Apparatus and methods for testing earth formations

摘要

Improved apparatus and methods are provided for conducting drill stem and production testing operations. A bypass sub removably receives a wireline tool in sealing engagement within a bypass sub bore, with the bypass sub including bypass passage means and selectively actuable port closure means to permit fluid from below the bypass sub to flow into conduit means above the bypass sub when the wireline tool is seated and secured in the bypass sub. In one embodiment, the means for selectively actuating the port closure means is a motorized shifter means incorporated in the wireline tool. The wireline tool carries selected sensor devices for sensing earth formation characteristics. Improved and unique means are provided for securing the wireline tool in the bypass sub and for selectively engaging the motorized shifter apparatus with the port closure means. In addition, unique "fail safe" means are provided to ensure that the wireline tool and the bypass sub can be effectively removed from the well even in case of a malfunction of the motorized shifter means.