Well cementation retarder

Abstract

The invention provides a well cementation retarder. The well cementation retarder added into 100 parts by weight of cement consists of the following raw materials in parts by weight through mixing: 0.8-1.5 parts of a quaternary compounded ionic copolymer, 0.1-0.3 part of sodium gluconate and 0.05-0.25 part of 1-hydroxyethylidene-1,1-diphosphonic acid, wherein the quaternary compounded ionic copolymer is a quaternary copolymer of itaconic acid, sodium p-styrenesulfonate, acryloyloxyethyl trimethyl ammonium chloride and methyl allyl polyethenoxy ether; the mole ratio of the itaconic acid to the sodium p-styrenesulfonate, the acryloyloxyethyl trimethyl ammonium chloride and the methyl allyl polyethenoxy ether is 25:60:15:0.05. The retarder provided by the invention is a mixture, properties of the quaternary compounded ionic copolymer, the sodium gluconate and the 1-hydroxyethylidene-1,1-diphosphonic acid can supplement one another, defects of single retarders can be overcome, for example, the problem that the strength develops slowly is made up by using the 1-hydroxyethylidene-1,1-diphosphonic acid, and the temperature resistance of the retarder is improved due to the sodium gluconate.

Description

technical field [0001] The invention relates to the field of additives for oil well cement, in particular to a retarder for well cementing. Background technique [0002] In recent years, with the continuous development of exploration and development to deep wells and ultra-deep wells, it has also brought great challenges to cementing projects, such as long-sealing section cementing. [0003] There is no uniform definition standard for the "long sealing section" in the industry. Some studies believe that the cementing section with a cementing section exceeding 1500m or the cementing section using graded cementing with a total length of more than 2600m is long sealing; According to another study, when the circulating temperature at the bottom of the well is 40°C higher than the static temperature at the top of the cement, it can be considered as a long seal, also known as a large temperature difference. For long-sealing section cementing, the commonly used cementing technolog...

AI Technical Summary

Problems solved by technology

Due to the long back-sealing section of the cement slurry at one time and the large temperature difference between the top and bottom of the sealing section (>40°C), the cementing cement admixture is used across temperature zones, which seriously affects the use effect of most admixtures , and directly affect the cementing quality

In order to ensure the safe pumping of cement slurry under high temperature conditions, a large amount of high-temperature retarders are usually added. Most of the high-temperature retarders currently used do not have the characteristics of adapting to large temperature differences. When the cement slurry returns from the bottom of the well to the top low-temperature well section , its retarding effect cannot be eliminated in time, resulting in long-term non-setting of the top cement slurry, making it difficult to guarantee the top cementing quality

[0005] Therefore, there is an urgent need to develop a retarder with high temperature resistance, low sensitivity to temperature and dosage, and a wide range of temperature applications to solve the problem of safe thickening of cement slurry caused by insufficient retarder performance in long-term sealing and large temperature difference cementing construction. The contradiction between the curing time and the slow development of the compressive strength of the top cement stone

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