摘要
海上中深层薄互层岩性油气藏勘探是一大难点问题,中深层的地震资料往往品质较差,分辨率低,且常常存在盖层强反射的遮挡问题,制约单砂体预测研究。为解决此类薄砂层预测难点问题,这里提出了一种面向海上中深层地震强反射干扰背景下的薄弱储层预测方法,从地震资料出发进行两次优化处理,以提高地震对薄层的分辨率,通过子波反褶积对地震资料开展以储层预测为导向的拓频,提高地震对薄层分辨率,再考虑去除盖层强反射的影响,采用匹配追踪算法对地震资料进行分解,通过强反射层频率范围约束原子匹配过程,识别出区域上的强反射层地震信息,从拓频后的地震资料中剥离强反射轴,利用二次优化后的地震资料开展叠前反演预测优质储层分布范围,基于此策略解决复杂中深层储层预测难题。具体介绍了拓频和去强轴二次优化处理的原理,并通过模型正演分析了薄砂层地震响应及盖层强反射轴的形成机理并验证了该方法的可行性。在南海西部某目标区块储层预测应用中,该方法能很好地预测薄砂储层的分布特征,提高了隐蔽型目标层的油气预测精度,为此类中深层强反射干扰背景下隐蔽油气藏的预测提供了一种新的参考,对油气勘探开发具有重要意义。
The mid-deep thin interbedding lithologic oil reservoirs remain one of the challenging targets for offshore exploration.Mid-deep seismic data generally suffer from poor quality,low resolution,and strong reflections from the caprock.For better prediction on such types of reservoirs,a workflow that implements explicitly thin-layer oil prediction in the presence of substantial reflecting interference is proposed in this paper.The workflow applies two optimization processing on seismic data to improve the resolution for the thin sand layer.First,Optimized wavelet deconvolution is performed to broaden the frequency bands of seismic data.The enhanced high frequency may result in better resolution for thin sand layers,whereas the performance is limited on actual seismic data.The matching pursuit algorithm is used to decompose the seismic data to remove the influence of solid reflections the caprock.The strong seismic reflections are identified by the matching pursuit algorithm that is locally constrained by the frequency of strong reflections.The strong reflections can be removed from the seismic data after frequency broadening.Based on the optimized seismic data,pre-stack inversion and reservoir prediction are carried out for complex mid-deep reservoir prediction.This paper introduces the principle of processing of frequency broadening and vital reflections removal.It analyzes the seismic response of thin-sand layers and the formation of strong reflections due to caprock via forward modeling.The proposed techniques are applied to the reservoir prediction on real seismic data from the Western South China Sea.The results suggest that this workflow performs well in predicting the distribution characteristics of thin sand reservoirs and improving the subtle target layer's oil and gas prediction accuracy.The method may provide a new reference for the prediction of subtle oil and gas reservoirs in the presence of strong reflections in mid-deep layers and is of great significance to oil and gas exploration and development.
作者
满建
胡林
隋波
马光克
满勇
MAN Jian;HU Lin;SUI Bo;MA Guangke;MAN Yong(CNOOC China Limited,HaiNan Branch,Haikou 570311,China)
出处
《物探化探计算技术》
CAS
2023年第2期129-137,共9页
Computing Techniques For Geophysical and Geochemical Exploration
基金
中海石油(中国)有限公司科技项目(YXKY-20190ZY-05)。
关键词
海上中深层
拓频
强反射去除
二次优化
地震反演
储层预测
offshore mid-deep layer
frequency broadening
strong reflections removal
quadratic optimization
seismic inversion
reservoir prediction
