Oilfield associated gas complete liquefaction recovery system and method thereof

Abstract

The invention discloses an oilfield associated gas complete liquefaction recovery system and a method thereof. The system comprises, sequentially connected, an associated gas pretreatment apparatus, a heat regenerator, a first condenser, a gas-liquid separation device, a throttle valve, a second condenser, an LNG storage tank and a regulating valve, the associated gas pretreatment apparatus comprises, sequentially connected, an oil removal device, a dedusting purification device, an acidic gas removal device, a hydration device and a nitrogen adsorption and separation device, the light hydrocarbon outlet of the heat regenerator is connected with the regulating valve, and the lower portion of the gas-liquid separation device is connected with the light hydrocarbon inlet of the heat regenerator. Separating recovery of light hydrocarbons in the oilfield associated gas and liquefaction of natural gas are simultaneously realized by using cold energy provided with above two stage condensing heat exchange devices. The system and the method have the advantages of solving of the recovery problem of remote region oil and gas wellhead associated gas, convenient operation, low cost, high resource recovery rate, no pollution, realization of zero discharge in the oilfield oil extraction process, and obvious resource saving and environment protection effects.

Description

technical field [0001] The field of the invention belongs to the field of petrochemical industry, energy conservation and environmental protection, and in particular relates to a full liquefaction recovery system and method for oilfield associated gas. Background technique [0002] Petroleum-associated gas is a combustible mixture composed of low-molecular saturated hydrocarbon-based hydrocarbon gas and a small amount of non-hydrocarbon gas in the subsurface porous formation, and it is often associated with crude oil. Most of the petroleum-associated gas components are mainly methane, including ethane, propane, butane, pentane and other hydrocarbons, and a small amount of nitrogen, carbon dioxide, hydrogen sulfide, helium, oxygen, hydrogen and other gases. [0003] my country is a developing country, and the full utilization and recovery of associated gas resources in oilfields is of great significance to my country's economic and social development and environmental protect...

AI Technical Summary

Problems solved by technology

In the existing oilfield associated gas recovery methods, ammonia refrigeration, expander refrigeration or mixed working fluid refrigeration are basically used to provide cooling capacity to separate and produce light hydrocarbons, liquefied gas and dry gas. The equipment is huge, the investment cost is relatively high, and it is not suitable for Recycling of associated gas with a small amount of gas in a single well, and oil and gas fields in remote areas without pipeline networks

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