/PRODUCT REVIEW
Survey Twice as Fast with the TwinGyro by Duncan McLeod, Owner / Product Manager at Inertial Sensing AB
“TwinGyro is the fastest and simplest gyro we've used onsite. Two surveys in one... Brilliant” - drilling contractor, Goldfields, Western Australia The TwinGyro™ is the latest gyro survey system available from Inertial Sensing. Launched at PDAC 2017 in Toronto, it is making inroads into the surveying markets around the world in both the mining and the oil and gas sectors. In mining it halves the time required to generate multiple fully quality assured surveys. Combining a new fast continuous survey mode with the ability to get two surveys from a single run in-hole, it is possible to survey a hole more often during the drilling process, with very little rig downtime. Since the gyro is used for considerably less time on each run it can be economically shared between a number of rigs on location. So not only is survey time per rig dramatically reduced, the number of gyros required on location is also reduced. This saves both operating costs and capital equipment expenditure. No other gyro system can offer these savings.
By achieving this, the TwinGyro™ represents the combination of a series of developments that have been ongoing at Inertial Sensing over the years that we have been working on gyro survey tools:
Two surveys for the price of one
Miniaturization Our SlimGyro™ is the world’s smallest gyro survey tool. The TwinGyro™ contains two independent SlimGyro™ systems in a platform the size of a standard gyro tool.
The fundamental idea behind the TwinGyro™ is simple. If two independent gyro systems could be built inside a standard gyro tool body and operated as easily as a single gyro then the tool could be run just once in a hole to get two surveys. Two surveys for the price of one. The two independent surveys would serve as a check on each other and eliminate the need to run consecutive surveys of the same hole (e.g. an 'in' and an 'out' pair), as is the standard practice in many operations to ensure survey quality. But such a dual gyro tool would need to be power efficient in order to run on a single battery, be highly accurate so that the data can be sensibly compared and, of course, have a very small electronics platform to fit two systems inside one standard casing. 22
MEMS technology We use only MEMS sensors in our gyro tools. The gyros used in the TwinGyro™ represent the peak of performance for their size available today, which is considerably better than that available even only five years ago. Low power systems We go to extreme lengths to ensure the electronics and embedded systems are as power efficient as possible. Because of this, the TwinGyro™ can survey for over 100 hours, if needed, on a single standard battery charge. Consequently, its power consumption of 0.4 W is so low that it generates virtually no heat while downhole, making it possible to do long and deep surveys.
Furthermore, since they are reference systems and navigate from point-to-point throughout the survey they do not suffer the latitude and directional limits of accuracy experienced by north-finding gyro tools and magnetic tools. Such tools are inherently less accurate surveying in east/west directions compared to surveying north/south, as a matter of pure physics. The TwinGyro™ is equally accurate in all directions and at all inclinations. In a test performed by a user in Australia a test pipe of 124-meters length was setup and carefully land-surveyed. A range of commercially available tools was used to survey the pipe for the purposes of comparison, with each tool performing eight surveys of the hole. The TwinGyro™ was the clear winner, with a maximum misclose at end-of-hole of 0.6 meters, or less than 0.5%.
Continuous improvement Our software, navigation and calibration systems are under continuous development. Our users always have access to the most up-to-date technology possible.
Superior performance at speed The TwinGyro™ uses the latest commercially proven MEMS gyros released to the market. A testament to their performance is the fact that the rugged isGyro™, TwinGyro™ and SlimGyro™ are all used for deep vertical surveys in the US and Russian shale gas fields.
TwinGyro™ Coring Magazine #6