模型法自适应层间多次波压制技术应用研究——以塔里木盆地玉北资料为例
Application of an internal multiples suppression technique combined with modeling method and adaptive matching subtraction:A case study of the Yubei area in the Tarim Basin
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摘要: 在塔里木盆地勘探程度较低的探区,地震地质条件复杂,多次波发育广泛,特别是受古生界膏岩等强反射界面产生的层间多次波影响,破坏了奥陶系地层真实信息的成像,导致奥陶系碳酸盐岩裂缝孔洞型储层成像不清晰,影响了地层解释。精确对玉北地区层间多次波预测及压制是多次波处理的难题,制约了该区油气勘探部署。常规的层间多次波预测每个反射界面产生的多次波,其运算量大且效果不理想。为此,提出模型法自适应层间多次波压制技术,从层间多次波预测原理出发,利用模型正演结果,将产生多次波的主要反射界面作为模型层,采用逐层预测和压制的思路,最后采用自适应匹配相减技术进行压制。实际资料处理结果表明,本文方法能够有效预测和压制有影响的层间多次波,消除多次波干涉效应,解决了穿层现象及平层产状问题,提高了地层构造、断裂和裂缝孔洞型储层成像精度。Abstract: Areas with low exploration degrees in the Tarim Basin exhibit intricate seismic-geologic conditions and extensively developed multiples.The internal multiples generated by strong reflection interfaces involving Paleozoic gypsum rocks undermine the imaging of the Ordovician stratigraphic information,resulting in vague images for Ordovician fractured-vuggy carbonate reservoirs and thus affecting stratigraphic interpretation.Accurate prediction and suppression of internal multiples in the Yubei area is challenging,thus restricting the deployment of oil and gas exploration in the area.The conventional prediction method for internal multiples is computationally intensive and ineffective.Hence,this study proposed an internal multiples suppression technique combined with the modeling method and adaptive matching subtraction.Based on the principles of internal multiples prediction and the forward modeling results,the proposed technique takes the main reflection interfaces generating internal multiples as the model layers and follows the approach of layer-by-layer prediction and suppression.Finally,it employs adaptive matching subtraction for the suppression of internal multiples.As demonstrated by the processing results of actual data,the proposed technique can effectively predict and suppress the dominant internal multiples to eliminate their interference effects.It solves the problems of layer-crossing phenomenon and flat formation occurrence,improving the imaging accuracy of formation structures,faults,and fractured-vuggy reservoirs.
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