Моделювання сейсмічних ефектів при зміні фізичних властивостей геологічного середовищана прикладі Одеського газового родовища

Abstract

The paper deals with the methodology and results of seismic modeling performed on the example of the Odessa gas field located within the north-western shelf of the Black Sea of the Southern oil and gas region of Ukraine in order to assess the possibility of using seismic monitoring in the development and operation of oil and gas fields. The geological structure of the Odessa gas field allows to clearly demonstrate the nature of the change in the dynamic characteristics of the seismic record when changing the physical properties of the geological environment. To assess the seismic effects, time sections were modelled for two models of environments with different porosity values, the waveform change was analysed, the time shift between the maximum amplitude values within the productive sediments was calculated, and the reflection coefficients of the longitudinal wave at normal beam incidence were calculated, and the instantaneous phases, amplitudes and instantaneous frequencies of seismic recording were calculated by Hilbert transformation. The conducted studies allow us to draw conclusions about the degree of contrast of the dynamic characteristics of the seismic recording and the possibility of using them to monitor the state of oil and gas fields. According to the simulation results, it was established that the change in porosity in different productive horizons of the Odessa gas field has a different reflection in the seismic field. In particular, to control the physical state of the productive horizons of the Upper Paleocene and Lower Paleocene, a more informative indicator is the temporal shift, and the productive horizon Eocene-1 is the instantaneous amplitude. The choice of the indicator depends on the seismic and geological conditions of a particular deposit or research area, and the involvement of dynamic characteristics of the wavefield in solving seismic monitoring problems requires a high quality of seismic information.