Anti-pollution back pressure valve tool

Abstract

The invention discloses an anti-pollution back pressure valve tool, comprising a valve body; the valve body is provided with a cavity which runs through along the axial direction of the valve body and is capable of passing through a thermal fluid column, and the bottom of the valve body is further provided with a plate valve which is capable of elastically sealing the cavity. In the invention, by arranging a back pressure valve which is capable of elastically sealing, when the thermal fluid column is inserted into the valve body, the plate valve is pushed open by the thermal fluid column, and the thermal fluid column is further inserted into a heat injection heavy oil reservoir at the lower part of the back pressure valve, thus thermal fluid is injected into the heavy oil reservoir for soaking and can be pumped out of the thermal fluid column without blow-out or kick-killing. At the moment, the plate valve restores elastically to seal the cavity, and high pressure thermal fluid at the heavy oil reservoir is sealed by the invention. When mining is needed, corresponding oil pipe is inserted for mining. After the back pressure valve structure of the invention is adopted, blow-out and kick-killing operations are not needed, thus avoiding the pollution to the oil reservoir and greatly improving the safety of the operations.

Description

technical field [0001] The invention relates to an anti-pollution back pressure valve tool used for oil recovery of heavy oil wells in the sea. Background technique [0002] In heavy oil wells in offshore oilfields, the method of injecting hot fluid (such as steam or hot water) is mainly used to reduce the viscosity of heavy oil in the formation by increasing the temperature of heavy oil in the formation, change the flow capacity of heavy oil in the formation, and improve crude oil recovery. yield purposes. [0003] In the past, in the process of injecting thermal fluid huff and puff into heavy oil wells in oilfields, there were mainly problems: 1. After injecting thermal fluid into the well and basking in the well, the formation fluid pressure of the heavy oil layer injected with thermal fluid was relatively high, and it took a long time For blowout and well killing operations, it is necessary to wait for the pressure of the formation fluid to drop before pulling out the h...

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Problems solved by technology

[0003] In the past, in the process of injecting thermal fluid huff and puff into heavy oil wells in oilfields, there were mainly problems: 1. After injecting thermal fluid into the well and basking in the well, the formation fluid pressure of the heavy oil layer injected with thermal fluid was relatively high, and it took a long time For blowout and well killing operations, it is necessary to wait for the pressure of the formation fluid to drop before pulling out the hot fluid injection string; As far as the oil layer is concerned, the killing fluid will cause a large amount of heat loss and cause cold damage (that is, pollute the heavy oil layer), which will seriously affect the thermal recovery effect of the heavy oil layer after injecting the hot fluid; There is still a relatively high fluid (crude oil, water) pressure in the formation of the oil reservoir, that is, a relatively high back pressure. This back pressure is an unsafe factor once a control error occurs during the extraction and injection of the hot fluid string. Certain hidden dangers of safety accidents

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