海拉尔盆地巴彦呼舒凹陷南屯组沉积相特征研究

Sedimentary Facies Characteristics of Nantun Formation in Bayanhushu Sag in Hailaer Basin

为了促进对巴彦呼舒凹陷南屯组的勘探,开展了该区域沉积相精细研究。根据岩心观测资料、录井数据、测井曲线和地震等资料,发现南屯组基本发育为扇三角洲、湖泊相、辫状河三角洲、水下扇等沉积相,其中湖泊相为主要沉积相。根据巴彦呼舒凹陷南屯组沉积体系的平面分布,扇三角洲沉积体系和水下扇沉积体系主要发育在凹陷西部陡坡带近控盆断层附近;东部缓坡带主要发育辫状河三角洲沉积体系,而湖泊体系的滨浅湖亚相沉积为主要发育;湖泊体系的深湖—较深湖和浅湖亚相发育在中部深凹带。而基本处于断陷湖盆的扩张发展期的南屯组,水域范围逐渐扩张,沉积中心渐渐向盆地中心迁移,形成了南屯组扇三角洲—辫状河三角洲—湖泊的沉积模式。

In order to promote the favorable exploration area of Nantun Formation in Bayanhushu Depression, a detailed study of sedimentary facies in this area has been carried out. According to core observation data, logging data, logging curves and seismic data, it is found that Nantun Formation is basically developed into fan delta, lacustrine facies, braided river delta, underwater fan and other sedimentary facies, of which lacustrine facies is the main sedimentary facies. According to the plane distribution of Nantun Formation sedimentary system in Bayanhushu Depression, fan delta sedimentary system and underwater fan sedimentary system are mainly developed near basin-controlling faults in the steep slope zone of the western part of the depression. Braided river delta sedimentary system is mainly developed in the gentle slope zone of eastern part, and shore-shallow lake subfacies of the lake system is mainly developed. The deep lake deep lake and shallow lake subfacies are developed in the central deep concave belt. However, Nantun Formation, which is basically in the stage of expansion and development of rift lake basin, has gradually expanded its water area. It gradually moved its sedimentary center to the center of the basin, forming a sedimentary model of fan delta, braided River Delta and lake in Nantun Formation.