冷43块稠油油藏氮气泡沫驱油试验研究

冷43块稠油油藏氮气泡沫驱油试验研究付美龙 (长江大学石油工程学院,湖北荆州434023)易发新,张振华 (辽河石油勘探局工程技术研究院,辽宁盘锦124010)刘尧文 (江汉油田分公司勘探开发研究院,湖北潜江433124)熊艳军 (中原石油化工有限责任公司,河南濮阳457001)[摘要]根据冷43块油藏实际情况,压制了平面非均质性单层模型、纵向非均质性三层模型,研究了不同气液比、不同起泡剂浓度、不同温度和回压下氮气泡沫在模型中的驱油能力,为该油藏开展氮气泡沫驱油矿场试验提供了理论指导。

[关键词]稠油油藏;氮气;泡沫;驱动(油气藏);单层模型;多层模型;驱替试验[中图分类号]T E345;T E357146[文献标识码]A [文章编号]10009752(2004)01008602根据冷家堡油田冷43块Es 23稠油油藏的地质特点及开发现状,为提高原油采收率,改善经济效益和开发方式及工艺技术,笔者提出了采用/热水加驱油助剂及氮气泡沫段塞驱提高采收率技术0这一新的开发方式。

该技术的主要设计思路是:¹既注入驱替能量补充油层压力,又注入足够的热能以提高波及体积系数和驱油效率。

º由于注氮气的同时加入耐温的起泡剂,在水驱指进带中形成稳定的泡沫流,增加流动阻力,迫使注入水向纵向及平面上吸水差的区域和未驱替层位扩展,扩大波及体积;而且热水与氮气混合后,密度变小,向上超覆,扩大油层上部的动用程度,对块状巨厚油藏尤为重要[1~4]。

为此,针对热水氮气泡沫驱提高波及系数和稠油油藏采收率的机理等开展三维模型试验研究。

1 试验准备1)人造岩心制作 主要包括4大部分:胶结剂的配制,砂子拌和与压制,模型烧结,加工成型。

整个过程必须严格按照操作规程进行,否则难以达到理想的结果。

2)高压三维模型制作 本次试验在高压容器中进行,要求高压试验容器最大耐压50MPa,模型最大尺寸250mm @150mm @30mm 。

本次试验研究用的三维模型采用不同目数的刚玉砂按配比高压(27MPa)压制、高温烧结而成,整个模型用环氧树脂浇铸密封,并装入特制的模型高压容器中,以模拟油层的上覆压力等环境。

对压制的三维模型取小岩心样测其渗透率,保证与要求的渗透率值基本一致,其中高渗层为908@10-3L m 2,低渗层为426@10-3L m 2。

浇铸用环氧树脂为90e 热固化树脂,耐温极限200e 。

3)试验用模型 试验研究中采用的三维模型有以下两种:平面非均质性模型、纵向非均质性三层模型,单层模型基本规格为250mm @150mm @20mm,多层模型基本规格为250mm @150mm @30mm,制作好的三维模型可耐压40MPa,耐温200e 。

4)试验流体和驱替介质 ¹原油。

冷43块的原油为稠油,50e 时原油粘度平均3570mPa #s,密度平均019405,凝固点215e ,含蜡量414%,胶质沥青含量44116%。

本次试验油样为冷43-32-562井脱气原油,对其粘温关系测定表明,原油粘度高,粘度对温度敏感。

º地层水。

冷43块的地层水总矿化度3000mg/L,水型为NaHCO 3型,注入水总矿化度127517mg/L 。

本次试验采用按水分析结果人工配置模拟地层水,模拟地层水60e 粘度为014903mPa #s 。

饱和岩心用水、驱替水和配置起泡剂溶液全部采用该模拟地层水。

»氮气。

氮气泡沫调剖用气体为商品氮气。

¼起泡剂。

起泡剂采用辽河油田工程院提供的起泡剂LH-1。

5)试验装置 试验流程主要由注入泵系统、高压岩心夹持器、回压调节器、压差表、控温系统、计量系统等组成。

其中高压岩心夹持器是驱替装置中的关键部分。

#86#江汉石油学院学报 2004年3月 第26卷 第1期Journal of Jianghan Petroleum Institute M ar 12004 Vol 126 No 11[收稿日期]20031210 [作者简介]付美龙(1967),男,1990年大学毕业,硕士,副教授,现从事油田化学和提高采收率方面的教科研工作。

