The present study analyzes spectral gamma ray data of low-radioactivity rock cores from Rotliegend Basin. The main goal of this research was standardization of archival gamma ray logs measured in counts per minute to American Petroleum Institute units. Selected core intervals, log data, and additional crushed samples covered three different boreholes: J-1, L-7, and K-2 from Zielona Góra Basin, localized in western Poland, where J-1 was a reference borehole. Core measurements were performed on the sandstone and conglomerate formations by Gamma Logger GT spectrometer, which uses two scintillation detectors containing bismuth germanate crystals. In the cores, real concentrations of potassium, uranium, and thorium were acquired what enabled to calculate total content of radioactive elements and total uninfluenced by uranium. Delivered new total GR_GLGT curve from cores allowed accurate standardization of archival GR curves from L-7 and K-2 boreholes. Presented results showed a very good correlation between logs, core data, and laboratory analyses. These data allow precise shale volume reinterpretation.

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Improvement spectrometric gamma measurements on shale cores with the use of the BGO scintillation detector Spectrometric gamma measurements carried out on rock cores of shale formations belong to standard petrophysical analyses. The paper presents the work performed to improve the possibilities of recording natural gamma radiation on cores. The performed work was related to the modification of a gamma logger device, creating calibration standards and developing new computer software to calculate real element concentrations from the measured spectra. Results obtained from various methods have been compared in order to choose a methodology which is as good as possible.The final conclusions were based on the comparison of gamma measurements on the core with measurement results from a logging SGR logging probe and with the results of laboratory measurements.

This paper describes the application and calculation of hydrocarbon anomalies in two different boreholes located in Eastern Pomerania (northern Poland). Spectrometric data from borehole geophysical probe (borehole 1) and portable gamma logger (borehole 2) were used to analyze shale formations. The results from borehole 1 presented a statistically significant, moderate correlation between calculated hydrocarbon anomalies and hydrocarbon saturation data obtained from well log interpretation. Borehole 2 has been analyzed focusing on the gamma radiation of the core samples, and the positive results of borehole 1. Hydrocarbon anomalies calculated from spectral gamma radiation are reliable indicators of sweet spots, based solely on a cursory evaluation of core measurements. These preliminary information acquired from gamma-ray measurements could help increase sampling precision of further geochemical analysis.

Zmiany składu chemicznego i izotopowego (inwersja) metanu, etanu i propanu na przykładzie gazów z formacji łupkowych Barnett (basen Fort Worth) oraz Fayetteville (basen Arkoma) W złożach gazu z formacji łupkowych w USA o najwyższej produktywności zazwyczaj występuje inwersja skła-du izotopowego węgla w metanie, etanie i propanie. Efekt roll-over polega na zmianie normalnego trendu izotopowego (δ. Przyczyny takiej inwersji nie zostały dokładnie określone; najczęstszym wytłumaczeniem jest występowanie wtórnego krakingu ropy naftowej w skale macierzystej typu łupkowego. zumberge wraz ze współpracownikami oznaczyli skład molekularny oraz izotopowy ponad 200 próbek gazów z formacji Barnett (basen Fort Worth) oraz Fayetteville (basen Arkoma). Dojrzałość termiczna tych basenów została określona na -odpowiednio -od około 1% do 2% oraz od około 2% do 3% w skali refleksyjności witrynitu. Wyniki analiz składu gazu z formacji Barnett i Fayetteville zostały wykorzystane w tej pracy do określenia różnic w interpretacji, jakie napotyka się, stosując wzory i wykresy opracowane dla gazów konwencjonalnych do scharakteryzowania gazów niekonwencjonalnych.Słowa kluczowe: shale gas, gaz z formacji łupkowych, skład chemiczny, skład izotopowy, δ 13 C, gaz ziemny. Methane, ethane and propane chemical and isotopic composition changes (inversion) in natural gases from Barnett and Fayetteville shale playsinversion of the isotopic composition of carbon in methane, ethane and propane is common in the highest productivity shale formations in the united States. Roll-over effect is the reversion of normal isotopic trend from δThe reasons for this inversion have not been clarified, but the most common explanation is the presence of secondary cracking of crude oil in shale source rock. zumberge and colleagues determined the molecular and isotopic composition of more than 200 samples of gas from the Barnett formation (Fort Worth basin) and Fayetteville formation (Arkoma basin). Thermal maturity of these basins was determined, respectively, from about 1 to 2%, and from about 2 to 3% vitrinite reflectance equivalent [9,10]. The results of these analyzes were used to determine the differences in gas interpretation with formulas and diagrams developed for the conventional gases when used for unconventional gases.