The concept had many names—Intelligent Wells, the Downhole Factory, the Field of the Future. But all of these monikers described a new form of completion technology that would give operators the ability to better control their wells downhole.

The term “intelligent completions” is often used to describe a variety of different technologies that have evolved over the past 10 to 15 years to address operators’ needs. In its infancy the concept spawned several highly ambitious ideas.

“There was originally a vision of these fully autonomous wells that would control themselves and provide the ability to self-optimise and have wireless communication up the wellbore,” said Darrin Willauer, director of intelligent production systems at Baker Hughes. “We had the vision of the downhole factories where all of the separation would happen downhole. There were a lot of crazy concepts being tossed around back then.”

But there also were some compelling drivers. For one thing, drilling technology was undergoing dramatic changes. “The industry’s key challenge was how to drill wells to intercept and maximise the contact with the reservoir,” said Mohamed Aly Sadek, completions marketing and technology manager at Schlumberger. “We started with horizontal wells, then extended-reach, and now multilaterals. The drilling technology started to evolve very fast, and what used to be out of reach in the 1980s and 1990s is a common practice today.

“While this was happening, many challenges started to come up. We could drill the wells, but how could we complete them and produce them efficiently? It became very obvious that the current completion technology was no longer suitable.”

Another very real driver was the rising cost of well intervention, particularly offshore. “People didn’t want to go in and move a sleeve because they wanted to shut off a zone that was producing water,” said Savio Saldanha, senior product manager for intelligent flow control at Halliburton. “That meant they would have to mobilise a rig just to do a sleeve movement on one well. Given the expensive day rates, it didn’t make economic sense.”

The need for intelligent systems also was driven by the difficulty of obtaining production logs in horizontal sections or multilateral wells. Sadek said that in a multilateral well only the mother bore can be logged. “You can have four or five laterals in the same well,” he said. “We cannot ignore the production coming from these wells.”

So, intelligent completion technologies were developed. Early deployments were relatively simple, combining flow control valves with pressure and temperature sensors. As they have evolved over time, these systems have become more complex, but they also have provided tremendous benefits to the industry.

Current technology

Saldanha outlined numerous situations that have benefited from intelligent completions. They help reduce opex and capex by enabling commingling of zones with different pressure profiles. They can shut off water or gas breakthrough from particular zones. And they can enable the production of marginal assets.

“If you have a smaller asset that is only going to produce 50,000 bbl overall, it doesn’t make economic sense when you’re spending $100,000 to drill a well,” he said. “But if you’re drilling it as part of a major find and you use intelligent completions to extract whatever comes from that marginal reservoir, those are incremental reserves.”

Operators also are using intelligent completions for secondary and tertiary recovery, particularly in water injection wells to control the sweep, he said.

Technology enhancements are having an impact as well. Willauer said that downhole flow meters enable operators to determine the amount of production coming from each zone, or each well in a subsea completion. Fiber optics are also playing a larger role since this technology enables distributed sensing.

Key challenges remain

One of the major questions regarding intelligent completions is how to power the downhole instruments. Early electric systems were notoriously unreliable. “It’s not like a drilling tool that’s going to drill the well and pull out,” Sadek said. “We have to design a system that will stay downhole for at least 10 years.”

So the industry moved to hydraulic systems and hybrid systems combining both electronics and hydraulics. Early versions of the hybrid system were also plagued by reliability issues, and Saldanha said that any electronic failure in the system caused the operator to lose control of the well. Hydraulic systems are much more reliable, but the wellbore can get pretty congested with multiple lines.

“Real estate is beginning to be reduced,” he said. “You might need a line for a safety valve, for injection, for gauges, for other valves. Pretty soon you end up with eight or nine lines.”

The industry is slowly revisiting the idea of all-electric systems as reliability has improved. Baker Hughes installed an all-electric system several years ago that is still functioning properly, but many operators are still hesitant to embrace the technology.

Weatherford, meanwhile, relies on a radio-frequency identification (RFID) system in a wireless completion set-up. “When you move into a wireless scenario, you have to talk about downhole power generation,” said Yvonne McAnally, global product line director, upper completions for Weatherford’s Well Completion Technologies division. “Our RFID system is powered by batteries. We can actuate a sleeve without any control lines. But we have the restriction of the lifespan of the batteries.”

Tendeka has licenced technology from Statoil to produce its FloSure autonomous inflow control valve, allowing operators to even out the inflow profile to prevent fluid coning. The valve operates by responding to the velocity of the fluid coming into the well.

Finally, there is the issue of cost. While intelligent completions might save a subsea well from watering out, the systems are becoming so complex and expensive that operators might begin to question their return on investment.

“Some operators might struggle with the cost-benefit proposition since the benefits are not realised until several years into the future,” McAnally said. “They might be wondering if there is a better way.”

What is needed

While intelligent completions technology has come a long way from its early beginnings, most agree that it’s still evolving. The main issues driving current development are simplicity and integration.

“We have to simplify these systems in terms of the number of control lines and the number of electric cables,” Sadek said, adding that Schlumberger is perfecting an integrated platform that can be deployed as one piece of kit. The first generation, the IntelliZone Compact modular multizonal management system, was launched about four years ago, and he said that many customers who are not usually early technology adopters have been asking for the system.

Willauer agreed that an integrated system is more than the sum of its parts. “There is no one key technology,” he said. “It’s really the aggregation of all of these technologies that are enabling multiple markets right now. It’s not just the high-end markets. We can provide solutions for some of the lower end markets now.”

He added that the intelligent completion of the future will be an integrated solution that goes from the downhole hardware through the subsea infrastructure all the way to the desktop. “It’s that level of intimacy and integration that we need to continue to pursue,” he said.

The challenge in realizing a fully automated intelligent completion will require more than the participation of the completions engineers. Sadek said that it’s necessary to work closely with the drilling department to understand their well construction plans. “There’s no value in drilling a well if we can’t complete it,” he said. “We have to have a clear understanding of how they’re going to be drilling the wells.”

And production engineers need to be involved as well. “I see a blending of the completions engineer and the production engineer,” Willauer said. “The completion design is impacted by the production goals to a much greater extent than it has been in the past.”

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