石油学报 ›› 2012, Vol. 33 ›› Issue (4): 617-624.DOI: 10.7623/syxb201204011

• 地质勘探 • 上一篇    下一篇

琼东南盆地南部梅山组强振幅体成因及油气地质意义

何云龙 1,2 解习农 1 陆永潮 1 李绪深 3 徐 伟 4 邹卓超 3   

  1. 1 中国地质大学构造与油气资源教育部重点实验室 湖北武汉 430074;2 中国科学院广州地球化学研究所边缘海地质重点实验室 广东广州 510640;3 中海石油有限公司湛江分公司 广东湛江 524057;4 中海油研究总院 北京 100027
  • 收稿日期:2011-11-29 修回日期:2012-04-05 出版日期:2012-07-25 发布日期:2012-08-01
  • 通讯作者: 何云龙
  • 作者简介:何云龙,男,1983年11月生,2009年获得中国地质大学(武汉)硕士学位,现为中国地质大学(武汉)和英国阿伯丁大学联合培养博士研究生,主要从事海洋沉积学及其油气效应研究。
  • 基金资助:

    国家自然科学基金重点项目(No.91028009)、中国科学院边缘海地质重点实验室和广州地球化学研究所开放基金项目(MSGL11-04)、教育部高等学校博士学科点博导类科研基金项目 (20100145110002)与湖北省自然科学基金重点项目(2008CDA095)资助。

Origin of high-amplitude reflections in Meishan Formation of the southern Qiongdongnan Basin and its significance in hydrocarbon exploration

HE Yunlong 1,2 XIE Xinong 1 LU Yongchao 1 LI Xushen 3 XU Wei 4 ZOU Zhuochao 3   

  • Received:2011-11-29 Revised:2012-04-05 Online:2012-07-25 Published:2012-08-01

摘要:

基于高精度三维地震资料,利用等比例方差体切片技术,发现琼东南盆地南部深水区梅山组发育有一系列的强振幅地质体。通过对这些强振幅体的精细研究发现,平面上强振幅地质体的规模大小不等,长度约2~15 km,宽度约500~5000 m,整体走向为近东西向。在强振幅地质体内部发育一系列的小断层系。强振幅体在东西部表现出不同的特征:东部表现为不规则的斑点状;西部表现为条带状。同时,在垂直于其走向的剖面上,强振幅体多表现为“V”或者“U”型的外部形态。这些强振幅地质体主要发育在隆起上的梅山组中,其下往往有断陷期开始发育的隐伏断层,且走向与渐新世末期断层的展布一致。盆地裂后期断层的活化使下伏古近系中的流体向上输导,深部流体沿梅山组内发育的断层系发生水—岩反应和随后可能的流体充注,导致了强振幅地质体的形成。这套强振幅地质体的发现对于琼东南盆地南部的深水油气勘探具有重要的指导作用。

关键词: 南海北部, 琼东南盆地, 深水区;梅山组;断层活化;强振幅地质体

Abstract:

ed on 3D high-resolution seismic data, a series of the high-amplitude reflections (HARs) were discovered in Meishan Formation in deepwater areas of the southern Qiongdongnan Basin using an isometric variance slice technique. The detailed observation of these HARs revealed that the generally E-W oriented HARs have variable scales, being 2-15km in length and 500-5000m in width. Small-scale faults are well developed within the HARs. Furthermore, the HARs show various features in different parts of the study area, for instance, they come in an irregular spotted shape in the east but stripped shape in the west. In sections perpendicular to the strike, the HARs are generally V-shaped or U-shaped by appearances and develop mainly on the uplifted Meishan Formation, beneath which there often exist buried faults formed during the rift-subsidence stage and having a strike consistent with the extension of terminal Oligocene faults. Therefore, the origin of HARs was attributed to the fault activation after the rifting of the basin, which resulted in an upward migration of fluids from underlying Paleogene strata, a water-rock interaction of deep fluids along the fault system developed within Meishan Formation, and probably a fluid charge thereafter. The discovery of the HARs in the study area is of directive importance in hydrocarbon exploration in deepwater areas of Qiongdongnan Basin.

Key words: northern South China Sea, Qiongdongnan Basin, deepwater area, Meishan Formation, fault activation, high-amplitude reflection