Đang tải... (xem toàn văn)
Vietnam Block B Gas Project Well Cost Estimation How to perform a LOT or FIT 1 4/16/2018 Ask question any time Pls set your mobile phone in silence mode Pls do not surf internet Pls do not have privat[.]
How to perform a LOT or FIT Few suggestions during my presentation Ask question any time Pls set your mobile phone in silence mode Pls not surf internet Pls not have private talk If you want to talk, please go outside and talk CONTENTS Objective How to perform a leak off test (LOT) or formation integrity test (FIT) I II III IV V Why a LOT or FIT LOT or FIT application A common procedure to perform a LOT or FIT LOT or FIT Calculation Some high lights when performing a LOT or FIT Questions and Answers 1) Objective To provide you/students more information and knowledge on how to perform a leak of test (LOT) or formation integrity test (FIT) during drilling operation 2) How to perform a LOT or FIT I Why a LOT or FIT After each casing string is cemented in place and cement is hard, an LOT or FIT should be conducted to verify that : Casing integrity (casing leak) Cement bond quality behind the casing shoe Formation strength below casing shoe can withstand the predicted wellbore pressures required to get to the next designed section total depth 2) How to perform a LOT or FIT II LOT or FIT application LOT applied for : Exploration wells, including wild cat and appraisal wells Development well on a new platform or new fault block Development well in an old field, that has not been drilled in lately FIT applied for : Development well with valid offset data Can not perform a LOT 2) How to perform a LOT or FIT III A common procedure to perform LOT or FIT After the BHA tagged TOC Ensure surface cement sample hard Drill out cement , float collar, float shoe, rate hole and 5-50 ft new formation Circulate bottoms up and condition mud (MW in =MW out) Pull bit inside casing shoe and position tool joint Open chock and flush line through choke manifold until return Close choke Line up and pressure test surface line to a low and high pressure for minutes Shut in blow out preventer (top pipe rams) Pump mud down the drill pipe and annular the same time with ẳ or ẵ bpm by cement pump 2) How to perform a LOT or FIT III A common procedure to perform LOT or FIT Record and plot the drill pipe pressure and casing pressure at a constant volume increment (0.1 bbls pumped) in the graph paper 10 Stop pumping after having gathered data points from the time a break occur (leak off test pressure = casing pressure at break occur) Note: If for subsea well, record the subsea stack gauges(s) pressure(s) 11 Bleed off pressure and record the volume led back 12 Open BOP (top pipe ram) 13 LOT completed For FIT It will be the same with LOT procedures except for step #10, stop pumping after casing pressure reach to desired pressure 2) How to perform a LOT or FIT IV LOT or FIT Calculation Formation break down pressure( psi) Maximum equivalent mud weight(ppg) Leak off test pressure (psi) + Formation break down pressure (psi) = Csg shoe true vertical depth (ft) Hydrostatic pressure of mud to casing shoe (psi) Leak off test pressure( psi) Hydrostatic pressure of mud to casing shoe (psi) = = = Mud weight (ppg) * * Pressure recorded on the casing gauge (psi) 0.052 0.052 * Csg shoe true vertical depth (ft) 2) How to perform a LOT or FIT V Some high lights when performing a LOT or FIT a Can perform FIT with mud pump, not LOT b Can pump down drilling fluid to annulus only c Can pump down drilling fluid through drill pipe from TDS for rig up a circulating head to perform d Check the line up, make sure it done properly e Make sure flush out all the air in the choke manifold with drilling fluid f Use top pipe rams, not use annular preventer g When pull bit inside the casing shoe, not rotate the PDC bit h When circulate bottoms up, not bring the bit inside the casing shoe i Some time, it is requested to perform the extended LOT 4) Questions and answers Thank you for your attention