Increasing fracture pressures, risk profiles push market for ELH, hybrid and wireless tools
By Joanne Liou, Associate Editor
Following the industry’s path to deeper operations and longer laterals, liner hanger systems are amping up in terms of higher load capacities and higher-pressure ratings. However, being able to install these liners while maintaining high compression capabilities continues to be a challenge. In the Bakken, for example, having 20 to 30 fracturing stages per well has become the norm.
“For the companies to be economical, they have to go as far as they possibly can horizontally. We needed something stronger to be able to handle where the industry’s headed, in terms of horizontal gas or oil drilling,” John McCormick, Technical Advisor at Halliburton, stated.
Increasing fracture pressures also are driving the market for open-hole horizontal completions using expandable liner hangers. Although deployment of these new systems has been exclusive to onshore US, companies, such as Halliburton, expect to expand its reach overseas to China where shale gas operations are on the rise.
Offshore, the risk profiles for deepwater and ultra-deepwater operations have become increasingly high. To improve safety related to the handling of these strings, operators, such as PEMEX, are seeking wireless tools that would remove personnel from hazardous areas, Faraz Ali, Product Manager at Baker Hughes, said. Such tools often feature simplified operations and increased reliability.
In addition to the time savings, “the greatest benefit (of wireless tools) is the fact that there is no manual operation required to drop the darts,” Silvestre Ramirez Quintanar, Litoral Tabasco Region Drilling Manager for PEMEX, stated.
The market for liner hanger systems can traditionally be divided into two distinct categories – conventional and expandable – but a hybrid liner hanger system being developed aims to embody advantages of both systems. Weatherford’s SwageHammer utilizes a sealing technology called SwageSeal that is rated to 15,000 psi and 400°F in some sizes. “The high-performance seal has a metal chassis, and we physically swage that metal chassis out against the casing,” George Givens, Global Product Line Manager for Liner Systems at Weatherford, said. “It allows us to go to a much higher sealing capability mode because it’s not all rubber as conventional packers are.”
The system, which can accommodate a 600,000-lb load, will be available in the 7 5⁄8-in. x 9 5⁄8-in. size. The system targets deepwater applications and is set in the same manner as conventional hangers, where the running tools are released prior to cementing operations. “The running tools are hydraulically balanced to prevent premature activation of the liner hanger while running in the hole. To set the hanger, a dropped ball is seated in the running tool and applied pressure sets the hanger,” Mr Givens explained. “All the hydraulics are in the running tool; there are no hydraulics on the liner hanger or packer.”
“The advantage of SwageHammer is that it does not have a hydraulic cylinder on the hanger like most conventional liner hanger equipment does,” Mr Givens said. “All the setting mechanisms are part of the running tool, not part of the hanger and packer that stay in the hole. You don’t have a hydraulic cylinder with seals that have to maintain their integrity for life of well – only for a day or two,” he continued. “What’s left in the (wellbore) is a system that has no hole in the pipe, which is one of the advantages of an expandable hanger.”
Removing the hydraulic cylinder also increases the system’s ability to hold the higher pressures often associated with deepwater operations, and it eliminates potential leak paths in connections, seals, etc. “We’ve basically removed all that out of the design and reconfigured the design such that we’re not depending on ports, seals, cylinders and hydraulics to maintain its integrity for the life of well,” he said. “We only have to maintain it through the installation process. Then, once we take the running tools out, what we have in place is a complete pressure integrity system: no ports, no seals, no additional hydraulics.”
While most conventional systems are not hydraulically balanced, SwageHammer’s running tool is hydraulically balanced so that any kind of circulation pressures or surge pressures will not prematurely activate the system. “The hydraulics of the system stay completely neutral, which enhances the reliability and the ability to be able to robustly work a liner to the bottom of the hole,” Mr Givens said.
Weatherford will begin field trials for this technology in the US onshore at the end of this year before moving offshore to the Gulf of Mexico. The system will be available in other sizes, including 14 in. x 16 in.
Targeting the onshore market, particularly 10,000-psi hydraulic fracturing operations in North America, Halliburton commercially launched VersaStim Expandable Liner System in July 2013. Designed to withstand 10,000-lb fracture pressures, the system eliminates the need for packers and optimizes the liner hanger configuration to run in horizontal applications where conventional mechanical liner hangers or production packers are traditionally used. “When we talk about expandable liner hangers, it’s about being reliable, being versatile and being simple,” Daniel Hayward, Account Representative for Completion Tools Halliburton, said.
