RESULTS OF INTERPRETATION OF SEISMIC SECTIONS DURING ENGINEERING SURVEYS WITHIN OF THE SOUTH-KIRINSKOYE OIL AND GAS CONDENSATE FIELD (SHELF OF SAKHALIN ISLAND)

Abstract

High-resolution 2D seismic is the main and optimal method in marine engineering geophysics, which for many years has worked well for the production of semi-submersible drilling rigs, self-lifting drilling rigs, construction of berthing facilities and bridges. The main objective of this method is to identify near-surface gas, faults, which are geological hazards. The method used for performing marine research is longitudinal profiling of reflected waves with a 48-fold overlap of the reflecting horizons. To obtain high-quality seismic migrated sections, we have previously developed a unified data processing algorithm for the offshore areas of the South-Kirinskoye oil and gas condensate field (Sakhalin shelf). More than 8,000 line km of seismic data were processed. The article presents the sequence of interpretation, as well as an analysis of the presence of hazards in the project wells (objects). To isolate potentially dangerous objects for each horizon, a dynamic analysis was carried out, which included the definition of the following parameters: maximum and minimum peak amplitude. The systematization and classification of amplitude anomalies was carried out according to such features as a phase change, frequency reduction, the presence of a supply channel and distortion (false deflection) of all underlying boundaries, indicating the possible presence of gas. The probable hazard levels for drilling operations were determined. All the identified anomalies in the process of interpreting seismic sections were mapped to the geological hazards to select the optimal and safe installation point for drilling a prospecting or exploration well.