A cathodic protection device for protecting the inner wall of oil pipe and casing and its manufacturing method

Abstract

The invention provides a cathode protection device for protecting inner walls of an oil pipe and a casing pipe and a manufacturing method of the cathode protection device, and includes the cathode protection device for protecting the inner walls of the oil pipe and the casing pipe and the manufacturing method of the cathode protection device. The cathode protection device for protecting the inner walls of the oil pipe and the casing pipe consists of short joints, casing pipe conductors, out-of-pipe sacrificial anodes and screw threads or consists of the short joints, the casing pipe conductors, the out-of-pipe sacrificial anodes, the screw threads and out in-pipe sacrificial anodes. During the manufacturing, in-pipe molds are firstly installed on the short joints according to design requirements; the in-pipe sacrificial anodes are cast, and excessive anodes are milled away; then, out-of-pipe molds are installed; the out-of-pipe sacrificial anodes are cast, and excessive anodes are milled away; next, the screw threads are manufactured; and finally, the casing pipe conductors are welded. The inner and outer walls of the oil pipe or the outer wall of the oil pipe can be protected according to requirements, and meanwhile, the inner wall of the casing pipe can be protected.

Description

technical field [0001] The invention relates to the technical field of anticorrosion of oilfield production systems, in particular to a cathodic protection device for protecting the inner walls of oil pipes and casings for corrosion control of the inner and outer walls of oil wells and water injection wells in oilfield production systems and a manufacturing method thereof. Background technique [0002] In the oilfield production system, with the extension of oilfield development time, the water content of the oil well output fluid continues to rise. Due to the high salinity of the separated water of the output fluid, which contains a large amount of carbon dioxide and hydrogen sulfide, a certain amount of bacteria will cause the output fluid medium to affect the oil well. The inner walls of oil pipes and casings are severely corroded; for water injection wells, because the sewage injected comes from oil wells, the sewage has the same corrosiveness as oil wells. The annular s...

AI Technical Summary

Problems solved by technology

[0002] In the oilfield production system, with the extension of the oilfield development time, the water content of the oil well output fluid continues to rise. Due to the high salinity of the separated water of the output fluid, it contains a large amount of carbon dioxide and hydrogen sulfide, and a certain amount of bacteria causes the output fluid medium to affect the oil well. The inner walls of oil pipes and casings are severely corroded; for water injection wells, because the sewage injected comes from oil wells, the sewage has the same corrosiveness as oil wells. The annular space of the water well is a dead water area. The reproduction and proliferation of bacteria is more serious than that of the oil well, which leads to the deterioration of the water quality in the annular space of the water injection well, and causes serious corrosion to the outer wall of the tubing and the inner wall of the casing.

[0003] At present, the sacrificial anode protection technology adopted for the corrosion control of oil well and water injection well casing can not protect the inner wall of oil well or water injection well, can not protect the inner wall of casing of oil well or water injection well, but can only protect the outer wall of oil pipe

Therefore, in the production process of the oil field, the internal corrosion of the tubing will lead to the perforation and breakage of the tubing, the corrosion of the inner wall of the casing will lead to a decrease in the strength of the casing, the deformation and dislocation of the casing, and the perforation of the casing, resulting in the operation and overhaul of the oil well and water injection well, or even scrapping , the economic loss is heavy, and at the same time, it also affects the normal production of the oil field, resulting in a decline in crude oil production in the oil field and a reduction in economic benefits, etc.

Images