LIVE WELL INJECTION

An apparatus and method for injecting and/or withdrawing items into/from a pressurized downhole, pipeline or the like when carried on or by a tubular length are disclosed. The apparatus can include two or more pressure sealing units for sealing against the length as it is injected. The sealing units can be joined by a pressure lock section, and the sealing units can be movable between a sealed position in which they are sealing against the tubular length and a retracted position. The apparatus may also include means for controlling pressure in the pressure lock section, in which the sealing units can be selectively and sequentially moved from the sealed position to the retracted position to allow introduction of an item therethrough, and in which the pressure lock section is selectively pressurizable and depressurizable to allow the item to move from low to high or high to low pressure during injection or removal.