CO2乳(ru)(ru)液(ye)在驅油過程中能(neng)夠有(you)效控制CO2流(liu)(liu)度，大幅改善(shan)CO2驅油效果(guo)(guo)，提高(gao)采收(shou)率。選擇AOT作為CO2乳(ru)(ru)液(ye)用表(biao)面(mian)(mian)(mian)活性(xing)(xing)(xing)劑(ji)，通(tong)(tong)過TRACKER-H界(jie)(jie)(jie)(jie)面(mian)(mian)(mian)流(liu)(liu)變(bian)儀測定AOT水溶(rong)液(ye)與(yu)CO2體(ti)(ti)系(xi)在不同(tong)溫(wen)度壓(ya)力(li)(li)(li)條件下的界(jie)(jie)(jie)(jie)面(mian)(mian)(mian)特(te)(te)性(xing)(xing)(xing)，通(tong)(tong)過巖心實驗測定不同(tong)溫(wen)度壓(ya)力(li)(li)(li)條件下CO2乳(ru)(ru)液(ye)的封(feng)(feng)(feng)堵(du)和(he)調(diao)剖(pou)分流(liu)(liu)效果(guo)(guo)。結(jie)果(guo)(guo)表(biao)明:隨(sui)著壓(ya)力(li)(li)(li)的增(zeng)大，CO2乳(ru)(ru)液(ye)界(jie)(jie)(jie)(jie)面(mian)(mian)(mian)張力(li)(li)(li)隨(sui)之降低，界(jie)(jie)(jie)(jie)面(mian)(mian)(mian)黏彈性(xing)(xing)(xing)隨(sui)之增(zeng)大;隨(sui)著溫(wen)度的增(zeng)加(jia)，CO2乳(ru)(ru)液(ye)界(jie)(jie)(jie)(jie)面(mian)(mian)(mian)張力(li)(li)(li)增(zeng)加(jia)，界(jie)(jie)(jie)(jie)面(mian)(mian)(mian)黏彈性(xing)(xing)(xing)降低;溫(wen)度越(yue)(yue)(yue)高(gao)越(yue)(yue)(yue)不利于乳(ru)(ru)液(ye)的封(feng)(feng)(feng)堵(du)，壓(ya)力(li)(li)(li)越(yue)(yue)(yue)高(gao)越(yue)(yue)(yue)有(you)利于乳(ru)(ru)液(ye)的封(feng)(feng)(feng)堵(du)，這與(yu)體(ti)(ti)系(xi)界(jie)(jie)(jie)(jie)面(mian)(mian)(mian)特(te)(te)性(xing)(xing)(xing)研究所得的結(jie)果(guo)(guo)相對應，說明CO2乳(ru)(ru)液(ye)的封(feng)(feng)(feng)堵(du)效果(guo)(guo)與(yu)其(qi)(qi)界(jie)(jie)(jie)(jie)面(mian)(mian)(mian)特(te)(te)性(xing)(xing)(xing)有(you)關;溫(wen)度和(he)壓(ya)力(li)(li)(li)通(tong)(tong)過影響(xiang)CO2乳(ru)(ru)液(ye)的界(jie)(jie)(jie)(jie)面(mian)(mian)(mian)特(te)(te)性(xing)(xing)(xing)從(cong)而影響(xiang)其(qi)(qi)滲流(liu)(liu)特(te)(te)征，CO2乳(ru)(ru)液(ye)的強度越(yue)(yue)(yue)高(gao)、體(ti)(ti)系(xi)界(jie)(jie)(jie)(jie)面(mian)(mian)(mian)張力(li)(li)(li)越(yue)(yue)(yue)低、界(jie)(jie)(jie)(jie)面(mian)(mian)(mian)黏彈性(xing)(xing)(xing)越(yue)(yue)(yue)好(hao)，其(qi)(qi)分流(liu)(liu)效果(guo)(guo)也會越(yue)(yue)(yue)明顯。

