全波形反演(FWI)是一种较为精确的速度建模方法,但是在缺少低频和背景速度场不准确的情况下,容易引起周波跳跃现象.为了快速构建三维背景速度模型,提出了一种新的平面波编码策略,即构建新的平面波形态——锥面波,通过控制射线参数,实现多尺度锥面波编码全波形反演方法(CFWI),达到反演背景速度模型的目的.通过动态锥面波编码策略,仅用少量的平面波,就可以实现背景速度场的建立,大大降低了反演的计算量.将动态锥面波反演方法应用于三维洼陷和逆冲速度模型测试,结合多震源的FWI(MFWI),对于较差的初始模型和不含低频地震数据,能够准确地反演出速度模型.

东濮凹陷上古生界地层油气显示活跃,烃源条件较好,分布范围较广,特别是近年在文留、胡庆地区相继发现自生自储油气藏,展示了上古生界良好的勘探前景.目前上古生界油气勘探还未形成规模储量,尤其是有效储层的地震预测是上古生界勘探的卡脖子技术之一.文中以胡庆地区上古生界储层为例,首先,通过针对性资料处理提升古生界地震资料品质;然后,利用钻井试油结果、精细岩石物理分析与正演模拟,建立上古生界甜点储层识别标准及地震响应特征;最后,采用"分频振幅描河道、联合反演找砂体、频率属性检油气"等递进式技术对甜点砂岩进行预测.甜点砂岩预测结果与钻井资料吻合率达80％以上.

银额盆地拐子湖凹陷沙漠探区特殊的地形、地貌条件对地震资料的激发和接受产生不利的影响,其表层被巨厚且松散的沙土覆盖,沙丘厚度在50～100 m间.在该区开展可控震源采集时,受可控震源机械特征和近地表结构双重影响,在近道范围内,形成"黑三角"干扰,导致地震记录信噪比低."黑三角"干扰具有能量强、频带宽、分布广、形态差异大等特征,在共炮点域、共检波点域等单一排列内,无法准确统计其振幅强度,导致压制"黑三角"噪声后残留噪声过多,为此提出先按照共炮—偏移距域进行数据重排,然后进行去噪处理的思路,基于银额盆地拐子湖地区的实际可控震源资料应用,验证了该方法在有效压制"黑三角"的同时,能有效保护近道反射信号,特别是深层弱反射信息,也验证了该方法在提高资料信噪比上的有效性.

川东北普光地区长兴组生物礁具备广阔的勘探潜力.文中对比了普光和元坝地区生物礁的生长模式,分析了生物礁及储层的地质特征,总结了礁相白云岩储层的纵横向分布规律.在此基础上,利用测井资料、地震资料,进行生物礁模型地震正演,确定生物礁及储层的地震相识别模式;采用古地貌分析确定储层发育的有利沉积相带,并通过沉积相带的展布和适宜的时窗选取规避不利岩性(泥灰岩)的干扰,再使用相面法、属性分析、波阻抗反演对有效储层进行精细预测,建立了一套适用于普光地区的生物礁储层地震预测方法,定量预测了普光地区长兴组生物礁储层的分布,认为生物礁储层垂向上主要发育于礁盖,横向上主要分布在台地边缘的狭窄条带上.预测结果与钻井资料、礁相储层分布规律相符,证明了方法的有效性.

Compared with the conventional migration method, least-squares reverse time migration (LSRTM) has a lot of advantages, such as higher imaging resolution, amplitude preservation and amplitude balance and so on. But, the L2 norm based LSRTM algorithm is very sensitive to noise, especially when the data contains outliers. Compared to L2 norm, Student’s t distribution has better robustness. We extend the Student's t distribution to the LSRTM algorithm. In addition, multi-sources inversion is an effective way to reduce the computational cost. However, it often generates crosstalk noise. In this paper, we use L1 norm sparse regularization constraints with K-SVD dictionary learning to suppress the crosstalk noise caused by phase encoding. Theoretical models and field data processing verify the effectiveness of the algorithm and suitability for complex models. Presentation Date: Tuesday, September 17, 2019 Session Start Time: 1:50 PM Presentation Start Time: 3:30 PM Location: Poster Station 10 Presentation Type: Poster

Dongpu Depression is geologically characterized by deeply-buried targets, complex fracture systems and thin beds. In order to accurately depict complex subsurface fracture system, we have conducted prestack migration imaging approach including prestack data regularization, high density automatic velocity picking, anisotropic migration and curved ray migration etc. Based on high density 3D seismic data, this approach improves greatly 3D seismic data imaging, and provides reliable final results for future exploration and development.

东濮凹陷的主要地震、地质特点是目的层埋藏深、断裂体系复杂、储集层单层厚度薄.为了提高勘探、开发效益,精确刻画地下复杂断裂体系,结合东濮高精度三维地震资料的特点,开展了叠前数据规则化、高密度自动速度拾取、各向异性偏移和弯曲射线偏移等技术研究,形成了一套适用于东濮凹陷复杂断块区的高精度三维地震资料叠前偏移关键技术,有效地提高了高精度三维地震资料的品质和成像精度,为勘探、开发提供了可靠的地震成果资料.

The features of Dongpu depression in Zhongyuan Oilfield include complex faults,many faulted blocks,multiple sets of source-reservoir-seal assemblages.It is difficult for post-stack migration to get perfect migration imaging effect in complex faulted blocks.However,pre-stack migration can improve the imaging effect.An effective Optimized Method for obtaining migration velocity field for pre-stack time migration is presented,which is based on velocity iteration and constrained by geological information.The method can improve accuracy of migration velocity.Through analyzing four key parameters of pre-stack time migration such as migration aperture,maximum migration angle,ray trace and anti-aliased,some parameter value is proposed,which is effective for the seismic data in Dongpu depression.Consequently,testing workload of processing procedure and blindness of parameter test are decreased so as to increase processing efficiency.Through pre-stack time migration,imaging accuracy in complex faulted blocks is improved,the positions of faults can be accurately ascertained,the relationships among faulted blocks are clarified,which are highly accorded with well data.

有限差分法是求波动方程数值解的一种常用方法,但常规的有限差分法难以克服数值频散的干扰.在总结、分析前人工作的基础上,本文对有关技术做了整合和扩展,形成了有限差分的优化算法,主要内容包括高阶有限差分、优化差分参数和通量校正传输(FCT)技术.与常规方法相比,本文方法既提高了波动方程正演的精度又减少了计算量,可广泛用于起伏地形和复杂地下地质构造的波场模拟和分析.通过对煤层模型和BM工区进行正演模拟,验证了本文方法的有效性.

针对东濮凹陷复杂断块油气田的特点,在马厂地区三维老资料连片处理中,应用了三维叠前时间偏移处理技术,提高了地震资料的成像精度.在断块小而多的破碎带,使用该技术效果尤其明显,剖面上断裂系统结构清楚,断点可靠,和井资料吻合程度高,为定向井的井位设计提供了可靠的地震资料.