Abstract: Integrated drilling and evaluation systems and methods for drilling, logging and testing wells are provided. The drilling and evaluation systems are basically comprised of a drill string, a drill bit carried on a lower end of the drill string for drilling a well bore, logging while drilling means included in the drill string for identifying subsurface zones or formations of interest, packer means carried on the drill string above the drill bit for sealing a zone or formation of interest below the packer means, and a fluid testing means included in the drill string for controlling the flow of well fluid from the zone or formation of interest into the drill string. The drilling and evaluation systems and methods for using the systems allow one or more subsurface zones or formations of interest in a well to be drilled, logged and tested without the necessity of removing the drill string from the well.

Abstract: Early evaluation testing of a subsurface formation is provided by monitoring pressure fall-off in the formation. This is accomplished by providing a column of fluid in the well having an overbalanced, hydrostatic pressure at the subsurface formation greater than a natural formation pressure of the subsurface formation. A testing string is run into the well, and the testing string includes a packer, a pressure monitor and a closure tool arranged to close a bore of the testing string. The formation is shut in by setting the packer and closing the bore of the testing string with the closure tool and thereby initially trapping the overbalanced hydrostatic pressure of the column of fluid in the well below the packer. Then the pressure in the well below the packer is monitored as it falls off toward the natural formation pressure. This data can be extrapolated to estimate the natural formation pressure based upon a relatively short actual test interval on the order of ten to fifteen minutes.

Abstract: A number of improvements are provided in early evaluation systems which can be utilized to test and/or treat a subsurface formation intersected by an open uncased borehole. An outer tubing string is run into the well and has a packer which is set in the open, uncased borehole above the subsurface formation of interest. An inflation passage is provided and preferably has an inflation valve associated therewith which is operated by manipulation of the tubing string. A communication passage communicates the interior of the outer tubing string with the borehole below the packer. An inner well tool is run into the outer tubing string and engaged therewith, whereupon it is placed in fluid communication with the subsurface formation to either sample the formation or treat the formation. Preferably, a circulating valve is provided above the packer to allow fluid circulation in the well annulus during the testing procedure to prevent differential sticking of the outer tubing string.

Abstract: A hydraulic set packer for use in a well bore as part of a testing apparatus. The packer comprises a housing defining a generally annular piston chamber therein. A cylindrical portion of an annular piston is slidably disposed in the piston chamber. The piston also has a shoe portion adjacent to a packer element on the housing. An inner mandrel is disposed in the housing, and the housing and inner mandrel define a passageway therein such that fluid pressure may be applied to the piston for moving it against the packer element such that the packer is set in sealing engagement with the well bore. The passageway extends the full length of the housing so that it may be in communication with another hydraulic packer positioned therebelow. One or more packers may be used in a downhole tool on a testing string for use in testing a well formation. The packer may also be used on a tubing string for testing a blowout preventer.

Abstract: A well fluid sampling apparatus provides a time delay after actuation of the tool and before a sample is taken. The tool is operated by well pressure acting on a piston. The piston is initially hydraulically blocked so that it cannot move. The time delay is provided after the piston begins moving. Additional time delay devices can optionally be included.

Abstract: An above packer perforate, test and sample tool for use in obtaining a sample of fluid from a formation reservoir in a well. The apparatus includes a sampler and an actuator cylinder positioned above a packer and a valve body below the packer. An operating mandrel opens a valve below the packer to flow the fluid from a well annulus defined below the packer to a sampling chamber in the sampler above the packer. The operating mandrel is moved in response to a pressure differential between the pressure in the well annulus above the packer and a pressure in the tool. In another embodiment, a second packer may be positioned below the first packer to sealingly engage the well bore below the well formation. A method of sampling fluid from a well formation is also disclosed.