Rig Comparison: Drilling Rig Selection Guide

DRILLING RIG SELECTION GUIDE Rig Comparison STATIONARY DRILLING RIGS Advantage: •Stands are in the tripple – faster tripping • Powerfull equipment – drawwork over 1000 HP, mud pumps over 1000 HP •Uses 5” DP – at greater depth less pressure losses. •Heavy casing string run deeper –Hook loads over 200 t •Diesel electric drive. •Flexible range of RPM and SPM •Substructure higher and drilling floor greater area. •DP length upper limit for range •Better Contractor’s References. Disadvantage: • Greater investmens at start •More days for moving •More truck loads •Longer rigging up •Large surface of well site •More personnel –more experienced and specialist •Heavy drilling and handling equipment •More investment for spare part stock

MOBILE DRILLING RIGS Advantage: • Smaller investment at start • Faster moving •Less truck loads •Less area for well site •Smaller waste pit •Less number of drilling crew •Less sparet parts stock Disadvantage: • Stands in the double- slow triping • When drill deeper with 4 ½” DP or less, greater pressure drops. • Restricted running depth of intermediate casing if well construction is complex due overpressure and lost circulation zones. • Mostly mechanical rigs – high noise level. • Mud pump SPM restricted due drive diesel engine. Required 3 liner size •Restricted height bellow rotary table for BOP stack •Less surface of drilling floor – safety •DP length restricted on bottom length limit.