Method and device for sampling and for the investigation of uncased oil - and gasb ear piercing

摘要

Method and apparatus for testing and sampling open-hole oil and gas wells. The apparatus includes a packer, a surge chamber, a closure valve which may be opened to flow fluid into the surge chamber, and a sampler. The surge chamber may be one of a pair of surge chambers, and the closure valve may be one of a pair of closure valves so that two surges may be carried out prior to obtaining a fluid sample in the sampler. In operation, the packer is placed in a set position by setting down weight. The closure valves are also actuated when weight is set down. The first closure valve has a first predetermined time delay before opening so that the packer may be set, and the second closure valve has a second predetermined time delay so that the packer may be set and the first closure valve opened before a fluid sample is captured. By opening a vent tool at an upper end of the uppermost surge chamber, formation fluid may be forced back into the formation or zone of interest by a bull- heading operation. In a preferred embodiment, portions of the apparatus are detachable in the event of sticking of the apparatus in the well. In the method of the two-surge test, a clean fluid sample for capturing in the sampler is provided. All of the steps are carried out without flowing fluid to the surface.