Manufacturing method of prestressed heat insulating oil casing

Abstract

The invention relates to a prestressed thermal insulation oil casing. The prestressed thermal insulation oil casing is characterized by comprising an outer tube, a middle tube and an inner tube which are sleeved at intervals, wherein an internal thread is processed on one end of the middle tube, an external thread is processed on the other end of the middle tube, one end, which is provided with the internal thread, of the middle tube is welded with the outer tube at a tube end, and is welded with the inner tube at a reserved internal thread length position, one end, which is provided with the external thread, of the middle tube is welded with the outer tube at a reserved external thread length position, and is welded with the inner tube at a tube end; an annulus, which is formed by the outer tube and the middle tube, is filled with a thermal insulation material, and is vacuumized so as to form a first thermal insulation layer, after an annulus, which is formed by the middle tube and the inner tube, is vacuumized, inert gas is filled so as to form a second thermal insulation layer; the prestressed thermal insulation oil casing comprises the following production steps of pretreating three tubes, sleeving and welding the inner tube and the middle tube, treating the annulus of the inner tube and the middle tube, sleeving and welding the outer tube and the middle tube, treating the annulus of the outer tube and the middle tube, testing a visible heat conductivity coefficient and processing screw threads on two ends of the middle tube in sequence. The prestressed thermal insulation oil casing is provided with three layers of steel pipes and two layers of thermal insulation structures, so that the prestressed thermal insulation oil casing has good thermal insulation performance and excellent working performance.

Description

technical field [0001] The invention relates to a method for manufacturing a prestressed heat-insulating oil casing, in particular to a steam injection and oil extraction tool for heavy oil thermal recovery in the petroleum industry and its manufacturing method, belonging to the technical field of petroleum exploitation Background technique [0002] With the continuous development of the oil extraction industry and the continuous increase in oil consumption, the exploitation of heavy oil has become the main source of production for oil companies at home and abroad, and the exploitation of heavy oil usually adopts two processes: steam huff and puff and steam flooding, and these two processes Both require the use of heat-insulated oil pipes and casings as steam injection and oil recovery tools. The current heat-insulated oil pipes are all produced according to or with reference to a "vacuum heat-insulated oil pipe and its manufacturing process" disclosed in the Chinese patent ...

AI Technical Summary

Problems solved by technology

The current heat-insulated oil pipes are all produced according to or with reference to a "vacuum heat-insulated oil pipe and its manufacturing process" disclosed in the Chinese patent (application number 97115719.7). Tube, heat insulation layer, centralizing block, hydrogen absorbing agent, etc., wherein the structure of the heat insulating layer is: the inner tube is multi-layer aluminum foil, glass mesh is wound at intervals, the annular space is evacuated, and hydrogen absorbing agent is added. This kind of manufacturing process produces The heat-insulated oil casing has a good thermal conductivity, which plays a positive role in protecting the oil well casing, reducing the heat loss of the wellbore, and improving the injection-production effect. The existence of the phenomenon, the heat insulation performance of the heat insulation tubing has been significantly attenuated after about 2 years of steam injection and oil production in the downhole or 15 steam injection cycles, which seriously affects the service life of the heat insulation tubing. At the same time, the heat loss at the coupling joint is serious, causing the Casing damage occurs in the cementing casing, thus causing a huge waste of economic benefits

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