How can geothermal operators deal with corrosion worries of their wells? NOV’s established TK-Liner methodology claims a trusted, worth tag-helpful resolution.
All-natural gasoline is presently the most important electrical energy supply heating the Netherlands’ buildings, greenhouses, and industrial infrastructure. The place is actively transitioning absent from the usage of all-natural gas and changing it with sustainable vitality sources together with heat water that’s created from geothermal wells. By providing sustainable warmth, geothermal wells present the guarantee of strengthening the monetary system and electrical energy self-sufficiency of the place.
The geothermal trade shouldn’t be new within the Netherlands, nevertheless it’s coping with substantial troubles that will maybe restrict its very long-time interval viability. Geothermal operators traditionally designed their wells on restricted budgets working with very low-expense carbon steel for the successfully casing. However the regular working environment of a substantial proportion of those wells—water temperatures starting from 85°C to 95°C, giant salinity fluids, and the existence of oxygen—contributes to a massively corrosive pure surroundings for carbon steel.
Frequent treatments pose troubles
The oil and gas trade usually combats corrosion in its carbon-metal tubing with chemical corrosion inhibitors. However new resistance to creating use of chemical corrosion inhibitors within the Netherlands curbs the very long-term use of those sorts of chemical substances in foreseeable future geothermal functions.
Different potential alternate options reveal problematic. Increased-chrome corrosion-resistant alloys (CRAs) can face up to corrosive assault, however CRA pipe may be as much as 10 situations the speed of carbon-metal and difficult to provide.
Some geothermal operators have thought of glass-reinforced epoxy (GRE), mono-wall pipe. However introduced the properly illnesses, this pipe can’t current ample structural integrity, particularly within the threaded areas.
A good, robust choice
Given the prolonged payback intervals for his or her wells, geothermal operators need wise successfully designs working with expense-powerful parts to verify dependable, many years-long process. Of their search for for non-chemical, non-CRA strategies for his or her corrosion points, operators within the Netherlands turned to NOV and its Tuboscope objects for help. For lots greater than 80 a number of years, Tuboscope has supplied incredible corrosion security, hydraulic enchancment, and deposit mitigation in tubular merchandise.
For the particular requires of geothermal wells, the Tuboscope TK-Liner technological know-how supplies significant-efficiency corrosion safety. TK-Liner objects comprise a slender-walled GRE liner cemented inside a lower-alloy carbon steel pipe. The liner supplies an useful corrosion and thermal insulation barrier whereas the carbon steel pipe reliably stands as much as stress and properly loadings.
The know-how’s corrosion safety extends to the threaded connections, because of the TK-Ring II process. Constructed to in form any coupling program, the ring is ready up into the joint between every pipe half and lets for the total hyperlink tolerance-range. The TK-Ring II technological know-how is a mechanically-engaged concept that stands as much as all nicely-induced stresses—making certain a flush-changeover, steady gasoline-limited seal, corrosion safety and a prolonged on a regular basis dwelling of the steel connections.
Proving its alternative
Much more than 70 million ft of TK-Liner pipe are mounted in higher-temperature functions all-around the planet. Essentially the most important diameter pipe earlier lined was 10 ¾”, however for the Netherlands’ geothermal market, operators requested for lined pipe as much as 13-3/8” in diameter.
NOV launched into extra merchandise improvement, like refining the pumping procedures for Tuboscope’s regular uncooked provides and element layouts. The agency took particular remedy to ensure that every one elements—together with the TK-Ring II technological innovation, liners, and link-systems—would perform as anticipated on the greater ID.
Whole-scale pumping was carried out on purchaser “free situation” pipes. The entire-diameter product, which embody the extra substantial TK-Ring II resolution prototype, had been assembled and arrange with out incident. An individual massive Netherlands operator observed the set up screening and thought of the huge-diameter TK-Liner resolution in form for companies.
To day, Tuboscope has equipped plenty of a whole lot of metres of TK-Liner strategies for the Netherlands geothermal sector, with dimensions like 7 5/8”, 9 5/8”, 10 ¾” and 13 3/8”. The liner works by utilizing regular off-the-shelf base-pipe with un-modified top quality connections, supported by Tuboscope and backed by the thread-proprietors’ licensee community.
“So considerably, 9 wells have been appropriately deployed into this thrilling, rising market,” suggests Tom McLaughlin with Tuboscope. “We’re happy to report that we now have important new contracts in place for 2022 duties within the Netherlands.”
For extra knowledge on NOV’s TK-Liner know-how, go to https://www.nov.com/options/tk-liner.