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1、摘要射孔參數(shù)優(yōu)化研究,對(duì)射孔完井水平井穩(wěn)油控水尤為重要。本文利用油藏流體滲流模型和水平井筒內(nèi)流體流動(dòng)模型,建立油藏.井筒流體流動(dòng)耦合模型,采用約束非線性規(guī)劃算法,分別對(duì)有限導(dǎo)流和無(wú)限導(dǎo)流的射孔分布進(jìn)行優(yōu)化研究,以期為水平井的優(yōu)化設(shè)計(jì)提供理論依據(jù)。針對(duì)均質(zhì)各向異性頂、底封閉的無(wú)限大板狀油藏中射孔完井水平井,應(yīng)用格林函數(shù)、源函數(shù)法以及疊加原理,結(jié)合拉普拉斯變換,得到擬徑向流井筒頂部壓力響應(yīng)方程。根據(jù)井簡(jiǎn)表面壓力和流量的連續(xù)性,建立射孔完井水平井的油藏.井筒流動(dòng)耦合模型。利用Newton-Raphson迭代算法求解耦合模型,計(jì)算
2、結(jié)果顯示,流入剖面不均勻,流入量從水平井趾端到跟端逐漸增大,計(jì)算產(chǎn)量接近于油井實(shí)際產(chǎn)量。射孔水平井產(chǎn)能指數(shù)敏感性分析表明,射孔長(zhǎng)度在孔密較小時(shí)影響顯著;當(dāng)射孔長(zhǎng)度為0.3米時(shí),射孔密度小于3孔/米,孔密對(duì)產(chǎn)能指數(shù)有較大影響;各向異性地層中射孔相位對(duì)產(chǎn)能指數(shù)影響較大;射孔孔徑對(duì)產(chǎn)能指數(shù)影響很小。編程實(shí)現(xiàn)了廣義Lagrange乘子算法,并驗(yàn)證了該算法的可行性。以水平井產(chǎn)量為目標(biāo)函數(shù),以孔眼分布為決策變量,分別對(duì)無(wú)限導(dǎo)流和有限導(dǎo)流的水平井射孔分布進(jìn)行優(yōu)化,并與均勻射孔進(jìn)行了對(duì)比。結(jié)果表明,無(wú)限導(dǎo)流情況下,三種射孔分布方式下的總產(chǎn)
3、量差別不大,流入剖面呈“U”型;考慮均勻流入,則射孔密度分布呈拱橋形;若不考慮均勻流入,射孔密度分布呈“U”型,兩端密度大,中間密度小。有限導(dǎo)流情況下,流入剖面不均勻,約在井筒長(zhǎng)度的4/5處最小,越靠近水平井跟端,流入流量越大;若不考慮均勻流入,則在水平井長(zhǎng)度3/4處射孔密度取最大值,沿水平井的兩端射孔密度遞減;若考慮均勻流入,則在水平井長(zhǎng)度3/4處射孔密度取最小值,沿水平井的兩端射孔密度遞增。上述研究為水平井射孔參數(shù)優(yōu)化提供一種新思路。關(guān)鍵詞:水平井,射孔分布,耦合模型,約束非線性規(guī)劃,優(yōu)化OptimizationofP
4、erforationDistributionoftheHorizontalWellUsingNonlinearConstrainedProgrammingAbstractoftheperforatingparameterisveryimportanttostabilizetheproductionandcontrolthewatercutintheperforatedhorizontalwell.Amodelforcouplingreservoir·wellborefluidpatternswasdeduced舶mthes
5、eepageflowmodelofreservoirfluidandthefluidflowmodelofhorizontalwellbore.Thenonlinearconstrainedprogrammingwasappliedtooptimizetheperforationdistributionofthehorizontalwellunderthecircumstancesofinfiniteandfiniteconductivityrespectively.Thisapproachishopedtobetheth
6、eoreticalfoundationonwhichtheoptimizationofthehorizontalwellisbased.Aperforatedhorizontalwelllocatedatthecenterofaninfiniteanduniformlyanisotropicslabreservoirimpermeableatbothtopandbottomwasstudied.Thepressureresponseofpseudo-radialflowatthetopofthewellborewasobt
7、ainedusingGreen’Sfunction,sourcefunctionmethod,principleofsuperpositionandLaplacetransform.Based011thecontinuityofthepressureandthefluxalongthesurfaceofthewellbore,amodelforcouplingreservoir—wellboreflowpatternsWasestablishedtodescribetheinteractionbetweenthereser
8、voirandtheperforatedhorizontalwell.Newton-Raphsoniterativemethodisdevelopedtosolvethecoupledmodel.Theresultsshowtheinflowprofileisnonuniform,theinflowfl