6)相似条件 为了克服模型内水驱过程中出现的末端效应,达到稳定水驱条件,根据驱动力与毛管力的标配系数\1确定最小驱替速度V mi n 。

按模型长度25c m 、地层温度60e 下模拟地层水粘度为014903mPa #s ,计算得V mi n =0108c m/min ,换算为驱替流量Q mi n =1196c m 3/min 。

其他温度下同样照此计算即可。

2 试验程序1)模型在一定压力下用氮气进行密封性测试,确认其密封性、渗透性是否良好。

2)对模型称重W 1,抽真空8h 以上,饱和地层水,自吸饱和12h 以上,然后再称重W 2,计算模型孔隙体积、孔隙度。

3)将饱和好的模型装入高压岩心夹持器中,加环压,保持环压大于内压2M Pa 并恒温12h 以上。

4)用地层水测水相渗透率,如果为平面非均质模型则先测高渗层水相渗透率,后测低渗层水相渗透率,最后合测整个模型的水相渗透率;如果为纵向非均质性三层模型则只需合测整个模型水相渗透率。

5)用冷43-32-562井脱气原油驱替,建立束缚水饱和度,非特别声明外回压一般定为5M Pa,记录产水量,饱和至不产水为止,计算束缚水饱和度。

6)采用地层水驱油,驱替排量为210cm 3/min,记录产油量、产液量,计算含水率、采出程度,驱替至含水98%为止。

7)同时注入氮气和泡沫剂驱油,总驱替排量为210cm 3/min,记录产油量、产液量,计算采出程度,驱替至含水98%为止。

3 试验结果311 平面非均质模型氮气泡沫驱油试验模型长2510cm,宽1415cm,厚118cm,孔隙度3019%~3114%,试验温度60e ,泡沫剂LH -1浓度110%,气液比采用015B 1,1B 1,2B 1,3B 1。

试验结果表明,气液比从015B 1逐步增加到3B 1,采收率增加值分别为13113%,17191%,13149%,8169%,说明1B 1是合适的气液比,能最大限度提高原油采收率。

气液比处于最佳比时,能产生稳定的微小泡沫,使流动阻力迅速增加,最大限度地使后续驱替流体转向,起到明显的调剖作用,提高波及系数和波及体积,最有效、最大限度地提高原油采收率。

312 纵向非均质模型氮气泡沫驱油试验模型长2112cm,宽1412cm,厚217cm,孔隙度3019%~3318%,试验温度60,100,120e ,泡沫剂LH -1浓度分别为012%,015%,0175%,110%,气液比1B 1。

试验结果表明,随着泡沫剂浓度的增加,采出程度逐步增加,开始时增加较快,然后增加速度缓慢,012%,015%,0175%,110%泡沫剂对应采出程度增加值分别为9113%,15121%,17108%,18120%;对于单一水驱,温度增加,原油粘度下降,可使采收率明显增加,相对于60e 而言,100,120e 的水驱采收率分别提高了6123%,9195%;对于氮气泡沫驱油而言,60,100,120e 的氮气泡沫驱增加采收率值分别为15121%,20158%,26110%,油藏温度的升高,氮气泡沫驱可更加有效地提高采收率;氮气泡沫驱的同时采取降低原油粘度的办法,将更有效地改善油藏开发效果,说明热水氮气泡沫驱比单纯氮气泡沫驱将更有效、提高采收率更多。

