Seismic exploration work in the transit zones in the north of Western Siberia

Due to reduction in the stock of major production fields, it is required that geological features which are small size ones both laterally and vertically be researched. Hydrocarbon traps, from present day perspective, are, as a rule, unstructured with complicated distribution of properties in space. Consequently, in order to optimize the process of oil prospecting and for profitable oil and gas field development, maximally reliable information is needed. It is note worthy that seismic survey has its constraints in application and limitations in terms of the method resolution capacity. Additional difficulties arise when operating under challenging surface conditions, and specifically speaking, this article deals with research of oil and gas bearing features using seismic exploration under shallow water conditions, in transition zones or land-to-sea transition zones.
Materials and methods
Using the example of 3D seismic exploration surveys carried out by “NOVATEC” Company in its licensed sites located in the area of the Taz Gulf and the Gulf of Ob in Western Siberia, aspects for solution of the issues identified are under consideration using polyvariant systems of stimulation, acceptance and registration, i.e. combined use of explosions, near surface sources - combined with bottom, surface and submerged geophones and hydrophones, use of shut-down and a special technologyof coordinating data obtained by different systems including different (summer, winter) field seasons.
Results
Research undertaken and the technology of work developed have enabled higher quality and reliability of seismic survey materials obtained in the transition zones, which, consequently, increases reliability of the geological and hydrodynamic models created using these data and, hence, economic efficiency of the company’s operations. Uniqueness of the result consists in the fact that, despite the use of non-uniform package of technical means and methodological techniques, in the environment of the most severe surface conditions of the Arctic Circle, a complete array of 3D data has been successfully obtained.
Сonclusions
A set of summer and winter operations developed and used for transition zones of the north in Western Siberia enables the problems of transition zones to be resolved for this region with high quality seismic survey 3D materials obtained. This experience can be used by other companies and applied to other areas. For example, when working in the surface area of the numerous lakes situated in the territory of Western Siberia. Currently, when using standard technologies for seismic survey operations in such areas, irregularity of monitoring system characteristics results (stacking fold, distance spectrum, azimuths in bin), which reduces reliability and lowers the quality of the final survey materials.