深海水道在盐底辟型微盆地中的发育演化

Development and Evolution of Deep-sea Channels in Salt Diapir Typed Microbasins

穆柏雨 赵晓明 齐昆 刘飞 李发有

MUBoyu ZHAOXiaoming QIKun LIUFei LIFayou

西南石油大学地球科学与技术学院, 四川 成都 610500 天然气地质四川省重点实验室, 四川 成都 610500 中国石化石油勘探开发研究院, 北京 昌平 102206

School of Geoscience and Technology, Southwest Petroleum University, Chengdu, Sichuan 610500, China Sichuan Key Laboratory of Natural Gas Geology, Chengdu, Sichuan 610500, China Petroleum Exploration and Production Research Institute, SINOPEC, Changping, Beijing 102206, China

针对盐底辟型微盆地内深海水道的发育演化特征不明确，阻碍了深海油气勘探开发，增加了深海油气的勘探开发难度等问题。以安哥拉陆缘深水区中新统某盐底辟型微盆地为例，基于三维地震资料，采用RGB三色融合技术，分析了盆地内水道的发育演化特征和演化模式。研究认为，微盆地的构造发育控制着深水水道的发育演化，沿着微盆地短轴方向发育的水道C1、C2和C3主要发育溢出微盆地的模式，而沿着盆地长轴方向发育的水道C4和C5主要发育充填微盆地的模式。水道在微盆地内发生充填还是溢出主要跟盐构造的活动时期与水道形成演化时期的先后关系、水道中重力流的侵蚀能力与盐构造活动速率的相对大小、微盆地的构造发育特征和水道流向与构造走向之间的角度有关。水道C4和C5在重力流的作用下，沿着构造低部位流动，随着可容空间逐渐变大，水道末端逐渐开始朵叶化，形成朵叶沉积。

The unclear development and evolution characteristics of deep-sea channels in salt diapir typed microbasins hinders the exploration and development of deep-sea oil and gas and increases the difficulty of deep-sea oil and gas exploration and development. To solve such problems we made a case study on a Miocene salt diapir typed microbasin in the deep-water area of the continental margin of Angola, based on 3D seismic data and using RGB color blending technique, and analyzed the development and evolution characteristics and evolution model of channels in the basin. The study shows that the structural development of the microbasin controls the development and evolution of the deep-water channel. The channels C1, C2 and C3 developed along the short axis of the microbasin mainly develop the model of overflowing the microbasin, while channels C4 and C5 developed along the long axis of the basin mainly developed the model of filling microbasins. Whether the channel fills or overflows in the microbasin is mainly related to the relationship between the active period of the salt structure and the formation and evolution of the channel, the relative magnitude of the erosion ability of the gravity flow in the channel to the active rate of the salt structure, the structural development characteristics of the microbasin and the angle between channel flow direction and tectonic trend. The channels C4 and C5 flow along the bottom of the structure under the action of gravity flow. With the increase of the accommodation space, the end of the channel gradually begins to lobe and form leaf deposits.

10.11885/j.issn.1674-5086.2024.08.28.05