在层序地层学研究中，层序界面的划分是基础和重要的环节，而利用测井资料分析可以进行层序界面划分和进行较长期基准面旋回识别。测井曲线的值是深度的函数，测井曲线的一阶导数表示了曲线变化的趋势和变化的快慢，在某一范围内，当一阶导数呈现符号转换时，相对应的深度点的测井值即为该范围内极大（极小）值；测井曲线的二阶导数则表示曲线的凹凸性，在某一范围内，当二阶导数呈现符号转换时，相对应的深度点代表了测井曲线的拐点，即反映曲线凹凸性变化的转折点，亦即地层的分界面。基于以上特点，提出利用测井曲线拐点进行层序界面划分的原理和方法，并结合岩心和录井资料，对白音查干凹陷达28井腾格尔组不同级次沉积旋回、地层垒积、旋回特征随沉积厚度变化特点和不同级次基准面旋回进行研究，最后得到该地层单井测井层序地层分析结果。

The judgment of sequence surface is an essential and important parts in research of sequence Stratigraphy. Geophysical logging curve reflect the sedimetal change, and the value of geophysical logging curve is a function of depth. The first rank derivative is a reflection of curve change and its rate, at certain range, if the sign of the first rank derivative has changed, the logging value of the correspondence depth point means maximum （minimum） in this range; the second rank derivative is the knaggy property reflection of curve, at certain range, if the sign of the second rank derivative has changed, the correspondence depth point represent the inflexion of geophysical logging curve, it＇s also a turning point of the reflection of knaggy change property of the curve, it is the interface of stratum. At the base of those characteristics, this article put forward a new principal and method to judge interface of stratum and sequence, and also gives the sequence stratigraphy analysis resolute of wall Da28 Tengge＇er member, Baiyingchagan depression after doing research work in analysis of sedimentary cycle in different lever, stratum accumulation, specialty of cycle characteristic change to sediment thickness, and base-lever cycle in different lever.