Uses and Limitations of a Drillstring Tension and Torque Model To Monitor Hole Conditions

Abstract

ABSTRACT This paper presents the results of the application of a Tension-Torque model to directional wells drilled worldwide. The final inclination of the wells ranged from 25° to 70°, and the Tension-Torque model was effectively used in these cases to aid in planning the directional program prior to spud, monitor the wells while drilling, or to postanalyze some particular drilling problem. The examples presented are representative of the situations to which the Tension-Torque model can be routinely applied. These examples show that the model can effectively aid the well planner in selecting the best well path, drillstring designs, casing program, and mud system prior to spud. A second set of examples shows how real time monitoring of drilling conditions, combined with model use, can develop a baseline so that deviations from expected behavior can be analyzed and explained. Appropriate action can then be taken to remedy problems before they became serious. A final set of examples is presented to show how a Tension-Torque model can be effectively used to determine the actual cause of a particular drilling problem after a well is completed. Experience gained from postanalysis of problems in this manner can be used to improve later operations. The chief technical contributions of this paper are to compare field data with model predictions for a wide range of different inclinations, to show how torque and drag models can be used to monitor hole conditions in real time, as well as demonstrate that the tool can be used to improve the planning and postanalysis of drilling operations.