在(zai)(zai)油藏(zang)條(tiao)件(jian)(jian)下，CO2一(yi)般(ban)處于超(chao)(chao)臨界(jie)狀態(31.26℃，7.38 MPa以上)，超(chao)(chao)臨界(jie)CO2密度(du)接近液(ye)(ye)體(ti)，與(yu)水(shui)溶液(ye)(ye)形成(cheng)的分散體(ti)系稱為乳液(ye)(ye)更為合(he)適，驅(qu)油過程(cheng)(cheng)中將超(chao)(chao)臨界(jie)CO2和表(biao)面(mian)(mian)活性(xing)(xing)劑水(shui)溶液(ye)(ye)形成(cheng)超(chao)(chao)臨界(jie)CO2乳液(ye)(ye)是控制(zhi)CO2流度(du)的有效(xiao)(xiao)方法，能夠(gou)大幅改善CO2驅(qu)油效(xiao)(xiao)果(guo)(guo)。在(zai)(zai)超(chao)(chao)臨界(jie)CO2乳液(ye)(ye)驅(qu)替(ti)過程(cheng)(cheng)中，CO2乳液(ye)(ye)的界(jie)面(mian)(mian)特性(xing)(xing)會直接影(ying)響其穩(wen)定(ding)性(xing)(xing)，從而影(ying)響CO2乳液(ye)(ye)在(zai)(zai)驅(qu)替(ti)過程(cheng)(cheng)中的封堵效(xiao)(xiao)果(guo)(guo)。目前，對CO2乳液(ye)(ye)的研究主要集中在(zai)(zai)反相微乳萃(cui)取分離、酶催化和納米(mi)材(cai)料(liao)制(zhi)備等方面(mian)(mian)。筆者通過實驗研究不同溫度(du)、壓(ya)力條(tiao)件(jian)(jian)下CO2乳液(ye)(ye)界(jie)面(mian)(mian)特性(xing)(xing)及其封堵效(xiao)(xiao)果(guo)(guo)。

1實驗

1.1實驗(yan)材(cai)料與儀器

主要實(shi)(shi)驗(yan)材料:選用(yong)2-(2-乙基己基)-磺酸琥珀(po)酸鈉(AOT)為(wei)表面(mian)活性(xing)劑;實(shi)(shi)驗(yan)用(yong)CO2純度為(wei)99.9%;實(shi)(shi)驗(yan)用(yong)水為(wei)蒸(zheng)餾水;實(shi)(shi)驗(yan)巖心為(wei)填(tian)砂管(guan)模型，規格(ge)參數:600 mm×Φ25 mm。表1、2所(suo)給出的回(hui)壓(ya)(ya)值即為(wei)巖心中流(liu)體所(suo)處的最低壓(ya)(ya)力，只(zhi)有(you)高于該(gai)回(hui)壓(ya)(ya)值，流(liu)體才可以流(liu)動。

表(biao)1單巖心實驗參數

表2并(bing)聯巖心實驗參數(shu)

主要實驗儀(yi)器:TRACKER-H型界面(mian)流變儀(yi)(法國TECLIS公司)，溫度(du)和(he)壓力上限分別為(wei)150℃和(he)25 MPa。

1.2實驗方法

1.2.1 CO2乳液界(jie)面(mian)性能(neng)實驗

利用TRACKER-H型界(jie)面(mian)流變(bian)儀測量(liang)不同溫度、壓力(li)條(tiao)件下CO2與(yu)表(biao)面(mian)活性劑(ji)水(shui)溶液的界(jie)面(mian)擴張模量(liang)(ε)，溫度為25～70℃，壓力(li)為2～12 MPa。

圖1界面張力實(shi)驗裝置(zhi)流程(cheng)

