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1、大慶石油學(xué)院博士學(xué)位論文粘彈性流體偏心環(huán)空非定常流的數(shù)值計(jì)算姓名:楊樹(shù)人申請(qǐng)學(xué)位級(jí)別:博士專(zhuān)業(yè):油氣田開(kāi)發(fā)工程指導(dǎo)教師:崔海清20060510大慶石油學(xué)院博:卜{iff究生學(xué)位論文粘彈性流體偏心環(huán)空非定常流的數(shù)值計(jì)算摘要聚合物驅(qū)油技術(shù)可在水驅(qū)油的基礎(chǔ)上可將原油采收率提高12%以上,在獲得巨人經(jīng)濟(jì)效益的同時(shí),也出現(xiàn)了諸如抽油桿偏磨加重,檢泵周期縮短和抽油桿斷桿率增加等問(wèn)題。抽油桿偏磨已成為油田生產(chǎn)中亟待解決的問(wèn)題。室內(nèi)實(shí)驗(yàn)表明.聚驅(qū)井抽油桿在井筒偏心環(huán)空內(nèi)作周期性往復(fù)運(yùn)動(dòng)時(shí),由于聚合物水溶液所具有的彈性使抽油桿受到一個(gè)蕊直于軸線的徑向力。這個(gè)徑向力使抽油桿在下行程運(yùn)動(dòng)過(guò)程中
2、受壓火穩(wěn)提前,造成聚驅(qū)升抽油桿偏磨加重。本文選_I_lj共轉(zhuǎn)OIdroyd.Maxwell流體本構(gòu)方程建立起了粘彈性流體偏心環(huán)空內(nèi)非定常流的流動(dòng)方程:采川控制體積法對(duì)流動(dòng)方程進(jìn)行了離散化處理;利川交替方向隱式迭代法求解出了流場(chǎng)的速度分布,詳細(xì)分析了環(huán)空的偏心度和抽油桿的運(yùn)動(dòng)參數(shù)對(duì)速度分布的影響:計(jì)算了作用在抽油桿上法向應(yīng)力和作用在內(nèi)管上的徑向力,分析了流場(chǎng)幾何參數(shù)、流體的彈性及抽油桿的運(yùn)動(dòng)對(duì)徑向力的影響。結(jié)果表明:偏心度平¨
3、.iJ管運(yùn)動(dòng)速度對(duì)流動(dòng)的影響最為明顯,偏心度和流體的彈性是產(chǎn)生徑向力根本原因,偏心度增大時(shí)流量和徑向力均增大,內(nèi)管運(yùn)動(dòng)速度增火流量和徑向力的峰值也增
4、大:徑向力的存在是聚驅(qū)井抽油桿偏磨加重的主要原因;預(yù)防偏磨應(yīng)從減小偏心度入手,據(jù)此提出了全井抽油桿扶正防偏磨措施,并已應(yīng)用于火慶油田的6000多口聚驅(qū)井,取得了可觀的經(jīng)濟(jì)效益。關(guān)鍵詞:粘彈性流體.偏心環(huán)空,非定常流,徑向力,偏磨ABSTRACTNumericalcalculationofunsteadyflowofviscoelasticfluidintheeccentricannulusThetechniqueofpolyme卜nood{ngcanincreaseoilrecoverybymorethan12%onthebasisofwater-flooding,and
5、gainenormouseconomicbenefits,meanwhile,comeforthafewproblems,suchastheeccentricwearofthesuckerrodsaggravates,theperiodofexaminingpumpsandthelifespanofthesuckerrodsshortens,brokenrodincreasesandSOon.So,theeccentricwearofthesuckerrodshasbeenaproblemthatneedstobesolvedquickly.Theexperimentpr
6、ovesthattheelasticityofpolymersolutionmakesthesuckerrodsgetaradialforceperpendiculartoitsaxeswhenthesuckerrodsofpolymerfloodingwelldoesperiodicalin-and·fromotionintheeccentricannulus,andtheradialforcemakesthesuckerrodslosestabilityearlierwhenitWaspresseddownstroke,andaggravateeccentricwea
7、rofthesuckerrodsofpolymerfloodingwell.AdoptingcommonconversionOldroyd-Maxwellconstitutiveequation,inthispaper,theflowequationoftheunsteadyflowofviscoelasticfluidintheeccentricannuluswasestablished,andwasdiscretizedwithcontrolvolumemethod;velocityprofileoftheflowfieldWasobtainedbyusingADI(
8、AlteringDirectionImplicit)iteratingmethod;theinfluenceofeccentricityofannulusandmotionparameterofthesuckerrodsonthevelocityprofileWasdiscusseddetailedly;thenormalforceactingonthesuckerrodsandtheradialforceactingontheinnerrodswerecalculated,geometryparameterofflowfie