海洋二维双船拖缆与宽频带地震采集实验

双船拖缆地震采集可以布设灵活的观测系统,如形成大炮检距、增加覆盖次数、中间激发提供两个方向照明等,进而改善复杂构造的地震成像效果。同时,宽频地震技术日益受到重视,通过大容量宽频震源激发,变深度拖缆接收,并进行数据去鬼波处理,达到拓宽频带的效果。综合双船拖缆与宽频采集的优势所开展的实验表明,成像剖面的浅层分辨率得到提高,中深目标层揭示效果有了改善,该技术在构造成像难点区值得尝试。

KF油田模糊带成因分析及技术对策

Kingfisher油田位于乌干达Albert湖区东南岸,Albert湖区为克拉通之上的大型裂谷盆地。受近岸东西向物源快速沉积等地质因素、采集参数、资料处理等因素影响,油田主体区成像差,地震资料在上新统目的层,存在明显模糊区,地层产状难以刻画,模糊区成像问题制约了中浅部目的层储层预测及表征。为解决模糊带成像问题,针对KF油田,结合地震地质条件,系统开展了模糊带地震波场传播机理分析,模糊带成像主要由于因为高部位自冲沟而下的快速现代沉积,造成边界断层附近浅部地层欠压实,地层速度偏低,这是影响模糊带成因最主要因素。现有资料采集参数主要以勘探评价为主要目的,气枪震源穿透力弱,不利于成像;覆盖次数低,不利于提高信噪比;纵横向采样密度不够,不利于断层成像和油藏描述,难以满足油气田开发需求,是影响模糊带成因次要因素。厘清了影响地震资料品质的因素,提出了改善成像采集和处理对策,为KF油田下一步开发提供了指导依据。

Experiments on excitation and data processing of low-frequency vibroseis in permafrost area of the tibetan plateau

Few seismic exploration work was carried out in Tibetan Plateau due to the characteristics of alpine hypoxia and harsh environmental protection needs.Complex near surface geological conditions,especially the signal shielding and static correction of permafrost make the quality of seismic data is not ideal,the signal to noise ratio(SNR)is low,and deep target horizon imaging is difficult.These data cannot provide high quality information for oil and gas geological survey and structural sedimentary research in the area.To solve the issue of seismic exploration in Tibetan Plateau,this test used low frequency vibroseis wide-line and high-density acquisition scheme.In view of the actual situation of the study area,the terrain,the source and the diff erent observation system were simulated,and the processing technique was adopted to improve the quality of seismic data.Low-frequency components with a minimum of 1.5Hz of vibroseis ensure the deep geological target imaging quality in the area,the seismic profi le wave group is clear,and the SNR is relatively high,which can meet the needs of oil and gas exploration.Seismic data can provide the support for the development of oil and gas survey in the Tibet plateau.

中国深层油气勘探地球物理技术与展望

中国深层油气资源丰富,勘探潜力巨大。深地探测历程和油气勘探实践表明,地球物理技术发挥了极其重要的作用。聚焦深层勘探目的层埋藏深度大、地震能量弱、成像精度低、储层复杂等关键难题,对地震装备、采集、处理、解释和重力-磁法-电法-地震联合勘探开展了科学研究和技术攻关,形成了深层油气勘探地震配套技术。大量实践证明,大吨位宽频可控震源是提高深层信号能量和信噪比的重要装备,"两宽一高"(宽频、宽方位、高密度)地震采集技术是实现深层油气目标勘探的有效手段,深层弱信号处理技术、深层复杂构造成像技术及五维地震解释技术是解决深层勘探的关键处理解释技术,重力、磁法、电法、地震等多物理场联合是降低深层油气勘探开发风险的有效途径。深层油气勘探地震配套技术已在塔里木盆地、四川盆地等多个盆地成功应用,支撑了塔里木盆地富满地区发现10亿吨级大油田、四川盆地川中地区北斜坡发现蓬莱万亿立方米大气区等重大突破。面向深层油气勘探当前和未来地质研究、勘探发现和安全高效钻井工程的需求,建议在基础理论、采集、处理、目标识别、井中地震与非地震5个方面开展持续攻关,积极拓展深层—超深层油气勘探领域,同时开展以深海海底节点(OBN)为核心的海洋地球物理勘探技术研发与现场实验,为深海勘探做好技术储备。