彈性波阻抗理論和實(shí)現(xiàn)方法課件

彈性阻抗理論Hampson-Russell軟件實(shí)現(xiàn)彈性波阻抗反演彈性波阻抗理論和實(shí)現(xiàn)方法介紹先回顧彈性阻抗反演的原理,然后利用Hampson-Russell一組軟件分析彈性阻抗反演一個實(shí)際例子.彈性阻抗ElasticImpedance

(EI)

是由BP公司PatrickConnolly提出.實(shí)現(xiàn)彈性阻抗反演可用AVO和STRATA軟件自然組合來完成.在談?wù)搹椥宰杩狗囱葜?簡單回顧反演方法在地震勘探運(yùn)用的歷史.2023/11/3彈性波阻抗理論和實(shí)現(xiàn)方法CDP/CRP道集迭加反演估算Z=

VP地震巖性估算傳統(tǒng)的地震巖性估算是在地震數(shù)據(jù)疊加偏移后數(shù)據(jù)(疊后數(shù)據(jù))道進(jìn)行反演.這只能估算聲阻抗,不足于推測流體成分.2023/11/3彈性波阻抗理論和實(shí)現(xiàn)方法道集疊加反演AVO分析屬性1屬性2估算VP,VS,和

估算Z=

VPAVO方法

同時使用多屬性估算VP,VS,和

,可估算推測流體和巖性.2023/11/3彈性波阻抗理論和實(shí)現(xiàn)方法AVO分析可能用的屬性但是哪兩種(或更多屬性)可用來最好地預(yù)測流體和巖性這些參數(shù)?目前AVO可提取和使用的一系列不同屬性:

偏移距或角度段限(范圍限制)疊加

彈性阻抗反演

截距和梯度

提取的縱橫波反射系數(shù)RP,RS

由RP

和RS

反演到縱橫波阻抗ZP,ZS

縱橫波阻抗ZP,ZS

轉(zhuǎn)換Lambda-Mu-Rho分析本討論先使用前面兩個屬性的方法.后面再討論其它的屬性方法.2023/11/3彈性波阻抗理論和實(shí)現(xiàn)方法范圍限制疊加道集AVO分析近疊加遠(yuǎn)疊加以上是范圍限制疊加的簡單流程.利用常偏移距或常角度的范圍疊加已經(jīng)非常成熟.問題是如何解釋其結(jié)果?2023/11/3彈性波阻抗理論和實(shí)現(xiàn)方法(a)(b)近角度(0o-15o)疊加遠(yuǎn)角度(15o-30o)疊加數(shù)據(jù)來自加拿大Colony區(qū)塊.在630MS有一個“亮點(diǎn)”震幅在遠(yuǎn)角度

疊加上比近角度疊加要強(qiáng)的多.從井資料分析這是氣砂巖導(dǎo)致“亮點(diǎn)”.氣砂巖范圍限制疊加2023/11/3彈性波阻抗理論和實(shí)現(xiàn)方法這是近遠(yuǎn)偏移距(角度)的交繪圖,高震幅區(qū)塊用不同顏色突出顯示.角度疊加進(jìn)行交繪圖2023/11/3彈性波阻抗理論和實(shí)現(xiàn)方法這是交繪圖中的突出區(qū)塊對應(yīng)在剖面上的位置.可看出氣砂巖已被很好地描繪.TopGASBaseGASCoal2023/11/3彈性波阻抗理論和實(shí)現(xiàn)方法(a)近角度疊加(0-15o)時間切片,(b)遠(yuǎn)角度疊加

(15-30o)時間切片(三維河道砂).對時間切片震幅包絡(luò)求得是10MS窗口內(nèi)的平均值并運(yùn)用了Z-SCORE轉(zhuǎn)換.異常河道砂得以清楚顯示.角度范圍疊加(a)(b)2023/11/3彈性波阻抗理論和實(shí)現(xiàn)方法

從范圍限制疊加到彈性阻抗范圍限制疊加使用的是常偏移距或常相位道集,方法很成熟并可避免同相軸未拉平問題.但它究竟有何含義?PatrickConnolly(BP),提出新穎的方法來解釋范圍疊加的含義,稱之為彈性阻抗.彈性阻抗是基于Aki-Richards等式,下幾張圖片解釋彈性阻抗的概念和由來.2023/11/3彈性波阻抗理論和實(shí)現(xiàn)方法彈性阻抗理論Aki-Richards等式可寫為(三項式):Connolly(1999)提出,類似于聲阻抗,我們定義彈性阻抗(EI)

