Packer leak and zonal Isolation
Short description about the job
The well is multilateral and is drilled in the North Sea to provide offtake in this area. The later of interest is completed with oil swellable packers and sliding sleeves, and the base plan is to stimulate this branch after sealing the leak.
Based on observed pressure data and leak detection with test packer the leak path is out PBR at and most likely past 5 swell packers in 7-5/8” liner to (lateral) based on pressure response.
Downhole leak was later confirmed in separate operations, first by applying positive pressure with N2 at surface, then with rate measurements by pumping water from surface.
The overall objective of this operation is to obtain a satisfactory high pressure seal that will allow high pressure stimulation operation to be performed after sealing with ExperWELL® ResAMBER® Green resin sealing.
The operation includes
- Set a bridge plug below PBR
- Set cement retainer above PBR
- Inject sealant into leak path. Preliminary leak test
- Mill out cement retainer/bridge plug/cleanout/drift run to ensure wellbore clean of residual sealant
- Pressure test well to planned stimulation pressure.
ResAMBER® was mixed according to the procedure. The pumping schedule is successfully deployed. ResAMBER® resin is placed at the right position as planned.
After waiting for well to heat back up and resin being totally cured, the pressure test was carried out. The packer and zone are sealed as planned. And the job is concluded as a success and ready for the stimulation job.
Water Shut Off
The well was producing 3789bpd with 70% w/c
The objective of this workover is to:
. Squeeze off all the perforations
. Recompletion of the well with ESP will be decided based on TDT log result
- Pull out old completion.
- Prepare 3 IBC (18 bbls) ResAMBER® pill and 10 bbls MaxSpacer with 9,0 ppg (higher than killed brine in the well).
- Add additives to have 2hrs setting time at reservoir temperature.
- RIH with blank pipe and tag TOC inside 7” casing.
- Pick up 3 ft.
- Circulate in 10 bbls MaxSpacer follow by ResAMBER® pill, displaced by brine (Ref Pump Procedure).
- As soon as the ResAMBER® level inside the pipe is equal to the ResAMBER® level outside the pipe, stop the pump and POOH.
- Pull up 1000 ft (bottom of the pipe is 50 m above the top of the MaxSpacer level) then stop
- Close BOP annular and squeeze 8 bbls to the formation at max allowable pressure (Ref Figure Start to Squeeze).
- Close well and wait for setting time plus 2hrs.
- Pressure up 200-300 psi to confirm ResAMBER®
- Open annular and POOH.
- RIH with drill bit to drill out the remaining.
- Do the required positive test and confirm sealing.
- The job declared to a success.
SHUT OFF PERFORATED INTERVAL
Challenges: Microfine cement was used. Three squeezed cement jobs were done but it is still exist drop pressure.
The failure of cement jobs because of low injectivity (at p=65 bar, Q=50 l/min).
ResAMBER® resin is used to shut off the current perforated interval, then perforate new interval 30m below
Well ID 5 ½, Volume: 12,126 L/m
2 7/8 in tubing ID, Volume: 3,02 l/m
Production casing: 5 ½
Workover fluid: brine 1,06 SG
Primary cement sheath is damaged in range of perforated interval
- Prepare 2 bbls of HighVis Pill with density slightly heavier (+0,05 g/ml) than brine
- Prepare 1 IBC of ResAMBER® at 1,08 g/cc (0,02 g/ml heavier than brine). Setting time at 2 hours at formation temperature.
- RIH with 2 7/8” tubing to 35 m below bottom of perf zone
- Pump High Vis pill into the well, follow by 2 bbl of MaxSpacer (same density as ResAMBER®), then ResAMBER® then brine. Pump rate from 3 bbls/min. Take returns from annulus
- Reduce to 1 bbl/min when High Vis Pill is 50 m from the bottom of the tubing.
- As soon as High Vis pill is completely out of the 2 7/8” tubing, stop pump.
- Slowly pull the tubing up to 2 m below the bottom of perf zone
- Continue pumping out 1 bbl/min for another 8 bbls (2 bbls of MaxSpacer and 6 bbls ResAMBER®). Stop pump
- Pull tubing up 200 m. Circulate with brine at high speed.
- Close annular then squeeze ResAMBER® into the formation by pumping at max allowed injection rate
- After squeezing 4 bbls, stop pump and keep annular close.
- Wait for ResAMBER® to set
- Pressure test the ResAMBER® Plug at 65 bar. Hold, no pressure drop.
- Drill out the plug
- Pressure test the shutoff zone. Hold. The job declared a success.
The well was P&A in late 2019. Wellhead was removed and P&A flange was welded to 9 5/8” casing. There are 2 x 1” port with pressure gauges on the flange. Client experiences sustained pressure below the flange.