The VersaStim hanger features an upper ratch-latch connection. The connection allows modular components – a latch-down frac-through seal unit for 10,000-psi frac work or a latch-down production seal unit on an upper tie-back receptacle (TBR) and a tie-back seal unit – to be securely latched and sealed on top of the hanger as needed. “The TBR allows more movement of the seals when higher pressures are seen during the completion operation,” Mr McCormick explained. “If the stresses are lower than the mechanical limitations of the ratch latch, the TBR is not needed and the completion string can latch directly into the hanger.”
Halliburton has so far primarily deployed the system in the US Rockies region but plans to expand to the southern US by the end of this year. “With the VersaStim system, you have a mechanism that latches into your completion string 6,000 ft downhole. When you start fracking at 10,000 lb, forces will naturally try to force that tie-back assembly up hole, but this ratchet mechanism holds it in place,” Mr Hayward explained.
Halliburton has also developed the VersaFlex Breech Lock system to increase by up to five times the compressive load capacity of the VersaFlex expandable liner hanger (ELH) system to approximately 150,000 lb. The system allows operators to reach TD, particularly in extended-reach wells, when deploying and setting the liner hanger. “With most US land wells, rigs will drill straight down several thousand feet, then drill horizontally for 5,000 or 6,000 ft,” Mr McCormick said. “In certain areas in the Bakken, they will drill 8,000 to 10,000 ft out in the horizontal, and it gets incredibly difficult to push the liner to bottom.”
The Breech Lock system uses lugs at the front of the breech so that the compression positions the liner toward the open hole. The system, which is capable of handling the higher compression, has been applied in the Williston area in the Bakken, and plays in Oklahoma are in the process of switching to the Breech Lock system, he added.
The weight of the liner is also a factor in many completions in Oklahoma and in the Bakken. “They deploy either hydraulically operated or swellable packer elements on the outside,” My Hayward explained. “At that point, they will not require cement, but with swellable packers and frac sleeves, you have an increased outer diameter of the casing. It creates a lot more drag to get this liner down to depth.” The Breech Lock system enables the additional force necessary to install the completion string to depth, according to Halliburton.
To hydraulically set liner hangers and darts for a cement job, Baker Hughes has developed the LaunchPRO Wireless TD Cement Head. The tool allows cementing while running a liner hanger string in the hole. “It allows you to launch balls and darts wirelessly, so no longer do you have to send your personnel up the derrick to manually release these balls and darts,” Mr Ali said. “The balls are used to set your hydraulically set liner hangers, and the darts are there for your cement job.”
The wireless tool is operated with a handheld remote control, such as an iPad. The tool communicates via radio frequency with the control pad, which provides a visual indicator of the tool’s status. The tool also provides an audio indicator. “There’s an indicator on the tool that shifts as the balls and darts are released. The release of balls is indicated on the tool and control pad. When the darts are released, there’s a flag indicator on the tool, so as the dart passes through the tool, it activates a flag that pops out as the dart passes by. When that flag pops out, a sensor sends a signal to the control pad for visual indication and rig air box for audible indication via a horn,” Mr Ali explained.
The wireless feature also leads to better cycle times. “You don’t have to wait on your personnel to ride up the belt and manually operate the tool,” Mr Ali stated. “You can operate the tool from the doghouse, where you press buttons on a tablet and command the tool to release balls or release darts and open and close cement valves.”
The tool, which received a Spotlight on New Technology Award at the Offshore Technology Conference this year, is designed to meet specifications of deepwater and ultra-deepwater drilling. “As deepwater and ultra-deepwater drilling activity increases, you’ll see a lot more weight suspended off of the cement head. As your liner hanger string is made up, it’s the very top piece on the string above the surface, so it supports the weight of the entire string below it,” Mr Ali explained. “The significance of this is it allows 2.5 million lb to be suspended off of it, which is the highest in the industry right now.” The average load capacity of similar systems is between 1.5-2 million lb, according to Baker Hughes.
The tool has a working pressure rating of 10,000 psi and a minimum operating temperature rating of -20°F, which makes it particularly suitable for harsh environments, such as Norway. Baker Hughes had a successful field trial of the LaunchPRO cement head with PEMEX offshore Mexico in June 2013. PEMEX was working in deepwater and selected LaunchPRO since the cement head was 62 ft higher than the rig floor, making it more time consuming and less safe to operate manually. The cement head removed the risk to personnel and increased efficiency of the operation.
LaunchPRO took about 1-2 hours to launch, Mr Quintanar or PEMEX stated. “The main benefits obtained were the decrease in potential accidents by better control of the cementing process, given that it is monitored and controlled electronically, and reduction in the disconnecting time, avoiding issues concerning cement hardening.”
SwageHammer is a trademark of Weatherford. VersaStim and VersaFlex are registered trademarks of Halliburton. LaunchPRO is a trademark of Baker Hughes.