Document Type : Review Paper


Petroleum Engineering department. Baghdad university


The problems that accompany the drilling process of oil wells are often due to the different balance of ground stresses around the borehole and resulting from drilling operations inside the well, as well as because of the interactions between the drilling fluid and the rock formation. Even in very carefully planned wells, problems will almost certainly arise during the drilling of the well. For example, in areas where similar drilling practices are used, bore problems may be reported because formations are heterogeneous even though such problems have not occurred before. In well planning, the key to successfully achieving the objectives is to design the drilling program on the basis of anticipating potential drilling problems rather than being cautious or contained. Drilling problems can be very costly, so the design of drilling program must be carefully studied. The most common drilling problems included: Pipe sticking, drilling mud loss (Loss of circulation), Hole deviation, Drill pipe failures, Borehole instability, Formation damage, Hole cleaning, H2S fulcrum areas, Shallow gas zones, Equipment related drilling problems, and mud contamination. In this review, the most common well problems that are encountered during the drilling of oil and gas wells will be highlighted. The compilation of oil field data and previous studies related to the subject, as well as the field knowledge of the drilling supervisors, were all the information centers for this study. Especially the most important problems occurring in Iraqi fields and the solutions that these problems were dealt with were discussed in this review