Compound low dosage natural gas hydrate inhibitor

A hydrate inhibitor, low-dose technology, applied in the direction of drilling composition, chemical instruments and methods, etc., can solve the problems of kinetic inhibitor failure, achieve the effect of reducing cost and logistics support burden, and reducing environmental hazards

Inactive Publication Date: 2015-08-12
CHINA UNIV OF PETROLEUM (EAST CHINA)
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, research and practice have shown that kinetic inhibitors are severely ineffective at high subcooling, and during deepwater drilling, the subsea low-temperature and high-pressure environment provides high subcooling conditions, and the deeper the water depth, the higher the subcooling pressure. The higher the value is, the use of kinetic inhibitors alone cannot meet the requirements for hydrate control in deepwater drilling and completion operations, and a higher concentration of thermodynamic inhibitors is still required.

Method used

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  • Compound low dosage natural gas hydrate inhibitor

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0042] Polyvinylpyrrolidone and polyoxyethylene were prepared in a mass ratio of 2:1 to prepare a composite low-dose natural gas hydrate inhibitor aqueous solution with a mass percentage of 1.2%. Put it into the reaction kettle of the natural gas hydrate inhibition evaluation experimental device, and simulate the drilling environment at a water depth of 500m, that is, the experimental pressure is 5MPa, the experimental temperature is 2°C, the stirring speed is 200r / min, and no hydrate is formed in the reaction kettle within 16 hours.

Embodiment 2

[0044] Polyvinyl caprolactam and ethylene glycol phenyl ether were prepared according to the mass ratio of 2:1 to prepare a composite low-dose natural gas hydrate inhibitor aqueous solution with a mass percentage of 1.5%. Put it into the reaction kettle of the natural gas hydrate inhibition evaluation experimental device, and simulate the drilling environment at a water depth of 800m, that is, the experimental pressure is 8MPa, the experimental temperature is 2°C, the stirring speed is 200r / min, and no hydrate is formed in the reaction kettle within 16h.

Embodiment 3

[0046] Prepare the copolymer generated by the reaction of vinyl caprolactam, vinyl pyrrolidone, vinyl sulfonic acid and isopropyl methacrylamide, the preparation method is as follows:

[0047] Into a four-neck flask equipped with a reflux condenser, a thermometer, a stirrer and a nitrogen inlet and outlet, add 200mL of methanol, then add 14.4g of vinylpyrrolidone and 18g of vinylcaprolactam, stir and heat through nitrogen to a temperature of 60°C, add 0.32 g azobisisobutyronitrile. The aqueous solution containing 7g of vinylsulfonic acid was added dropwise to the four-necked flask, and the addition was completed within 2 hours, and the reaction was carried out at 60°C for 8 hours. Add 4.2 g of isopropyl methacrylamide and react at 60° C. for 8 hours to obtain a reaction product. The product was precipitated into excess hexane, redissolved in tetrahydrofuran, reprecipitated into hexane, and dried in vacuo to obtain a sample of the inhibitor.

[0048] The prepared inhibitor sa...

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Abstract

The invention discloses a compound low dosage natural gas hydrate inhibitor. The hydrate inhibitor benchmarked against the mass of water in a deepwater drilling fluid completion fluid comprises, by mass, 0.1-2% of a hydrate kinetic inhibitor, 0.1-2% of a kinetic inhibitor synergist and 0-10% of a hydrate thermodynamic inhibitor. The hydrate kinetic inhibitor is at least one of polyvinyl pyrrolidone, polyvinyl caprolactam, and a copolymer generated through a reaction of vinyl pyrrolidone, vinyl caprolactam, alkenyl sulfonic acid and isopropylmethacrylamide. The kinetic inhibitor synergist is at least one of benzyltributylammonium chloride, tetraheptylammonium bromide, ethylene glycol phenyl ether, propylene glycol phenyl ether, polyoxyethylene and polyoxypropylene. The hydrate inhibitor can effectively inhibit generation of hydrates under a low dosage (0.2-10%), is suitable for deepwater and ultra-deep water drilling and completion, greatly reduces the cost and the logistical support burden, and has small harms to environment.

Description

technical field [0001] The invention relates to a composite low-dose natural gas hydrate inhibitor, which is used for inhibiting the formation of natural gas hydrate in deep water drilling and completion operations. Background technique [0002] Natural gas hydrate is an ice-like substance formed by water and natural gas under low temperature and high pressure conditions. During deepwater drilling and completion in the ocean, the temperature of seabed seawater and formations is low, and the hydrostatic pressure is high, creating conditions for the formation of hydrates. Hydrates will grow and accumulate rapidly after formation, causing drilling and completion fluid flow obstacles, wellbore, choke pipeline and blowout preventer blockage, affecting the normal drilling and completion operations, and blowout preventer blockage may even cause serious accidents such as blowout . [0003] The formation of natural gas hydrate requires the following conditions: first, the presence ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C09K8/035C09K8/524
CPCC09K8/035C09K8/524C09K2208/22
Inventor 邱正松赵欣江琳周国伟黄维安钟汉毅王明亮
Owner CHINA UNIV OF PETROLEUM (EAST CHINA)
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