丽水—椒江凹陷明月峰组多因素综合取证沉积体系分析

ANALYSIS OF DEPOSITIONAL SYSTEMS OF MINGYUEFENG FORMATION IN THE LISHUI-JIAOJIANG SAG BASED ON COMPREHENSIVE MULTIPLE-FACTOR STUDIES

通过对丽水—椒江凹陷古近系明月峰组的多种单因素沉积学分析要素——岩心相、测井相、地震属性和地震相、古生物相、有机地化与岩石地化(颜色)、古地貌与构造等的详细研究,系统阐明了各沉积学分析要素的展布规律及空间配置关系。多种单因素沉积学分析要素综合取证,相互补充,相互佐证,有效地对研究区的沉积体系类型、空间配置关系进行了客观分析与评价。研究认为,丽水—椒江凹陷古近系明月峰组发育三角洲体系、扇三角洲体系、重力流体系及海洋体系等4种主要的沉积体系。在较强断裂活动发育的东缘陡坡区域以扇三角洲发育为主;而在西缘缓坡区域主要发育三角洲及受次级断层控制的滑塌重力流。研究证明"多因素综合取证分析"方法在沉积体系研究中十分奏效。

The Lishui-Jiaojiang Sag is a typical fault basin in China with great oil potential. Multiple factors, such as core facies, logging facies, seismic attributes, seismic facies, biofacies, organic geo- chemistry, rock color, paleogeomorphology and structures, are studied in details in this paper for the Paleogene Mingyuefeng Formation in the Lishui-Jiaojiang Sag. The spatial distribution pattern of these factors is systematically analyzed to decipher the depositional systems of the sag. There are four types of depositional systems in the Paleogene Mingyuefeng Formation in the sag, i. e. , fan delta sys- tem, delta system, sea system and gravity flow system. The fan delta system is developed in the east on steep hills under the control of syndepositionaI faults, the delta system developed in the west on gentle slope, and the gravity flow system deposited under the control of intrabasinal secondary faults. The comprehensive analysis of multiple factors is proven effective for the depositional system analysis.