Injectivity test results shows diminishing squeeze trend:
o Pump small volume of water immediate build up to 25 bar with a bleed off to 10 bar in 4 min
o Pump small volume to 25 bar with a bleed off to 10 bar in 5 min
o Pump small volume to 25 bar with a bleed off to 10 bar in 7 min
o Pump small volume to 25 bar with a bleed of to 10 bar in 10 min
24 hours shut in pressure: 0.3 bar, Qgas < = 6 liters/day
In both tubing and tubing-7” casing annulus, water occupies the top 20 m.
o Bleed off any gas below the flange
o Remove the flange from the 9 5/8” casing
o Prepare 4 bbls ResAMBER® pill, 5hrs at surface temperature.
o Meanwhile, observe gas bubbles (using soap water on top of the 7”-9 5/8” casing (B) annulus to observe the bubbles).
o Pump out all the water from tubing and annuli.
o Meanwhile, remove cement in 7”-9 5/8” casing (B) annulus to at least 20 cm below the top of 9 5/8” casing
o Pump into all the void till full the ExperWELL® CLEAN solution (to clean casing surface and create bonds with water wet surface). Pump the ExperWELL® CLEAN out.
o Reinstall the P&A flange
o Pump ResAMBER® pill into one port (injection port) and ventilate out the trapped air from the other port (ventilation port) until ResAMBER® is seen from the return port.
o Stop pump. Double check the total volume pump vs the expected volume.
o Close the injection port. Slowly pump in 0,5 l GreenWASH while operating the valves on the ventilation port to clear the line. Close the valves.
o Open the injection port. Squeeze ResAMBER® into the injection line to maximum allowed pressure (25 bar), close the valve then wait for pressure drop to below 10 bar.
o Repeat the squeeze step 20 times or until the squeeze volume reaches 30 L, whichever comes first.
o Open the injection port, squeeze 0,5 l of GreenWASH to displace ResAMBER® at the gauge and valve. Open/Close the valve to clear the resin.
o Maintain the squeeze pressure above 5 bar. If pressure drop below 5bar before setting time is due, open the injection valve, pump in small volume of water to maintain pressure. Close the valve.
o Wait for the ResAMBER® to set, then pressure test to 25 bar. Pressure hold. The job declared a success.
o Rig down
Sustained Annulus Pressure
In annulus between casing 13 5/8 and 9 5/8 exists sustained pressure. It happened a few years ago. Now, the client wants to solve casing sustained pressure in annulus.
Detailed technical data:
Offshore, 65 degree inclination well
Annuli fluid: mud 1.80s.g
TOC in annulus 3272m
Max SCP=70 bar. When the pressure is bled off it raises in a few days again
Composition of gases in annulus: CO, CO2, H2S, CH4
The annulus was tested with water by pressure 70 bar for 30 min. No injection.
There is a possible deposit of weighting agents (mud for primary cementing job were made with barite) above TOC in annuli.
Prior to Pumping Procedure, open gate valve and bleed the pressure in Cc annulus as low as possible.
The annulus is full of fluid. The pump rate (displaced ResAMBER® rate) shall be low, therefore ResAMBER® shall be divided into half and pump twice.
5m3 ResAMBER® (pure) is used to make ResAMBER® 2.2 SG Pill for this treatment.
Prepare ½ ResAMBER® pill at 2.2 SG density and setting time of ca. 24hrs (whereas setting time at 110 ⁰C is ca. 10hrs and it is not able to set at 90 ⁰C).
Rig up pump and hose to have pump outlet connect to one side of the annulus. The valve on the other side of the annulus is connected to drain tank. Close gate valve and test surface line.
Pump ½ ResAMBER® 2.2 SG pill into the annulus, fluid from annulus to be returned into the drain tank. Adjust the pump rate so that ResAMBER® doesn’t go out at the drain line on the other side of the annulus. (Due to significant difference in density between ResAMBER® and well fluid, ResAMBER® will drop down the annulus and displaced fluid will flow out at the drain line).
Pump ca. 0,5 m3 of Greenwash (density 0.91SG) at max pumping speed (return to drain tank) in order to get Greenwash flushing through all the pump, valves and drain hoses.
As soon as finish the above steps (try to manage these steps within 8hrs, counting from the moment ResAMBER® is first injected into the annulus), with the valve on the drain line closed, pump treated water to pressure up annulus to squeeze ResAMBER® into the leak path at maximum pressure. Maintain the squeeze step for a few hours. Stop squeezing step when it is 20hrs from the moment ResAMBER® is first injected into the annulus.
Maintain this pressure and wait for ResAMBER® to set.
Repeat these steps for another ½ ResAMBER® pill.
Do the inflow test for 2 days. No flow and No pressure built up in the annulus. The job is declared a success.