腰英台油田青山口组沉积特征与储层预测

摘要

文中通过沉积相分析、地震属性优选及测井约束反演,分析了腰英台油田青山口组三角洲砂体的展布规律,得出以下认识:①砂泥岩总体呈薄互层分布,有利储集相带为青二段下部的三角洲前缘细-中砂,其次为青一段中部的破坏性三角洲席状浅滩砂,曲流河点坝砂体和决口河道砂体,平面上规模小,孤立分布;②由于泥岩含钙质,导致泥岩与砂岩的速度、自然伽马、电阻率等值接近,除自然电位测井外,其他测井系列对砂岩的识别效果不好,振幅类、波阻抗等地震属性也无法识别砂体;③砂岩发育指数可以较好地反映砂岩发育程度,振幅加速度属性能有效地反映不同微相骨架砂体展布,低加速度属性与井点高砂岩发育指数吻合较好,据此确定了青一段湖泊分布范围,识别出新的朵状腰西三角洲砂体.钻井验证其上发育厚约10m的河口坝和分流河道中-细砂岩,单井产量高于其他地区.%Based on sedimentary facies analysis, seismic attribute optimization and well logging constraint inversion, the distribution of delta sand body of Qingshankou Formation in Yaoyingtai Oilfield is indentified, and conclusions obtained in this paper are as follows: Firstly, Qingshankou Formation is thin sand-mud interbed in general. The most favourable reservoir is grained-middle delta frontsandstone in lower part of the second member of Qingshankou Formation. Relatively favorable reservoirs are destroyed delta front sheet shape sand body, point bar sand body and crevasse channel sand body of the first Member of Qingshankou Formation. Secondly, because mudstone contains calcium, sandstone and mudstone has similar seismic velocity,natural gamma-ray value and resistivity value. The other log data,seismic amplitude and wave impedance attributes cannot be used to identify sandstone effectively except spontaneous potential logs. Lastly, sandstone growth index can effectively indicate the development of sandstone. The acceleration of amplitude is effectual in recognizing and predicting the sand body distribution of different sedimentary microfacies. The lower acceleration of amplitude value is in good agreement with higher sandstone growth index. Thus the ancient lake distribution of the first member of Qingshankou Formation was discriminated,and the lobe shape delta front sand body of the second member of Qingshankou Formation in west Yaoy-ingtai area was identified. The drilling proves that Qingshankou Formation in this area developed grained-middle mouth bar sand body and distributary channel sand body with thickness about 10 meters. An exploration well drilled in this target area gains higher commercial oil output than other areas.