for oilfields and preparation method

Abstract

The invention provides a scale inhibitor formula for intraformational multi-crack fracturing for oilfields. The scale inhibitor formula comprises, by weight, 30-50% of coating agent, 45-65% of scale inhibitor and 2-5% of adhesive. The scale inhibitor is high in compatibility and applicable to formation water of formations at different temperatures and in different ranges of pH and mineralization degree; the acting range is large, the antiscale radius can be enlarged, the valid period of scale prevention is prolonged, and all-sided scale prevention for immediate vicinity of wellbores, production wellbores and surface pipelines is achieved; the release time is long, the dissolving time in oil and water is more than 400 days, the scale-inhibition effect is good, and the scale inhibition rate reaches over 92.2%.

Description

technical field [0001] The invention belongs to the technical field of oil field fracturing, and in particular relates to a formula and a preparation method of a scale inhibitor for multi-fracture fracturing in an oil field. Background technique [0002] In the process of oil field production, when the fluid flows into and out of the wellbore, scale is formed due to sudden changes in temperature, pressure and flow velocity, resulting in scaling in the perforation section of the wellbore of the production well, the inner wall of the downhole tubing, the screen pipe, the liner pipe, and the inner wall of the pump pipe. , the liquid production rate drops or no liquid is produced; due to the incompatibility of the injected water and the formation water, the water injection well scales near the wellbore, which increases the pressure of the water injection well, fails to meet the injection requirements, and seriously affects the oilfield production. [0003] For oil-water wells th...

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Problems solved by technology

[0007] The main problem of antiscalants represented by the above-mentioned patent documents is that the methods currently used to remove or prevent scale have limitations:

The measures are relatively small, and the intensity of reconstruction of the original pore throats of the reservoir is low, so it is impossible to greatly improve the seepage of the reservoir

[0009] 2. Acidification, damage to the rock matrix, acid discharge after acidification operation will cause serious pollution, and secondary scaling will easily lead to acidification failure

[0010] 3. Fracturing can greatly increase the conductivity of the formation in the short term, but during the production process, formation scaling, clay swelling, iron ion precipitation and organic matter precipitation will greatly reduce the conductivity of the fractures filled with proppant and the measures will fail

[0011] 4. Composite measures, acidification and extrusion injection plugging removal are relatively single, and have a relatively small effect on improving the formation conductivity; the joint operation of extrusion anti-scaling agent and fracturing can greatly improve the formation conductivity and delay scaling Speed, but squeezing the antiscalant Relying on a single injection of antiscalant cannot solve the long-term antiscaling problem

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