封隔器技术新进展（三）

Liner Hanger Packers

Packers Plus is also introducing a new liner hanger packer for the compression forces required in horizontal wells where equipment needs to be pushed into the well. Configured with an anti-preset mechanism, the new design will ensure the completion system is fully installed and provide the high-pressure sealing capability of a production packer, Mr Themig noted.

Liner hanger packers, installed permanently in the well as part of the liner hanger assembly commonly used in cased holes, are increasingly being used to achieve greater well integrity and for cost efficiency, according to Terry Howard, Director of Technical Support and Training for TIW, a provider of custom-engineered drilling and completions equipment for the oil and gas industry. “Back in the 1980s, liner-top packers were run on about 20% of liners installed in wells,” he said. “Today, they are used 80% to 90% of the time.”

In many cases, operators are running the packer as standard equipment with the liner to avoid having to install one later in case of a poor cement job. “In the past, operators chose not to run the packer with the liner. However, if the top of the liner did not test well after the cement was pumped, they had to suspend operations and go back in with the packer, which involves extra days and rig time and more trips in and out of the hole,” Mr Howard said. “It comes down to overall cost, and being preemptive saves money in the long run.”

Deeper wells and higher pressures and temperatures have been drivers for improving the strength and capabilities of liner hanger packers. “Thirty years ago, a liner-top packer that would hold 5,000 differential strength was considered top of the line,” he noted. “Today, we’re at 10,000 psi and looking to go to 15,000 psi.”

TIW’s liner hanger packers are used globally, but deepwater is a key market as customers see the importance of having the additional seal, he continued. “Customers also want liner-top packers to be more robust in terms of how much pressure they will hold at increasingly higher temperatures,” Mr Howard said. “The temperature ceiling is typically around 400°F, but we have seen environments as high as 450°F, and some operators are predicting 500°F.”

To overcome the limitations of elastomers in high temperatures, TIW has developed an expandable liner hanger packer, the XPak, which creates a metal-to-metal seal between the liner hanger and the casing where the packer is being set. Expansion is provided with a hydraulic tool that exerts a tremendous amount of force and stretches the steel tube until it contacts the outer casing. “The packer is similar to solid expandable technology in the setting method, but it provides a much more reliable seal, holds higher pressures and can operate in higher temperatures than conventional rubber compression-set packers,” he explained. “It is ideal for extreme environments.” An elastomer installed in the packer serves a secondary seal.