琼东南盆地陆坡区地质-地球物理特征分析
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摘要
琼东南盆地陆坡区布格重力异常值均为正异常,磁异常一般是负异常值。重、磁模拟结果推测本区沉积基底主要为火成岩体和古生代变质岩或未变质岩体。地震剖面上可识别七个区域不整合面和七个地震层序,对应的乐东组和莺歌海组、黄流组、梅山组、三亚组、陵水组和崖城组、始新统、古新统等新生代地层总体上呈现西北部厚度大,东南部厚度较薄的特征,并具有典型的下部断陷、断坳沉积和上部广海型披盖沉积这种双层结构。区内的断裂多为古近纪以来就开始发育且长期活动的边界断层,断陷湖盆和沉积凹陷的发育基本上受这些断层的控制。箕状断陷边界断裂上升盘的大型背斜圈闭、断裂坡折带等部位是有利的油气勘探目标,渐新统和中新统是主要勘探目的层。
Bouguer anomaly is all normal gravity and the magnetic anomaly is almost negative signature in the slop of Qiongdongnan Basin. The calculated results of gravity and magnetic analog show that the sedimentary basement of the slop is consisted of the igneous rocks and Paleozoic metamorphic or un-metamorphic deposited rocks. There are 7 regional unconformities and 7 seismic sequences, which can distinguished on the seismic profiles, in this area and the 7 seismic sequences correspond respectively the strata of Leshang Formation and Yinggehai Formation, Huangliu Formations, Meishan Formation, Sanya Formation, Linshui Formation and Yacheng Formation, Eocene and Paleocene. The thickness of the Cenozoic strata in the northwest is totally larger than that in the southeast and the sedimentary layers are characteristics of double-deck construction that is fault-depression with continental and transition sedimentation in the lower and down-warped with mainly marine sedimentation in the upper. The faults in the slop are mainly boundary-faults, which developed from Palaeogene and moved for a long time, so the development of the fault-depressive lake-basins and down-warped basins were basically controlled by these faults. The large anticline traps that located at the upper side of the boundary-faults controlling the semi-grabens, slop-break zone and so on are the beneficial oil-gas targets and Oligocene and Miocene are the main resource strata.
Bouguer anomaly is all normal gravity and the magnetic anomaly is almost negative signature in the slop of Qiongdongnan Basin. The calculated results of gravity and magnetic analog show that the sedimentary basement of the slop is consisted of the igneous rocks and Paleozoic metamorphic or un-metamorphic deposited rocks. There are 7 regional unconformities and 7 seismic sequences, which can distinguished on the seismic profiles, in this area and the 7 seismic sequences correspond respectively the strata of Leshang Formation and Yinggehai Formation, Huangliu Formations, Meishan Formation, Sanya Formation, Linshui Formation and Yacheng Formation, Eocene and Paleocene. The thickness of the Cenozoic strata in the northwest is totally larger than that in the southeast and the sedimentary layers are characteristics of double-deck construction that is fault-depression with continental and transition sedimentation in the lower and down-warped with mainly marine sedimentation in the upper. The faults in the slop are mainly boundary-faults, which developed from Palaeogene and moved for a long time, so the development of the fault-depressive lake-basins and down-warped basins were basically controlled by these faults. The large anticline traps that located at the upper side of the boundary-faults controlling the semi-grabens, slop-break zone and so on are the beneficial oil-gas targets and Oligocene and Miocene are the main resource strata.
引文
龚再升，王善书，毛希森等．1987．沿海大陆架及毗邻海域油气区．中国石油地质志(卷十六)．北京：石油工业出版社
黄保家．1999．琼东南盆地天然气潜力及有利勘探方向．天然气工业，19(1)
刘铁树，何仕斌．2001．南海北部陆缘盆地深水区油气勘探前景．中国海上油气(地质)，15(3)
李家彪，高抒主编．2003．中国边缘海岩石层结构与动力过程．北京：海洋出版社
王根发，吴冲龙，周江羽等．1998．琼东南盆地第三系层序地层分析(第20卷)．石油实验．北京：地质出版社
肖军，王华，陆永潮等．2003．琼东南盆地构造坡折带特征及其对沉积的控制作用．海洋地质与第四纪地质，23(3)
Gardener M H, Borer J M. 2000. Submarine Channel Architecture Along a Slope to Basin Profile, Brushy Canyon Formation, West Texas. In Bouma A H, Stone C G, Eds. Fine-grained turbidite systems. AAPG Memoir 72/SEPM special Publication 68,195～214
黄保家．1999．琼东南盆地天然气潜力及有利勘探方向．天然气工业，19(1)
刘铁树，何仕斌．2001．南海北部陆缘盆地深水区油气勘探前景．中国海上油气(地质)，15(3)
李家彪，高抒主编．2003．中国边缘海岩石层结构与动力过程．北京：海洋出版社
王根发，吴冲龙，周江羽等．1998．琼东南盆地第三系层序地层分析(第20卷)．石油实验．北京：地质出版社
肖军，王华，陆永潮等．2003．琼东南盆地构造坡折带特征及其对沉积的控制作用．海洋地质与第四纪地质，23(3)
Gardener M H, Borer J M. 2000. Submarine Channel Architecture Along a Slope to Basin Profile, Brushy Canyon Formation, West Texas. In Bouma A H, Stone C G, Eds. Fine-grained turbidite systems. AAPG Memoir 72/SEPM special Publication 68,195～214
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