Straight-joint type insulated tubing and processing technology thereof

Abstract

The invention discloses a straight-joint type insulated tubing and a processing technology thereof, wherein the effects of steam injection and oil extraction are improved through improving the structure of the product of the existing insulated tubing. The straight-joint type insulated tubing comprises an external pipe and an internal pipe; an internal insulation layer is arranged between the external pipe and the internal pipe; the external diameters of the two ends of the internal pipe are larger than that of the middle part; one end of the internal pipe is provided with internal threads and the other end of the internal pipe is provided with external threads; and an external insulation layer is arranged at the joint of the internal pipe. The processing technology of the straight-joint type insulated tubing comprises the following steps of: processing the external pipe, processing the internal pipe, and assembling the internal pipe and the external pipe. In the step of processing the internal pipe, the continuous upsetting is carried out on the external cycles of the both ends of the internal pipe through an upsetter after both ends of the internal pipe are heated through middle frequency, and then the internal threads at one end of the internal pipe and the external threads at the other end of the internal pipe are processed. Through directly processing the threads at both ends of the internal pipe for connection, the hoop connection of the existing insulated tubing is prevented, and the external diameter of the pile of the insulated tubing is effectively reduced. At the joint of the internal pipe, the diameter of the internal hole is not changed so that the turbulent flow can be prevented while steam injecting, the flow resistance is reduced, and the work tools can be conveniently put upside down.

Description

technical field [0001] The invention relates to a heat-insulating oil pipe and a processing technology for steam injection to exploit heavy oil in the petroleum industry, especially a direct-connection heat-insulating oil pipe and a processing technology thereof. By improving the product structure of the existing heat-insulating oil pipe, the effect of steam injection and oil recovery is improved. Background technique [0002] Insulated tubing is an important equipment for steam injection to exploit heavy oil. It is used as a steam injection channel to inject high-temperature and high-pressure steam downhole. Because the insulated tubing has high thermal insulation performance, it can protect oil well casing and cementing The cement sheath is protected from thermal stress damage, and can reduce wellbore heat loss and improve the effect of steam injection and oil recovery. [0003] The Chinese patent application number 97115719.7 discloses "Vacuum Insulated Oil Pipe and Its M...

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Problems solved by technology

[0013] The purpose of the present invention is to provide a direct-connection heat-insulated oil pipe and its processing technology. The heat-insulated oil pipe processed in the prior art has a large steam flow resistance, poor heat insulation performance at the joint, and the lower tool is stuck and stuck in the integrated operation of injection and production. To solve the problem of large outer diameter of the coupling, improve the product structure and manufacturing method to reduce the flow resistance of steam, improve the heat insulation performance of the joint and reduce the outer diameter of the heat-insulated tubing string, so as to improve the efficiency of steam injection and oil production. Effect

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