When a Chevron well was placed on gas lift, leaks were discovered between the outer annulus and conductor. These leaks resulted in an inability to safely gas lift the well, resulting in reduced production. Additionally, Chevron was concerned about the potential safety and environmental risks of the leaks.
A Seal-Tite® engineer was deployed to the platform and, with no well intervention, was able to cure the leaks. All Seal-Tite® operations were conducted through test ports in the wellhead. The well was returned to gas lift, production re-established and pressure on the outer annulus and conductor was eliminated. Chevron increased production, reduced gas loss, eliminated potential operational risks and increased production to 350 Bbl per day.
Without Seal-Tite®, a major rig operation would have been required at a cost in excess of $2.5 million, in addition to the risk of damage to the reservoir and loss of production because of killing the well.
A testimonial letter from Chevron is available for this operation.
Seal-Tite® performed eight pack-off sealant jobs on six wells for Arco Alaska, two of which had dual pack-off leaks. In selecting the wells to be repaired, Arco chose a broad spectrum of leak rates, from minor to severe. Although Arco expected that Seal-Tite® would only be able to seal approximately one-half of the leaks, Seal-Tite® cured all eight problems.
In Australia, the operator was unable to gas lift a number of wells due to wellhead leaks that prevented pressurization of the casing. Seal-Tite® has performed successful sealant operations on three of the leaking wellheads. By curing the wellhead leaks, the operator has been able to gas lift the wells and increase production by in excess of 3,000 barrels per day.
Wellhead Tubing and Casing Hanger Leak Repair Seal Longevity
Late in 2016, a producer was experiencing leaks in both its tubing and casing hangers. The Seal-Tite technician attempted to pressure test the 9 5/8” casing hanger but could not build any pressure after injecting 3 liters of hydraulic oil. Because of the inability to build up pressure, a time activated sealant was selected to rebuild the extremely damaged seal. 700 mL of the sealant was injected at 800 psi pump pressure until the pressure had increased to 3500 psi. Sealant was locked in overnight to cure. Upon returning the next morning, the hanger was found to still be leaking at a rate of 300 mL/min, which was remedied by injecting 200 mL of pressure-activated sealant. It was allowed to cure at 1200 psi and tested successfully at this pressure for 15 minutes. The technician then moved on to the tubing hanger, which was able to be pressured up to 3000 psi, but lost pressure in less than 10 seconds. A leak rate was recorded as 3L/min @ 2500 psi. This severe leak rate necessitated a time-activated sealant as well. 1 L of the sealant was injected at 1000 psi and locked in to cure overnight. When pressured to 3500 psi the following day, the seals passed a 15 minute test.
Another well on the platform had a leaking 9 5/8” casing hanger body seal. No pressure could be built after injecting 6 L, indicating a severe leak to be treated using time-activated sealant. 1 liter was injected into the void at 1100 psi pump pressure and locked in overnight. The next morning, the body seal was tested successfully to 1200 psi for 15 minutes.
When on location in June 2019 for another repair campaign, a technician tested all three hanger voids successfully. The Seal-Tite repaired seals are holding steadily after three years and counting
Wellhead Tubing Hanger Leak Repair Seal Longevity
A producing well in Australia was experiencing a number of wellhead leaks. The 13 3/8” pack-off seals were reported to be leaking. The void was pressured up to 3000 psi and a leak-off test showed a 600 psi loss over a 10 minute duration. The 10 ¾” pack-off seals were also leaking. This void was also pressured up to 3000 psi, but lost 1300 psi over 6.5 minutes before leveling out. The tubing hanger body seal lost 1300 psi over 10 minutes after being pressure up to 300 psi. Gly-Flo pressure-activated sealant was injected into all three voids and allowed to cure at 3000 psi. All three seals were repaired successfully to the desired test pressure.
After returning to location for a multi-well campaign in May 2019, the previously repaired seals were tested to ensure integrity. Over seven years after the initial repairs, all seals passed a 3000 psi pressure test.