Geochemical analysis and preparation the well abandonment projects on the Polana Ostre field

This article covers the methodology of geochemical analysis, interpretation of results and solution that was proposed to abandon a depleted oil reservoir Polana Ostre, Poland. Polana Ostre as a reservoir was discovered in the 19th century and in 1870 the main facilities were built. Several dozens of wells were drilled and their depth varies between 60–497 m. Furthermore, on the field many hand‑drilled wells are located. Oil was produced through the 60 years with breaks. After the 2nd World War the facility was suddenly discarded due to political and economic reasons. As a result of inadequate operation, oil leakages can be observed. It causes an environmental pollution and a serious hazard. The remains were recognized and documented. A series of geochemical measurements were taken to indicate gas concentrations throughout the field. An analysis of the results showed significant concentrations of hydrocarbons in the soil. In order to mitigate the threat, a proper plug and abandonment operation of the deepest well was designed. Project executors hope to attract the attention of industry and academia to the problems depleted reservoirs that were not correctly abandoned.