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[.]
Trang 1How to perform a LOT or FIT
Trang 21 Ask question any time
2 Pls set your mobile phone in silence mode
3 Pls do not surf internet
4 Pls do not have private talk
5 If you want to talk, please go outside and talk
Few suggestions during my presentation
Trang 31 Objective
2 How to perform a leak off test (LOT) or
formation integrity test (FIT)
I Why do a LOT or FIT
II LOT or FIT application
III A common procedure to perform a LOT or FIT
IV LOT or FIT Calculation
V Some high lights when performing a LOT or FIT
CONTENTS
Trang 41) 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
Trang 52) How to perform 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 :
-1 Casing integrity (casing leak)
2 Cement bond quality behind the casing shoe
3 Formation strength below casing shoe
can withstand the predicted wellbore pressures required to get to the next designed section total depth.
I Why do a LOT or FIT
Trang 62) How to perform a LOT or FIT
LOT applied for :
-1 Exploration wells, including wild cat and appraisal wells
2 Development well on a new platform or new fault block
3 Development well in an old field, that has not been drilled in
lately
FIT applied for :
-4 Development well with valid offset data
5 Can not perform a LOT
II LOT or FIT application
Trang 72) How to perform a LOT or FIT
1 After the BHA tagged TOC Ensure surface cement sample hard
2 Drill out cement , float collar, float shoe, rate hole and 5-50 ft new
formation
3 Circulate bottoms up and condition mud (MW in =MW out)
4 Pull bit inside casing shoe and position tool joint
5 Open chock and flush line through choke manifold until return
Close choke.
6 Line up and pressure test surface line to a low and high pressure for
5 minutes
7 Shut in blow out preventer (top pipe rams)
8 Pump mud down the drill pipe and annular the same time with ¼ or
½ bpm by cement pump.
III A common procedure to perform LOT or FIT
Trang 82) How to perform a LOT or FIT
9 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 4 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.
III A common procedure to perform LOT or FIT
Trang 92) How to perform a LOT or FIT
IV LOT or FIT Calculation
Maximum equivalent
Mud weight (ppg)
Hydrostatic pressure of
Csg shoe true vertical depth (ft)
* 0.052
Pressure recorded on the casing gauge (psi)
Leak off test
Hydrostatic pressure of mud to casing shoe (psi)
Formation break
Leak off test pressure (psi)
Formation break down pressure (psi)
Csg shoe true
Trang 102) How to perform 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, do not use annular preventer
g When pull bit inside the casing shoe, do not rotate the PDC bit
h When circulate bottoms up, do not bring the bit inside the casing shoe
i Some time, it is requested to perform the extended LOT.
V Some high lights when performing a LOT or FIT
Trang 114) Questions and answers Thank you for your attention