Safety valve in pipe

Abstract

The invention discloses a safety valve in a pipe, comprising an upper joint, a safety valve body and a lower joint which are sequentially connected from top down, wherein the upper joint, the safety valve body and the lower joint form a main perforating hollow structure; a piston assembly, a valve plate assembly and a first spring are sequentially arranged between an upper step and a lower step in the main hollow structure from the top down; a liquid injection channel is formed over the piston assembly in the main hollow structure; a bridge channel is formed at the periphery of the piston assembly; and the valve plate assembly is sealed at the lower end of the bridge channel. In the invention, the piston assembly is pushed by hydraulic pressure by forming the central liquid injection channel at the upper end part, and the piston assembly pushes the valve plate assembly, and then a production oil side output channel is opened, so that the production oil enters the space between a large-diameter oil pipe and a small-diameter oil pipe to form an oil extracting channel; while extracting the oil, high-temperature liquid is cycled in the mall-diameter oil pipe for transferring heat to the production oil through heat conduction, so that the temperature of the production oil is higher than wax deposition temperature so as to achieve the purpose of removing the wax and preventing the deposition of wax.

Description

Technical field [0001] The invention relates to a safety valve, in particular to a safety valve used in downhole tubing. Background technique [0002] Tubing waxing is a problem that occurs during the production of waxy oil wells, which seriously affects the normal production of oil wells. Waxing on the inner wall of the tubing will increase the viscosity of crude oil and increase the difficulty of exploitation. At present, chemical wax prevention, mechanical wax removal and physical wax prevention are mainly used. These methods have different performance and application effects in the field. However, the application of the above wax removal and control methods in offshore oilfield production has the following problems: (1) The cost of workover operations on offshore platforms is high, and the cost of platform workover operations without workover rigs is more expensive; (2) The wax removal and control methods are not thorough. , The need for continuous operation, can not fundame...

AI Technical Summary

Problems solved by technology

However, there are following problems in the application of the above-mentioned method for removing and preventing wax in offshore oil field production: (1) the cost of workover operation is high on offshore platforms, and the cost of workover operations on platforms without workover rigs is more expensive; (2) the removal and prevention of wax is not thorough , need to continue to work, can not fundamentally solve the problem of wax deposition

In the production of offshore oil wells, safety valves are required downhole for well control, but the existing downhole safety valves cannot be applied to the above-mentioned wax removal and prevention oil recovery process, so it is necessary to design an in-line safety valve that can be applied to the above wax removal and prevention oil recovery process

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