Cases

ThermaSet® has been used in hundreds of successful projects all over the world. Listed below are some cases where ThermaSet® has succesfully been applied to solve a variety of technical challenges.

Sustained casing pressure 13 3/8” x 9 5/8”

The challenge
The purpose of the ThermaSet® job is to seal off the micro channel in 13 3/8” x 9 5/8” CCA to avoid communication of gas / pressure to surface.

The solution
  • Mixed 20L & filled CCA with 12L slurry. Squeezed 2.5L more into the CCA. Closed the valves in 13 3/8” x 9 5/8” CCA while maintaining 1000psi. Waited for 8hrs, pressure tested to 500 psi, pressure dropped 400psi/10min.
  • Mixed 20L & filled CCA with 6L slurry. Squeezed 2L more into the CCA. Closed the valves in 13 3/8” x 9 5/8” CCA while maintaining 1000psi. Waited for 2hrs, pressure tested to 500 psi, pressure holds for 15min.

The result 
Total 18L slurry injected into CCA. Pressure tested CCA to 500psi successfully for 15 minutes.

Lost Circulation Control

Background & Challenges
  • Total mud losses (> 12 BPM) while drilling 12 ¼” section at 10 753 ft mD of a high pressure gas well. 
  • 250 Bbl conventional LCM pills were pumped without success

Solution
  • Mixed 55 bbl ThermaSet® pill with same density as mud. 
  • Pulled the bit up and stationed at 700 ft above the thief zone. Pumped ThermaSet® pill followed by mud to displace the pill. ThermaSet® pill was staged out of bit incrementally to allow the ThermaSet® pill to react to formation temperature while dropping down hydrostatical towards the loss zone. Once the pill was out of drill string - few more stands were pulled while waiting on curing for 30 min.

Results
  • Circulated the well at 7 BPM with full return.
  • Tagged top of plug at 10705 ft (48 ft above the TD). Approximately 7 Bbl of ThermaSet® was found cured in the OH while 48 Bbl cured in the thief zone.
  • Drilled ThermaSet® plug @ 100 ft/hour and continued drilling the section.
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P&A

Background & Challenges
  • Candidate for first phase P&A with the following challenges:
  • Low reservoir pressure (max 1900 psi) - well on vacuum
  • Pre-maturely set plug (3rd party product)  in tubing – TOP at 137 mMD. Possible communication with reservoir- Via A annulus and from annulus through GLV in SPM to tubing and down to perforated interval
  • Questionable tubing integrity. Several pills of various products were pumped in the well to plug the reservoir -  No success
  • Possible accumulation of CaCO3 particles around SPM.

Solution
  • Prepared 15 M3 ThermaSet® pill for 30 min curing time at 85° C (at SPM depth-2907 mMD) and 10 min curing time at 92° C (reservoir temperature). 
  • Pumped the pill via A annulus followed by 24 m3 sea water (The hydrostatic pressure of ThermaSet® pill + 24 m3 sea water column was equal to reservoir pressure -1900 psi). 
  • Stop the pump and waited for curing of ThermaSet® plug.

Results
Successfully tested the as per BP procedures – No pressure build up – No gas migration.
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Plugging a well with no mechanical integrity

Challenge:
  • Abnormally low reservoir pressure - vacuum
  • Collapsed/parted-off tubing in the middle at 1000 m depth
  • Keeping TOP at a tag able point (above collapse point)

Solution:    
  • Prepared low density ThermaSet® pill (0.8 S.G)
  • Pumped and displaced with calculated volume of sea water having positive pump pressure
  • Tag the TOP pressure tested successfully
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GAS CHANNELING IN CEMENT BEHIND CASING

Challenge:
  • Observed gas around WH on sea bed and in mud return
  • Pumped/squeezed several cement pills without success.

Solution:
  • Perforated casing at a suitable spot
  • Pumped/squeezed 4 m3 ThermaSet® pill
  • Tested the well successfully
screen shot 2016-11-23 at 15 27 02

Lost Circulation Control

Challenge:
  • Total loss of mud in carbonate formation at 3280 m depth in 12 ¼” section of a well in Arabian gulf
  • 40 m3 conventional LCM was pumped without any success

Solution:
  • Stationed bit at 210 m above the thief zone and Pumped a pre-mixed ThermaSet® LCM pill
  • Within 30 minutes circulated the well with full return and resumed further drilling

Water shut off in horizontal well

The challenge
Operator sought to remediate complications of water breakthrough from water injector. The well has a 7” CAJ (Controlled Acid Jetting) liner across the production interval. This liner is perforated in selected zones that can be independently opened and closed from surface. Acid has previously been used to stimulate the formation and has led to compromised integrity of the CAJ liner. Formation fractures coupled with reservoir depletion has led to water breakthrough into the neighboring production well.

The solution
To isolate the upper water injection zone by squeezing ThermaSet® into the pre-existing fracture network while leaving a residual volume in the annulus outside the 7” to form an impenetrable plug and isolate that zone.

The result
Initial Hi-Vis Spacer placement, mixing, pumping and displacement operations went according to plan. The squeeze pressures observed during ThermaSet® displacement were indicative of sound operational placement.
No injectivity testing was performed following conformance treatment. Isolation of the upper water zone will be confirmed during injection operations once well services are completed.  
Cuttings returned to surface following milling operations, confirmed cured ThermaSet® indicating sound operational placement. 

Casing Leak (SPE-182978-MS)

Introduction
The well was drilled to 7,335 ft. and completed with a 4 ½” liner and tubing 18 3/8” & 9 5/8” Casing was cemented without returns.

