高家河地区盒_8段地层地震-沉积响应特征研究

Features of Seismic-sedimentation Responses in He-8 Interval of the Gaojiahe Area

针对鄂尔多斯盆地延长探区高家河地区上古生界盒_8段地层沉积体系平面分布特征复杂的问题,利用岩石物性、90°相位地震数据体、时频分析技术及地震沉积学等方法,在地震剖面上建立高频等时地层格架,将地质、测井及地震相结合,对不同主频的地层切片进行沉积学解释,研究盒_8段地层地震-沉积响应特征,确定目的层沉积相带平面分布规律。研究表明:盒_8段地层砂岩、泥岩声波速度范围重叠较大,砂岩声波速度整体上略高于泥岩声波速度,孔隙度对纵波速度有较大的影响;盒_8段地层受山西组煤层地震反射波干涉作用影响强烈,地震有效频带为40~100 Hz;研究区盒_8段地层沉积时期主要发育三角洲前缘亚相,较大规模的2条水下分流河道为其主要微相,一条水下分流河道沿S228—S232—S204—S205—Yq2—S216井呈南东—北西向展布,另一条水下分流河道沿Y218—S222—Y120—S226井近东西向展布。研究结果对研究区下步油气勘探具有指导意义。

Upper Paleozoic He-8 Interval in （;aojiahe Area of Yanchang Exploration Block in the Ordos Basin is characterized by eomplic, ated horizontal distribution of sedimentation system. By using lithologic properties, 90° phase seismic data volume, time-frequency analysis, seismic sedimentology and other techniques, high-frequency isochronous tormation framework has been established on seismic profile. By combining geologic, logging and seis- mic phases, sedimentological interpretation has been performed for fornmtion slices with different frequencies te highlight features of seismic-sedimentation responses of the He-8 Interval to determine patterns in horizontal distri- hution of sedimentary phases in the target formation. Research results show extents of acoustic velocities of sandstone and mudstone in the lte-8 lnterval overlapped on each other significantly. Generally speaking, samtstone has a- coustic velocity slightly higher than that of nmdstone, and porosity has significant impacts on velocities of P-waves; Formatinn in the lie-8 Inter＇,＇al is subject to intense impacts of seismie reflection waves fi＇om coal layers in Shanxi Fornmtion with el＇feetive seismic frequencies at 40-lOOHz; He-8 Interval in the concerned area has delta frent sub -fueies developed during sedimentation. Two undenvuter distributary channel with relative large scales can he con- sidered as the dominant micro-facies. One underwater distributary channel distributed in SE-NW ahmg the Well S228--S232--S204--S205--Yq2--S216, whereas the other underwater distrlbutary channel distributed in approx- imately cast-west direction along the Well Y218 --S222--Y120-S226. Relevant researches may play vital role in further oil/gas exploration operations in the concerned area.