Uncertainty after CSR shears as to If tubular does not move up and clear BSR, BSR Up or down there is opportunity to seal well bore (-) (+) how the tubular will respond, up or cannot be closed. with a BSR. down. * Most likely that string will move up due to * If hung off with non-shearable then string will tension. Driller can also pick up, or if in drive-off need to be dropped (preferable to drop even with scenario, rig will drag pipe up. shearable tubular prior to closing BSR to avoid * Most likely to be hung off therefore string will small fish scenario). not move down. (+) (-) CSR shear takes place and tubular is Redundant BSR to seal wellbore. Only one BSR (upper) to seal well bore. picked clear of both BSR. * Main positive for this option. Most likely * Main negative for this option. Most likely scenario. scenario. (-) (+) Well bore integrity is breached at CSR No BSR to isolate well. One BSR below CSR to isolate well. bonnet. * Very unlikely scenario. (-) (+) Conversion of third cavity down to a More difficult to achieve. Less difficult to achieve. pipe ram bonnet. * This is almost certain to never happen with a 7 ram stack. I would rather lose the test ram if I needed another set of pipe rams. Failure of Upper BSR. Still leaves you a good configuration with BSR Leaves you a poor configuration with CSR above (+) (-) above CSR. BSR. * Agree. Major point.
Uncertainty after CSR shears as to how the tubular will respond, up or down. If tubular does not move up and clear BSR, BSR cannot be closed. (-) * Most likely that string will move up due to tension. Driller can also pick up, or if in drive-off scenario, rig will drag pipe up. * Most likely to be hung off therefore string will not move down. Up or down there is opportunity to seal well bore with a BSR. (+) * If hung off with non-shearable then string will need to be dropped (preferable to drop even with shearable tubular prior to closing BSR to avoid small fish scenario). CSR shear takes place and tubular is picked clear of both BSR. Redundant BSR to seal wellbore. (+) * Main positive for this option. Most likely scenario. Only one BSR (upper) to seal well bore. (-) * Main negative for this option. Most likely scenario. Well bore integrity is breached at CSR bonnet. * Very unlikely scenario. No BSR to isolate well. (-) One BSR below CSR to isolate well. (+) Conversion of third cavity down to a pipe ram bonnet. * This is almost certain to never happen with a 7 ram stack. I would rather lose the test ram if I needed another set of pipe rams. More difficult to achieve. (-) Less difficult to achieve. (+) Failure of Upper BSR. Still leaves you a good configuration with BSR above CSR. (+) * Agree. Major point. Leaves you a poor configuration with CSR above BSR. (-)