為:2023/11/3彈性波阻抗理論和實(shí)現(xiàn)方法假設(shè)

注意到我們可以把

Aki-Richards等式重寫為:假設(shè)

K

為常數(shù),可以將上式寫為:2023/11/3彈性波阻抗理論和實(shí)現(xiàn)方法然后進(jìn)行積分和取冪,可得到以下彈性阻抗

EI等式:

如果

=0o,EI彈性阻抗就還原為聲阻抗(AI),等式為:2023/11/3彈性波阻抗理論和實(shí)現(xiàn)方法

以上等式使用的是Aki-Richards所有三項等式.對于入射角大于300,該等式將不是線性的擬合.對于大角度(大偏移距),如果只用等式的前兩項,等式可寫為:

當(dāng)

=0o,得到:2023/11/3彈性波阻抗理論和實(shí)現(xiàn)方法將聲阻抗(AI)轉(zhuǎn)換入射角為30°的彈性阻抗通常曲線類似但阻抗絕對值變低.角度增加其視聲波阻抗降低.油砂巖比頁巖視聲波阻抗降低幅度更大.如下圖Connolly1999彈性阻抗–油飽和度的影響2023/11/3彈性波阻抗理論和實(shí)現(xiàn)方法彈性阻抗–實(shí)例下圖

顯示聲阻抗和彈性阻抗(30度角)的曲線比較:2023/11/3彈性波阻抗理論和實(shí)現(xiàn)方法 重疊顯示更好地區(qū)分彈性阻抗和聲阻抗在含油砂巖處的差別:2023/11/3彈性波阻抗理論和實(shí)現(xiàn)方法EI

反演步驟道集AVO分析近角度疊加q1遠(yuǎn)角度疊加q2反演彈性阻抗

EI(q1)反演彈性阻抗

EI(q2)2023/11/3彈性波阻抗理論和實(shí)現(xiàn)方法CaseStudyfromtheColonySandPlayinAlberta,Canada2023/11/3彈性波阻抗理論和實(shí)現(xiàn)方法ApplyingElasticImpedancetotheColonyDataInthisexercise,wewillstartwiththe2DColonydatasetwhichweanalyzedearlierandapplytheElasticImpedanceanalysistoit.Firstre-opentheavo_classdatabaseinGEOVIEW.OntheGEOVIEWwindow,clickonDatabase/Open.Selectavo_class.wdbfromthepullDownlist,asshown,andclickonOK:2023/11/3彈性波阻抗理論和實(shí)現(xiàn)方法OntheGEOVIEWmainwindow,clickontheAVO/AVObuttontorestarttheAVOprogram:SelecttheoptiontoOpenPreviousProjectandchoosethecolony.prjproject:2023/11/3彈性波阻抗理論和實(shí)現(xiàn)方法Beforeanalyzingthedata,wewillcreatetheelasticimpedancelogsinthemodelingwindow.Ifitisnotvisible,clickontheModeling/SingleWellbuttononaseismicwindowandselectAVO_WELLontheOpenWellmenutogetthefollowingwindow:2023/11/3彈性波阻抗理論和實(shí)現(xiàn)方法Next,clickontheLogs/Transformsbuttonasshownontheleft,andselecttheElasticImpedanceoptionfromtheTransformsmenushownbelow:2023/11/3彈性波阻抗理論和實(shí)現(xiàn)方法ClickNext>>ontheTransformsmenuandselectthecorrectwell(AVO_WELL)fortheP-andS-wavelogsandforstoringtheElasticImpedancelog,asshownbelow.2023/11/3彈性波阻抗理論和實(shí)現(xiàn)方法Onthenextmenu,makesuretheFRMeditedlogsareusedforthecalculationoftheelasticimpedanceandcalltheresultEI_Nearasshown.2023/11/3彈性波阻抗理論和實(shí)現(xiàn)方法ClickonNext>>andfillinthenextmenuasshown,choosingConstantAngleandfillinginanangleof7.5degrees.2023/11/3彈性波阻抗理論和實(shí)現(xiàn)方法WhentheEI_Nearloghasbeencreated,selecttheLogs/Transformsoptionagain,andfillinthemenusasshownpreviouslyexceptforthelasttwomenusshownhere.Onthesemenus,createanewlogcalledEI_Far(makingsurethattheFRMeditedlogsareusedinthecalculation)ataconstantangleof22.5degrees.2023/11/3彈性波阻抗理論和實(shí)現(xiàn)方法Todisplaythetwoelasticimpedancetracestogether,clickonthe“eyeball”icontobringuptheParametermenu.UndertheLayouttab,turnofftheDisplayOnlyActiveLogsbuttontoseeallofthelogs,andputtheEI_NearandtheEI_Farlogsonthesametrack,asshown.2023/11/3彈性波阻抗理論和實(shí)現(xiàn)方法ClickonOkandyouwillseethedisplaybelow.NoticethattheEI_Farlogplotstotheleftinthegaszoneandtotherightintherestofthelog.Now,let’scrossplotthesetwologs.2023/11/3彈性波阻抗理論和實(shí)現(xiàn)方法ClickonCrossplotandfilloutthemenuasshownbelow,selectingtheElasticImpedancelogtypeaswellas<VerticalDepth>and<Time>.Then,clickonNext>>.Onthismenu,selectthewell,andclickonNext>>.2023/11/3彈性波阻抗理論和實(shí)現(xiàn)方法Onthismenu,selectElasticImpedanceforboththeXandYaxes,andchangethePlotTitleasshownbelow.(Notethatwewillselectadifferentelasticimpedancelogforeachaxisonthenextmenu).ClickonNext>>.2023/11/3彈性波阻抗理論和實(shí)現(xiàn)方法Onthismenu,selectEI_NearfortheXaxisandEI_FarfortheYaxis,asshown.ClickonNext>>.Onthismenu,selectTimeasthedomain,withstartandendvaluesof600and675.ClickonOktogetthecrossplot.2023/11/3彈性波阻抗理論和實(shí)現(xiàn)方法

