Cement-dispersing retarder for high-temperature-resistant oil well and preparation method of retarder

Abstract

The invention discloses a cement-dispersing retarder for a high-temperature-resistant oil well and a preparation method of the retarder. The cement-dispersing retarder comprises three structure units, namely sodium p-styrenesulfonate, methacrylic acid-2-hydroxyl ethyl ester and itaconic acid, and the viscosity-average molecular weight is 30000-50000. The preparation method comprises the following steps of (1) respectively dissolving sodium p-styrenesulfonate, methacrylic acid-2-hydroxyl ethyl ester and itaconic acid in deionized water, mixing and adjusting pH to be neutral; (2) introducing nitrogen to remove oxygen, reacting for 4-6 hours in water bath with the temperature of 50-70 DEG C based on potassium persulfate as an initiating agent; and (3) cooling obtained slightly-viscous solution, purifying, drying and grinding, thereby obtaining the cement-dispersing retarder for the high-temperature-resistant oil well. The cement-dispersing retarder disclosed by the invention has the advantages that the thickening time can be effectively prolonged under the high-temperature condition, the right-angled thickening phenomenon is obvious, the compatibility with other oil-well cement admixtures is good, the strength of cement stone can also be rapidly developed under the low-temperature condition, the preparation method is reliable in principle and simple to operate and has wide market prospect.

Description

technical field [0001] The invention relates to a high-temperature-resistant oil well cement dispersion retarder and a preparation method thereof, belonging to the field of Portland cement admixtures. Background technique [0002] With the development of the petroleum industry and drilling technology, the field of exploration and development is expanding day by day, and the exploitation of oilfields gradually extends to deep oil and gas reservoirs, and more medium-deep wells, deep wells and ultra-deep wells are encountered, and the following problems are mainly as follows: The thickening time of the bottom cement slurry is shortened due to the high bottom cycle temperature, the rheological properties are changed, the oil and water flow together, and the super retarded phenomenon occurs due to the slow development of the strength of the top cement slurry. In recent years, in view of the problems that have arisen, it is proposed to develop a high-quality retarder with low temp...

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Problems solved by technology

However, when AMPS polymer retarders adapt to high temperatures, they often have high initial consistency, "bulging" and "stepping" phenomena in the thickening curve, long thickening transition time, prone to "gas channeling", and cannot achieve sealing. Oil-gas-water layer and protective casing, and in the environment of large temperature difference, the cement slurry on the top is prone to over-retarding phenomenon, which seriously affects the quality of cementing and construction safety

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