Analysis of Torque and Drag in Abu Ghirab Horizontal Well Using Landmark (WellPlan) Software

Abstract

Studying and building torque and drag model close to the reality has become very important to achieve the well target successfully by analyzing the mechanical behavior of the drillstring and wellbore conditions. While drilling any particular well, tight hole conditions, sloughing shale, keyseating, differential sticking, sliding wellbore friction and accumulation of cuttings due to inefficient hole cleaning result in excessive torque and drag which usually occur together. In this study, Halliburton's Landmark software (WellPlan) was utilized on selected well; Well-AG horizontal well in Abu Ghirab oilfield, Missan oilfields. Modeling of Torque and drag is important to predict the drillstring effective tension, buckling, torque, slack off and pick up drag, weight on bit and fatigue ratio which can be considered as drillstring operational windows. Three main processes are used in torque and drag modeling. First, utilizing offset wells data; hierarchical data, survey data, casing and open hole section depth, drillstring and BHA specifications, drilling fluid properties, subsurface temperature and operations parameters. Correction hookload weight, using stiff string and using viscous torque and drag option were included in the second process. Third process comprised friction coefficient calibration with actual field data.Drilling operations, tripping in/out the hole, rotating on bottom, rotating off bottom, Backreaming and slide drilling in open hole section 8 1/4 inch was studied.The most significant conclusion is as the inclination angle of the well path was increased above 76° and reached 88.2°,the drillstring buckling can be occurred with much higher WOB (compression force) requirement. The studied well was closed to buckle at 2408 m (MD). Calibrated friction coefficient in WellPlan software depending on actual well data where used in tripping in/ out and rotating off bottom operations.