Possibilities of Solving the Stability of Salt Strata Penetrated by Drilling: A Descriptive Study

The penetration of some salt deposits of substantial thickness (500-3,000 m) positioned above the structures with petroleum potential in Romania is conditioned by the rendering of oil structures visible in the deep strata (6,000 m). The crossing of these salt deposits by drilling is a key risk issue both during construction (drilling, cementing) and thereafter to assure the wells' stability and reliability. These considerations determined the approach of the research problem of the salt deformation behaviour. The purpose of this article is to analyse the following: salt behaviour deformation; establishment of the required parameters to ensure the stability of the drillings until the bore-hole lining (especially the secondary stress state around the drilling, the density of the drilling fluid in correlation with the temperature, respectively the depth), and also after casing (type of the cement pastes, the nature, the quality and the dimensions of pipes), namely the reliability of the wells. The obtained results can be useful in the choice of some solutions for ensuring the stability of the bore-holes that penetrate salt strata.