During a South Texas summer an anticipated 13 hour gyro survey was planned to be run inside coiled tubing, where the Twin Gyro's low power consumption would allow MS Energy Services to pull off an almost impossible hot-hole job. By knowing the expected downhole temperature and rate of temperature rise over time while inside the wellbore, the decision was made to proceed with the job under the condition that the heatshield’s heat sink would be cooled down to 2 C / 35 F before going into the hole.
This coiled tubing drilling and completions job was a complex re-entry and sidetrack of an extended reach well that was not producing enough hydrocarbons due to incorrect well placement. The MWD had quit working with 400 feet remaining to be drilled to get to a MD of over 13,000 feet. The decision was made to continue drilling blindly to total depth, with the expectation of gyro surveying the newly drilled footage afterward and using the coiled tubing unit for conveyance.
The operator/surveyor almost botched this job by taking the heat sink out of the ice chest and leaving it on the truck tailgate in the hot July sun until the brass heatsink was very hot before loading into the heat shield. The survey starting temperature was 38 C / 100 F and the final temperature inside the heatshield hit over 100 C / 212 F.
Upon retrieving the tool from the coiled tubing unit, the operator was surprised to see the gyro communicating and downloading, even as steam was still coming out of the heatshield. The survey was downloaded and processed successfully with outstanding results. The in-run vs out-run azimuth and inclination results matched almost perfectly with the last good MWD survey tie-in shots.
Had the operator followed the instructions for cooling the heatsink before surveying, the temperature limit would not have been breached. Nonetheless, the TwinGyro was still able to download and process a very accurate survey despite the final shots being acquired while the gyro was running much hotter than the temperature calibration limit.
The TwinGyro’s sensors were still generating data that was within the tool’s specifications for accuracy. The TwinGyro’s exceptional performance on this job underscores the care, the quality, and the advanced technology and methodology used by Inertial Sensing in all of their gyros.
Kim Carrier
Multishot Energy Services