SERVICE DESCRIPTION
Target’s ESA MWD service increases the accuracy of MWD survey data. This is accomplished even when the MWD system is used with the steel drill string components in close proximity.
The service involves the transmission of raw accelerometer and magnetometer values together with downhole temperature and applying patented correction algorithm to the data to eliminate the effects of axial magnetic interference caused by steel drill string components such as steel stabilisers, mud motors etc.
The patented algorithm compares the dip angle and total Earth’s magnetic field as calculated from the MWD data to known geomagnetic data for the location of the well. This comparison enables the effects of magnetic interference from the steel components to be eliminated. In addition, the algorithm eliminates errors caused by BHA misalignment within the borehole and hot spots by implementing cross axial corrections. The cross axial corrections are derived from 4 - 6 rotational surveys taken at one depth. The cross axial variations from the magnetometers and accelerometers are then characterised and subtracted from the MWD survey data.
SERVICE BENIFITS
- Improved survey accuracy to high accuracy gyro survey standard
- Elimination of expensive non-magnetic drill string components
- MWD measurements made close to the bit for better Directional control
- Enhanced quality assurance of MWD data or offset well
Service Availability
Target’s ESA service is available with all Target MWD service types in all hole sizes.
