Downhole camera technology puts eyes underground, enhancing a company's understanding of what is going on within the furthest depths of production and helping operators make important decisions that benefit from the all too valuable sense of sight.
"Today, thanks to EV's telemetry, which can transmit up to 300 kilobits per second of data, we can send a full-colour video of 25 frames per second to surface in real time," says Federico Casavantes, vice-president of marketing at EV, a U.K.-based company with a team of technical specialists and engineers at the technological development centre in Norwich, England.
"We see events as they happen--no gimmicks, no delays and, most importantly, no image degradation. We can send data on any logging cable, allowing our customers to see whats happening downhole and, whenever possible, we also transmit the data in real time from the wellsite to the customers office, enabling even quicker decisions."
He adds: "We do this a lot in Canada, mainly because of the sophistication and wide coverage of telecommunication systems in the country. Canada is a great example of how operators are adopting EVs technology to arrive to better answers."
The operating principle of his company's downhole camera technology is not dissimilar to a typical smartphone camera. The difference is that EV cameras are purposely designed? for the oilfield and regularly operate at temperatures of up? to 150 degrees Celsius and pressures of 15,000 pounds per square inch (psi), whereas a smartphone would likely fail at around 6080 degrees Celsius. According to Casavantes, EV's technology trumps the competition, too.
"Right now, we are at field trial stage with our continuous 175 [degree Celsius] and 20,000 psi camera, and we have an EV team of 35 specialists working on this and other projects nobody else has this capability."
If running on coiled tubing or slickline, EV provides memory cameras that can record up to five hours of continuous video, with potential for segmented recording up to 60 intervals depending on operations. The data is then downloaded from memory as soon as the tool comes to surface.
"Our memory cameras are the best in the industry. Competitor memory options only provide still black-and-white pictures. Our memory cameras provide full-colour video at 30 frames per second, which is high-definition [HD] video."
While Halliburton also offers HD colour for those who request it, Darren Walters, global champion for plugging and abandonment, says the black-and-white camera technology is just as effective at imaging beneath the earth, because colour is not a factor in that environment.
"We don't paint the inside of a well with colours. Everything that you see downhole is black and white. It is like being out at night and there are no street lamps, and you usually just have grey vision. That is what you are getting downhole. For a crisp, clear picture, black and white usually works better than HD colour, although Halliburton offers both options for different operations."
For mature wells with planned intervention or abandonments, running Halliburton cameras as part of the diagnostic provides key insight into the wells condition and can help optimize the operation, thus saving time and money. Walters says, "An operators specific goal will dictate how the proper camera is selected to ensure a complete and individualized solution."
GLIMPSING THE UNDERWORLD
With most applications, Halliburton's downhole camera technology is geared toward mature wells or well intervention. For example, if the operator sends down a slickline that gets hung up at a certain depth, a "worm's-eye" view can prove quite beneficial.
"At this point they have limited options," Walters says. "Operators don't know what they have hung up on. They can go in with a lead impression block and hammer it hard to try and get an impression of what is in the hole, but thats inefficient when finesse is required."
A lead impression block is a tool containing soft lead in the bottom used to take an impression of an object (or fish) downhole to determine its size and shape, so that the appropriate fishing tools can be selected to remove the blockage during fishing operations.
He adds: "If you lost something in the well and don't know how it is sitting, then hitting it with the lead impression block could manoeuver it into a more difficult position for fishing. For example, if fishing for wire with a camera, operators have the ability to determine exactly how the wire is lying, reducing potential risks.
"If there is a tool string in the well and no wire, operators will be able to identify how the fish? is lying in order to use the most appropriate overshot or recovery tool to recover the fish from the well. Downhole cameras bring an added advantage to see potential hazards which could result in a longer, more expensive job."
Halliburton offers three cameras--two of them are deployed on electric line (e-line) and one on slickline. The e-line cameras offer a downward and sideways view, providing information about what obstructions are in the way for a wireline fish or what problems an operator might be having downhole.
"You'll run in hole to up to 30,000 feet on 7/32 line that will provide video frames back to the surface, Walters says. So it is a live feed, although there is a slight delay as you might expect, as it transmits through the conductor, which is 1.25 images per second going up the hole on mono cable. We can run on fibre optics, which is also live feed."
When running a tool with down- and side-view cameras, Halliburton can detect and investigate potential downhole issues with greater precision. For example, if the down-view camera sees gas bubbles coming from a sidewall of the tubing, switching to side view at that depth allows a 360-degree turn to help determine what is occurring in that area.
"You may find that there is a crack in the pipe, or you could learn that when the well was constructed the thread itself was not fully tightened, causing a leak path," Walters says. "This has been seen downhole with the e-line cameras."
