Solid high-temperature retarding agent for oil-well cement and preparation method thereof

A technology of oil well cement and retarder, which is applied in the direction of chemical instruments and methods, drilling compositions, etc., can solve problems such as narrow applicable temperature range, non-setting of cement slurry, and large change in cement stone strength, and achieve thickening transition Short time, good compatibility, and good curve shape

Active Publication Date: 2012-10-03
天津宁赛科技有限公司
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AI Technical Summary

Problems solved by technology

[0004] At present, several commonly used retarder systems include lignosulfonate, sugar compounds, cellulose derivatives and organic phosphates. Oil well cement retarders used for high temperature generally have a narrow applicable temperature range and are sensitive to temperature. The disadvantage of most products is that when the well temperature rises or falls by 10°C, the dosage will be more than doubled or cut by more than half, and the strength of cement stone will change greatly, which will have a negative impact on the safety of cementing operations.
Due to the large temperature difference between the upper and lower formations in the deep well sealing section, a small difference in the amount of addition will cause the cement slurry to remain uncondensed for a long time, causing serious consequences

Method used

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  • Solid high-temperature retarding agent for oil-well cement and preparation method thereof

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preparation example Construction

[0021] The preparation method of the oxidized starch comprises the following steps: prepare the starch emulsion with water with a concentration of 25%-30% by mass, keep stirring continuously, adjust the pH to 9-10 with alkali, and maintain the reaction at 45-55°C temperature, adding an oxidizing agent, and reacting for 2-3 hours. After the reaction, stand and separate layers, pour off the supernatant, and dry the lower emulsion to obtain oxidized starch.

[0022] The starch is one of potato starch, corn starch, tapioca starch or wheat starch.

[0023] The oxidizing agent is an aqueous hydrogen peroxide solution with a mass percentage concentration of 30%, and the addition amount is 5%-15% of the dry starch mass.

[0024] The alkali is a 2% sodium hydroxide solution in mass percent concentration.

[0025] In the preparation method of the above-mentioned solid high-temperature retarder for oil well cement, each raw material is weighed according to its percentage, and then added...

Embodiment 1

[0029] First prepare the oxidized starch. Prepare 30% potato starch milk, keep stirring, the stirring speed is 60r / min, adjust the pH to 9-10 with 2% NaOH solution, maintain the reaction temperature at 50°C, add starch (dry basis) in a mass percentage of 15% For hydrogen peroxide solution with a concentration of 30%, the formation of carboxyl groups during the oxidation process will cause a drop in pH value, and 2% NaOH solution should be added to control the pH value within a stable range (9-10), react for 2 hours, filter, and dry to obtain oxidized starch.

[0030] Take 325g of oxidized starch, 100g of hydroxyethylidene diphosphonic acid, 50g of zinc oxide, and 25g of sodium borate, and stir the four kinds of raw materials in a mixer for 30 minutes to obtain a solid high-temperature retarder sample 1.

Embodiment 2

[0032] First prepare the oxidized starch. Prepare 25% cornstarch milk, adjust the pH to 9-10, maintain the reaction temperature at 45°C, and add a 30% hydrogen peroxide solution with a mass percent concentration of 8% starch (dry basis).

[0033] Operate according to the method described in Example 1 to obtain oxidized starch.

[0034] Take 300g of oxidized starch, 115g of aminotrimethylene phosphonic acid, 60g of zinc oxide, and 25g of sodium borate, and stir the four kinds of raw materials in a mixer for 30 minutes to obtain solid high-temperature retarder sample 2.

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Abstract

The invention discloses a solid high-temperature retarding agent for oil-well cement and a preparation method thereof. The retarding agent is prepared by mixing the following components in percentage by mass: 60-70 percent of oxidized starch, 15-25 percent of organic phosphonic acid, 5-15 percent of zinc oxide and 1-10 percent of sodium borate. The retarding agent can be used for adjusting the thickening time of cement grout within the temperature range of 50-200 DEG C, does not influence the strength development of set cement, is not sensitive to dosage, and has high compatibility with otheroil-well cement additives.

Description

technical field [0001] The invention relates to a retarder and a preparation method thereof, in particular to a high-temperature retarder for oil well cement and a preparation method thereof. Background technique [0002] In the cementing operation of oil and gas wells, cement slurry is usually injected into the casing, and the cement slurry is returned from the annular space. After it solidifies, the annulus between the well wall and the casing is sealed. The grout must remain pumpable until it reaches the desired location for the seal. During the cementing process, as the hydration reaction of the cement slurry proceeds, the fluidity of the cement slurry becomes poor. When the consistency of the cement slurry reaches a certain value, the cement slurry loses its fluidity and cannot be pumped. [0003] With the deepening of oilfield exploration and development, there are more and more cases of deep well cementing. With the increase of the bottom hole temperature, the solid...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C08L3/10C08K13/02C08K5/5317C08K3/22C08K3/38C04B24/38C09K8/467C04B103/22
Inventor 刘中华
Owner 天津宁赛科技有限公司
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