Inertial positioning system for both up-hole and down-hole measurement

摘要

Downhole surveying tool (TRIPS, Trip Retrievable Inertial Positioning System) for the oil industry comprising an inertial positioning system permanently mounted within an integral part of the drilling assembly which can be used for both conventional angular measurement while drilling (MWD) on the way down-hole and inertial definitive surveying on the trip up-hole without the use of the drill pipe depth. The tool can provide high accuracy surveys because errors due to drillstring measurement, stretch and thermal expansion are removed. The tool is non magnetic and requires no magnetic protection. The positioning system may be mounted at two or more locations in the bottom hole assembly (BHA). The positioning system may be mounted inside a pressure chamber, at the centre of a roll spring to minimize the effects of temperature, pressure and shock.