Apparatus and method for obtaining a core at in situ pressure

Abstract

A method and apparatus are disclosed for obtaining a core at in situ pressure of sedimentary deposits at the bottom of a well bore or body of water. The core barrel has a pressure chamber that is closed and opened by a ball valve actuated from the surface. When in position above the sedimentary deposits to be cored, a sample tube is extended from the pressure chamber into the sedimentary deposits to obtain a core. The sample tube is retracted into the pressure chamber and the valve closed to trap ambient pressure in the chamber. The sample tube and valve are operated from the surface.