利用三维地震透镜体反射识别C8段河道砂体——鄂尔多斯盆地西南部黄土塬区储层预测实例

发布时间：2018-04-17 21:16

本文选题：储层预测 + 透镜体反射　；参考：《石油地球物理勘探》2017年03期

【摘要】：黄土塬区三维地震资料质量欠佳和砂、泥岩波阻抗相近,导致无论是在常规还是拓频三维地震剖面上都难以识别延长组河道砂岩储层。目标区C8段透镜体在地震剖面上表现为C813底界的波峰同相轴下弯、C812小层对应的波谷加宽或在C81段内部多出一个波峰。与常规三维资料相比,拓频剖面上识别河道砂岩透镜体反射宽度更窄、面积变小,且预测结果与钻井的吻合率并未明显提高,脱离钻井标定更难以确定透镜体反射来自C8段内哪个小层的河道砂体。根据拓频剖面上C8段反射的振幅和波形特征将透镜体反射划分为7类,其中方波有轴、方波谷、圆波谷和圆波谷有轴这四种较发育的透镜体含厚砂层的概率依次减小。延安组煤层产生的多次波是影响C8河道砂岩识别的主要因素之一;某些透镜体反射内并未钻遇砂岩层可能与废弃河道泥质塞或透镜体中心圈定不准等因素有关;部分C8段较厚砂岩未形成透镜体反射可能缘于泥岩中含较多粉砂或钙质从而与砂岩波阻抗十分接近。总之,应用三维地震透镜体反射识别C8河道砂岩储层在目标区水平井开发中发挥了重要作用。
[Abstract]:The quality of 3D seismic data in Loess Plateau is poor, sand and mudstone wave impedance are similar, so it is difficult to identify the channel sandstone reservoir of Yanchang formation in either conventional or frequency-extending 3D seismic profile.On the seismic profile of the target region, the lens of section C _ 8 shows a wave peak of the bottom boundary of C _ 813. The wave trough corresponding to the sublayer C812 is widened or one more wave peak appears inside the section C81.Compared with the conventional 3D data, the reflection width and area of the identification channel sandstone lens are narrower and smaller on the frequency extension profile, and the predicted results do not obviously increase the rate of agreement with the drilling.It is more difficult to determine which small layer of channel sand in C _ 8 section is reflected by lens.According to the amplitude and waveform characteristics of reflection in C _ 8 section, the reflection of lens body is divided into seven categories, in which the probability of having thick sand layer in four kinds of developed lens bodies is reduced in turn, in which the square wave has an axis, a square wave valley, a circular wave valley and a circular wave valley have an axis.The multiple waves produced by Yan'an formation coal seam are one of the main factors that affect the identification of C8 channel sandstone, and the fact that some lens bodies do not drill into sandstone layer in reflection may be related to the abandoned channel muddy plug or the inaccuracy of lens center delineation.Some of the thicker sandstone in the C _ 8 section did not form lens reflection, which may be due to more silt or calcareous content in the mudstone, which is very close to the wave impedance of the sandstone.In conclusion, 3D seismic lens reflection recognition of C _ 8 channel sandstone reservoir plays an important role in horizontal well development in target area.
【作者单位】：西北大学大陆动力学国家重点实验室/地质学系;中国石化华北分公司研究院;
【基金】：国家自然科学基金重大项目“非常规油气勘探与开发地球物理基础理论与研究方法”的课题“中国非常规油气储层特征、分类与典型地质模型建立”(41390451) 中石化华北分公司企业委托项目(G13YTKF-12-ZS-QT-ZJ-008)联合资助
【分类号】：P618.13

【相似文献】