The Exploration Method Of Broad Frequency Band And High Resolution Seismogram

Recognition of thin inter-bed reservoirs using normal seismic data in the middle-shallow strata in the Songliao Basin is a great difficulty. In order to resolve this problem, we present an exploration method of broad frequency band and high resolution seismogram. It mainly include analysis of seismic wave attenuation rule, physical mechanism of seismic attenuation in a two-phase medium, seismic wave attenuation and recovering method, and application of broad frequency band and high resolution seismogram.In this paper, I present some research on high-frequency seismic attenuation and the exploration method of high resolution seismogram, and propose four points of views.1, After analyzing the near surface dual holes micro-seismogram survey data, it shows that the main reason of surface seismic data's resolution is low is resulted from wave attenuation in near source area and near surface low velocity layers.2, I propose a new theory on wave propagation in a two-phase medium which is based on the concept that the basic unit for wave propagation is a nanomass, and propose that the physical mechanism results from the interference of elastic microscopic multiple scattering waves.3, A new deterministic deconvolution method, which improves the seismic resolution in a large scale, is proposed. Using MVSP from dual holes micro-seismogram survey deriving filter operator of near source area, ghost reflection and near surface low velocity layers, using the filter operator to do deconvolution to the surface seismic data and recover the mentioned several seismic wave decays.4, Based on forward modeling, we recognized that a thin bed seismic reflection is characterized by changing amplitude with changing frequency (amplitude versus frequency, AVF). Tuning thickness of thin bed reservoirs is a function of frequency. The narrower the frequency band, the larger the tuning thickness and, conversely, the broader the frequency band, the smaller the tuning thickness. Based on the AVF characteristics, we can identify the tuning amplitudes of thin bed reservoirs, confirm their tuning frequencies, calculate the bed thickness, and map the reservoir distribution.The technique has been applied in the 3D seismic area of Zhaoyuan in the northern part of the Songliao Basin. The seismic resolution is increased by two or three times over that of conventional seismic and many thin reservoirs have been identified.