辫-曲体系的探地雷达相及其定量三维沉积构型研究

The fluvial has always been a hot topic. As a research new areas of fluvial, the architecture element has a significant value to predict favorable oil and tap the remaining oil . The outcrops and modern fluvials are selected as the research object in this project, and intends to combine outcrop survey, GRP and trunch to systematically reseach radar facies and architecture element. We are primarily focus on the following two issues:(1) the radar facies of Toutunhe Formation and Qigu Formation in the southern Junggar Basin, and the internal architecture elements are described of braided-meandering system. (2) the radar facies and internal architecture elements of breaches of braided, meandering, diara, point bar in Burqin County. Eventually the the architecture elements of braided-meandering system are clarified , the relationship between plane and section are established, the mechanisms of braided-meandering system (merge-bifurcation, surface flow- under flow, one way circulation-two way circulation are cleared. The change of hydrodynamic, tomorphology, internal architecture elements of sediment and assemble patterns are made breakthrough. Providing proposals for the geologists, and experience for the geomophologists to study fluvial geomorpholgy.

河流沉积体系历来是国内外研究的热点话题，沉积构型作为河流沉积研究新领域，对预测有利油气储集体和挖潜剩余油具有重要意义。本项目选取古代露头和现代河流为研究对象，拟将沉积观测、探地雷达及探槽相结合，系统开展雷达相、构型等方面的研究。重点研究：（1）准噶尔盆地南缘头屯河组和齐古组露头雷达相，刻画辫-曲体系各沉积单元的内部结构；（2）布尔津县现代辫状河、曲流河段、心滩、边滩的雷达相及其沉积单元的内部结构。最终明确辫-曲体系内部结构，建立平面-剖面构型对应关系，理清辫-曲转换成因机理（河道合并-分岔、表流-底流、单向环流-双向环流），力求突破辫-曲体系在沉积水动力、地形地貌、沉积物内部结构和组合样式等方面的变化。为地质学家预测有利储集体提供依据，为地貌学家研究河流地貌提供经验。

本项目选取古代露头和现代河流为研究对象，拟将沉积观测、探地雷达及探槽相结合，系统开展雷达相、构型等方面的研究。1）凝练出一套多元线性回归预测模型、Hungarian聚类算法及地震多属性拟合含砂/砾率等沉积参数量编图方法，并在新疆油田玛湖、红山嘴地区,青海油田南八仙地区取得良好应用；2）厘清了沙湾凹陷二叠系佳木河组一直备受争议的物源体系具有一源四区的特征，其大陆岛弧环境的构造分异造成沉积体系的的差异；3）通过对西北缘吐孜阿克内沟实地考察，对辫状河的河道、心滩及其垂向演化、横向迁移的沉积构型进行了详细的刻画；4）基于野外露头，结合井下头屯河组研究，建立了曲流河道、点坝、废弃河道的露头（宏观）与岩心（微观）对应关系。进一步明确了受构造影响，导致地形坡度、物源、粒度发生变化，使得曲流带呈现连片向单一曲流河转变，由低弯度向高弯度转变；5）明确了红山嘴地区下侏罗统（八道湾组）发育的扇三角洲在湖进期，其沉积展布具有“大平原、小前缘”与砂体具有“毯式分布”特征；而在湖退期，沉积展布具有“小平原、大前缘”与砂体具有“条带状分布”的特征；中侏罗统（西山窑组）发育的辫状河三角洲沉积展布具有 “水道为主，侧向迁移”与砂体具有“辫状分布”的特征；6）结合现代沉积和古代露头，运用先进的辅助工具（航拍、遥感影像、探地雷达）和数学方法，对点坝砂体的分布和迁移过程进行了表征，精细解剖了扩张型、迁移型、扩张旋转型及迁移旋转型四种点坝的平剖构造，建立了相应的点坝砂体叠迁模式。7）共识别出5种探地雷达相，探地雷达相I：连续、近水平或平行的反射波；探地雷达相II：倾斜的次平行反射波；探地雷达相III：向下凹的反射波；探地雷达相Ⅳ：规模较小、不连续、波形的反射波；探地雷达V相：中等规模、低振幅、垂直拉伸的反射波。