100,120e 的氮气泡沫驱试验回压较高,分别为10,30MPa,但提高采收率幅度仍然增大。

这表明,氮气和泡沫剂同时注入,在多孔介质中高压下仍能形成泡沫,仍能提高采收率,压力环境对其影响有限。

水气交替注入本身就能在多孔介质中形成泡沫,只是泡沫剂的加入使泡沫的形成更容易、形成的泡沫更微小、更稳定,更有利于调剖和提高采收率。

[参考文献][1]刘文章.稠油注蒸汽热采工程[M ].北京:石油工业出版社,1997.458~470.[2]贾忠盛.泡沫及泡沫驱油室内实验研究[J].油田化学,1986,3(4):279~283.[3]颜五和.泡沫与泡沫驱油[J].油田化学,1990,7(4):380~385.[4]廖广志.常规泡沫驱油技术[M ].北京:石油工业出版社,1999.239~256.[编辑] 舍 予#87#第26卷第1期付美龙等:冷43块稠油油藏氮气泡沫驱油试验研究#Ö#T he fracture distributi onal Law s of the block are calculated analytically by using th e method of main curvature,the fracture distri butional law s in different layers are discussed in combination w ith reservoir structural characteristics an d dynamic data analysis1On the basis stated,w ell pattern adaptabi lity is s tudied and the w ell pattern in th e block i s adjusted,thus the injecti on producing system is more suitable to in-si tu condition with good development effect1Key words:low permeability reservoir;vertical fracture;fracture azimuth,fracture extensi on;well pattern adjustment;W endong Oilfield84Well Completion Technique Application of Viscous Oil Well in Liaohe Oilf ieldZHU Yie-yun,WANG Yu(China Univer s ity of Geosciences,Wuhan430074)Abstract:Because of the speciality of viscous oil producing method and very complex geological conditions in L i aohe oil region,special w ell com-pletion techniques are needed1Thus a study is performed on the completion method for vi scous oil production in Liaohe Oilfield,the fundamental principles of perforati on,completion,san d control completion and completion of external pipe pluggi ng and their advantages,shortcomings and the application tools are discussed1Key words:viscous oil reservoir;w ell dri lling;well cementing;completi on;completion quality;sand control;Liaohe Oi lfield86Experiment of Nitrogen-f oam Displacement in Viscous Reservoir of Block Leng43FU Mei-long(Yan gtz e University,Jingzhou434023)YI F a-x i n,ZH ANG Z hen-hua(L ia oh e Petroleum Explor a tion Bureau,Panjin124010)LIU Ya o-wen(Jian ghan Oilf ield Branch Company,SI NOPEC,Qian jian g433124)XI ONG Ya n-jun(Zhongyuan Petrochemical Co1Ltd1,SIN OPEC,Puyang457001)Abstract:According to the actual reservoir situation of Block Leng43,a single-layer model for areal heterogeneity and a3-layer model for vertical heterogenei ty are denoted1T he oil displacement capacity of nitrogen-foam in the model is studied under different gas-li quid ratios,different foamer concentrations,temperature and pressure to provi de a theoretical guidance for field testing of nitrogen foam di s placement in the reservoir1 Key words:viscous reservoir;nitrogen gas;foam;drive(Reservoir);single-layer model;multiplayer model;displacement test88Experimental Study of Fluid Percolating C haracteristics in Extremely Low Perm eable Reservoirs ZH ANG Gua ng-ming,LI AO Rui-quan(Yangtze University,Jingzhou434023)XU Yo ng-g ao(Changqing Oilf ield Branch Compan y,CNPC,Xi p an710060)XU We i(Zhongyua n Oilf ield Br an ch Comp a ny,SINOPEC,Pu yang,457001)Abstract:By taking reservoir Chang6in Changqing Oilfield as an exam ple,an experimental study is carried out on th e effects of press ure,tem-perature on th e percolating characteristics of low permeable reservoirs as w ell as on the result of i m provi ng tw o phase percolation by adding surfac-tant1The result demonstrates that in the low permeable reservoirs,the initial starting pressure could be reduced in crude oil,non-Darcy percolat-ing characteristics could be improved by raisi ng temperature and system pressure1Oi-l w ater2phase of combined flow area can be improved effec-tively,thus to raise the recovery efficiency of w ater injection by adding surfactant system in injected w ater1Key words:low permeable oil and gas reservoir;percolation;property;performance test90Development Scheme of Low Permeability Oil and Gas Field in Pingbei AreaGUO Qing-an(Ch ina Un iversity of Geosciences,Wuhan430074;Jianghan Oilfield Br an ch Comp an y,SIN O PEC,Qian jiang433124)92Fracture Extension Simulating Experim ent in Ref racturing