Well problem
A 120 ft. casing leak was located from 6,750 ft. to 6,870 ft. by running a corrosion and CBL log.

Objectives of operation
Squeeze ThermaSet® pill  to seal off leakage and restore well integrity 

The solution
•    A mechanical barrier was set at 6,920 ft., stablished injectivity of 0.3 BBL at 500 psi.
•    Spot 50 ft. Hi-Vis heavy weight spacer above packer.
•    Mixed and spot 20 BBL ThermaSet® designed to set in 3 hours at 175 °F.
•    Squeezed 5 BBL through parted casing.
•    Tagged top of the pill at 6515 ft. and tested with 500 psi for 10 min. holding.
•    Drilled out ThermaSet® plug and tested as per above parameters. Holding.

The results
Sealed off leakage, pressure tested ok – integrity restored.

Curing of total loss

Tried to cure losses with conventional LCM – Not successful.
Tried to establish the loss rate – Not successful. 

Solution:
Pulled the bit to 300 M above the thief zone.
Pumped 55 bbl. ThermaSet® LCM and displaced with mud out of the bit.
When the pill entered the formation, the curing reaction started and the loss rate reduced to zero. 

Results:
Established circulation with full return.
Tagged top of plug and resumed drilling.

Gas in the return mud

Gas observed in the mud return –peak@ 26% by gas detector.
Gas observed on sea bed around BOP by ROV cameras.
The well was already plugged from TD up to 646 m MD with several cement plugs, each 200 m MD long. 13 3/8” casing was cut at 500 m MD(RT) and the 20” casing shoe at 355 m MD. 

Solution:
Design was a 3 hours curing time at BHST, (down hole temperature) ≈ 10 °C. Pumped  ThermaSet® down the drill pipe stung into the EZSV and squeezed ThermaSet® pill through perforations @ 50 liter/min continuously
Over-displaced the pill with ≈ 300 liter seawater. 2 m3 ThermaSet® was squeezed while approximately 0.5 m3 remained in the casing below EZS.
Stung out of EZSV, monitor the well and waited for ThermaSet® to cure. Observed that  sample at surface, kept at 10 °C, cured according to design 

Results:
Circulated the well bottom up, observed no gas in mud return.
Channel plugged.
Job declared successful. 
 

Collapse in the tubing and casing

The well was plugged and abandoned with Liquid Stone reservoir plug, due to collapse in both tubing and casing. Top of cement was at 2.638 m. The well integrity was lost due to the communication with Miocene gas formation at 1.890 m. Well remained dead for two months before the pressure started to increase in in both tubing and annulus.

Solution:
To seal the channels through the leaking Liquid Stone plug, it was decided to perforate the tubing at 1.829 m. Then we would pump a balanced ThermaSet® plug in both tubing and A-annulus. Thiswould establish the well integrity and prepare for second stage P&A.

ThermaSet® was designed and weighed up to a density of SG 1.045; to match the weight of well fluid. It was designed to cure after 6 hours exposure to the temperature of 63 °C. The ThermaSet® plug material was injected into the well by the use of a well simulation hose.

Results:
Mixing and pumping from the vessel to the platform, was done according to plan and without incident. A total of 1,75 m² was placed in the well, resulting in a column of 50 m. both in the tubing and A-annulus.
After 6 hours, inflow test was performed, and both tubing and annulus was pressure tested to172 bar.
 
All four tests proved successful.

The challenge with cementing

The well was drilled as a gas producer. A 40 inch casing was cemented with casing shoe depth at 314 ft.   Unable to get cement all the way to surface after several attempts, they tried to cement from top side, also without success. The result was oil flow through annulus between 40 and 36 inch casings, 15–18 bbl/day.  At the same time there was communication in the top section to surface and into annulus between 36 and 32 inch casings.
 
Solution:
200 gal ThermaSet® plug in top casing section of 40 and 36 inch, was designed to cure after 2 hours. A second plug of 180 bbl and 10,4 ppg. ThermaSet® was then used as casing cement in 40-36 inch annulus. We used a low temp ThermaSet® designed to cure after 220 minutes, both at 70 °F surface temperature, as well as 40 °F sea bed temperature.

Communication test in 40-36 inch annulus was done with 60 bbl drill water and slick 5, with an injectionate of 1.75 bpm.ThermaSet® Cleaner  was used to clean out the residue of slick 5.180 bbl ThermaSet® pill with 10,4 ppg was prepared on site in batch mixer. A third ThermaSet® low  temp pill, 6.5 bbl at 11,9 ppg , was pumped and dropped on top of cement in annulus of 36-32 inch casings, to seal off any future  communication/cement leaks.

Results:
Top section in 40 inch was plugged and oil flow in annulus was shut off and secured. ThermaSet® plug in 40 inch was essential, in order to successfully cement the casing.  Mixing and pumping operation was conducted as planned. All three plugs tested ok, oil leakage was stopped, and both casings secured.
Wellcem
Orstadveien 108
N-4353  Klepp stasjon
Phone: +47 52 98 65 00
post@wellcem.no
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Wellcem AS
Orstadveien 108, , N-4353  Klepp Stasjon, Norway
Phone: +47 52 98 65 00, info@wellcem.com
Saudi Arabia
Phone:KSA nr +966 533470070
Wellcem AS
Orstadveien 108, N 4353 Klepp stasjon
Phone: +47 52 98 65 00 info@wellcem.com

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