REDUCED CONTAMINATION SAMPLING

摘要

A sample module for use in a downhole tool includes a sample chamber for receiving and storing pressurized fluid. A piston is slidably disposed in the chamber to define a sample cavity and a buffer cavity, and the cavities have variable volumes determined by movement of the piston. A first flowline is provided for communicating fluid obtained from a subsurface formation through the sample module. A second flowline connects the first flowline to the sample cavity, and a third flowline connects the first flowline to the buffe r cavity for communicating buffer fluid out of the buffer cavity. A first valve capable o f moving between a closed position and an open position is disposed in the second flowline for communicating flow of fluid from the first flowline to the sample cavity. When the first valve is in the open position, the sample cavity and the buffer cavity are in fluid communication with the first flowline and therefore have equivalent pressures.