FORMATION FLUID FLOW RATE DETERMINATION METHOD AND APPARATUS FOR ELECTRIC WIRELINE FORMATION TESTING TOOLS

摘要

A method of determining the volume of a fluid sample withdrawn from anearth formation penetrated by a wellbore is disclosed. The method includes the stepof positioning a formation testing tool adjacent to the earth formation. The toolincludes a probe which can be selectively placed in hydraulic communication with theformation and excluded from hydraulic communication with the wellbore. The probecan be in hydraulic communication with a pressure transducer. The tool includes asample chamber selectively placed in hydraulic communication with the probe. Thechamber includes means for measuring the volume of the chamber and means forselectively controlling the volume of the chamber.The method further includes the steps of placing the probe in hydrauliccommunication with the formation, placing the sample chamber in hydrauliccommunication with the probe and selectively increasing the volume of the chamberwhile measuring the volume of the chamber and the pressure, determining the volumeof the chamber when a fluid from the wellbore disposed within the probe at the startof withdrawal of the sample ceases to expand, by determining an expansion volumeat which the pressure decreases less rapidly with respect to an increase in chambervolume, and determining the volume of the fluid sample by subtracting the expansionvolume from a total volume of fluid withdrawn into the sample chamber.