山东埕岛东部东营组三角洲砂体地震预测技术

Application of seismic technology to predicting the delta sand body of Dongying Formation in Chengdao Eastern Slope of Shandong Province

山东埕岛地区东营组是胜利油田近年来的一个勘探热点地区,资源潜力巨大。其主要发育河流和三角洲沉积体系,但砂体地震反射特征复杂,横向变化快,储层识别描述难度较大。通过建立全区高分辨率层序地层格架,在等时层序格架的基础上,开展储层描述。湖相沉积与三角洲相沉积在沉积物特征和地震响应上都具有较大差异,通过对已钻井的岩心、测井和录井等资料的分析,结合地震属性和地震相等宏观描述方法,在湖相沉积的背景之下刻画出三角洲的整体展布形态。在此基础上,针对三角洲主体区地震反射较弱、砂泥岩速度差异较小的特点,利用地震波形识别技术,采用6种参数对波形进行描述,得出12种波形分类,分别对应4种主要沉积微相。最终利用神经网络方法在平面上进行沉积微相的识别和刻画,取得了较好的效果。

In recent years, more attentions have been paid to the Dongying Formation of Chengdao area for its tremen-dous exploration potential in Shengli oilfield. The sediments are dominated by fluvial and delta sedimentary system, butthe seismic reflection characteristics of sand bodies are complex; the lateral variation is large; and it is difficult to iden-tify and evaluate the reservoir. To descript the reservoirs more effective, the high resolution sequence stratigraphicframework is established according to the isochronous formation framework. There are distinct differences between thelacustrine deposition and delta deposition in sediment characteristics and seismic response. Based on the cores, geolog-ical and geophysical logging data, and combined with the macroscopic characteristics of seismic attribution and seismicfacies, the general range of delta deposition could be separated approximately from lacustrine deposition. The seismicreflection is relatively weak in delta area and the difference value of seismic velocity between sandstone and mudstoneis small. The technology of waveform analysis integrated with 6 parameters is used to distinguish and describe the typeof waveform, and twelve kinds of seismic waveform which corresponding to 4 primary sedimentary micro-facies are de-termined. At last, the method of neural network is used successfully to identify the sedimentary micro-facies.