| 中国南海海域北部地区现今地应力实测及综合分析研究 |
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| 引用本文： | 陈群策,范桃园,李绪深,何胜林,张重远,孟文.中国南海海域北部地区现今地应力实测及综合分析研究[J].地球物理学报,2014,57(8):2518-2529. |
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| 作者姓名： | 陈群策 范桃园 李绪深 何胜林 张重远 孟文 |
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| 作者单位： | 1. 国土资源部新构造运动与地质灾害重点实验室, 北京 100081;
2. 中国地质科学院地质力学研究所, 北京 100081;
3. 中海石油(中国)有限公司湛江分公司, 广东 湛江 524057 |
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| 基金项目： | 中国地质调查项目(1212011220122,12120114002401)资助 |
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| 摘 要： | 南海北部区域现今地应力场的状态和分布特征是进行海洋资源开发、地质环境和工程安全评价的主要参考依据，也是地球动力学研究的主要内容之一. 由于受到测量技术水平和自然条件等因素的影响，整个南海海域的地应力研究程度还比较低，有待于对该区域的地应力场的状态和控制因素进行较深入和细致的研究. 原地地应力测量是直接获取地壳浅表层现今主应力大小和方向特征的有效途径，同时利用海上油气田测井FMI资料能够有效地提取地应力信息. 结合区域构造环境，在实测地应力约束条件下，数值模拟方法能够有效地推测区域地应力的状态和分布特征. 在海南省乐东县开展了水压致裂原地地应力测量，测量获得的最大主应力方向区间为NW-NWW向. 根据Byerlee准则判别，钻孔附近的地应力远远小于引起断层活动地应力值的下限，钻孔邻近区域的断层活动性较弱. 对南海北部边缘海盆地有限的FMI测井资料进行地应力解译，获得莺歌海的最大主应力优势方位为NW-NNW向，琼东南的最大主应力优势方位为NWW向. 在对南海海域北部区域的板块构造环境和地球动力学背景分析的基础上，以上述地应力观测数据以及震源机制解资料为约束，对该区域现今地应力场进行了数值模拟分析，模拟结果表明，由于受印度板块、菲律宾板块和欧亚板块不同程度的影响，南海北部区域的地应力分布特征呈现了不同区域分化的趋势. 在靠近台湾岛区域，主要受到菲律宾板块与欧亚板块发生碰撞的影响，最大主应力方向为近E-W向；沿着滨海海岸带向西，由于受到欧亚板块在马尼拉海沟向下俯冲形成的拉伸作用，最大主应力的方向逐渐转换为S-N向、NW向.
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| 关 键 词： | 南海北部 地应力 水压致裂 FMI 有限元模拟 |
| 收稿时间： | 2014-04-04 |
In situ measurements and comprehensive research on the present crustal stress of Northern South China Sea |
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| CHEN Qun-Ce,FAN Tao-Yuan,LI Xu-Shen,HE Sheng-Lin,ZHANG Chong-Yuan,MENG Wen.In situ measurements and comprehensive research on the present crustal stress of Northern South China Sea[J].Chinese Journal of Geophysics,2014,57(8):2518-2529. |
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| Authors: | CHEN Qun-Ce FAN Tao-Yuan LI Xu-Shen HE Sheng-Lin ZHANG Chong-Yuan MENG Wen |
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| Institution: | 1. Key Laboratory of Neotectonic Movement & Geohazard, Ministry of Land and Resources, Beijing 100081, China;
2. Institute of Geomechanics, Chinese Academy of Geological Science, Beijing 100081, China;
3. CNOOC Zhanjiang Branch, Zhanjiang Guangdong 524057, China |
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| Abstract: | It is necessary for developing of ocean resources, safety evaluation of geological environment and engineering to understand the status and distribution of present crustal stress in the northern South China Sea. The nature conditions restrict the research on the crustal stress of the whole South China Sea, whose characters and controlling factors are not clear. In situ stress measurement is a useful way to get the stress magnitude and direction. The stress direction can be got through the logging FMI data in ocean oil field. The numerical modeling can extrapolate the stress status and distribution in the interested area under the constraint of the in situ measured stress, FMI deduced stress and the plate tectonic environment. The west bound of northern South China Sea is Red River Fault-Eastern Vietnam strike slip large Fault which is controlled by the collision of India plate and Euro-Asia plate and the uplift of Tibet. The east bound of northern South China Sea is Manila trench, which have three different tectonic stress sections, plate collision near Taiwan and near Luzon, and extension between Taiwan and Luzon induced by South China Sea subduction under the Philippines plate. The authors measured in situ the magnitude and direction of stress in Ledong county, Hainan province through hydraulic fracturing, where the exposed rock body is intact and the landform is gentle. The measured rock in well is intact and the curve of measured pressure is fit to the standard, which shows that the measured stress is reliable. The optimal direction of measured maximum stress is NW-NWW. According to the Byerlee criteria, the measured stress cannot induce the active fault to be reactivated recently. The logging FMI interpretation of marginal oil basin in the northern South China Sea shows that the optimal direction of maximum principal stress is NW-NNW in Yinggehai basin, and NNW in Qiongdongnan basin. Constrained by the in situ measured stress and the focal mechanism the numerical modeling shows that the crustal stress in northern South China Sea is characterized by the different stress status in different zone due to India plate, Euro-Asia plate and Philippine plate playing different role. In the area near Taiwan the crustal stress is dominated by the collision of Philippe plate and Euro-Asia plate, and the direction of maximum principal stress is E-W. Along marginal northern South China Sea the crustal stress is influenced by extension induced by the Euro-Asia plate subduction under the Philippine plate at the Manila trench, and the maximum principal stress gradually turns to S-N and NW. |
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| Keywords: | Northern South China Sea Crustal stress Hydraulic fracturing FMI FE Modeling |
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