Thomas Stark - application marketing manager, oil and gas at Borealis Polyolefine - and Markus Haager, head of business unit lining at AGRU Kunststofftechnik, explain how the companies' PE-X tubing liners offer increased resistance to corrosion and abrasion in oil wells, bringing measurable benefits in terms of minimised maintenance and downtime costs, and extended well life.
Oil continues to be one of the driving resources of our global economy but, with the low prices seen in recent months, the importance of being able to explore oil in a resource-efficient manner increases. There are even more challenges for production in mature oil fields with high water cuts in addition to the exposure of the tubing pipes to some components of crude oil, which can cause corrosion. Abrasion is also an issue because the movement of the rods wears away at the tubing walls.
Borealis, a leading supplier of innovative plastics solutions, and its shareholder, OMV, have patented a unique solution where a cross-linked polyethylene (PE-X) liner is used in combination with special rod couplings to protect the inside of the well tubing of sucker rod pumps and progressive cavity pump wells against corrosion and, specifically, against heavy wear, which occurs when the moving parts scratch the inside of the tubing.
The experts of AGRU Kunststofftechnik, a major international manufacturer of innovative plastic products such as piping systems, semi-finished products, concrete protective liners and geomembranes based in Bad Hall, Austria, are offering such tailored PE-X liners and can provide lined tubing via its partners.
These thermoplastic tubing liners are made from cross-linked polyethylene, which achieved superior results in tests designed to simulate the movement of the rod couplings against the lining material set in conditions similar to the oilfield environment, thus testing the combined effect of corrosion and abrasion.
The cross-linked polyethylene material proved to have high abrasion resistance as well as withstanding temperatures up to 90°C.
The applications of these PE-X tubing liners are primarily in onshore oil production, specifically with sucker rod pumps and progressive cavity pumps, but they can also be used in water injection wells. The benefits include an improved lifetime of the wells, increased resistance to abrasion and corrosion, and extended run time between maintenance.
In using these tubing liners, significantly reduced downhole failure times could be observed, leading to lower cost of exploration, less maintenance and lower energy consumption due to less friction. The saving potential greatly depends on the condition of the well, the amount of sand present, the straightness of the drill, temperature and the corrosiveness of the environment.
This technology can allow an extended exploration time and oil volume when other operators have been forced to abandon the well due to high maintenance costs. Through their use in oil wells so far, these liners have proven to help extend the intervals between necessary maintenance and to extend the overall lifetimes of the wells.