Combined interpretation of well logs, laboratory results and seismic data in the Miocene sandy-shaly thinly-bedded formation
Elastic properties of rocks, which constitute the same physical background for P- and S-waves velocity determination in seismic, acoustic log and laboratory measurements, were the common platform for combined interpretation and scaling of petrophysical parameters obtained from different sources. Research was done in the Miocene sandy-shaly thinly-bedded formation of the Polish part of the Carpathian Foredeep.
In very complicated geological succession, gas and water saturated sandstone-mudstone-claystone mixtures of several cm thickness layers were a big challenge for petrophysicists and geophysicists in aspects of selecting the gas traps. The main reason of combining the data was to join values determined from methods of various vertical resolutions and obtain comprehensive information about reservoir of complex geology.
Acoustic full waveforms (AFW) were processed in the same way as seismic signals using the commercial software where similar attributes were calculated. Next, the results were combined with reservoir properties determined from well logs and laboratory experiments. Results of standard (bulk density, total porosity, permeability) and more advanced laboratory measurements (NMR and MIP) were used in joint interpretation to improve rock properties determination. P-wave velocity from laboratory measurements was included in acoustic log in order to construct velocity model for seismic inversion.
A lot of 2D relationships between AFW attributes (envelopes of P- and S-wave amplitudes or instantaneous frequency of P-, S- and Stoneley wave) and seismic attributes (for instance frequency components from spectral decomposition) were constructed (Go to Search and Discovery to view Fig. 1 & 2). Correlations, that were found, were applied to 3D presentation of seismic, well logging and laboratory results. 3D visualization of selected seismic data and AFW attributes provided valuable insight into rock formation and made easier the selection of layers with better hydraulic properties than adjacent beds. 3D results presentation illustrated the parameters changes on the background of seismic data, resulting from lithology, sedimentology environment and tectonics in global scale. As a result different type of information: point (micro scale) from rock samples, 1D (mezzo scale) from logs, and 2D or 3D (macro scale) from seismic were integrated for petrophysical data scaling.
This study was financed in project No. NN 307 294439 (2010-2013) by MS&HE Poland and by statutory funds No. 126.96.36.1999 at AGH UST, Faculty of GG&EP Krakow, Poland.
AAPG Datapages/Search and Discovery Article #90226 © 2015 European Regional Conference and Exhibition, Lisbon, Portugal, May 18-19, 2015