CO2驱产出气回注的驱油效果  

OIL DISPLACED EFFECTS OF THE PRODUCED GAS REINJECTION FOR CO2 FLOODING

作　　者：殷丹丹[1,2] 李宜强[1,2] 赵东锋[2] 

机构地区：[1]中国石油大学提高采收率研究院,北京102249 [2]中国石油大学石油工程教育部重点实验室,北京102249

出　　处：《大庆石油地质与开发》2014年第2期137-140,共4页Petroleum Geology & Oilfield Development in Daqing

基　　金：国家科技支撑计划项目(2012BAC26B05)

摘　　要：CO2驱的后期有大量气体突破,将产出的气体收集后回注油层可提高经济效益,但产出气中混有的烃类和氮气对地层原油相态和驱油效果有一定影响.因此,分析了吉林油田产出气在原油中的溶解量和降低原油黏度的程度;采用细管实验法确定了不同组成的产出气与原油的最小混相压力,并分析了不同气体对最小混相压力的影响;通过长岩心注气实验分析了不同气体对驱替过程的影响.研究结果表明：产出气中氮气和甲烷在原油中的溶解量较小,不利于降黏;最小混相压力随氮气和甲烷摩尔分数的增加而增加;氮气和甲烷含量较大时会使气体过早突破而使抽提原油的效果差且驱油效率低;CO2含量高的产出气回注后可获得较高的驱油效率.A large amount of the gas will break though at the late stage of CO2 flooding, the reinjection of the col- lected produced gas can raise the economy benefit, the contained hydrocarbon and nitrogen will affect the phase behaviors and displacement effects of the crude oil. the produced gas solubility and reduced degree of the oil viscosi- ty for Jilin Oilfield are analyzed; by the slim-tube test, the produced gas with different compositions and the crude oil MMP are determined; different gases influences on the pressure are analyzed; by long-core gas injection exper- iment, different gases effects on the flooding process are figured out. The study results show that there are smaller account of solutions of nitrogen and methane in the crude oil, thus the viscosity reduction is not easy to be realized ; the MMP rises with the increases of the nitrogen and the mole fractions of the methane ; when the contents of the a- bove two gases are rather higher, the gases are prone to break through too early and result in the poorer effect of the crude oil extraction and lower oil flooded efficiency ; after the reinjection with high-content CO2, the pretty higher oil flooded efficiency can be obtained.

关 键 词：CO2驱产出气 相态分析 最小混相压力 长岩心实验 

分 类 号：TE353[石油与天然气工程—油气田开发工程]