海底滑坡对天然气水合物和游离气分布及富集的影响  

The influence of submarine landslides on the distribution and enrichment of gas hydrate and free gas

作　　者：周吉林 王秀娟 朱振宇[6] 靳佳澎 宋海斌 苏丕波[8] 钱进[1,2] 张广旭[1,2] ZHOU JiLin;WANG XiuJuan;ZHU ZhenYu;JIN JiaPeng;SONG HaiBin;SU PiBo;QIAN Jin;ZHANG GuangXu(Key Laboratory of Marine Geology and Environment,Institute of Oceanology,Institute of Oceanology,Chinese Academy of Sciences,Qingdao Shandong 266071,China;Pilot National Laboratory for Marine Science and Technology(Qingdao),Laboratory for Marine Mineral Resources,Qingdao Shandong 266237,China;Southern Marine Science and Engineering Guangdong Laboratory(Guangzhou),Guangzhou 511458,China;University of Chinese Academy of Sciences,Beijing 100049,China;Key Lab of Submarine Geosciences and Prospecting Techniques,MOE and College of Marine Geosciences,Ocean University of China,Qingdao Shandong 266100,China;CNOOC Research Institute Co.,Ltd.,Beijing 100027,China;School of Ocean and Earth Science,Tongji University,Shanghai 200092,China;Guangzhou Marine Geological Survey,MNR,Guangzhou 510760,China)

机构地区：[1]中国科学院海洋研究所海洋地质与环境重点实验室,山东青岛266071 [2]青岛海洋科学与技术试点国家实验室,海洋矿产资源评价与探测技术功能实验室,山东青岛266237 [3]南方海洋科学与工程广东省实验室(广州),广州511458 [4]中国科学院大学,北京100049 [5]中国海洋大学,海底科学与探测技术教育部重点实验室,山东青岛266100 [6]中海油研究总院,北京100027 [7]同济大学海洋与地球科学学院,上海200092 [8]广州海洋地质调查局,广州510760

出　　处：《地球物理学报》2022年第9期3674-3689,共16页Chinese Journal of Geophysics

基　　金：南方海洋科学与工程广东省实验室(广州)人才团队引进重大专项(GML2019ZD0104);青岛海洋科学与技术试点国家实验室山东省专项经费(2021QNLM020002);国家自然科学基金(41976077)资助。

摘　　要：三维地震和随钻测井数据表明在珠江口盆地南部发育了海底滑坡、天然气水合物和游离气,是研究海底滑坡对天然气水合物和游离气分布与富集影响的典型区域.本文基于有效介质模型与阿尔奇方程计算了饱和水层的纵波速度和电阻率,并与实测的纵波速度和电阻率对比,识别了天然气水合物层和多个游离气层.结合三维地震数据的相干、振幅等属性变化,发现海底滑坡不同位置天然气水合物、游离气和断层的空间分布存在差异.由于海底滑坡侵蚀作用导致天然气水合物稳定带底界下移,当相对富砂储层位于新调整的稳定带底界之上,并且局部发育的断层连通了游离气层时,水合物广泛分布;而稳定带底界下方缺乏断层的区域,游离气缺乏向上运移的有利通道,被圈闭在相对较深的地层,水合物并不发育.该研究为进一步探讨水合物和游离气的分布与海底滑坡作用的关系提供了直接证据,并为水合物与游离气合采目标的探寻提供思路.Submarine landslides,gas hydrate and free gas are identified from the three dimensional(3D)seismic data and logging while drilling(LWD)data in the southern Pearl River Mouth Basin.It is a typical area to study the influence of submarine slides on the distribution and enrichment of gas hydrate and free gas.Based on the effective medium model and Archie equation,the P-wave velocity and resistivity of water-saturated sediments are calculated and compared with the measured P-wave velocity and resistivity from LWD data,and gas hydrate-bearing layer and multiple free gas-bearing layers are identified from the anomalies.The differences of the spatial distributions of gas hydrate,free gas and faults in different submarine landslide zones are shown from the coherence and amplitude attributes generated from 3D seismic data.The base of gas hydrate stability zone(BGHSZ)shifts downward due to seafloor erosion caused by submarine landslides.Gas hydrates are widely distributed if the modified BGHSZ is located beneath the sand-rich sediments and the locally developed faults connect free gas-bearing layers to BGHSZ.However,gas hydrate will not be formed where faults cannot arrive at the BGHSZ and free gas is just trapped in local strata due to the lack of fluid flow conduits.This study provides direct evidence to reveal the relationship between the distributions of gas hydrate,free gas and submarine landslides,and also provides the suggestions to find the joint exploitation target of gas hydrate and free gas in the future.

关 键 词：滑坡 天然气水合物 游离气 断层 珠江口盆地 

分 类 号：P631[天文地球—地质矿产勘探] P738[天文地球—地质学]