A method for comprehensive utilization of oilfield associated gas

Abstract

The invention provides a method for comprehensive utilization of oilfield associated gas, including three sections of condensate oil preparation, hydrocarbon separation, and product recovery, and adopts the method of "step-by-step boosting of liquefied product separation + step-by-step drying and dehydration" for associated gas in oilfields method. Step-by-step pressurization liquefaction, one-stage pressurization to separate components above C2+; two-stage pressurization to separate CO 2 and methane; three-stage pressurized liquefied methane gas to produce LNG products. Step-by-step drying and dehydration, the associated gas from the imported gathering and transportation pipeline is first separated by pressurized dehydration to separate most of C5 and C5+, and then dehydrated and dried to a dew point of ‑100°C to separate C2 and C2+, CO 2 , and finally undergo three-stage dehydration and drying to a dew point of -180°C for natural gas liquefaction. The invention minimizes process energy consumption, can realize product diversification, and product transportation is not restricted by the surrounding conditions of the oil field, has high environmental protection and economic benefits, and realizes comprehensive and efficient utilization of associated gas in the oil field.

Description

technical field [0001] The invention belongs to the technical field of oilfield gas recovery and separation, and in particular relates to a comprehensive utilization method of oilfield associated gas. Background technique [0002] Oilfield associated gas, also known as oilfield gas, is a gas that escapes from oil wells. Its main components are low molecular alkanes such as methane (C1) and ethane (C2), and a certain amount of propane (C3), butane alkanes (C4) and pentanes (C5) and above heavy components (C5+), and acid gases such as H 2 S and CO 2 , the acid gas concentration varies in different oilfields. [0003] Such as figure 1 As shown, the typical route of the existing oilfield associated gas recovery technology can be summarized as follows: the wellhead associated gas enters the pressurization unit after pretreatment to remove sand and water; the condensate produced during the pressurization process enters the heavy hydrocarbon stabilization unit, and the produced ...

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Problems solved by technology

[0009] 2. The normal pressure boiling point of the lean gas after the separation of heavy hydrocarbons in the above process is too low, for example, the normal pressure boiling point of C1 is about -160°C, so it is difficult to liquefy or transport under high pressure, and its lean gas products are restricted by the surrounding power plants or long-distance pipeline network Or CNG tanker, transportation is difficult

[0010] 3. When the CO contained in the oilfield associated gas 2 H 2 In case of S, when the alcohol amine absorption method or membrane separation or pressure swing adsorption deacidification is used, the H in the acid gas produced 2 S concentration is too low for sulfur treatment by Claus process

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