Abstract
Drilling offshore oilwells is a very expensive and complex job, in which all efforts must be spent to keep the annular pressure between a minimum (pore pressure) and a maximum pressure (frac pressure). A lot has been invested in downhole sensors and data transmission systems but there is a common sense in the industry that very little is available in real time data interpretation. The correct interpretation of PWD (Pressure While Drilling) data is a very powerful tool to identify undesired phenomena. The anticipation and remediation of potential hole problems is an ultimate goal of most real time measurement devices installed on drilling rigs. The accurate quantification of the phenomena that impact bottom hole pressures is a must on anticipation operational problems. This paper presents a comprehensive methodology to accurately quantify some of the most common phenomena that occur during the drilling job. Transient modeling, pattern recognition and AI strategies were considered. The final goal is the development of a real time computational tool to interpret the operational parameters, identify and remediate problems, reducing risks, time and costs.
Examples of problems detection (such as cuttings excessive accumulation, kicks, wash outs, hydraulic packers, instability related issues, etc) will be addressed. Besides, the impact of remedial actions on downhole pressures and solids concentration profiles will be also detailed.
