| 琼东南盆地陵水区中央峡谷水道沉积数值模拟 |
| |
| 引用本文： | 汪新光,张辉,陈之贺,田冬梅,李文睿,张冬月,曹立成.琼东南盆地陵水区中央峡谷水道沉积数值模拟[J].地质科技通报,2021,40(5):42-53. |
| |
| 作者姓名： | 汪新光 张辉 陈之贺 田冬梅 李文睿 张冬月 曹立成 |
| |
| 基金项目： | 青岛海洋科学与技术试点国家实验室开放基金资助项目MMRKF201801中海油有限公司综合科研项目YXKY-2019-ZJ-02 |
| |
| 摘 要： | 深水峡谷是当今海洋油气勘探领域的研究热点。南海西北部琼东南盆地的中央峡谷已部署了多口深水钻井来勘探沉积充填的岩性油气藏，然而，由于这些探井数量相对有限、井间距离大以及地震资料分辨率较低，峡谷内砂体的叠复关系、边界接触关系以及沉积演化等问题尚不清楚，严重制约着储层空间分布与储层物性的精细刻画。对琼东南盆地陵水区中央峡谷开展了沉积数值模拟研究，根据研究区具体地质背景建立了地质模型和数学模型，通过流体动力学软件ANSYS FLUENT正演模拟了多个沉积期次和多套砂组在不同初始条件（如物源和入流速度）下的浊流沉积几何形态，包括砂体平面分布特征和隔夹层分布特征。模拟结果表明:峡谷平直段内，浊流受底床摩擦力的持续影响，流速降低且湍流强度减弱，使得较粗颗粒可沉降于底床，细颗粒可随浊流头部涡流悬浮；峡谷狭窄段内，浊流头部的湍流较强，侵蚀峡谷壁并使峡谷走向发生偏移，悬浮颗粒受离心力作用形成溢岸沉积；峡谷内砂体展布具有垂向分异性，砂体内部泥岩以夹层为主，厚度一般较小且横向连续性差。与现有地震、钻井资料的对比分析显示本次数值模拟结果具有有效性。本研究成果揭示了中央峡谷不同沉积期次和不同砂组的沉积水动力学过程，进而预测了砂体的空间展布特征，为储层物性预测提供了坚实支撑。
|
| 关 键 词： | 琼东南盆地 陵水区 中央峡谷 数值模拟 沉积水动力学 |
| 收稿时间： | 2020-11-03 |
Numerical simulation of sedimentation in the Central Canyon of Lingshui area,Qiongdongnan Basin |
| |
| Abstract: | Deepwater canyon is now the focus of the research field of offshore oil and gas exploration.In the Qiongdongnan Basin of the northwestern South China Sea, several deepwater exploration boreholes have been deployed in the Central Canyon to reveal the lithologic hydrocarbon reservoir of sediment infill therein.However, due to the relatively limited number of these boreholes, the large distance between each borehole, as well as the low resolution of seismic data, the issues regarding the superposition relationship between different sandstone bodies within the canyon, their contact relationship with boundaries, and sedimentary evolution remain poorly understood, which severely hinder the delicate characterization of reservoir physical properties.This study investigates the Lingshui area of the Central Canyon from the perspective of numerical simulation of sedimentation.Geological and mathematical models are established based on the specific geological observations.The hydrodynamic simulation software ANSYS FLUENT is used for the forward modeling of multiple sedimentary stages and sandstone bodies with different initial conditions (e.g., provenance and inlet velocity) to reveal the geometry of modeled turbidite sedimentation, including the horizontal and vertical distribution patterns of sandstone bodies.The simulation results show that: Within the straight section of the canyon, the flow rate and intensity of the turbidity current gradually decrease due to the effect of substrate friction; Relatively coarse and fine particles can be deposited on the substrate and suspended along with the vortex at the head of the turbidity flow, respectively; Within the narrow section of the canyon, the turbulence of the head of the turbidity flow is strong enough to erode the canyon wall and also shift the strike of the canyon.Suspended particles can be affected by centrifugation force to form the overflow sedimentation; In addition, the results show a vertical heterogeneity of sandstone bodies distributed within the canyon: sandstone bodies are usually interlayered by mudstone that features a small thickness and poor lateral continuity.A comparison with the available seismic and borehole data shows the validity of the obtained simulation results.This study attempts to reveal the hydrodynamic processes in terms of different sedimentary stages and sandstone bodies, and then to predict the configuration of sandstone bodies that provides a favorable basis for reservoir prediction. |
| |
| Keywords: | |
|
| 点击此处可从《地质科技通报》浏览原始摘要信息 |
|
点击此处可从《地质科技通报》下载全文 |
|