The e-line cameras can be conveyed on the vast majority of electric line cable used in the energy sector, whether single- or multi-conductor wireline. According to Walters, downhole camera technology once implied a lot of accompanying surface equipment panels for communicating with the cameras, recording the data and changing it to video. Today, though, Halliburton cameras only require a laptop and a small communication panel at surface a bonus for offshore operations.
"What makes Halliburton different than others is our complete solution. We can conduct the camera service and perform the fishing operation as an integrated solution. Halliburton wireline specializes in intervention, so we can enter the well, conduct and survey the problem, and then offer a solution directed at the detected problem, whether fishing, perforating, mandrel replacement or other invention."
With more than 120 people in 26 locations around the world, EV is a truly global diagnosis company that must routinely innovate and stretch technical boundaries to meet the challenges encountered by its global customer base in some of the most extreme environments, says Casavantes.
EV's downhole camera technology has a wide range of applications, from identifying unknown objects stuck downhole to diagnosing well-integrity issues on land and offshore, such as corrosion or valve conditions. EV also provides measurements in conjunction with video images.
"Thanks to our powerful telemetry, we can combine pressure, temperature, gamma ray, casing-collar locator and log as we acquire the video, and this is also unique to EV."
EVs combination of video with sensors--whether to look at sand screens, sand entry, mineral deposits, frac efficiency, or a wide range of other situations encountered downhole makes for a more powerful, clearer understanding of the condition being evaluated, Casavantes says.
FRAC ASSESSMENT
"In the U.S., we are undertaking a lot of frac efficiency diagnostics. We are called in to multistage wells to measure the perforations before and after the fracturing operation and provide the customer [with] a perforation variance evaluation. This ultimately provides the operator with an understanding of fracture efficiency. [Companies] have been able to save millions of dollars by tailoring subsequent fracturing operations based on the information provided by EV.
"By combining both visual and physical measurement data in the same run, EV provides significant cost efficiencies. Not only do operators get a better answer, they get it in less time."
The advantage of downhole camera technology is that it actually cuts down on non-productive time by eliminating guesswork and minimizing interpretation time. Video-based solutions provide a clear, unequivocal understanding of the issues at hand so customers can decide exactly what actions to take in the shortest time frame possible, says Casavantes.
For example, he adds, while recently trying to complete a well intervention, an operator lost ?a nozzle assembly in the well, and it was causing an obstruction across the downhole packer. The operator had been working unsuccessfully to resolve the problem for several days. "When they finally called EV, they had a clear diagnostic within 24 hours and were able to resolve the issue expediently."
In this particular case, costs were in the order of $650,000 per day. The operator spent over $5 million before deciding to engage EV. "They would have saved a lot of money if they had done so sooner," notes Casavantes.
"On the positive side, operators are increasingly relying on EV to provide reliable solutions. More and more, we are being pulled into and considered at the planning stage of operations, and less and less as a last resort call-out. It is great to know that people are starting to understand the unique advantages offered by EV.
"In Canada, for example, we have been very successful with our Integrated Video Caliper (IVC), which not only was field tested in the country, but is now utilized regularly by many of our customers."
While many companies provide multi-finger caliper tools, he adds, only EV does so with a camera on its IVC. "The benefits include considerable time savings and an unequivocal diagnosis. We run into the well and perform a preliminary visual inspection and, by the time we get to bottom, we have a fairly good idea of where the key issues are.
"We then log the caliper across the area of interest, and finally inspect close up with a side-view camera. A multi-finger caliper is a mechanical device, so you need to interpret it. When you combine it with a video, the interpretation becomes a ?lot more robust supported with visual evidence."
OPAQUENESS OBSCURES EFFECTIVENESS?
Sometimes when trying to use camera technology to answer questions downhole, the answers along with the environment are not always clear.
According to Casavantes, the biggest advantage of a downhole video is also its greatest disadvantage: the technology works within the visual spectrum. "If your environment is predominantly oil, or just dirty water with mud, then cameras wont work unless there is adequate well preparation," he says, adding that EV typically achieves 95 per cent efficiency in acquiring video-based diagnostics in a wide range of environments around the world.
"Out of more than 100 jobs we run in any given month, at least on 95 of those we capture the necessary video images to provide our customers with answers. Even in the cases? where we are challenged beyond the physical capability of the technology, thanks to our vast global experience we are able to provide guidance for appropriate well preparation to get the best picture possible."
The downhole environment has to be suitable for camera operations. If the operator cannot see through the fluid with his or her own eyes, then the camera images are going to be less effective. According to Walters, because Halliburton uses a light source behind its visual device, too many suspended solids in the well fluid adds to reflectiveness, which degrades picture quality.
He says: "The key to an effective camera operation is knowing how to work within the well itself, which includes proper fluid usage and management. This knowledge, coupled with special surfactants applied to the lens to stop heavy oils from sticking to it, requires detailed pre-job planning rather than just running in the hole and hoping for the best."
