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2018 Offshore Technology Yearbook

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EPmag.com | December 2017 | 31 DRILLING TECHNOLOGY | 2018 OFFSHORE TECHNOLOGY YEARBOOK down the drilling to get good quality data." He explained that with a higher data rate an operator can still get good log data to the surface even while drill- ing a section in less time. "The other aspect is that with a particular drilling speed, by having a higher data rate, you can have a more detailed log. You can get more data points per foot as you're drilling the well." The JetPulse is designed to operate in any kind of mud. "One thing we find is a gen- eral principle that applies to telemetry—the deeper you go, the more attenuation of the signal you see. Heavier muds tend to attenuate more than lighter muds. We have found the performance of this new sys-tem is actually very consistent as far as depth is concerned," Parker continued. There is very little loss of data rate with increas- ing depth. "We can work in some of the deepest wells that are drilled in the Gulf of Mexico [GoM] to about 30,000 ft," he added. The system also is able to maintain a high data rate that is similar to what other systems would get at much shallower depths. The company also has a new software system that is an add-on to its data acquisition system, which is a more sophisticated filtering and tun- ing system than the company had before. It helps to detect the pulses more easily as they come to the surface. The new system takes into account the characteristics of the entire drillstring in filtering out drilling noise, he explained. When the system first begins operation it sends out a predetermined sequence that the surface sys- tem analyzes and decides how best to handle the subsequent data that comes up from the tool. "It's like a sort of auto-tuning to take account of vari- ations in the drillstring, depth, etc." he said. Pre- viously it was a manual system that people on the surface had to monitor and adjust. The JetPulse is being used for the more high- end markets such as deepwater markets and more mature markets where a lot of tools are being run. In general the customers are happier the more data they have. They appreciate not having to moderate their drilling rate significantly now that there is a higher data rate. The system can provide a good log at typical drilling speeds in the GoM. "I've got examples where we've run the JetPulse system with multiple sensors in the string where you can plot the real-time and memory logs next to each other, and it's very difficult to tell them apart," Parker emphasized. Cutter block for underreamer reduces vibration If there is a limitation to underreamers, it is the cutting structure or what that structure does to the entire bottomhole assembly (BHA). Under- reaming operations can be notorious for having high levels of vibration. That is one of the things Schlumberger wanted to address with its Sting- ALD provides downhole density measurements, including high-quality borehole image logs, to help optimize wellbore placement through geosteering and to reduce geological uncertainties. The measurements, delivered via LWD, also eliminate costly wireline conveyance runs and capture data immediately after drilling when the borehole is in the best condition. (Image courtesy of Halliburton)

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