The main aim of the research presented in the paper was to study the phenomena of shale swelling induced by CH4 and CO2 sorption. In the study, a Silurian gas shale sample from the Baltic Basin in Poland was used. Samples represented typical characteristic features of polish shale gas formations with relatively low total organic carbon (0.8%) and high clay mineral content. The first part of the study was devoted to competitive adsorption of CO2 and CH4. The second part was devoted to observation of the sorption induced swelling phenomena, where sample linear strains were monitored with the use of strain gauges. Swelling tests were conducted up to the pressure of approximately 8 MPa with CO2, CH4 and helium as the baseline. Experimental results were compared with the Seidle and Huitt model where Langmuir constants where determined with volumetric sorption tests. Results of the study showed that matrix swelling in case of CO2 adsorption was greater than in the case of CH4 adsorption. The swelling value was directly proportional to adsorption and was about 5 to 10 times smaller than in the case of coal. Sorption of methane and carbon dioxide in the gas-bearing shale was about 10-times lower than in hard coals. The Seidle and Huitt model developed for coals was equally suitable to describe the processes of shale swelling.
W artykule przedstawiono teoretyczne podstawy adsorpcji, porównano izotermy adsorpcji azotu, argonu i metanu otrzymane dla materiału łupkowego złoża niekonwencjonalnego. Badania zostały wykonane za pomocą urządzenia TriStar II 3020 firmy Micromeritics w INiG – PIB (azot i argon) oraz 3Flex tej samej firmy w USA (metan). Przedstawiono wartości powierzchni właściwej obliczonej metodą BET dla azotu, argonu i metanu.
EN
Presented are the theoretical basis of adsorption, compared are adsorption isotherms of nitrogen, argon and methane obtained for a shale sample derived from a non-conventional deposit. The tests were carried out using the Micromeritics Tristar II 3020 in the Oil and Gas Institute – National Research Institute (nitrogen and argon) and the Micromeritics 3Flex apparatus in USA (methane). Values of BET surface area obtained from sorption of nitrogen, argon and methane are given.
Experimental isotherm data obtained for the samples collected from a selected shale gas borehole at the depth from 2803 to 2834 meters for both Argon and Nitrogen analysis at 77.4 K are presented. The results are compared for the mean value of Pore Size Distribution (PSD) using BJH (Barret–Joyner–Halenda) algorithm for desorption curves with application of thickness curve based on Halsey equation and also on Faas correction. Pore Size Distributions (PSD) and their volumes are characterized and compared for both the BJH and DFT (Density Functional Theory) methods.
PL
Przedstawiono eksperymentalne dane izotermiczne otrzymane dla próbek pobranych z wybranego odwiertu w niekonwencjonalnym złożu gazu z głębokości od 2803 do 2834 metrów, dla analizy z użyciem argonu i azotu w temperaturze 77,4 K. Porównano wyniki dla średnich wartości Rozkładu Wielkości Porów (ang. pore size distribution, tj. PSD) używając algorytmu BJH (ang. Barret–Joyner–Halenda) dla krzywych desorpcji z użyciem krzywej grubości zgodnie z równaniem Halsey’a oraz zastosowaniem poprawki Faas. Scharakteryzowano i porównano rozkład wielkości porów (PSD) i odpowiednio zajmowanych przez nie objętości przy użyciu metod BJH i DFT (ang. Density Functional Theory).
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