低渗和特低渗油层CO2-N2复合驱研究  

Carbon Dioxide-nitrogen Compound Flooding in Low Permeability and Ultra-low Permeability Layer

作　　者：陈涛平[1] 毕佳琪 赵斌 孙文 CHEN Tao-ping;BI Jia-qi;ZHAO Bin;SUN Wen(Enhanced Oil and Gas Recovery Key Laboratory of Ministry of Education,Northeast Petroleum University,Daqing 163318,China;Petrochina north China oilfield branch,Renqiu 062552,China)

机构地区：[1]东北石油大学提高油气采收率教育部重点实验室,大庆163318 [2]中国石油华北油田公司采油三厂,河间062450

出　　处：《科学技术与工程》2020年第27期11067-11073,共7页Science Technology and Engineering

基　　金：国家科技重大专项(2017ZX05009-004)。

摘　　要：针对低渗、特低渗油层CO 2-N 2复合驱提高采收率,以大庆外围YS油田的特低渗透油层为背景,进行了数值模拟和物理模拟两方面的研究。利用CMG油藏数值模拟软件GEM模块,建立了一维长细管、均质、非均质理想模型及五点法井网单元模型,分别对CO 2-N 2复合驱的驱油方式、影响因素、五点法井网单元模型下的段塞组成进行了模拟计算及分析。与此同时,在室内分别选用30 cm长的低渗透、特低渗透天然岩心,各进行了5种不同驱替方案的实验研究,确定了CO 2-N 2复合中CO 2合理段塞尺寸及驱油效果,验证了数值模拟计算的可靠性。研究结果表明,低渗、特低渗透油层CO 2-N 2复合驱不宜采用CO 2与N 2混合驱方式,而应采用一次注入合理的CO 2段塞(约0.3 PV)+N 2的段塞组合驱方式,这样不仅可以减少CO 2用量,而且可以充分发挥CO 2与N 2各自的优势,获得优于全部注CO 2驱的驱油效果;且油层渗透率越低、渗透率级差越小或长厚比越大,越有利于提高CO 2-N 2复合驱采收率;厚度小于井距1%的油层也有利于CO 2-N 2复合驱提高采收率。To the enhance oil recovery of CO 2-N 2 compound flooding in low to ultra-low permeability layer,the ultra-low permeability layer in Daqing YS oil field was taken as the research target,for which numerical and physical simulations were performed.Using the GEM model of CMG reservoir numerical simulation software,a one-dimensional long slim tube,homogeneous or non-homogeneous ideal model,and five-spot well pattern element model were built.The slug compositions of the CO 2-N 2 compound flooding,the impact factor,and the five-spot well pattern element model were calculated and analyzed.Meanwhile,30-cm long natural cores of low and ultra-low permeability were selected and tested in five different experimental flooding ways,from which the suitable size of carbon dioxide slug and flooding effect in CO 2-N 2 compound flooding was determined.In addition,the experimental results prove that the numerical calculated results are reliable.Results also suggest that in low and ultra-low permeability layers,CO 2-N 2 compound flooding is not a suitable way but one-time reasonable CO 2 injection of slug in size of about 0.3 PV plus nitrogen is a better flooding way,by which the CO 2 dosage could be reduced,the respective advantage of carbon dioxide and nitrogen could be fully displayed,and a better effect than that of CO 2 flooding.For low and ultra-low permeability layers,the lower the permeability,or the smaller the permeability ratio,or the greater the length-thickness ratio is,the more favorable it is for CO 2-N 2 compound flooding;when the layer thickness is<1%of the well spacing,it is also suitable to adapt this method.

关 键 词：低渗透油层 特低渗透油层 二氧化碳驱油 氮气驱油 提高采收率 

分 类 号：TE348[石油与天然气工程—油气田开发工程]