Environmental Risk Assessment for Exploration and Extraction Processes of Unconventional Hydrocarbon Deposits of Shale Gas and Tight Gas: Pomeranian and Carpathian Region Case Study as Largest Onshore Oilfields

Shale gas and tight gas exploration and extraction processes create potential threats to the environment. In Poland, no comprehensive guidelines for environmental risk assessment have been prepared so far. This paper presents a proposal of environmental risk assessment methodology which can be used for corporate risk management procedures during exploration and extraction of unconventional hydrocarbons in Poland. The most frequent environmental threats that may occur during the exploration and exploitation of unconventional hydrocarbon deposits include degradation of soils through construction of drilling rigs and access roads, landforms change, local soil pollution caused by fuels, cleaning agents and materials used to prepare drilling fluids, rubble, cement, gravel, pollution of surface and underground water as a result of emergency discharges of sewage, infiltration of pollution from waste reservoirs, disturbance of hydrogeological equilibrium through significant water intake, noise and atmospheric pollution resulting from the combustion of fuels. To check the level of these threats' six exploration sites form Pomeranian and Carpathian region of Poland (3 wells of shale gas and 3 wells of tight gas) have been evaluated in detail, and the risk quantification has been made. Because of a local, short-term and reversible environment impact, the environmental risks for the exploration and extraction processes of unconventional hydrocarbons have been found to be medium or negligibly small. It is recommended that using the same methodology for other regions of Poland where we can find unconventional hydrocarbons and it can be enriched in dedicated application with spatial maps to give the investors a quick feedback on the potential environmental risks.