Drillability in real-time.

Abstract

The formation drillability is an elusive parameter. For theoretical consideration it considered constant and given a value which is representative for the drillability for formations in the Mexican Gulf. The drillability has several applications: With proper drillability calculations, parameter like pore pressure can be estimated more correctly. The formation types can be determined while drilling into them so that drilling crews can better handle the drilling operation. These are important parts to consider when drilling a new well. To prevent loss of every calculation must be as close to reality as possible.In this thesis two methods have been chosen to be incorporated into an data agent that will calculate formation drillability in real time. The Bourgoyne-Young method with eight functions related to rate of penetration, and Eaton?s method utilizing the d-exponents to normalize penetration rate. Both methods uses a set of Real Time Drilling Data and other pressure gradients. The agent has successfully computed drillability for both methods, and the results have been analyzed and interpreted.The result of the analysis shows that both methods compute drillabilities that coincide with the information known about the formation. Since rate of penetration is responding both to drillability and pore pressure, it has been necessary in the present work to select areas in the field data where pore pressure has been constant. In this way only drillability has been the main unknown. In relatively shallow areas the pore pressure is normal, meaning it is constantly equal to the equivalent pore pressure density of 1.03 kg/l. The agent has potential to become a fully functional tool. It needs some work on its data processing feature, including compatibility with direct real time drilling data. The next priority in the development should be incorporating the results into a formation type classification tool.