Patent ID: 6659177
Filing Date: 2003-12-09
Classification: E21B

Abstract:
A sample module for use in a tool adapted for insertion into a subsurface wellbore for obtaining fluid samples, said sample module comprising:a sample chamber for receiving and storing pressurized fluid; a piston slidably disposed in said chamber to define a sample cavity and a buffer cavity, the cavities having variable volumes determined by movement of said piston; a first flowline for communicating fluid obtained from a subsurface formation through the sample module; a second flowline connecting the first flowline to the sample cavity; a third flowline connecting the first flowline to the buffer cavity of the sample chamber for communicating buffer fluid between the buffer cavity and the first flowline; a first valve capable of moving between a closed position and an open position disposed in the second flowline for communicating flow of fluid from the first flowline to the sample cavity; and wherein 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 approximately equivalent pressures.