Noticethattheaxesofthe plotarebothlabeledthe same.Tochangetheannotation,clickonEdit/Annotationsandchangethemenuasshownontheright:ClickonOkandtheplotwillappearasshownontheleft.Noticetheclearseparationofthepointsonthelowerleftoftheplot.2023/11/3彈性波阻抗理論和實(shí)現(xiàn)方法Letusnowperformzoneanalysistoseeiftheanomalyseenonthecrossplotreallyisthegassand.Todothis,firstdisplaythewelllogcurvesbyclickingontheCross-Sectionbutton.AfterusingtheZoomoption,youshouldseeaplotsimilartothis:2023/11/3彈性波阻抗理論和實(shí)現(xiàn)方法Now,clickontheZones/Addoptionandcreatetheellipticalgreybackgroundtrendasshownontheright.2023/11/3彈性波阻抗理論和實(shí)現(xiàn)方法Nowdefinetheellipticalyellowgastrendasshown.2023/11/3彈性波阻抗理論和實(shí)現(xiàn)方法Notethattheplotofthewelllogshasbeenupdatedwiththecolors,andtheanomalouspointsdoindeedcorrespondtothegassandzone.2023/11/3彈性波阻抗理論和實(shí)現(xiàn)方法NowgotothewindowcontainingtheoriginalCDPgathers.ClickonProcess/Stack/RangeLimitedStack:2023/11/3彈性波阻抗理論和實(shí)現(xiàn)方法Usethedefaultsonthefirstmenuasshownontheright,andclickonNext>>.Then,fillinthesecondmenuasshownontheleft.Noticethatwearecreating2anglestacksfrom0to30degrees.2023/11/3彈性波阻抗理論和實(shí)現(xiàn)方法Thetwoanglestacksarecreatedasshownhere,whererange_limit_stackisthenearanglestack,andrange_limit_stack2isthefaranglestack.2023/11/3彈性波阻抗理論和實(shí)現(xiàn)方法Selecttherange_limit_stack.volfromthemenuandclickonOpen.Next,clickontheSTRATAbuttonontheGEOVIEWmainwindow.Wewillcontinueusingthecolonyproject,asindicatedinthemenuontheright.ClickonOktobringuptheSTRATAmainwindow,andthenclickonDataManager/ImportData/OpenSeismic/OpenFromProject.2023/11/3彈性波阻抗理論和實(shí)現(xiàn)方法FillouttheWelltoSeismicMapmenuasshownandclickOk.TheSTRATAwindownowlookslikethis:2023/11/3彈性波阻抗理論和實(shí)現(xiàn)方法ClickonHorizon/PickHorizonsandpickasecondevent,asshown.Horizon1isthetroughatthetopofthegassand.2023/11/3彈性波阻抗理論和實(shí)現(xiàn)方法Finally,pickathirdevent,asshownhere.ThenclickOktofinishthepicking.2023/11/3彈性波阻抗理論和實(shí)現(xiàn)方法Next,clickonModel/Build/Rebuild

