A back pressure valve for ultra-high pressure and high temperature experiments

Abstract

The invention discloses an ultrahigh-pressure high-temperature experimental back-pressure valve which mainly comprises an upper valve body, a lower valve body, an ultrahigh-pressure gas chamber, an alloy diaphragm, a horizontal fluid channel, a vertical fluid channel, a central hole and a valve needle. The alloy diaphragm 4 is located between the upper valve body 1 and the lower valve body 1 and forms a multistage combined soft seal 10 with the upper valve body and the lower valve body, the ultrahigh-pressure gas chamber 3 is located in the upper valve body and is connected with a back-pressure pipeline end 9, and a through hole 11 is formed between the ultrahigh-pressure gas chamber and the horizontal fluid channel 5; the central hole 7 is formed in the intersection point of the horizontal fluid channel 5 and the vertical fluid channel 6 which are located in the lower valve body, the central hole extends upwards to the ultrahigh-pressure gas chamber, the valve needle 8 is located in the central hole, the top of the valve needle is machined into a first threaded rod 15, the needle tip of the valve needle 8 is sealed in a sealing pad 14 at the tail end of the central hole 7, and the central hole moves downwards to be connected to a sample line end 12. The ultrahigh-pressure high-temperature experimental back-pressure valve is high in sealing performance, high in pressure control, high in stability and free of dead volume, and the gap in the prior art is filled up.

Description

technical field [0001] The invention relates to a back pressure valve for ultra-high pressure and high temperature experiments used in various indoor core displacement experiments during oil and gas exploitation. Background technique [0002] The core displacement test is the main evaluation technique for enhancing oil recovery in the process of oil and gas exploitation, and it is a scientific research on the recovery of oil and gas in core pores under formation (temperature, pressure) conditions. Stable and precise control of the formation pressure during the experiment is the key to the experiment. The deeper the well, the higher the formation pressure and temperature. At present, oil and gas reservoirs with ultra-high temperature and high pressure are constantly being discovered. The formation pressure of such oil and gas reservoirs exceeds 100MPa, and the formation temperature is above 160°C. This puts forward higher requirements for the sealing of various experimental ...

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Problems solved by technology

Although the ultra-high pressure experimental device or floating piston back pressure device currently developed has reliable sealing conditions and high pressure control accuracy, it cannot solve the problem of dead volume between the piston valve needle and the end face of the ultra-high pressure cylinder, which has a negative impact on the experimental results. Reliability has a big impact

Although a back pressure displacement device with high precision and no dead volume has been developed in China, its pressure control range is limited, and it cannot meet the displacement experiments above 70 MPa, and it cannot be used for displacement experiments under ultra-high pressure and high temperature conditions. pressure control

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