Separator and self-airlifting method for eliminating plug flow on serious segments by utilizing same

Abstract

A separator and its self-gas-lift method for eliminating severe slug flow. The separator includes a shell, which is connected with an incoming flow pipe and an air outlet pipe. A liquid level sensor and a pressure sensor are arranged on the shell. There is an ascending pipe extending to the bottom of the shell, and a control valve is arranged on the air outlet pipe close to the outlet of the shell, and the air outlet pipe communicates with the ascending pipe outside the shell. The separator of the present invention is installed at the junction of the gas-liquid mixed pipeline and the rising pipe, and the opening of the control valve is adjusted by controlling the liquid level signal and the pressure signal, so that the liquid level and pressure are stable, and the gas and liquid are in the separator. After separation, the liquid enters the riser, the gas enters the riser through the control valve through the outlet pipe, and the gas and liquid are mixed in the riser and then flow out into the onshore platform device. The invention has a simple structure, and can conveniently and accurately control the flow of gas and liquid to achieve the purpose of eliminating severe slug flow.

Description

technical field [0001] The invention relates to a separator and a method for eliminating severe slug flow by using the same, in particular to a separator for oil-gas mixed transportation and a seabed separation self-gas lift method for eliminating serious slug flow by using the same. Background technique [0002] In offshore oil exploitation, it is often encountered that gas and liquid are transported at the same time. When the multi-phase gathering and transportation pipeline on the seabed reaches the offshore platform or onshore processing facility, it needs to be connected with the riser. Under certain conditions, the gathering and transportation pipeline and A detrimental flow pattern known as severe slug can occur in systems consisting of risers. This flow pattern will produce a liquid plug several times the height of the riser, which will cause periodic changes in the pressure in the gathering pipeline, thereby affecting the wellhead pressure, and will also cause the g...

AI Technical Summary

Problems solved by technology

This flow pattern will produce a liquid plug several times the height of the riser, which will cause periodic changes in the pressure in the gathering pipeline, thereby affecting the wellhead pressure, and will also cause the gas and liquid to flow out intermittently at the outlet of the riser, causing the gas to spray at a high speed in a short period of time. out, causing the outlet liquid plug to enter the separator at high speed, and the severe slug flow phenomenon brings many problems to the design and production

As production facilities had to be scaled up, some separators were rated far greater than the actual liquid handling capacity, resulting in waste, and severe flow fluctuations also made it difficult to control separators and downstream processing facilities, sometimes even causing production interruptions

[0003] British patent GB2374161A "Gas injection controlling liquid slugs in pipelineriser" (publication date: October 9, 2002), announced a serious slug flow control method of gas injection at the bottom of the riser, which requires a large amount of gas injection to Completely eliminate severe slug flow, and can only weaken severe slug flow when the amount of gas injection is small, and the equipment investment and space requirements such as compressor units required for gas injection often limit the application of this method, and sometimes there is not enough on-site Gas source

U.S. Patent No. 5,478,504 "Method and apparatus for eliminating severe slug in multi-phase flow subsea lines" (publication date: December 26, 1995) discloses the use of the second riser to lead out the gas from the lower pipe before the main riser and then Injection into the main riser to control severe slug flow. This method also provides several schemes to control the gas flow by using pressure, differential pressure or density. However, the height of the pipe section under this method is small, and the flow is not easy to control accurately

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