摘要
为了分析观测系统炮道密度退化对目的层成像的影响,在保持偏移距和方位角分布规律前提下,对中国西部GSM地区高密度三维地震观测系统采用抽稀炮排、道距和炮距的方式使炮道密度退化,得到相同面元大小不同炮道密度A、B、C和D四套观测系统,对抽稀的资料进行分别处理,基于河道砂体叠置模式正演基础上,通过沿层提取相干和均方根等属性切片对川中侏罗统沙溪庙组河道砂体刻画和断层断距识别能力上进行实验对比,以指导后期针对该目的层的采集工程技术设计。通过分析得到以下认识:①针对大中型河道,观测系统A、B、C和D与高密度识别能力相当。②针对小型河道,观测系统A、B、C平面上能识别一部分小型河道,且随着炮道密度降低到一定程度,剖面河道亮点减弱,观测系统D在剖面上无法识别河道亮点。③高密度观测系统断层平面展布最为清晰,观测系统A、B、C和D断层平面展布大的地质规律与高密度数据相当,但细节上存在一定损失。④当川中沙溪庙组河道宽度约为55 m,断层断距约为6 m,薄砂体厚度约为6 m时,可采用高密度观测系统;当其河道宽度大于74 m,断层断距大于12,薄砂体厚度大于10 m时,可采用A、B、C观测系统。
In order to analyze the impact of the shot channel density degradation of the observation system on the imaging of the target layer,under the premise of maintaining the offset and azimuth angle distribution rules,this paper uses thinning shot platoons,track distances and shot distances for the high-density 3D seismic observation system in the GSM area of western China to degrade the shot channel density,four sets of observation systems A,B,C and D of the same bin size and different shot channel density are obtained,and the thinned data are processed separately.On the basis of the forward modeling of the channel sand body superimposition model,through the extraction of coherence and root mean square and other attribute slices along the layer,the sand body description and fault distance identification ability of the Jurassic Shaximiao Formation in Central Sichuan are compared experimentally in order to guide the later design of the acquisition engineering technology for the target layer.Through the comprehensive analysis,the following understandings are obtained.(1)For large and medium-sized rivers,the observation systems A,B,C and D are equivalent to high-density recognition capabilities.(2)For small rivers,observation systems A,B and C can identify some small rivers on the plane,and as the shot channel density decreases to a certain extent,the bright spots of the channel in the profile weaken,and the observation system D cannot identify the bright spots of the river channel on the profile.(3)The high-density observation system has the clearest fault plane distribution.The large-scale geological regularity of the observation systems A,B,C and D fault plane distribution is equivalent to the high-density data,but there is a certain loss in details.(4)When the channel width of the Shaximiao Formation in Central Sichuan is about 55m,the fault distance is about 6m,and the thickness of the thin sand body is about 6m,the high-density observation system can be used.As the channel width is greater than 74m,the fault distan
作者
李修明
刘志刚
闫小伟
乔彦国
侯小平
王聪
LI Xiuming;LIU Zhigang;YAN Xiaowei;QIAO Yanguo;HOU Xiaoping;WANG Cong(Southwest Geophysical Research Institute of BGP,CNPC,Chengdu 610084,Sichuan,China)
出处
《矿产与地质》
2022年第3期630-639,共10页
Mineral Resources and Geology
关键词
观测系统
高密度
面元大小
炮道密度
河道砂体
seismic observation system
high density
bin size
shot channel density
channel sand body
