Survey evaluation
The quality of a survey is determined by comparing the actual measured borehole uncertainties against the theoretical uncertainties of the survey tool. Survey uncertainties can be divided into tool, technique and running environment uncertainties.
The magnitude of tool uncertainties can be derived from quality assurance and quality control parameters. The magnitude of technique and, in particular, running environment uncertainties can only be determined if more than one survey is taken. For example, declination or gyro foresight are running environment uncertainties which can not be determined from a single survey but only if an additional independent . . .