西湖凹陷平湖组滨海型煤系烃源岩发育环境及其控制因素  

The controlling factors and sedimentary environment for developing coastal coal-bearing source rock of Pinghu Formation in Xihu depression

作　　者：魏恒飞[1,2] 陈践发[1,2] 陈晓东 曹冰 郭望[1,2] 张俊华[1,2] 

机构地区：[1]中国石油大学(北京)油气资源与探测国家重点实验室,北京102249 [2]中国石油大学(北京)地球科学学院,北京102249 [3]中国海洋石油(中国)有限公司上海分公司,上海200030

出　　处：《中国地质》2013年第2期487-497,共11页Geology in China

基　　金：国家重大专项大型油气田及煤层气开发项目(2011ZX05023-001-011)资助

摘　　要：西湖凹陷平湖组是凹陷内油气藏形成的主力源岩之一,其烃源岩岩石学类型主要有泥岩、炭质泥岩和煤,有机质类型为Ⅱ-Ⅲ型,有机质丰度较高,总体为中等—好烃源岩。西湖凹陷平湖组发育的沉积环境主要为海湾、潮汐影响的三角洲、辫状河三角洲及潮坪,而发育烃源岩的沉积环境主要为海湾和潮坪,此时期沉积水体介质条件为咸水—半咸水,在三角洲和潮坪发育的泥炭沼泽中表现为氧化性,海湾环境中表现为弱还原性。平湖组源岩的发育受控于古气候、沉积环境、海平面变化及古构造格局,其中古构造格局控制着烃源岩的发育厚度和位置,海平面变化控制着烃源岩在地层内部的分布特点,古气候为烃源岩的发育提供了良好的物质背景,沉积环境控制着烃源岩的丰度、类型和保存条件。在平湖组烃源岩发育环境及控制因素研究的基础上,建立了平湖组烃源岩发育的沉积模式。The Pinghu Formation is one of the major source rocks for oil and gas reservoirs in Xihu depression. The types of source rocks are mudstone, carbonaceous mudstone and coal, the organic matter type is 1] -III, the organic matter is abundant, and on the whole, the rocks are medium-good source rocks. The Pinghu Formation of X_ihu basin is mainly developed in bay, delta influenced by tide, braided river delta and tidal flat, with source rocks deposited in the bay and tidal flat environment. During the depositional stage of Pinghu Formation, the sedimentary water was brackish-saline, the characteristics were oxidative in peat swamp developed in delta and tidal flat, and low reducing in bay. There were four factors which dominated the development of source rocks in Pinghu Formation： paleo-structure, which determined the thickness and location of sources rocks; sea level, which controlled the distributive characteristics of source rocks within the strata; paleo-climate, which prodded approved material background for the development of source rocks; sedimentary environment, which governed the abundance, types and conservational conditions of source rocks. On the basis of the study of the controlling factors and sedimentary environment responsible for developing source rocks of Pinghu Formation, the authors have established a sedimentary model for developing source rocks in Pinghu Formation.

关 键 词：平湖组 烃源岩 古气候 沉积环境 海平面 古构造格局 

分 类 号：P618.13[天文地球—矿床学]