Study Of Low Pressure Oil Field Gas Gathering And Light Hydrocarbon Recovery Process

Oil field gas is one kind of energy depositing in stratum profundity with crude oil. At present most oil fields don't reclaim and make use of the energy effectively in the world and discharge and burn directly instead which cause serious environmental pollutio-n. With the intension on the rectification of environmental pollution and energy waste, reclaiming and making good use of the energy are of top priority and become an inevit-able trend of energy development enduringly in the homeland. Therefore, the study of oi-l fieid gas reclaiming is of great real significance.The data about component, gathering and transportation process, purification process and NGL reclaiming process of oil field gas were studied and collected. The gathering, t-ransportation and purification process for low pressure gas were proposed associated wit-h characteristic of oil field gas and the principle of choosing purification process was su-mmed up.The gas gathering and transportation processes for low pressure gas were proposed r-espectively for high and low pressure gas existing together and only low pressure gas b-ased on the the current situation of gas gathering and transportation process for low pre-ssure gas. Through analysis it was found that natural gas injector can be used in gas ga-thering and transportation process for and it provides a new way for low pressure gas.Based on the analysis of NGL reclaiming process, detailed simulation analysis of N-GL reclaiming process of typical oil field gas(its pressure is lower than transporting pres-sure and proper separation pressure) was made on the international famous chemical sim-ulating software HYSYS. Interrelation among parameters of process was studied and prop-er separation pressure and temperature were determined and propane recovery coefficient mathematic model was built.At the same time, thermodynamics exergie was introuduced into appraisal of NGL r-eclaiming device. Exergie analysis was carried out through gray box model and the we-akest part of NGL reclaiming device was found. And respective exergie analysis of refri-geration system and heat exchange system which are the most important systems in the NGL reclaiming system was carried out through gray box model and white box model a-nd main resources of exergie lose were found and corresponding improvement measures were brought forward.The conclusions of gas gathering and transportation processes and NGL reclaiming p-rocess for low pressure gas and exergie analysis are of guiding significance for reclaimi-ng process of oil fiels gas. And exergie can be introuduced into other fields of natural g-as process and it provides a new method for energy consumption evaluation natural gas process devices.