The North Sea provides a high economic contribution to four major countries (Denmark, Norway, UK and Netherlands) due to oil and gas discoveries from the 1960’s. Yet, seafloor subsidence, well deformation and damage of casing had occurred in some of the North Sea hydrocarbon fields caused by changes in situ conditions (stress, saturating fluids, temperature) that in turn result from deformation of chalk reservoirs during drilling, hydrocarbon production and waterflooding activities. Later, extensive studies on the mechanical behavior of chalk were done to avoid undesired consequences. This paper aims at assessing the effect of temperature, water saturation and porosity on the brittle and plastic deformation of Danian chalk.