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《鄂爾多斯盆地準(zhǔn)連續(xù)型低滲透_致密砂巖大油田成藏模式_趙靖舟》由會(huì)員上傳分享,免費(fèi)在線閱讀,更多相關(guān)內(nèi)容在行業(yè)資料-天天文庫(kù)。
1、第33卷第6期OIL&GASGEOLOGY2012年12月文章編號(hào):0253-9985(2012)06-0811-17鄂爾多斯盆地準(zhǔn)連續(xù)型低滲透-致密砂巖大油田成藏模式趙靖舟,白玉彬,曹青,耳闖(西安石油大學(xué)地球科學(xué)與工程學(xué)院,陜西西安710065)摘要:文中將致密油藏定義為儲(chǔ)層致密、只有經(jīng)過(guò)大型壓裂改造等特殊措施才可以獲得經(jīng)濟(jì)產(chǎn)量的烴源巖外油藏,其絕對(duì)-32滲透率約小于2×10μm,孔隙度約小于12%。以往普遍認(rèn)為,致密油藏屬于連續(xù)型油氣聚集,為非常規(guī)油氣之一類。研究表明,鄂爾多斯盆地伊陜斜坡三疊系延長(zhǎng)組中、下組合主要為致密和近致密砂巖油藏,其成藏模式既非以往認(rèn)為的典型
2、的常規(guī)巖性油藏,又非典型的連續(xù)型非常規(guī)油藏,而是介于常規(guī)與非常規(guī)油藏或連續(xù)與不連續(xù)型油氣聚集之間的一種過(guò)渡類型,文中稱之為準(zhǔn)連續(xù)型油藏或油氣聚集。它主要具有以下成藏特征:①油藏大面積準(zhǔn)連續(xù)分布,無(wú)明確邊界;②大面積生烴,高強(qiáng)度充注;③儲(chǔ)層物性差,非均質(zhì)性強(qiáng);④圈閉介于常規(guī)圈閉與無(wú)圈閉之間,為非常規(guī)圈閉;⑤油、水分異差,無(wú)明顯邊、底水;⑥油藏壓力系統(tǒng)復(fù)雜,且多具負(fù)壓異常;⑦油氣運(yùn)移聚集主要為非浮力驅(qū)動(dòng),近距離運(yùn)移成藏;⑧油藏形成和分布主要受烴源和儲(chǔ)層控制,構(gòu)造影響小;⑨保存條件好,油藏變化小;⑩資源豐富,勘探開發(fā)潛力大。準(zhǔn)連續(xù)型致密砂巖油藏成藏模式的提出,預(yù)示著這類油藏具有
3、較大的勘探潛力,但傳統(tǒng)的地質(zhì)研究和勘探思路需要作出相應(yīng)的調(diào)整。關(guān)鍵詞:準(zhǔn)連續(xù)型油藏;致密油;成藏模式;鄂爾多斯盆地中圖分類號(hào):TE122.3文獻(xiàn)標(biāo)識(shí)碼:AQuasi-continuoushydrocarbonaccumulation:anewpatternforlargetightsandoilfieldsintheOrdosBasinZhaoJingzhou,BaiYubin,CaoQingandErChuang(SchoolofEarthSciencesandEngineering,Xi’anShiyouUniversity,Xi’an,Shaanxi710065,C
4、hina)Abstract:Tightoilreservoirsarelow-permeabilityoilaccumulationsinnon-sourcerockreservoirsthatcanpro-duceeconomicflowonlythroughmassivefracturingorotherspecialmeasures.Theirabsolutepermeabilityisless-32than2×10μmandporositylessthan12%.Tightoilreservoirsarewidelyacceptedasthecontinuous-
5、typeaccumulationsofunconventionalhydrocarbons.BasedonourstudiesontheOrdosBasininChina,wefoundthatoilreservoirsinthelowerandmiddleplaysoftheTriassicYanchangFormationontheYi-Shanslopearemostlytightornear-tightsandoilaccumulations.Theiroilaccumulationpatternsareneithertheconventionalli-tholo
6、gicaccumulationsnorthecontinuousunconventionalaccumulations,insteadatransitionaltypethatwerefertoasthequasi-continuousaccumulation.Thequasi-continuoushydrocarbonaccumulationcanbedefinedasex-tensiveaccumulationsintightreservoirswithneitherdefinedboundariesnorwaterlegsandcontrolledbyuncon-v
7、entionaltrappingmechanisms.Studiesindicatethatthequasi-continuoustightsandoilaccumulationsintheOrdosBasinhavethefollowingcharacteristics:(1)oildistributionisextensivegeographicallyinquasi-continuousformwithoutadefinedboundary;(2)thehydrocarbongenerationcoversvastare