ProcessLIU Ying-xiang,ZH AO Yu-xin,YANG Yo ng-pi ng,LIFe ng-x i a,MIAO H o ng(Zhon gyuan Oilfield Br an ch Comp an y,SIN O PEC,Pu yang457001)Abstract:By using artifi cial cores,the method of laboratory refracturing simulati ng experiment is deployed to study the fracture mechani sm of the refracturing,quantify the possibility and conditions of new fractures for predicting fracture reversing and con ditions of creating new fractures in the oi lfields1It has great significance for instructing the selection of refracturing ti m e,optimizing fracturing design and improving refracturing ef-fect1Key words:refracturing;fracture;new fracture;simulating experi ment94Productivity Simulation of Dua-l medium Reservoir Fracture with Fracture Permeability Depending on Pressure LI Yo ng-mi ng,GUO Ji a n-chun,ZH AO Ji n-zho u(South w est Petroleum I nstitute,Chengdu610500)Abstract:On the basis of a dua-l pore and s i ngle-percolation model,an oil-w ater percolation math model for dua-l medium reservoir fracturing is established in consideration of natural fracture permeabi lity changing w ith pressure1The numerical model is derived in detail on the basis of im-plicit pressure explicit saturation(IM PES)method1The calculation of example shows that the model is easily programmed for solution,w hich is practical for studying single-w ell fracturing performance i n fractured reservoirs1Key words:natural fracture;fractured reservoir;fracture;math model;num erical si mulation97Factors of Fracturing Influencing on C asing FailureXI ANG Xu-jin,H U Gua ng-zhen,CHEN Shu-qing(Zhon gyuan Oilf ield Branch Compan y,SIN O PEC,Pu yang457001)LI Qing-g a ng(Zhongyu an Petr oleum Exploration Bur eau,Puyang457001)Abstract:A3D simulati ng model for calculating casing in fracturing w ells i s established based on the casing force-summing anal ysis1T he law s of casing stress changes caused by inner casing pressure changes are calculated by si mulation1Accordi ng to the calculation the factors of fracturing influencing on casing failure are analyzed1It is considered that the casing failure is th e result of combi n ed action caused by many factors1T hrough analyzing the data of casi ng failure w ells,the causes of casing failure i n the fracturi ng w el ls are compared analytically,by w hich theoretical bases are provided for preventi ng casing failure under special operation conditi on1Key words:fracture;casing failure;force-summing analysis;simulation;influence;prevention99Experiment of Displacement Mode Conversion in Ertao Unit of Region6in Gudong OilfieldLI Zha o(China University of Geoscien ces,Wuh an430079)Abstract:Ertao unit in Region6of Gudong Oi lfield has been i n high water-cut stage w ith low w ater displacement efficiency1Cost of w ater i n j ec-tion is reduced and oil displacement effi ciency is improved by converting w ater drive to expansion drive1T hus an experiment is conducted for con-verting displ acement mode and the pri nciple of expansion drive,principle of pressure transmis sion of the expansion drive as production remains constant and methods for calculating w ater drive production pressure difference are denoted1Expected result is achieved in field test1 Key words:h i gh w ater-cut stage;w ater dri ve;expansion drive;field test;Gudong Oilfield101Casing Repair Technique by Running4in Casing into5"-in Casing in Deep WellsZHU De-zhi,H UANG Li-bin,BAI Ya n-lin,MA Z hi-ming,TIAN We i-zhi(Zh ong yuan Oilf ield Branch Company,SIN OPEC,Puyang457001)Abstract:A study is carried out on deep w ell casing repair technique by runni ng4in casing in5"-in casing in H uz huangji Oi lfield so as to im-prove waterflood w ell pattern,and handle interbed contradictions by stratification1Its main technical principle and technical indexes in operati on are discussed1The result of application show s that w ell con ditions are improved and its purposes of oil increment and stimul ation improving are achieved1Key words:deep w ell;casing failure;casing repair;Huzhuangji Oilfield。