Abstract: A well fluid sampling tool and method for retrieving chemically accurate hydrocarbon samples from new wells. The sampling tool is provided with a chemically inert sample chamber and lowered to the required depth in the well where a well fluid sample is admitted to the sample chamber, which is subsequently sealed. The tool is preferably arranged so that pressures inside and outside the sample chamber remain substantially equal during and after sample taking. The sample may be subject to post-sampling pressurisation to keep the sample in its original single-phase state.The chemical inertness of the sample chamber avoids removal of reactive components of the well fluid from the sample by chemical reaction with the material of the sample chamber (which is conventionally metal). This enables accurate assessment of new wells without the need for extended flow testing.

Abstract: A well fluid sampling tool and method for retrieving single-phase hydrocarbon samples from deep wells. The sampling tool is lowered to the required depth, an internal sample chamber is opened to admit well fluid at a controlled rate, and the sample chamber is then automatically sealed. The well fluid sample is immediately subjected to a high pressure to keep the sample in its original single-phase form until it can be analyzed.The sample is pressurized by a hydraulically-driven floating piston powdered by high-pressure gas acting on another floating piston. Once sampling is initiated, e.g. by an internal clock, the entire sequence is automatic.Also disclosed is a sample transfer container for securing the pressurized sample from the tool and maintaining it in single-phase form during transport to an analytical laboratory.This invention avoids the disadvantages arising from phase separation of hydrocarbon well fluid samples.