应用INPEFA技术在源内层系中划分层序和识别高能砂——以川西坳陷新场构造带须五段为例

Sequence Division and Identification of High Energy Sand in Source Strata Based on INPEFA Technology:Taking the Fifth Member of Xujiahe Formation in Xinchang Structural Belt in Western Sichuan Depression as an Example

在缺乏地震资料的情况下,单纯利用测井资料和钻井资料进行层序划分和砂体连井对比,可能出现穿层现象。利用最大熵时频谱预测误差滤波(INPEFA)分析技术,可突出测井曲线包含的地质信息,反映砂体在沉积过程中的韵律变化特征。针对川西坳陷须家河组须五段建立层序地层格架,根据INPEFA曲线的特征,将须五段划分为1个三级层序、3个四级层序和9个五级层序;同时结合粒度中值的测井计算方法,在须五段中识别了5套粒级为中砂的相对高能砂。

Under the premise of lacking seismic data,if only logging data and drilling data are used to perform sequence division and sand body continuous well comparison,layer crossing may occur.The spectral prediction error filtering analysis(INPEFA)technology at the maximum entropy is very effective in highlighting the geological information in the logging curve and reflecting the rhythmic changes of the sand body during deposition.In this paper,a sequence stratigraphic framework is established for the fifth member of Xujiahe Formation in Western Sichuan depression.According to the characteristics of the INPEFA curve,the fifth member of Xujiahe Formation is divided into one grade 3 sequence and three grade 4 sequences and nine grade 5 sequences.At the same time,combined with the logging calculation method of the median particle size,five sets of relatively high-energy sands with medium particle size are identified in the fifth member of Xujiahe Formation.