Salt-containing flushing fluid for well cementing and preparation method thereof

A flushing fluid and cementing technology, applied in the field of oil drilling, can solve the problems of poor salt resistance, poor solubility, poor flushing effect of flushing fluid, etc., and achieves good temperature resistance, improved interface bonding strength, and strong flushing. effect of effect

CN104745165BActive Publication Date: 2018-03-13BC P INC CHINA NAT PETROLEUM CORP +1
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Patents(China)
Current Assignee / Owner
Publication Date
2018-03-13

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Abstract

The invention discloses a salty flushing fluid for well cementation. The formula of the salty flushing fluid comprises 100 parts of water, 10-36 parts of sodium chloride, 1-3 parts of sodium carbonate, 1-10 parts of betaine-type amphoteric surfactant and 0.1-5 parts of sodium lignin sulfonate; the invention further discloses a preparation method of the salty flushing fluid for well cementation. The method comprises the following steps: completely dissolving sodium chloride, sodium carbonate and sodium lignin sulfonate in water, and then adding the betaine-type amphoteric surfactant, further stirring for 10-20min to obtain the salty flushing fluid for well cementation. The salty flushing fluid for well cementation is used for reducing or preventing the dissolving to an salt gypsum bed when the well cementation is performed on the salt gypsum bed, and avoiding the hole-wall collapsing caused when the salt gypsum bed is excessively dissolved by the flushing fluid, and a sleeve wall can be effectively flushed, the interface bonding strength of the cement slurry and the sleeve is improved, the well cementation quality is improved, and the salty flushing fluid is suitable for oil-based drilling fluid or water-based drilling fluid.
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Description

technical field

[0001] The invention belongs to the technical field of petroleum drilling, in particular to a salt-containing flushing fluid for well cementing and a preparation method thereof. Background technique

[0002] In drilling operations, the long-term circulation of mud will form a thicker virtual mud cake on the well wall and casing. No cementation will seriously affect the cementing quality. Therefore, in the cementing operation, it is necessary to inject a certain amount of flushing fluid containing surfactant before cementing, dilute and remove the virtual mud cake, improve the affinity of the two interfaces, and improve the bonding quality between the cement slurry and the two interfaces , to improve the quality of cementing. In response to this situation, major domestic oil fields have developed a series of flushing fluids, which are used in cementing site construction, effectively improving the cementing quality.

[0003] However, with the development of ...

Examples

Embodiment 1

[0017] Add 15g of sodium chloride, 1.5g of sodium carbonate and 2g of sodium lignosulfonate to 100mL of clear water in turn, stir until completely dissolved, then add 6g of cocamidopropyl sulfobetaine, and stir for 10min to obtain a salt-containing solution for well cementing. Well cementing flushing fluid.

Embodiment 2

[0019] Add 20g of sodium chloride, 2g of sodium carbonate and 1.5g of sodium lignosulfonate in 100mL of clear water in turn, stir until completely dissolved, then add 5g of lauryl amidopropyl sulfobetaine, and stir for 18 minutes to obtain a salt-containing cement for well cementing. Well flushing fluid.

Embodiment 3

[0021] Add 25g of sodium chloride, 1g of sodium carbonate and 1g of sodium lignosulfonate to 100mL of clear water in turn, stir until completely dissolved, then add 3g of cocamidopropyl sulfobetaine, and stir for 20min to obtain a salt-containing cement for well cementing. Well flushing fluid.