RIASSUNTO
Abstract
The Bricol field is a naturally fractured reservoir, located in Southern Mexico primarily producing from a deep objective in the Upper Jurassic Kimmeridgian formation. The geological complexity includes fracturing, salt bodies, high pressure and temperature.
While drilling an HPHT directional well at 18,820 ft below an 11 ¾" drilling liner set at 13,763 ft, that required directional drilling with a 10 5/8" pilot bit, rotary steerable system (RSS), and simultaneously under reaming to 12 ¼", serious drilling operational problems were encountered. Severe hole drag in excess of 150,000 lb as well as high shock and vibrations were encountered that ultimately resulted in a drill string twist off, jeopardizing the success of the well.
After successfully fishing and recovering the twisted off drill string, a multidisciplinary team collaborated to find the root cause of the drilling problems. Wireline logs were run, including a six arm oriented caliper log, which identified a Keyseat in the wellbore, located between 16,733 ft – 18,275 ft (Length 1542 ft). A detailed review and evaluation of the wellbore conditions at that depth interval was performed in order to identify the root cause of this anomaly. The 12 ¼" hole section was successfully finished and the 9 7/8" liner was run and cemented
This paper will give a detailed description of the problems encountered and the unique solution that was developed to overcome problems on future wells, during the planning stage through sensitivity analysis to improve the trajectory. In cases where the trajectory cannot be modified we have recommended preventative actions to minimize drilling problems.