Sakhalin, Russia. Sakhalin - Okhotsk Shelf.
Exploration task; depth of investigation: 1600-2900 m
The LFS method can be used in coastal waters and offshore subject to the acquisition of low-frequency microseismic background field data with the use of specialised ocean-bottom seismometers (OBS). The microseismic survey was carried out using a wide-profile deployment formed of three parallel lines of OBSs. The profile traversed from well No. 1, with the presence of oil content in sediments of the Daghi formation, through the Okhotsk Sea to well No. 2, with no oil-bearing features in the section.
It should be noted from the geological features of the work area that during the course of the LFS survey, located along wells Nos. 1 - 2, there was a significant decrease in the markings of the surface of the Daghi deposits, to the order of 1000 m. Therefore, the use of the standard interpretation approach for comparison of area spectra with the support spectra was impossible.
Interpretation of collected data was carried out on the basis of the multivariate 3D modeling technique, which differs from the standard approach in that the most probable model of the oil deposit distribution is determined instead of predicting the oil prospectivity of each layer.
As a result, a map was constructed for a prognostic assessment of the prospects for the oil content of the deposits of the productive layer of the Daghi formation within the LFS survey profile area, on which a single perspective oilfield region was identified. From the west, this area is probably limited to a tectonic disturbance with an amplitude of about 60 m, and from the east - an absolute elevation -2075 m of the structural surface of the reservoir.
The drilling of the well within the allocated oil-prospecting area by the сustomer is scheduled for 2019.