Method for the isobaric transfer of a fluid from a deposit and device for implementing such a method

A method for transferring under pressure a fluid from a deposit, by means of a sampling vessel wherein the sample is maintained at the reservoir pressure (RP) and that comprises the following steps:

• a) measuring, in the absence of the contact with the sample, the pressure of the sample maintained at reservoir pressure (RP) in the sampling vessel;
• b) connecting the sampling vessel, maintained closed and at the reservoir pressure of a measuring device;
• c) filling in the measuring device with a second liquid fluid, neutral versus the sample, with a known density and superior to the density of the fluid from the deposit;
• d) increasing the pressure in the measuring device and the pressure of the second neutral liquid fluid containing it, up to a pressure equal to the pressure of the sample of the fluid from the deposit determined during the step (a);
• e) increasing the pressure of the fluid sample from the deposit contained in the sampling vessel to a pressure superior of the pressure of the second neutral liquid fluid contained in the measuring device;
• f) transferring simultaneously, all or part, of the fluid sample from the deposit from the sampling vessel to a measuring cell, by balancing the pressures of the sampling vessel and the measuring cell;
• and a volume equivalent to the second neutral liquid fluid, of the measuring cell to the sampling vessel,
• g) after disconnecting the sampling vessel, measuring the density of the second liquid, neutral fluid transferred into the sampling vessel, to a constant pressure in the absence of the contact with the sample of the fluid from the deposit;
• and
• h) calculating the volume of the sample of the fluid from the deposit, displaced and introduced in the measuring cell.