准噶尔盆地深层油气勘探地震采集关键技术及效果

Key techniques and effects of seismic acquisition for deep oil and gas exploration in Junggar Basin

准噶尔盆地目前4 500 m以深的深层油气探明率较低,近年来深层油气勘探目标成为该地区勘探发现的战略接替区。为了查清地下深层结构,重新构建和部署了准噶尔盆地二维地震格架线,利用以往采集资料和重新采集的新资料拼接形成了数十条线组成的二维格架网。基于“两宽一高”技术体系,采用一系列采集关键技术,如“高激发密度、高接收密度、高覆盖密度和长排列”的“三高一长”采集技术,解决了准噶尔盆地深层油气勘探地震采集面临的深层目标地震信号“能量低、干扰强、成像差和不成像”等难题。新采集并经后期处理后的资料成像效果显著提高,为建立盆地石炭系-二叠系统一的地层格架、明确石炭系隆凹格局、查清富烃凹陷下组合地层及烃源岩展布特征提供了良好的资料基础,为下一步深层油气勘探工作提供了有效指导。

The exploration rate of deep oil and gas in the Junggar basin is relatively low under the depth of 4500 m.In recent years,deep oil and gas exploration targets have become a strategic replacement area for exploration and discovery.In order to find out the deeper subsurface structure,the two-dimensional seismic grid in the Junggar basin was reconstructed and deployed.Using the previously acquired and newly acquired 2D data,two-dimensional grid survey networks were formed,including tens of lines.Based on the"two-wide and one-high"seismic technologies,a series of crucial acquisition technology are adopted,such as the"three-high and one-long"acquisition technology of"high-density shots,high-density receivers,high folds density,and long offset",which solved some critical issues of seismic signals characterized by weak energy,strong noise,poor imaging or un-imaging,etc.in deep targets exploration in Junggar basin.The imaging resolution of the newly processed data has been significantly improved,which provides a sound data basis for establishing the stratigraphic framework of the Carboniferous Permian system in the basin,defining the uplift and depression pattern of Carboniferous,and identifying the distribution characteristics of the lower combination strata and source rocks in the hydrocarbon-rich sag,and provides effective guidance for the next step of deep oil and gas exploration.