论文详情
针对断裂复杂、沉积相变化快,含油砂体分布范围小、厚度薄,预测难的问题,将无线电领域的频率域“载波调制”理念引入到地震资料处理中,用基于最大熵(Max Entropy)谱估计的最小二乘上、下三角阵分解(LS-LUD)算法,研发了ButHRS地震高分辨率双向拓频处理技术,将改进型Butterworth带通子波谱的包络作为目标函数,通过L1模计算方法得到谱调制加权因子,将短时窗数据的LS-LUD谱分解得到的振幅包络向改进型Butterworth带通子波谱的包络形态逼近,得到短时窗地震数据高分辨率谱。该技术不但在低频和高频两个方向上拓展了地震频带,有效压制了地震子波旁瓣,而且在提高地震资料分辨率的同时,保持了地震资料的信噪比、相对振幅关系和时频特性,提高了地震资料识别小薄砂体的能力。将该方法应用于乌尔逊断陷铜钵庙断裂带的储层预测,经过三维地震拓频处理,目的层频带拓宽了40Hz(由10～55Hz拓宽到8～95Hz),精细刻画了铜钵庙断裂带南屯组扇三角洲前缘砂体的三维轮廓和有利储层分布,并通过综合分析认为铜钵庙断裂带受东部物源控制,发育扇三角洲—湖底扇—半深湖(深湖)沉积体系。预测结果符合地质认识,与钻井结果吻合度较高。
This work was motivated by the need to overcome the issues related to complex faulting,rapid sedimentary transformation,narrow distribution and low thickness of oil-bearing sand bodies,and the difficulties in their prediction.To overcome these issues,for the first time,the concept of “carrier modulation” in the radio frequency domain was introduced to seismic data processing,and a ButHRS high-resolution seismic bidirectional frequency extension method was developed using the LS-LUD algorithm based on the estimation of the maximum entropy spectrum.In this method,the envelope of the improved Butterworth band signal spectrum is taken as the objective function,and the spectral modulation weighting factor is obtained through the L1-mode calculation method.The amplitude envelope of the LS-LUD spectrum decomposed from short-time window data is approximated to the envelope of the improved Butterworth band signal spectrum,thereby obtaining a high-resolution spectrum for the short duration seismic data.The HRSBFE method not only expands the seismic frequency band in both the low-frequency and high-frequency domains but also effectively suppresses the sub-wave lobe of the seismogram.This allows the signal-to-noise ratio,relative amplitude relationship,and time-frequency characteristics of the seismic data to be maintained,while improving their resolution.This is especially beneficial for identifying small and thin sand bodies.The proposed method was used for reservoir prediction in the Tongbomiao fault zone in the Wuerxun fault depression.The frequency band of the target layer could be widened by 40Hz (from '10~55Hz’ to ‘8~95Hz’) via frequency extension processing of three-dimensional (3D) seismic data.Based on these data,the 3D profile of fan delta front sand bodies and the distribution of favorable reservoirs in the Nantun Formation in the Tongbomiao structural belt could be described.It was found that fan delta-sub-lacustrine fan semi-deep- and deep-lake sedimentary systems developed in the Tongbomiao tectonic belt controlled by the eastern source area.The predicted results were in accordance with the geological trends,and exhibited good consistency with data from drilled cores.
国家重大科技专项“大型油气田及煤层气开发”(2011ZX05001-001-004)和中国石油天然气股份有限公司重大科技专项“大庆油田原油4000万吨持续稳产关键技术研究”(2011E-1202)共同资助。