The Studies On Ground Supporting Technology For Gas Flooding Of Tahe Oil Field

Gas flooding oil recovery technology,which has more than 80 years of history,is one of the methods for enhancing oil recovery.Initially it mainly applies LPG injection and later dry gas injection.Among those methods,nitrogen injection technology in oil field exploitation has become a mature and effective tertiary recovery method,which has great value in application and popularization.Using air to produce nitrogen is an essential part in oilfield nitrogen flooding,which needs to determine the most economical nitrogen production and injection in accordance withdifferent reservoir characteristics,size and the surrounding conditions,so as to obtain maximum economic benefits.Therefore,based on gas injection development of Tahe Oilfield,this thesisworked out different scales of nitrogen production and injection technology schemes for different stages of nitrogen flooding,completed evaluation on the investment and cost,got the best technology,so as to achieve maximum benefit.In addition,when using nitrogen flooding,part of nitrogen will return to the ground along with produced gas,resulting in high nitrogen content in produced gas.It must be processed based on the requirements of environmental protection and produced gas utilization.This thesisundertook technical feasibility analysis for different nitrogen removal technologies in gas and provided economical and feasible scheme of nitrogenous associated gas processing technology.In addition,excessive emissions of greenhouse gases will cause worldwide temperature change,so reducing CO₂ emissionhas become an important task.As a superior oil displacing agent,CO₂ can also be injected into reservoir to enhance oil recovery.Using CO₂ collected from industrial productionemission in oil recoverycan obtain not only economic benefits,but also good environmental benefits from carbon reduction emission.In view of this,this thesis also conducted an investigation on surrounding CO₂ source of Tahe Oilfield,and selected preferable CO₂collection technology schemes depending on different characteristics of gas source,and obtained project investment and collection,providing gas source technical support for CO₂ flooding pilot test to be launched in Tahe Oilfield.