基于地震沉积学的含煤岩系沉积相及其演化分析
Analysis on sedimentary facies and its evolution based on seismic sedimentology
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摘要: 为了探究含煤岩系聚煤前后沉积相及其演化特征,运用地震沉积学解释技术,通过基于最小等时单元地层切片的地震属性优选法及单井层序地层的岩性与微相划分标定法,建立了敏感属性与岩性、沉积相的对应关系,对沁水盆地中裕地区山西组2号煤层聚煤前后沉积相及其演化进行了研究。研究结果表明:中期旋回作为该区的最小等时研究单元,以短期旋回作为控制进行切片可以研究四-五级序界面内的沉积现象;均方根振幅属性可以作为沉积相平面展布特征预测的敏感属性;山西组2号煤层聚煤前为下三角洲沉积环境,聚煤后为上三角洲沉积环境,并识别出了分流河道、天然堤、泛滥盆地和泥炭沼泽等沉积微相及其空间分布。Abstract: In order to explore the sedimentary facies and its evolutionary characteristics of coal-bearing formation before and after coal accumulation, the seismic a ttribute optimization based on the minimum isochronal stratigraphic and the lithology and microfacies division of single well sequence stratigraphy were carried out by u sing seismic sedimentology interpretation technique, and the relationship between the sensitive attribute and the lithology and sedimentary facies was established. The se methods and techniques were applied to the study on the sedimentary facies before and after No.2 coal seam accumulation in Shanxi Formation of Zhongyu area in Qinshui Basin. The study results showed that the medium cycle as the minium isochronal strata unit in this region, and the short-cycle can be used as a control to study the deposition phenomenon in the four-fifth order interface. The root mean square amplitude attribute can be used as a sensitive attribute for predicting the sedimentary facies distribution characteristics. The sedimentary environment before accumulation of the No. 2 coal seam in Shanxi Formation was the lower delta sedimentary envir onment, and after accumulation of the No.2 coal seam in Shanxi Formation was the upper delta sedimentary environment. The sedimentary microfacies and their spatial distribution of the diversion channel, natural embankment, flood basin and peat swamp were identified.