利用井震结合刻画川东石炭系印支期古隆起特征及其意义

Drilling-seismic integration depicting characteristics of the Indosinian paleo-uplift developed in the Carboniferous,eastern Sichuan Basin

川东地区石炭系是四川盆地的主要产气层之一。然而,目前其勘探领域仅局限于构造背景的各类圈闭,广阔的向斜区及斜坡区亟需新的地质认识指导勘探。为此,从野外露头、实钻井及地球物理等资料入手,利用线性回归法,恢复了石炭系印支期古构造图,结合石炭系实际气藏分布,探讨了向斜区及斜坡区成藏的有利条件。结果表明:①川东地区石炭系在印支期发育3个地层—构造复合圈闭油藏;②石炭系印支期地层—构造复合圈闭古油藏控制了现今石炭系气藏的分布。结论认为:川东石炭系印支期发育的三个地层—构造复合圈闭气藏的古构造高部位石油充满度高,具备良好的油气成藏条件,是川东石炭系深化勘探的有利区带。

Most Carboniferous gas reservoirs in Sichuan Basin are distributed in eastern basin.There are more than 500 wells drilled to the Carboniferous,and most of them obtained industrial oil and gas flow or better show.Thus,the Carboniferous is one of the most important payzones in Sichuan Basin.However,at present,its exploration domains are limited in all types of structural traps,it is necessary to expand some new geological understanding on the vast syncline and slope areas for further exploration.So,based on outcrop observation,drilling practice,and geophysical data,an Indosinian paleo-structural map of the Carboniferous was reconstructed by linear regression method.Furthermore,according to the actual distribution of Carboniferous gas reservoirs,some favorable reservoir-forming conditions in the syncline and slope areas were discussed.Results show that,(1)in eastern basin,there are three oil reservoirs of stratigraphic-structural combination traps developed in the Carboniferous during the Indosinian;and(2)these oil reservoirs control the distribution of current Carboniferous gas reservoirs.In conclusion,with higher oil charge and better reservoir-forming conditions,the paleo-structral high of these three oil reservoirs should be a favorable zone for deepening exploration of the Carboniferous in eastern Sichuan Basin.