Abstract: A downhole tool for generating a fluid pressure pulse, and to a method of generating a fluid pressure pulse downhole. One example being, an improved downhole tool and method for transmitting data signals from a downhole environment to surface, the downhole tool comprising a fluid actuated flow restrictor; a first fluid flow path for flow of actuating fluid to actuate the flow restrictor; a second fluid flow path for flow of actuating fluid to actuate the flow restrictor; and a control member movable between a first closed position where the first fluid flow path is closed and the second fluid flow path is open, and a discrete second closed position where the first fluid flow path is open and the second fluid flow path is closed, for controlling actuation of the flow restrictor to generate a fluid pressure pulse.

Abstract: There is disclosed an electrically insulating device in the form of a sleeve (12) for a downhole tool, for electrically insulating a first threaded electrically conductive member in the form of an anchor sub (16) from a second threaded electrically conductive member in the form of an insulated sub (18). An assembly (10) including the sleeve (12) has particular use in measurement while drilling (MWD)/logging while drilling (LWD) procedures. In one embodiment, a third member in the form of a threaded electrically conductive sleeve sub (20) is coupled to the insulated sub by a second sleeve (14), to create an insulated gap between the anchor and sleeve subs (16, 20).