利用地震信息研究沉积体系平面分布特征——以鄂尔多斯盆地延长探区高家河三维区盒八段为例

Depositional facies mapping based on seismic data: A case study of the 8th member of Shihezi Formation, Gaojiahe 3D block, Yanchang exploration zone, Ordos Basin

赖生华 柳伟明 赵永刚 丁熙

Lai Shenghua Liu Weiming Zhao Yonggang Ding Xi

西安石油大学, 西安 710065 2. 中国石油 长庆油田分公司 第二采气厂, 陕西 榆林 719000

Xi'an Shiyou University, Xi'an, Shaanxi, 710065, China 2. No.2 Gas Production Plant, Changqing Oilfield, PetroChina, Xi'an, Shaanxi 719000, China

以鄂尔多斯盆地延长探区高家河三维区二叠系下石盒子组盒八段为例，阐明了利用地震信息研究沉积体系平面分布特征的方法。研究表明，岩石物性是地震资料进行沉积学解释的基础。基于90°相位地震数据体，利用时频分析技术，分析砂层地震反射频率；结合地震滤波，压制砂层地震干涉作用。地质、测井及地震相结合，对不同主频的地层切片进行沉积学解释，该方法有助于提高预测沉积体系的精度。研究区三角洲前缘亚相是盒八段的主要沉积亚相，其主要沉积微相为具有较大规模的2条分流河道。一条水下分流河道呈南东-北西向，沿S228、S232、S204、S205、Yq2和S216井展布；另一条分流水道近东西向，沿Y218、S222、Y120和S226井分布。这些水下分流水道充填砂体自然伽马曲线呈钟形、齿状钟形或箱形，在地层切片上表现为中、强能量带状反射模式。此外，一较小规模水下分流河道见于研究区西缘S212、Y217、S211、S210、S246及S247井区，在地层切片上表现为中弱能量蠕虫状、小斑块地震反射模式。

Seismic data were applied in the study of sedimentary facies distributions in the 8th member of Shihezi Formation in Gaojiahe 3D block in Yanchang exploration area, the Ordos Basin. Rock properties are the basis for the application of seismic data in sedimentological interpretation. The seismic reflection frequency in sand layers was analyzed using a time-frequency technique and based on 90° phase seismic data body. Seismic wave interfe-rence in sand layers was reduced using filtering techniques. Combining geological, well logging and seismic data, a sedimentological interpretation of strata slices with different principal frequencies was made, which helped improve the accuracy of sedimentary facies prediction. The 8th member of Shihezi Formation is mainly delta front subfacies arising from two large rivers. One underwater distributary channel goes from southeast to northwest along wells S228, S232, S204, S205, Yq2 and S216, and the other goes from east to west along wells Y218, S222, Y120 and S226. The gamma curves of sand bodies in these underwater distributary channels are bell-shaped, dentate-like or box-shaped, and are shown in the stratigraphic section as a medium-strong energy band reflection pattern. In addition, a smaller-scale underwater distributary channel was found along wells S212, Y217, S211, S210, S246 and S247 on the western margin of the study area, and featured a medium to weak energy worm-like and small patch seismic reflection pattern on a stratigraphic section.

国家自然科学基金项目（41372118）及陕西省科技计划项目（2014K10-12）资助。

https://doi.org/10.11781/sysydz201702272