摘要
廊固凹陷大兴断裂带相继发现兴8、兴9等砾岩油气藏,油气资源丰富,且多数油气藏处于近岸水下扇扇中辫状水道微相,因此对大兴断裂带近岸水下扇的沉积特征进行研究显得尤为重要。综合前人研究成果和廊固凹陷最近获取的岩心、地震、测井等资料,对近岸水下扇进行了沉积微相特征的识别及沉积微相类型的划分,总结了近岸水下扇分布特征,并分别建立了碎屑流及泥石流近岸水下扇沉积模式。碎屑流近岸水下扇在旧州地区发育,扇体表现为厚层砾岩与泥岩的突变接触,沉积物主要是颗粒支撑砾岩,杂基含量很少;而泥石流近岸水下扇在固安地区发育,扇体几乎无水道发育,沉积物主要为杂基支撑砾岩,杂基主要为泥质。碎屑流近岸水下扇识别出扇根主水道、扇根水道间、扇中辫状水道、扇中辫状水道间、扇端席状砂和扇端泥6种沉积微相,其中扇中辫状水道微相是扇中甚至整个碎屑流近岸水下扇的主体,扇端亚相相对不发育。近岸水下扇整体上沿大兴断层呈近北东—南西向展布,在沙三下亚段最为发育。
Conglomerate reservoirs with abundant oii and gas resources have been found in Daxing fault zone successively such as Xing 8 and Xing 9 etc. Most of these reservoirs are mid-fan braided channel of nearshore subaqueous fans. Therefore, it is very important to study the sedimentary characteristics of the nearshore subaqueous fans. Based on the previous research results and the latest core, seismic, well logging and other data obtained in the sag, the sedimentary microfaeies are identified and classified in this paper. The vertical and horizon- tal distributions of the nearshore subaqueous fans are summarized and the depositional models of them are established for debris flow and mud flow, respectively. The debris flow nearshore subaqueous fan is developed in Jiuzhou area with an abrupt contact between the thick conglomerate and mudstone in the fan body. The sediments are mainly composed of particle-supporting conglomerates with little matrix. Whereas, the mud flow nearshore subaqueous fan is found in Gu＇ an area. Few channel exists in the fan and the sediments are mainly matrix -supporting conglomerates with the matrix dominated by mud. The debris flow nearshore subaqueous fan can be classified into six sedimentary mierofacies such as main channel of root fan, interchannel of root fan, braided channel in midfan, braided interchannel in midfan, sheet sand in endfan and mud in endfan, among which the braided channel in midfan is the main body of the midfan and even the debris flow nearshore subaqueous fans. The endfan is relatively undeveloped. The nearshore subaqueous fans are in near NE trending distribution along Daxing fault zone with the lower third member of Shahejie formation being the most developed.
出处
《新疆石油地质》
CAS
CSCD
北大核心
2017年第2期137-143,共7页
Xinjiang Petroleum Geology
基金
中国石油科技重大专项(2014E-3504)
关键词
渤海湾盆地
廊固凹陷
大兴断裂带
沙河街组
近岸水下扇
沉积微相
Bohai Bay basin
Langgu sag
Daxing fault zone
Shahejie formation
nearshore subaqueous fan
sedimentary microfacies
