Apparatus and method for collecting and preserving in representative condition a fluid sample from a reservoir which comprises: positioning a sample container including a sampler in the vicinity of a subterranean zone to be sampled, and wherein the step of collecting and preserving the sample comprises allowing or causing the sample to first flow into the sample receptacle, wherein the movement of the sample into the sample receptacle is restricted by the movement of a sampling piston, and wherein the movement of the sampling piston is further controlled by the rotation of an electrical motor connected to the sample piston by mechanical linkage such that the rotation of the electric motor in either direction translates to lateral movement of the sample piston, the lateral movement of the sample piston in turn allowing sample to enter the sample receptacle, and wherein once an adequate volume of sample has been collected, reversing the direction of the electrical motor will serve to cause the sample piston to exert pressure on the collected sample and thus preserve the integrity of the sample from the deleterious effects of shrinkage as the sample is recovered to the surface.