红河断裂活动对琼东南盆地环崖南凹陷 构造-沉积-成藏的影响

作    者:王真真,王世朝,李安琪,李 明,李夏露,陈 奎
单    位:中海石油(中国)有限公司湛江分公司
基金项目:本文受国家科技重大专项课题“莺琼盆地高温高压天然气富集规律与勘探开发关键技术”资助
摘    要:
琼东南盆地西部环崖南凹陷的油气勘探亟需寻找接替领域。针对勘探研究中存在的3个地质问题,利用丰富的钻井和地震资料对红河断裂活动特征及其对环崖南凹陷构造-沉积-成藏的影响开展深入分析。认为红河断裂的走滑活动通过F1断层向琼东南盆地西部传递剪切应力,其演化与环崖南凹陷的构造-沉积作用具有良好的时空耦合关系,并控制了环崖南凹陷的油气运移。晚渐新世,红河断裂左行走滑活动,通过F1断层在琼东南盆地西部诱导产生EW向挤压应力和SN向拉张应力,加剧了盆地西部的南北向快速拉张裂陷,形成了崖北凹陷和崖南凹陷两个沉积中心。中中新世—晚中新世,红河断裂处于平静期,受区域右旋张扭应力控制及海南岛物源减少的影响,环崖南凹陷呈现局部隆升,碳酸盐台地发育,梅山组一段及黄流组二段大范围缺失。上新世至今,红河断裂右行走滑活动,通过F1断层在琼东南盆地西部诱导产生SN向挤压应力和EW向拉张应力,对盆地西部的拉张具有约束作用,并造成NEE、NE走向断层受挤压作用而处于封闭状态,NW走向断层受张扭应力作用而处于开启状态。上新世为盆地生排烃高峰期,NW走向断层可有效输导油气,而NEE、NE走向断层的油气输导能力较差,这合理解释了已钻构造的油气发现情况。环崖南凹陷下一步油气勘探应重点围绕NW走向断裂带展开。
关键词:红河断裂; 断层活动; 油气运移; 崖南凹陷; 琼东南盆地; 南海

Strike slip activity of Red River fault and its tectonic-sedimentary response and influence on hydrocarbon accumulation around Ya’nan Sag in the west of Qiongdongnan Basin

Author's Name: WANG Zhenzhen, WANG Shichao, LI Anqi, LI Ming, LI Xialu, CHEN Kui
Institution: 
Abstract:
It is urgent to find replacement fields for oil and gas exploration around Ya’nan Sag in the west of Qiong dongnan Basin. In view of the three geological problems existing in the exploration and research, the characteristics of Red River fault activity and its influence on the structure-sedimentation and hydrocarbon accumulation around Ya’nan Sag are analyzed by using abundant drilling and seismic data. It is considered that the strike slip activity of Red River fault transfers shear stress to the west of Qiongdongnan Basin through Fault F1, and its evolution has a good space-time coupling relationship with the structure-sedimentation around Ya’nan Sag, and controls the oil and gas migration around Ya’nan Sag. In Late Oligocene, the sinistral strike slip activity of Red River fault induced EW trending compressive stress and SN trending tensile stress in the west of Qiongdongnan Basin through Fault F1, resulting in the intense activity of NEE trending strike slip faults and the formation of two sedimentary centers, Yabei Sag and Ya’nan Sag. During the Middle and Late Miocene, the Red River fault was inactive, and under the control of regional dextral tension and torsion stress and the decrease of sedimentary source in Hainan Island, carbonate platform developed at the local uplift around Ya’nan Sag, and the Meishan Formation and Huangliu Formation were absent in wide. Since Pliocene, the dextral strike slip activity of Red River fault has induced SN trending compressive stress and EW trending tensile stress in the west of Qiongdongnan Basin through Fault F1, which has constrained the tension in the west of Qiongdongnan Basin and caused NEE and NE trending faults to be closed by compressive stress and NW trending faults to be open by tensile and torsional stress. The Pliocene is the peak period of hydrocarbon generation and expulsion in the basin. NW trending faults can effectively transport oil and gas, while NEE and NE trending faults have poor oil and gas transportation ability, which reasonably explains the oil and gas discovery in drilled structures. The next step of oil and gas exploration around Ya’nan Sag should focus on NW trending fault zones.
Keywords: Red River fault; fault activity; oil and gas migration; Ya’nan Sag; Qiongdongnan Basin; South China Sea
投稿时间: 2021-03-31  
pdf