Corebarrel

Claim 1

A corebarrel for use downhole, comprising: a. an outer tube defining a through bore; b. an inner tube disposed within the outer tube and defining a through bore; c. a bearing assembly between the inner tube and the outer tube providing rotation of the outer tube relative to the inner tube; d. a survey device disposed within the inner tube below the bearing assembly, said survey device including a solid state survey means for use in oriented coring; e. mutually co-operating splines on the survey device and the inner tube to prevent rotation of the survey device relative to the inner tube; f. a latch mechanism on the survey device; g. a downwardly-directed shoulder on the inner tube, said shoulder engaging the latch mechanism to prevent upward movement of the survey device relative to the inner tube; h. the inner tube and the outer tube defining between them a first annular passageway, and the survey device and the inner tube defining between them a second annular passageway, the inner tube having an aperture therein above said shoulder whereby the through bore in the inner tube communicates with said first annular passageway at a location above said second annular passageway; and i. means disposed in said inner tube for selectively closing the through bore of the inner tube at a location above said second annular passageway but below said aperture.