Analysis of selected problems encountered while testing natural gas-condensate fields in the Western Carpathians

• Autorzy: Rybicki Cz. , Dubiel S. , Blicharski J.

Identyfikatory

DOI

10.7494/drill.2015.32.3.575

• Języki publikacji: EN

Abstrakty

EN

The potential change of natural gas composition in the near-wel lbore zone creates a big problem with the selection of appropriate initial value of counterpressure exerted by the displacement fluid on reservoir during the test, and also with the interpretation of the reservoir and production tests results. The analysis of the industrial data reveals that the effect of condensate production in the near-wellbore zone could take place while using too high counterpres-sure during DST tests, as a consequence of using a relatively high column of water displacement fluid in the DST column, i.e. about 2500 m. This thesis can be confirmed after further detailed theoretical analysis of the occurring thermodynamic conditions. The paper addresses technological and interpretation problems encountered during drill stem tests (DST) of gas-bearing Devonian strata, on the example of the Stryszawa field in the Western Carpathians. Special attention was paid to the possible changes of gas compo sition during flow tests and the cases of gas condensation of heavier fractions during build-up tests. Attempts were made at explaining sudden drops of pressure at the build-up stage along with the thermodynamic conditions responsible for this effect. The authors explained the necessity of using an appropriate Ful-Flo sampler in the DST set for collecting gas samples at any time of the test, and devices for continuous measurement of temperature. The use of new types of drill stem testers and appropriate interpretation methods, which would account for a detailed analysis of technological and reservoir conditions allows for more efficient oil prospecting and deciding about enhancement methods in hydrocarbon production. The analysis of thermodynamic conditions on the bottom of the wellbore allow s for selecting proper counterpressure values in view of the condensation of heavier gas fractions in the near wellbore rocks. The analysis of conditions in which heavier gas fractions undergo condensation is approximate and general because the gas samples were collected at the outlet of the DST string (in surface conditions), without a Ful-Flo sampler and without temperature measurements.

Słowa kluczowe

EN

oil prospecting; Western Carpathians; gas-bearing Devonian strata; natural gas-condensate field in Stryszawa; testing technology; thermodynamic conditions of gas condensation

• Wydawca: AGH University of Science and Technology Press
• Czasopismo: AGH Drilling, Oil, Gas
• Rocznik: 2015
• Tom: Vol. 32, no. 3
• Strony: 575--580
• Opis fizyczny: Bibliogr. 8 poz., wykr.

Twórcy

autor

Rybicki Cz.

• AGH University of Science and Technology, Faculty of Drillin g, Oil and Gas, Krakow, Poland

autor

Dubiel S.

• AGH University of Science and Technology, Faculty of Drillin g, Oil and Gas, Krakow, Poland

autor

Blicharski J.

• AGH University of Science and Technology, Faculty of Drillin g, Oil and Gas, Krakow, Poland

Bibliografia

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• [2] Dubiel S.: Zastosowanie rurowych próbników złoża firmy Halliburton typu Ful-Flo w poszukiwaniach naftowych. Wiertnictwo, Nafta, Gaz, vol. 29, no. 3, 2011, pp. 617–628.
• [3] Dubiel S., Rzyczniak M.: Analiza rezultatów testów DST na złożu gazu ziemnego La-chowice-Stryszawa w Karpatach Zachodnich. Przegląd Górniczy, vol. 70, no. 7, 2014, pp. 131–138.
• [4] Dubiel S., Rzyczniak M., Wójtowicz T., Kułaga T.: Analiza i interpretacja wyników badań rurowy mi próbnikami złoża warstw perspektywicznych w rejonie Przedgórza Karpat, w celu oceny właściwości zbiornikowych skał i parametrów złożowych po-szczególnych poziomów. AGH University of Science and Technology, Faculty of Drill-ing Oil and Gas, Krakow 1993–1998 [research work, unpublished].
• [5] Dubiel S., Rybicki C., Zubrzycki A., Maruta M.: Interpretation of DST test results for the identification of HC accumulations or boundaries in the area of the Carpathians and Carpathians Foredeep (South Poland). AGH Drilling, Oil, Gas, vol. 31, no. 2, 2014, pp. 291–306.
• [6] Dubiel S., Rzyczniak M., Solecki M.L., Maruta M.: Granice złóż gazu ziemnego La-chowice i Stryszawa w świetle testów rurowym próbnikiem złoża. Przegląd Geologiczny, vol. 63, no. 1, 2015, pp. 60–66.
• [7] Jawor E.: Rozpoznanie geologiczno-złożowe i kierunki dalszych prac w środkowej i zachodniej części Karpat i Zapadliska Przedkarpackiego. Nafta – Gaz, no. 3, 1997, pp. 95–105.
• [8] Matthews C.S., Russel D.G.: Pressure build-up and flow tests in wells. Society of Pe-troleum Engineers of AIME, New York – Dallas 1967