IMPROVEMENTS TO DOWNHOLE SURVEYING

摘要

A drillstring first tube portion (10) for connection to further tube portions (24,26) of a drillstring via respective connection means has a side wall (16) including non ferromagnetic material, and at least one downhole survey device (12) mounted directly or indirectly on or within the side wall. The survey device has at least one survey instrument to obtain survey data, a power source (22) and wireless communication means (18) to wirelessly receive and/or transmit survey data within or on the side wall. A method of conducting a downhole survey of drilling using such an apparatus is also disclosed, as well as a method of obtaining data gathered downhole. The survey device and a core orientation device (32) may communicate wirelessly, such as when passing each other.