The geological image which we can build on an oil reservoir plays an important role during its production life, from the appraisal phase (seismic works, exploration wells, appraisal wells) to the last stage of reservoir production. The geological image of the reservoir includes four sections: (1) structural schematization in which are defined the shape and external geometry of the reservoir, as well as the accidents (faults, erosions) affecting the reservoir; (2) architectural schematization that is referring to the internal geometry of the reservoir, the knowledge of the development of the various sedimentary facieses, the evolution of the reservoir petrophysical parameters in the saturated hydrocarbon zone and in the adjacent aquifer; (3) tectonic schematization that is referring to the building of a fracturing diagram considering the existing tensions regime inside the reservoir; (4) fluid media referring to the nature of the fluids stored into the reservoir and their distribution. Finally, understanding the hydrocarbon accumulation mechanism is one of the key issues that should be solved for effective hydrocarbon production.
Structural schematization is one of the important phases of the building geological image of the reservoir in which are defined the external geometry of the reservoir as well as the faults that affect the reservoir.
In the paper, the authors emphasize the importance of fault characterization and the structure model for an oilfield located in the Eastern Carpathians Foredeep known as Diapir Folds Zone. The Diapir Folds Zone is the most prolific petroleum province in Romania.
The oilfield studied is composed of two main zones: East and West. The east zone is a faulted monocline with oil reservoirs in the Meotian formations of deeper southern flank and shallower northern flank. The exploration of the east structure started in 1835 with the shallow Meotian of the northern flank, and in 1951 with the Meotian of the down-dropped of the southern flank.
The west zone was recently discovered (2011-2012) based on the new 3D seismic interpretation. The main geological formations are Oligocene represented by Kliwa sandstones (complexes I-V). Till now was completed only 2D model, but recently was delivered a 3D model using Schlumberger Petrel software.
Using modeling-while-interpreting capabilities of Petrel seismic interpretations we can easily move from seismic interpretation to structural model building. Integrated work analysis including all 3D geological data developed a new static model.