Abnormal pressures in Azerbaijan: A brief critical review and recommendations

Abstract

The authors exhaustively reviewed Soviet publications on abnormal pressures in Azerbaijan. According to these data, pore pressures in shales are determined in Azerbaijan by a calculation using well-logging data; pore pressures in shales, even in thin beds, significantly exceed pore pressure in sand reservoirs. On the basis of their review, the authors recommend the following additional research work to achieve a higher efficiency of drilling and production operations in Azerbaijan. 1. (1) Differentiate causes of heaving and sloughing of different shales, in addition to that of the pressure abnormality, and identify cases when special formulations of drilling mud can be used instead of increasing mud density. 2. (2) Thoroughly evaluate the precision of pressure calculation using well-logging data for different shales and environments. 3. (3) Distinguish cases where pressure abnormality is due to other causes than undercompaction. 4. (4) Check the validity of indirect pressure measurements in thin shale beds. 5. (5) Analyze local and regional hydrodynamics of formations for better prediction of the difference between pore pressures in shales and sand reservoirs.