Sealed canister for vacuum-desorbing physically-adsorbed hydrocarbon in soil

Abstract

The invention provides a sealed canister for vacuum-desorbing physically-adsorbed hydrocarbon in soil, belonging to oil / gas exploration field in petroleum geology. The canister includes a canister body, an end cover, and a piston mobile degassing assembly. The end cover is detachably fixed at one end of the canister body. The piston mobile degassing assembly is fixed at the other end of the canister body, and used for changing volume of the sealed canister to realize interior gas pressure rise / fall, thereby realizing the objective of desorbing physically-adsorbed gas in soil sample in the canister and pumping gas under positive pressure. The canister provided by the invention is used to extract physically-adsorbed hydrocarbon in soil sample in manner of total sealing, vacuum degassing by moving piston, and pumping under positive pressure; and has the advantages of high sealability and degassing degree, simple operation, convenient carriage, suitability for batch sample test, shortened sample analysis time and period, and improved efficiency. Meanwhile, cylinder of the canister is marked with volumetric scale, to realize direct and quantitative sampling in the field, avoid sample gas loss due to secondary operation, and guarantee consistent sample size.

Description

technical field [0001] The invention belongs to the field of oil and gas exploration in petroleum geology, and in particular relates to a vacuum desorption sealed tank for soil physical adsorption of hydrocarbons. Background technique [0002] The degassing technology of physical adsorption gas currently used in geochemical exploration is mainly to desorb and release the gas adsorbed on the surface of solid particles into the container through vacuuming and heating technology, usually in the laboratory, where the experimental samples are isolated in advance. Use a vacuum pump to pump out the gas in the experimental device, and then connect to the container containing the sample to create a negative pressure condition to desorb the adsorbed gas. [0003] Light hydrocarbons in oil and gas reservoirs can leak into the surface soil approximately vertically in a weak but detectable amount, which is the theoretical basis for oil and gas geochemical exploration. In the near-surfac...

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Problems solved by technology

[0010] 1. The patent No. CN1308678C discloses a low-temperature desorption device and method for soil adsorbed hydrocarbons. Its disadvantages are: (1) high temperature and negative pressure act at the same time, and the degassing effect is good, but at the same time, water vapor will be mixed into the gas. Increased analysis error; (2) repeated operation of the sample will lead to gas leakage, resulting in human error; (3) complex operation of the equipment, suitable for analysis experiments of a small number of samples under laboratory conditions

[0015] 6. The patent No. US2010 / 0078435A1 discloses Seal jar1. The core technology is to divide a tank into multiple closed spaces, and different items can be placed separately, which solves the problem of using multiple tanks to occupy too much space

[0016] In short, there are many problems in the prior art. They are either low in desorption or complicated in operation, and are only suitable for degassing experiments of a small amount of samples under laboratory conditions.

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