Method vertical seismic profiling and evaluation of producibility of Miocene deposits in Hovsan oilfield

Abstract

The article is devoted to the analysis and interpretation of the VSP data (vertical seismic profiling) obtained in two wells of the Hovsan field. It gives information about the history of the study, the geological and geophysical characteristics of the field and the seismic surveys by the VSP method conducted here in 2010 and 2014 in the wells of 1856 and 1867, respectively. The main parameters of the VSP wells are briefly described and the quality of the seismic material is characterized. Analysis of the velocity obtained from the VSP and Sonic Log acquired in investigated wells shows that after a significant increase in the values of the interval velocities to 4500-4700 m / s at depths of 3600-3800 m, a sharp decrease is observed in their values to ~ 2000 m / s at depths of ~ 5150 m, which corresponds to the speed at a depth of 1000 m. This is confirmed by the seismic inversion of the VSP data. The interval of a sharp decrease in the velocities of seismic waves corresponds to the deposits of the Miocene. This clearly indicates the presence of abnormally high pore pressure in this oilfield, associated with fluid accumulations, which is of great practical interest.