塔河油田高压注氮气对沥青质沉积的影响

Influence of Gas Injection under High Pressure on Asphalt Deposition in Tahe Oilfield

张公社 何梦莹 汪伟英 柯文丽 袁肖肖 孙晨祥

ZHANG Gongshe HE Mengying WANG Weiying KE Wenli YUAN Xiaoxiao SUN Chenxiang

针对塔河油田注 N2提高采收率中可能发生沥青质沉积伤害储层的问题， 通过注气相态分析和黏度测试分析了注 N2对原油组分、 性质的影响， 采用岩心驱替装置通过注气吞吐沥青质沉积实验研究了注 N2对储层渗透率的影响， 以裂缝性岩心缝宽为指标评价了沥青质沉积对储层的伤害程度， 提出了减少沥青质沉积的措施。研究结果表明， 注 N2吞吐会破坏原油的原有平衡状态， 使油中重质组分含量增加， 轻质组分减小， 原油黏度增大； 注气轮次、 裂缝宽度和生产井井底流压均会影响沥青质的沉积程度， 井底流压高于饱和压力时沥青沉降情况不明显，井底流压低于饱和压力时沥青质沉积程度增大。在现场注气生产中应保持合理的生产压差预防沥青质沉积， 选择合适的化学解堵剂有效解除沥青质堵塞。图 2表 2参 13

During N2 injection process in Tahe Oilfield to enhance oil recovery，asphalt deposition may occur and cause reservoir damage problem. To solve this problem，through gas injection phase analysis test and viscosity test，the influence of N2 injection on crude oil composition and property was analyzed，the influence of the N2 injection on the permeability of reservoir was studied through gas injection huff and puff asphalt deposition experiment with core flow device，the degree of reservoir damage was evaluated by the index of fracture width，and the measures of reducing the deposition of asphalt were put forward. Experimental results showed that N2 huff and puff would destroy the original balance state of crude oil，increasing heavy component content in oil，decreasing light component，thus increasing viscosity of crude oil. The asphalt precipitation degree would be influenced by gas injection rounds，crack width and well bottom hole flowing pressure. The asphalt deposition was not obvious when the bottom hole flowing pressure was higher than the saturation pressure，while there were more asphalt depositions when that was lower than saturation pressure. It was suggested that the reasonable production differential pressure should be maintained to prevent the asphalt deposition in the field of gas injection production，and suitable chemical plugging agent could effectively relieve the asphalt precipitation. During N2 injection process in Tahe Oilfield to enhance oil recovery，asphalt deposition may occur and cause reservoir damage problem. To solve this problem，through gas injection phase analysis test and viscosity test，the influence of N2 injection on crude oil composition and property was analyzed，the influence of the N2 injection on the permeability of reservoir was studied through gas injection huff and puff asphalt deposition experiment with core flow device，the degree of reservoir damage was evaluated by the index of fracture width，and the measures of reducing the deposition of asphalt were put forward. Experimental results showed that N2 huff and puff would destroy the original balance state of crude oil，increasing heavy component content in oil，decreasing light component，thus increasing viscosity of crude oil. The asphalt precipitation degree would be influenced by gas injection rounds，crack width and well bottom hole flowing pressure. The asphalt deposition was not obvious when the bottom hole flowing pressure was higher than the saturation pressure，while there were more asphalt depositions when that was lower than saturation pressure. It was suggested that the reasonable production differential pressure should be maintained to prevent the asphalt deposition in the field of gas injection production，and suitable chemical plugging agent could effectively relieve the asphalt precipitation.During N2 injection process in Tahe Oilfield to enhance oil recovery，asphalt deposition may occur and cause reservoir damage problem. To solve this problem，through gas injection phase analysis test and viscosity test，the influence of N2 injection on crude oil composition and property was analyzed，the influence of the N2 injection on the permeability of reservoir was studied through gas injection huff and puff asphalt deposition experiment with core flow device，the degree of reservoir damage was evaluated by the index of fracture width，and the measures of reducing the deposition of asphalt were put forward. Experimental results showed that N2 huff and puff would destroy the original balance state of crude oil，increasing heavy component content in oil，decreasing light component，thus increasing viscosity of crude oil. The asphalt precipitation degree would be influenced by gas injection rounds，crack width and well bottom hole flowing pressure. The asphalt deposition was not obvious when the bottom hole flowing pressure was higher than the saturation pressure，while there were more asphalt depositions when that was lower than saturation pressure. It was suggested that the reasonable production differential pressure should be maintained to prevent the asphalt deposition in the field of gas injection production，and suitable chemical plugging agent could effectively relieve the asphalt precipitation.

10.19346./j.cnki.1000-4092.2017.03.019