放射性元素含量在民丰洼陷沙一段层序划分中的应用——以F17井为例

Application of radioactive element content in the sequence division of Es_1in Minfeng sag:A case history of Well FF17

放射性元素含量是根据自然伽马能谱测井测量到的铀、钍、钾伽马放射性的混合谱解析出来的数值,该数值真实地反映了泥岩含量的变化。而泥岩含量的旋回间接地反映了海平面的升降变化,钍、钾含量曲线与泥岩含量具有良好的相关性,铀含量与泥岩含量相关性最差,高铀含量段反映良好储集层。对钍、钾、铀数值处理后得到Th/K、U/GR比值曲线,根据放射性元素铀、钍、钾含量以及Th/K、U/GR比值曲线的响应特性,结合GR、CON1、POR等其他常规测井曲线,按其长、短期旋回,将民丰洼陷沙一段地层划分为8个(Es1~1—Es1~8)准层序组,识别出1个最大湖泛面(MFS)。

The radioactive element content is the numerical value from the analysis of the gamma radioactive mixed spectrum of the uranium, thorium and potassium measured by natural gamma-ray spectral logging, the numerical value truly reflect the changes of the mudstone content. The cyclic changes of the mudstone content indirectly reflect the cyclic changes of sea level, the curves of the thorium content and potassium content have a good correlation with the mudstone content. The curve of the uranium content has the worst correlation with the mudstone content, the section of the high uranium content reflects good reservoir. The curves of the Th/K and U/ GR are obtained by processing the values of the uranium, thorium and potassium. Combining with the conventional logging curves such as GR, CON1, POR and others, and according to the response characteristics of the curve of the Th/K,U/GR, the Es, is divided into eight parasequence sets（ES1^1-ES1^8） in the Minfeng subsag in accordance with the long term and short term cycle, and a maximum flooding surfaces （MFS） is recognized.