Aktualne udoskonalenia metodyki interpretacyjnej stosowanej w aplikacji Satun systemu GeoWin

Przedstawiono ostatnio wprowadzone udoskonalenia do aplikacji SATUN systemu interpretacji geofizyki wiertniczej GeoWin. Aplikacja SATUN jest interpretacyjnym narzędziem do analizy cienkowarstwowych utworów piaszczysto-ilastych pod kątem określania nasycenia węglowodorami. Kilkuletnie doświadczenia w stosowaniu aplikacji SATUN w warunkach gazonośnych formacji mioceńskich polskiego przedgórza Karpat skłoniły do wprowadzenia ulepszeń w metodyce. Po pierwsze, stały się dostępne nowe badania laboratoryjne rdzeni obejmujące analizy chemiczne i mineralogiczne, co pozwoliło wprowadzić nowe zależności z regresji wielokrotnej. Badania te potwierdziły wcześniej sygnalizowaną regułę, że przekrój czynny absorpcji neutronów Sigma/a/ma jest w tym regionie ważnym wskaźnikiem zailenia. Bor okazał się głównym pierwiastkiem decydującym o rozkładzie Sigma/a/ma. Po drugie, wprowadzono gęstościowo-neutronowy wykres krzyżowy jako alternatywny sposób określania porowatości i zailenia. Pokazano kompletny przykład polowy zastosowania zmodyfikowanej metodyki w sugerowanej nowej formie graficznej prezentacji wyników

Well logging in the world of shale gas plays : review of the logging methods

The purpose of this article is to review the possibilities of using well logging in the exploration and completion of the shale gas plays. This presentation is addressed to a broad geological community. The article is divided in two parts, the first is focused on the borehole logging tools and methods, while the second describes the construction of petrophysical models and considers some specific aspects of well logging application in the shale gas plays. For the more inquiring readers a comprehensive list of literature is presented. Well logging is the way to acquire an important geological information from the boreholes, parallel to the core data analysis. Laboratory core analysis gives most reliable and comprehensive description of rock parameters, like mineral and chemical composition, kerogen content and its maturity, porosity, the pore space structure, density, permeability etc. However, this kind of analysis is time consuming and expensive. On the other hand, well logs give less accurate and usually not directly measureable values, which must be interpreted to achieve the requested parameters. These measurements are made continuously in natural rock conditions and the results can be obtained very quickly. Proper calibration methods are necessary to link the logging data and the detailed laboratory core analyses. A wide range of well logging tools is described briefly in the paper, and the electrical, nuclear, NMR, and sonic methods are presented in more detail. Special attention is paid to the great technological progress in well logging during the last two decades. This progress allows to cope with the increasing difficulties in the reservoir evaluation. Complicated geometry of the directional borehole, thin beds, shaly-sand lithologies, low porosities, and the specific the pore space distributions are the main challenges in the shale gas plays

Well logging in the world of shale gas plays : interpretative models and specific applications in the shale gas research

The purpose of this article is to review the possibilities of using well logging in the exploration and completion of the shale gas plays. This presentation is addressed to a broad geological community. The article was divided in two parts: the first one, already published in PG, which was focused on the borehole logging tools and methods, and the current one, which deals with the construction of petrophysical models and considers some specific aspects of well-logging application in the shale gas plays. For more inquiring readers, a comprehensive list of literature is presented. The construction of petrophysical models in the thin-bedded shale-sand Miocene gas formation of the Carpathian Foredeep is presented briefly as a possible predecessor of the methodology applicable in the shale gas plays based on domestic experiences. However, the application of well logging in shale gas formations, both at the evaluation and completion steps, differs in the methodology in comparison to conventional and even to thin-bed formations. This specificity is also discussed, where attention is focused on the quantity and quality of organic matter and its relation to gas. Low porosity and a special kind of pore space in organic shales are considered as well