游荡型辫状河沉积特征及沉积相模式

Characteristics and Sedimentary Facies Model of Wandering Braided Rivers

王海考 王淼 于忠良 余成林 尹艳树

WANGHaikao WANGMiao YUZhongliang YUChenglin YINYanshu

中国石油冀东油田勘探开发研究院, 河北 唐山 063200 长江大学地球科学学院, 湖北 武汉 430100

Exploration and Development Research Institute, Jidong Oilfield Company, PetroChina, Tangshan, Hebei 063200, China School of Geosciences, Yangtze University, Wuhan, Hubei 430100, China

针对冀东油田高104-5区块馆陶组辫状河模式认识不清、砂体预测不准的问题，开展砂质辫状河河型分类研究。首先，根据区域地质背景、古气候、岩石粒度、层理构造、相序、溢岸、落淤层发育情况以及砂体形态等指标确定研究区为游荡型辫状河。随后，以Miall构型要素分析理论为指导，建立了辫流带、单一辫流带内河道和心滩边界识别标志，实现了研究区游荡型辫状河结构解剖，确定研究区单一辫流带宽度平均1 400.00 m，单一辫流带内心滩平均长度为414.47 m，宽度平均为158.86 m，河道宽度平均53.18 m。心滩长宽比集中在2.0~4.0，心滩宽度与辫状河道宽度比为2.2，为宽坝窄河道辫状河沉积模式。最后采用沉积数值模拟的方法，建立了研究区游荡型辫状河沉积相模式，可为油田开发提供指导。

Aiming at the problem of unclear knowledge and unclear patterns of sandy braided river in Guantao Formation of Block Gao 104-5 in Jidong Oilfield, a classification study of sandy braided rivers was carried out, using criteria including regional geological background, paleoclimate, rock grain size, bedding structure and facies sequence, levee and mud drapes, and sand body morphology. The study area is determined to be a wandering braided river. Then, the architectural element analysis method from Miall is adopted to anatomize the wandering braided river. The two types of identification marks of braided belt boundary and 3 types of identification marks of river channel and mid channel bar are constructed to anatomize the wandering braided channel. The result shows that the scale of the channel belts are about 1 400.00 m wide, the width and length of mid channel bar are about 158.86 m and 414.47 m, respectively; the width of channel is 53.18 m. and the length/width of mid channel is about 2~4; the average width of mid channel bar and channel is 2.2. So the study area is categorized as the wide bar and narrow channel pattern. Finally, using depositional simulation methods, a wandering braided river sedimentary facies model in the study area was established to guide oilfield development.

10.11885/j.issn.1674-5086.2022.01.13.04