aModel.Fillinthefirstpageasshownontheright,changingtheoptionto:TypicalsetupofElasticImpedanceforfar-offsetstackinversion.ClickonNext>>.Onthethirdpage,selectthewellAVO_WELLandclickNext>>.2023/11/3彈性波阻抗理論和實(shí)現(xiàn)方法Onthenextpage,wemustselecttheElasticImpedancelogwhichcorrespondstotheNearAnglestack.Sincethisstackcoversananglerangeof0to15degrees,chooseEI_Near,calculatedfortheangleof7.5degrees.NowclickonNext>>twiceandOKtobuildthemodel.Then,clickonInvert/ModelBasedasshown:Onthefirstpage,changetheoutputtonear_inversion.ClickonNext>>twice.Onthethirdpage,changetheAverageBlockSizeto4.ClickOKtoruntheinversion.2023/11/3彈性波阻抗理論和實(shí)現(xiàn)方法Theinversionresultwilllooklikethis:2023/11/3彈性波阻抗理論和實(shí)現(xiàn)方法

Next,clickonWindow/New Windowtocreateanempty STRATAwindow.Inthisnew window,clickonDataManager/ImportData/OpenSeismic/OpenFromProjectandselectrange_limit_stack2.vol,asshownontheright.ClickonOpentogettheresultshownbelow.Noticethattheexistingpicksareannotated.2023/11/3彈性波阻抗理論和實(shí)現(xiàn)方法

Next,clickonModel/Build/Rebuilda ModelandselecttheoptionTypicalsetup ofElasticImpedanceforfar-offsetstack inversiononthefirstpage,asdonepreviously.SelectAVO_WELLonthethirdpageandchoosetheEI_Farlog(22.5degrees)onthefourth,asshown.Thenewmodelwilllooklikethis(youmayneedtoupdatethecolorkey):2023/11/3彈性波阻抗理論和實(shí)現(xiàn)方法Next,clickonInvert/ModelBasedandchangethenameoftheoutputvolumeontheinversionmenuasshownbelow.Onthethirdpage,changetheAverageBlockSizeto4andclickonOKtostarttheinversionprocess:2023/11/3彈性波阻抗理論和實(shí)現(xiàn)方法Wenowhavetwoinversionresults.Notethatwehavehadtousetwodifferentcolorscales,sincetheimpedancevaluesarescaleddifferently.Near_inversionFar_inversion2023/11/3彈性波阻抗理論和實(shí)現(xiàn)方法Nowletuscomparethenear-angleinversionwiththefar-angleinversionbycross-plottingthetwovolumes.Oneitherofthetwoinversionresults,clickonProcess/CrossPlot:Onthefirstmenupage,selecttheCDPrangefrom300to360andthetwovolumesasshown:ClickNext>>untilyoureachthefourthpage.SpecifyaConstantTimeof630msasshown:2023/11/3彈性波阻抗理論和實(shí)現(xiàn)方法IftherewerenoAVOeffects,wewouldexpectthefarandnearimpedancestoberelatedbyastraightline.Inotherwords,therewouldbeasinglecluster.Let’saddsomezonestothecrossplotandviewthecross-sectiontoseewherethesezoneslie.ClickonZones/Add:2023/11/3彈性波阻抗理論和實(shí)現(xiàn)方法Makethefirstzoneusinganellipseandplaceitalongthemainaxis,asshown.PresstheApplybuttontosa