Method and system for enabling acquisition of borehole survey data and core orientation data

A method of enabling the acquisition of borehole survey data and core orientation data in a single instrument trip in a core drill having a drill string and an inner core barrel assembly having a longitudinal axis, the method comprising:

• running a borehole survey tool through the drill string in which is installed the inner core barrel assembly, wherein the borehole survey tool is arranged to at least log its position in three-dimensional space;
• enabling the inner core barrel assembly to provide or facilitate detection of an indication tool face of a core sample held in the inner core barrel assembly;
• and
• transferring the indication of tool face to the borehole survey tool;
• wherein enabling the inner core barrel assembly comprises arranging the inner core barrel assembly so that a head assembly and an inner core tube of the inner core barrel assembly have a known or otherwise detectable rotational position about the longitudinal axis relative to each other for a core orientation period which commences from a time at least immediately before breaking of a core sample from in situ strata to a time at which the indication of tool face is transferred to the borehole survey tool;
• wherein the inner core barrel assembly is provided with a spindle coupling the head assembly to the inner core tube, and
• wherein the method further comprises:
• providing a core tube marker on or in the inner core barrel assembly wherein the core tube marker has a known rotational position relative to the known point, and
• enabling communication between the borehole survey tool and the core tube marker at a time before or during the core orientation period,
• wherein transferring the indication of the known rotational position to the borehole survey tool comprises communicating a location of the core tube marker with respect to the longitudinal axis to the borehole survey tool via a relay device on the head assembly,
• wherein the method further comprises fitting a core orientation system to the inner core barrel assembly which is capable of determining a rotational position of the core sample held within the inner core tube, and wherein transferring the indication of the rotational position to the borehole survey tool comprises electronically communicating the rotational position from the core orientation system to the borehole survey tool, and
• wherein the method further comprises:
• mechanically coupling the borehole survey tool to the inner core barrel assembly and retrieving the inner core barrel assembly with the borehole survey tool,
• using the logged position of the borehole survey tool and the transferred indication of a rotational position to determine an in situ position of the core sample, and
• releasing latent rotational torque in the drill string prior to running a borehole survey tool through a drill string.