Abstract
The drilling industry has invested a lot, in the recent years, in the development of tools to measure and transmit real time drilling data. These technologies enabled obvious gains in wellbore orientation and navigation besides providing useful alerts of downhole conditions. There is a common sense among operators, however, that there is a misuse of such data in anticipating and remediating drilling problems. Pressure while drilling (PWD) data, for instance, is used in a subjective manner and interpretation depends a lot on the operator philosophy. The correct interpretation of PWD data is a powerful tool to identify and avoid problems, reducing operational risks, time and costs, especially in deep and ultra-deepwaters.
This article deals with the construction of an integrated methodology aiming the diagnosis and anticipation of drilling problems before they occur. The philosophy is to consider the wellbore, the reservoir vicinity and the drillstring as an integrated domain to be inspected, as a doctor would analyze a human being, considering body and mind. The drilling fluid which flows through all the portions of the domain, behaves as the human blood and its local pressures may reflect symptom of any abnormal behavior. In this way, pressure analysis would constitute the central core of the diagnosis system. Pressure analysis depends on several aspects, including solids segregation and loading, surge/swab effects, gel breaking, temperature and pressure dependency on fluid properties, etc.
The system, however, requires more information to help in the diagnosis task: that is where the several additional blocks coupled with the central core provide additional aid. Geopressures, torque & drag, temperature profiles, wellbore stability etc are different aspects to be considered.