Packer liquid capable of reducing carbon dioxide corrosion at high temperature under high pressure and preparation method thereof

Abstract

The invention discloses a packer liquid capable of reducing the carbon dioxide corrosion at a high temperature under a high pressure and a preparation method thereof. The packer liquid is composed of the following components in parts by weight: 100 parts of fresh water, 0.20 to 0.50 part of NaOH, 0.10 to 0.30 part of deoxidant, 1 to 6 parts of corrosion inhibitor, and 10 to 200 parts of composite salt weighting agent; wherein the composite salt weighting agent is prepared by compounding inorganic phosphate and organic phosphonate. The packer liquid is a non-solid phase, and the density can reach 1.60 g / cm3 or more. The packer liquid can tolerate a temperature of 150 DEG C, and is capable of reducing the corrosion of carbon dioxide on tubing in the wells at a high temperature under a high pressure. Furthermore, compatibility between the packer liquid and seawater / stratum produced water is good, and thus the packer liquid can be applied to the well-completion practice on an oil gas well with a high carbon dioxide content at a high temperature under a high pressure.

Description

technical field [0001] The invention relates to a working fluid in high-temperature and high-pressure well completion operations and a preparation method thereof, in particular to a packer fluid capable of reducing carbon dioxide corrosion under high temperature and high pressure and a preparation method thereof, belonging to the technical field of oilfield chemistry. Background technique [0002] During the completion operation, the liquid remaining in the annular gap between the oil well tubing and casing or the technical casing and the reservoir casing is called packer fluid or annular space protection fluid. The main purpose of the packer fluid is to maintain the static pressure of the liquid column between the surface layer or the technical casing, and prevent the pressure difference between the inside and the outside from endangering the casing. More importantly, the packer fluid needs to protect the surface layer and the inner wall of the intermediate casing and the o...

AI Technical Summary

Problems solved by technology

The raw material used to prepare high-density brine spacer fluid is usually bromide salt (such as CaBr 2 , ZnBr 2 etc.) and formate, due to CaBr 2 / ZnBr 2 It is highly corrosive itself, and its use in high-temperature and high-pressure wells is limited. Formate, such as HCOOK, etc., although it is not very corrosive, HCOOK brine can be used in the presence of CO 2 After the gas enters, its corrosiveness increases significantly, so it cannot meet the long-term anti-corrosion requirements of the packer fluid

At the same time, the existing technology also uses a single inorganic phosphate as a weighting agent to prepare the packer fluid, but it is easy to form precipitation with seawater or formation produced water with high calcium and magnesium ions

[0005] In the prior art, there is no packer fluid aimed at reducing carbon dioxide corrosion under high temperature and high pressure

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