Abstract: A method for obtaining a fluid sample downhole that has at least a target fluid and an undesirable fluid may include receiving the fluid sample into a sample tank positioned that has a main chamber and isolating at least a portion of the undesirable fluid from the target fluid in the main chamber. A related apparatus may include a conveyance device configured to be conveyed along a borehole and a fluid sampling tool positioned along the conveyance device. The conveyance device may include a probe receiving the fluid sample from a formation; a pump drawing the fluid sample through the probe; and at least one sample tank receiving the fluid sample from the pump. The sample tank may include a main chamber receiving the fluid sample and an isolation volume isolating at least a portion of the undesirable fluid from the target fluid in the main chamber.

Abstract: An apparatus for determining a closure pressure of a fractured formation surrounding a wellbore is disclosed. The apparatus, in one embodiment, includes an isolation device for isolating a section of the wellbore, a fluid supply unit for supplying a fluid from the wellbore under pressure into the isolated section of the wellbore to cause a fracture in the formation proximate the isolated section, a receiving unit for receiving fluid from the isolated section at a constant or substantially constant rate due to pressure difference between the formation and the receiving unit, and a sensor for determining pressure of the formation during receiving of the fluid into the receiving unit. The apparatus further includes a controller for determining the closure pressure from the determined pressure.