渗透率对低渗油藏CO_2驱气窜的影响规律研究  

A Study About Influence Law of Permeability on Gas Channeling of CO_2 Flooding Under Low Permeability Reservoirs

作　　者：杨大庆[1] 尚庆华 江绍静 黄春霞 汤瑞佳 

机构地区：[1]西南石油大学石油与天然气工程学院,四川成都610500 [2]陕西延长石油(集团)有限责任公司研究院,陕西西安710075

出　　处：《西南石油大学学报（自然科学版）》2014年第4期137-141,共5页Journal of Southwest Petroleum University(Science & Technology Edition)

基　　金：国家科技支撑计划"陕北煤化工CO2捕集;埋存与提高采收率技术示范"(2012BAC26B00)

摘　　要：为了确定低渗透油藏渗透率对CO2驱油过程气窜的影响规律,为延长油田筛选理想的油藏开展CO2驱矿场试验,通过室内实验研究了不同渗透率岩芯驱替下见气时间、气窜时间、扩散速度及不同阶段采收率的变化特点。实验结果表明:扩散速度随渗透率的增加而增加,见气时间和气窜时间随岩芯渗透率的增加而缩短,且当渗透率增加到某一值(本实验为10 mD左右)后,见气时间和气窜时间几乎都降为0。见气采收率随渗透率的增加而降低;渗透率在某一范围值内,气窜采收率和最终采收率随渗透率的增加先降低后缓幅上升。低渗透油藏CO2驱见气后仍有大幅的提高采收率空间,大量原油主要在见气后至气窜前采出。而且,一旦发生气窜,采收率进一步提高的幅度将非常有限。In order to determine the influence law of permeability on CO2 flooding gas channeling in low permeability reservoirs, so as to screen suitable reservoirs for CO2 flooding experiment at Yanchang Oilfield, this paper has studied the characteristics of gas breakthrough time, gas channeling time, diffusion speed and changes of recovery at different stages under different permeability through laboratory experiment in combination with the actual mine conditions. Results show that the diffusion velocity increases with permeability, and gas breakthrough time and gas channeling time shorten with the increase of core permeability, and when permeability increases to a certain value（the value of this experiment is about 10 mD）, breakthrough time and gas channeling time almost reduced to zero. The recovery when gas breakthrough decreases with increasing permeability. When permeability was within a certain range, gas channeling recovery and ultimate recovery first decrease with the increase of permeability, then rise slowly. There is significant space for recovery improvement after gas breakthrough of CO2 flooding in low permeability reservoirs, and huge quantities of crude oil is produced mainly after gas breakthrough and before channeling. But in the event of gas channeling, further recovery improvement will be extremely limited.

关 键 词：低渗透油藏 渗透率 CO2驱 见气时间 气窜时间 采收率 

分 类 号：TE341[石油与天然气工程—油气田开发工程]