Downhole surveying and core sample orientation systems, devices and methods

Abstract

System and method for core sample orientating uses an orientation data gathering device recording core sample orientation belowground at irregular time intervals, preferably while drilling is ceased and the irregular time intervals can be randomly generated by the orientation data gathering device. Target orientation data is closest to time Tx, Tx being greater than, less than or equal to T−t, where T is the time recorded by the data gathering device and t is the recorded elapsed time commenced by a communication device at the surface. The data gathering device is interrogated at the surface by the communication device. Timers in each are stopped or their individual times associated with each other (survey time T and elapsed time t). Target recorded orientation data Tx is identifiable as the largest Tx value<T−(t−W), where W is a delay period.