鄂尔多斯盆地靖边气田J井区储层小幅度构造研究

Study on Low Amplitude Structure of Reservoir in Well J Area,Jingbian Gas Field,Ordos Basin

鄂尔多斯盆地靖边气田现今构造面貌为一区域性西倾大单斜,其下古生界奥陶系主力气层为马五段马五31小层,该小层顶面构造是在极其平缓的构造背景上发育的小幅度褶皱,且局部小幅度构造与产能关系密切,是寻找高产区的有利指向。应用地震解释成果和测井、钻井资料,研究J井区主力气层马五31顶面的小幅度构造分布特征;分析马五31顶面与本溪组9号煤顶、马家沟组标志层(K1、K2)构造的相关性;总结鼻状构造的组合类型;研究鼻隆构造与天然气富集的关系;总结构造圈闭与复合圈闭类型;分析小幅度构造成因动力学特征。这些认识对该井区井位部署、扩边挖潜及水平井动态调整,提高气田开发钻井成功率有着重要的现实意义。

The present structure features of Jingbian gas field are shown as the regional big westward dipping monocline.It is the Mawu31 thin layer in Mawu segment that was the main gas layer in Ordovician of Lower Paleozoic.Low amplitude folds developed on the top of the thin layer which was extremely gentle,and the local low amplitude structures are closely related with productivity,which are favorable indicators of high-yield areas.Based on the seismic explanation and logging and drilling data,this paper studies the distribution characteristics of low amplitude structure on the top surface of Mawu31 defined as the main gas layer in well J area.Moreover,the structure correlation was analyzed between the top surface of Mawu31 and the top structure of coal No.9 of Benxi Formation as well as marker beds（i.e.K1,K2） of Majiagou Formation.And the combination types of nose structure were summed up,and the relationships between gas enrichment and nose structure were studied.Also,the types of structure trap and combination trap were summarized.In addition,the genetic dynamics of low amplitude structure were analyzed.Thus,this paper gives rise to highly important guiding and practical significances on the well deployment,expanding boundary,digging potential of gas field and dynamic adjustment of horizontal well as well as improvement of drilling success ratio in this well area.