The use of multi-scale 3D models for exploration and evaluation of the shale gas resources in central part of the Baltic Basin, Poland - preliminary results

Abstract

Shale gas and oil potential and the spatial distribution of the sweetspots after few years of exploration still are in principles unknown. All published estimates were based on very sparse, low quality data (EIA 2011, 2013, PGI 2012) and generally fake analogs to USA shale gas plays (USGS 2012). The team of the Department of Fossil Fuels, AGH-UST in Kraków, started the development of 3D structural-parametric models for the need of shale gas exploration and multiscale resources/reserves assessment.

The subject of the presented study is the central part of the Baltic Basin, developed on the western slope of the East European Craton (Northern Poland). The basin originated as a late Neoproterozoic rift related to the break-up of the Precambrian supercontinent Rodinia/Pannotia, evolving into the Cambrian-Middle Ordovician passive margin. The Upper Ordovician-Silurian Baltic Basin is a part of the foredeep of the Caledonian collision zone. Being initially a coherent sedimentary cover of the western slope of the East European Craton, during Variscan time it underwent selective tectonic uplift and erosion. The Ordovician-Silurian section of the basin contains numerous shale formations. The most important ones are the Caradocian Sasino Formation and the Lower Llandoverian Paslek Formation with the Jantar bituminous shale member in its bottom part (central-western Baltic Basin), as well as the Lower Wenlockian shale (eastern Baltic Basin).

The modelling of the Baltic Basin is under development, however, the completed up to now work has ensured close integration of the archival and new subsurface maps, 2D and 3D seismic, well-log and laboratory data from the central and western parts of the Baltic Basin within the frame of 3D static models. The modeling methodology used in the shale gas exploration does not differ, in principle, from the general assumptions used in geomodelling for the purpose of conventional hydrocarbon. Special methodological emphasis is placed on better integration of different data types on a common software platform, e.g. PetroMod/Petrel/Eclipse. The models are prepared at regional semi –detailed and local scales. At the present stage the obtained results are still very general due to low quantity of the input data their very variable quality of the input data. However, the preliminary results of the modeling has allowed to claim that with positive geochemical indices of the gas productivity (e.g. TOC), potentially productive series reveal moderately favorable reservoir and geomechanical properties. They also confirm that the Sasin Formation and Jantar Member are the most probable hot shales in the central part of Baltic Basin.

The modeling results for each of the model groups need further development and careful evaluation. The elaborated up to now models are deterministic solutions, which in the future will be base-cases for stochastic Uncertainty and Sensitivity analyzes, allowing for introduction of probabilistic techniques of resources assessment. The presented methodology will be modified and developed by a team of the Fossil Fuels Department, AGH-UST, under the BlueGas National Research Program The models will be applied not only for exploration purposes but first of all, they will serve as a static framework for elaboration of the shale gas resources documenting methodology based on PRMS and fitted to Polish conditions.

The modeling results are an effect of implementation of the following research funded by the National Centre for Research and Development programs: Innotech (K1/IN1/48/152754) Applied Research Program (PBS1/A2/11/2012) and BlueGas (BG1/LUPZAS/13). Spatial (3D) structural-parametric modeling was performed in the Petrel Software, shared to AGH-UST by Schlumberger Information Solutions for research and education purposes (agreement CTT-tt-4_2012_PL).

AAPG Datapages/Search and Discovery Article #90226 © 2015 European Regional Conference and Exhibition, Lisbon, Portugal, May 18-19, 2015