NORTHWESTERN RUSSIA (Timan-Pechora Basin) | CASE 1 | 2007

Northwestern Russia (Timan-Pechora Basin): Case 1

Summary

Geomage MultiFocusing© processing was applied to old, low fold data in a geologically complex area.

The area is characterized by thrust and block structures, steeply dipping layers, fault systems, and increasingly complex structures in the shallow section.  A complete package of conventional CMP processing procedures, including various kinds of filtering, deconvolution, DMO, and post-stack migration, did not reveal the reflections required to perform a proper geological interpretation.  

The use of the Multifocusing technology for data processing significantly increased the signal-to-noise ratio and enabled the interpretation of all key horizons. Several 2D lines were processed in this area, allowing the interpreter to build a 3D map that clearly delineated these complex structures.

The results of this Case Study have been confirmed by drilling.

Geological Analysis

This region is associated with the Timano-Pechora hydrocarbon basin.  All Timano-Pechora swells have a northwest trend and a horst-imbricate structure. They are broken up into wedge-like blocks that include anticlinal structures. The present structure of the Timano-Pechora swells resulted from the overlapping and different exposures of the Ural and Novaya Zemlya fold systems at some stages in their geological history. The swells developed during the Carboniferous and Lower Permian.  The development of local structures that further complicated the subsurface was completed in the early Triassic.

Ordovician-Silurian deposition took place under trough conditions (the right-hand part of the time sections).  These formations are considerably thicker than in the western areas (the left-hand part) where sedimentation took place in a shallower deep-sea environment.  Similar conditions existed in the subsequent Devonian and Permian periods.  At the end of the Permian, there were global tectonic movements in both vertical and horizontal directions, causing inversion of the most subsided areas.  This led to the formation of swells with high sediment thickness in the periclinal parts. The overlying Triassic formations inconsistently covered the underlying series.  A final tectonic episode at the of the Triassic period  caused a horst and graben structure in the Upper Permian deposits and an erosion of the Triassic formations, especially on the anticlinorium crests.

An interpreter would have a very difficult time unraveling this complex geological history using the conventionally processed section on the left. In the Geomage MultiFocusing© section on the right structural and stratigraphic detail is very clear.