频谱分解技术定量求取储层厚度方法研究

The Application of Spectral Decomposition in Quantitative Calculation of the Reservoir Thickness

老油田的勘探已经进入到以薄层为主的隐蔽油藏勘探阶段,厚度作为储层的主要特征参数,反映了物性、物源方向、沉积环境、沉积背景等。因此,储层厚度的精确求取关系到油藏勘探的成败。有关薄储层厚度的计算已有不少成熟的方法,如反射振幅法、反演法等,这些方法因适应性低或过程复杂,没有形成一种完全有效的厚度求取方法。近几年发展起来的频谱分解技术,是一种无井约束的高分辨率储层预测技术,也是储层厚度求取方法的补充和完善。频谱分解技术根据薄层调谐原理,利用全频段的信息,将地震数据从时间域转换到频率域,突出高频信号,相对提高地震资料的主频,从而提高了对薄储层厚度的识别能力。从基于离散傅里叶变换和小波变换两种原理的频谱分解技术出发,对两种方法处理的结果进行分析,并基于处理得到的不同参数,如调谐频率、最大能量等,提出了三种求取储层厚度的方法,并在实际应用中取得了较好效果。

Exploration of the old oilfield has entered into the stage of subtle reservoir exploration with thin layers mainly.As the characteristic parameters of the reservoirs,the thickness may reflect the physical property,source direction ,sedimentary environment,sedimentary background and other characters of the reservoir.Therefore ,accu- rate calculation of the thickness of reservoirs is vital for affecting the success or failure of the reservoir ex- ploration.There are quite a few mature methods for the thin reservoir thickness calculation,such as reflection amplitude,inversion and so on.But all of them can＇t form a completely effective thickness calculating method because of their poor adaptability or complex process.In recent years,the developing spectral decomposition technique is a kind of well-free reservoir prediction technique with high resolution,and has also been the supplement and perfection to the former methods of the thickness calculation.Based on the principle of thin- layer tuning, spectral decomposition technique can use the full spectrum of information to convert seismic data from time domain to frequency domain.By processing,the high frequency signal of the seismic data can be highlighted ,and the key frequency of the seismic data can be improved.The most important is that the recog- nition ability of the thin reservoir thickness can be enhanced.The base of the technique is two principles ：the discrete Fourier transform and wavelet transform.According to the analysis of the results by the spectral de- composition,frequency,maximum energy and other tuning parameters are obtained.After that,three methods for calculating the reservoir thickness are put forward ,and achieved good application effects in the practice.