摘要
以古地貌认识为指导,克服钻井少的特点,应用landmark地震地质解释平台,从平面和剖面两个角度开展了地震相分析,以进一步明确该区远岸湖底扇沉积的地震相特征、扇体的延伸距离及波及范围,为今后该区的井位部署工作提供有力的技术支撑。研究表明,在剖面上,横切物源方向能识别出强振幅、中频、低连续性的杂乱反射结构,代表了水动力不稳定的高能环境,是湖底扇、重力滑动或构造变动的标志之一,而在顺物源方向能识别出规模较小的叠瓦型前积反射构造,前积层倾角十分平缓,代表了该区发育小型沟道;在平面上,提取了均方根振幅、总能量及瞬时频率等地震属性,反映了该区砂体平面上的展布特征及岩性的变化规律,与上述地震剖面特征综合判断,该区沙一下段在张北断层及歧东断层下降盘处发育4个湖底扇体,主要发育中扇辫状沟道及外扇席状砂微相,向西北方向展布,与北部沧县物源砂体交互。
This study is based on previous studies, guided by the analysis of seismic facies and the palaeogeomorphology.For overcoming the characteristics of less drilling, and applying landmark seismic geological interpretation platform, from two perspectives of plane and profile, this paper further clarifies the seismic facies characteristics of sublacustrine fan of farshore gravity current, as well as the extension distance, which can provide strong technical support for future drilling location deployment in the area. The study shows that the direction of cross-section provenance can identify the chaotic reflection structure with strong amplitude, medium frequency and low continuity, which represents the high-energy environment of hydrodynamic instability and is one of the signs of lacustrine fan, gravity slip or tectonic change. The small-scaled imbricated foreset reflecting structure can be identified along the source direction, and the dip angle of the foreset is gently. It shows that the small-scaled channels exist in this area. Seismic attributes such as RMS amplitude, total energy and homeopathic frequency are extracted from the plane, which reflects the distribution characteristics and lithological variation of sand bodies in the area. Based on the above seismic profile characteristics, four underwater fans are identified at the downthrow walls of Zhangbei fault and Qidong fault in the lower part of the first Member of Shehejie Fm.They are mainly mid-fan braided channel deposits and outer-fan sand microfacies, extending northwest toward and interacting with the Cangxian sand bodies in the north provenance.
引文
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