實驗(yan)流程如圖1所示。實驗(yan)步驟:①清洗注(zhu)射(she)器和高溫(wen)(wen)(wen)高壓(ya)(ya)容(rong)器;②測(ce)(ce)試高溫(wen)(wen)(wen)高壓(ya)(ya)系統密封性(xing);③將(jiang)(jiang)裝滿表面活(huo)性(xing)劑水溶(rong)液的(de)(de)注(zhu)射(she)器安裝在(zai)高溫(wen)(wen)(wen)高壓(ya)(ya)容(rong)器中，調(diao)節好可視窗位(wei)置，并(bing)(bing)用(yong)CO2氣體(ti)排空高溫(wen)(wen)(wen)高壓(ya)(ya)容(rong)器中的(de)(de)空氣;④將(jiang)(jiang)預先(xian)加壓(ya)(ya)的(de)(de)CO2氣體(ti)注(zhu)入到高溫(wen)(wen)(wen)高壓(ya)(ya)容(rong)器中并(bing)(bing)加溫(wen)(wen)(wen)2 h，待溫(wen)(wen)(wen)度壓(ya)(ya)力穩定后，驅動馬達，在(zai)注(zhu)射(she)器針尖上形成一個懸滴;⑤采用(yong)測(ce)(ce)量(liang)(liang)(liang)軟件對液滴與CO2界面擴張(zhang)模量(liang)(liang)(liang)進行測(ce)(ce)量(liang)(liang)(liang);⑥每個條(tiao)件下液滴的(de)(de)界面擴張(zhang)模量(liang)(liang)(liang)均測(ce)(ce)量(liang)(liang)(liang)3次，保證實驗(yan)有較好的(de)(de)重復性(xing);⑦導(dao)出數據并(bing)(bing)進行分(fen)析。

1.2.2 CO2乳液巖心(xin)封堵實驗

實(shi)(shi)驗(yan)(yan)(yan)步(bu)驟:①利用不同目(mu)數的石英砂填制(zhi)滲(shen)(shen)透(tou)率約為(wei)(wei)400×10-3μm2的填砂管模型，初測(ce)氣測(ce)滲(shen)(shen)透(tou)率，滿足要求后(hou)測(ce)定(ding)(ding)水(shui)測(ce)滲(shen)(shen)透(tou)率，測(ce)定(ding)(ding)滲(shen)(shen)透(tou)率為(wei)(wei)(350～450)×10-3μm2時合格，可進行下一步(bu)實(shi)(shi)驗(yan)(yan)(yan)，稱(cheng)(cheng)取(qu)巖(yan)(yan)心(xin)(xin)管干重M0;②利用真(zhen)空(kong)泵(beng)對填砂管抽真(zhen)空(kong)3 h，飽和水(shui)后(hou)稱(cheng)(cheng)取(qu)巖(yan)(yan)心(xin)(xin)管濕重M1，則孔隙體積V=(M1-M0)/ρW;③按照(zhao)圖(tu)2所(suo)示流程(cheng)圖(tu)連(lian)接(jie)實(shi)(shi)驗(yan)(yan)(yan)裝置，并依(yi)據實(shi)(shi)驗(yan)(yan)(yan)方案(an)設(she)定(ding)(ding)恒(heng)溫(wen)箱溫(wen)度(du)，恒(heng)溫(wen)4 h;④依(yi)據實(shi)(shi)驗(yan)(yan)(yan)方案(an)設(she)定(ding)(ding)回壓，水(shui)驅(qu)(qu)時速(su)度(du)設(she)定(ding)(ding)為(wei)(wei)1.5 mL/min，CO2乳液驅(qu)(qu)時表面活性劑水(shui)溶液及CO2注入速(su)度(du)分別設(she)定(ding)(ding)為(wei)(wei)0.5和1 mL/min，即設(she)定(ding)(ding)氣液比為(wei)(wei)2∶1;⑤實(shi)(shi)驗(yan)(yan)(yan)過程(cheng)中記錄注入端壓力(li)變化;⑥并聯(lian)巖(yan)(yan)心(xin)(xin)驅(qu)(qu)替實(shi)(shi)驗(yan)(yan)(yan)與(yu)單巖(yan)(yan)心(xin)(xin)驅(qu)(qu)替實(shi)(shi)驗(yan)(yan)(yan)類(lei)似，總流量(liang)設(she)定(ding)(ding)為(wei)(wei)5 mL/min。

圖(tu)2并(bing)聯巖心(xin)驅替實驗裝置流(liu)程