Formation fluid flow rate determination method and apparatus for electric wireline formation testing tools
First Claim
1. An apparatus for withdrawing a fluid sample from an earth formation penetrated by a wellbore, comprising:
- an elongated housing adapted to traverse said wellbore;
a probe disposed within said housing and adapted to be selectively placed in contact with said earth formation;
a pumping chamber disposed within said housing and selectively placed in hydraulic communication with said probe, said pumping chamber having a selectively controllable volume;
a pressure transducer disposed within said housing and in hydraulic communication with said probe;
means for selectively increasing and selectively decreasing said volume of said pumping chamber;
means for measuring said volume of said pumping chamber; and
means for recording measurements of said volume of said pumping chamber and pressure measurements made by said transducer with respect to time so that a measurement of a volume of fluid withdrawn through said probe into said pumping chamber can be determined exclusive of an expansion volume of fluid from said wellbore disposed within said probe prior to initiation of withdrawal of said fluid sample.
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Accused Products
Abstract
A method of determining the volume of a fluid sample withdrawn from an earth formation penetrated by a wellbore is disclosed. The method includes the step of positioning a formation testing tool adjacent to the earth formation. The tool includes a probe which can be selectively placed in hydraulic communication with the formation and excluded from hydraulic communication with the wellbore. The probe can be in hydraulic communication with a pressure transducer. The tool includes a sample chamber selectively placed in hydraulic communication with the probe. The chamber includes means for measuring the volume of the chamber and means for selectively controlling the volume of the chamber. The method further includes the steps of placing the probe in hydraulic communication with the formation, placing the sample chamber in hydraulic communication with the probe and selectively increasing the volume of the chamber while measuring the volume of the chamber and the pressure, determining the volume of the chamber when a fluid from the wellbore disposed within the probe at the start of withdrawal of the sample ceases to expand, by determining an expansion volume at which the pressure decreases less rapidly with respect to an increase in chamber volume, and determining the volume of the fluid sample by subtracting the expansion volume from a total volume of fluid withdrawn into the sample chamber.
80 Citations
7 Claims
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1. An apparatus for withdrawing a fluid sample from an earth formation penetrated by a wellbore, comprising:
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an elongated housing adapted to traverse said wellbore; a probe disposed within said housing and adapted to be selectively placed in contact with said earth formation; a pumping chamber disposed within said housing and selectively placed in hydraulic communication with said probe, said pumping chamber having a selectively controllable volume; a pressure transducer disposed within said housing and in hydraulic communication with said probe; means for selectively increasing and selectively decreasing said volume of said pumping chamber; means for measuring said volume of said pumping chamber; and means for recording measurements of said volume of said pumping chamber and pressure measurements made by said transducer with respect to time so that a measurement of a volume of fluid withdrawn through said probe into said pumping chamber can be determined exclusive of an expansion volume of fluid from said wellbore disposed within said probe prior to initiation of withdrawal of said fluid sample. - View Dependent Claims (2, 3, 4)
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5. A method of determining the volume of a fluid sample withdrawn from an earth formation penetrated by a wellbore, comprising:
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positioning a formation testing tool adjacent to said earth formation, said tool including a probe selectively operable to be in contact with said earth formation, said tool including a pumping chamber having means for continuously measuring the volume of said pumping chamber, said pumping chamber having means for selectively placing said pumping chamber in hydraulic communication with said probe, said pumping chamber having selectively operable means for controlling said volume, said tool including a pressure transducer in hydraulic communication with said probe; placing said probe in hydraulic communication with said earth formation; placing said pumping chamber in hydraulic communication with said probe and selectively increasing said volume of said pumping chamber; measuring fluid pressure in said probe by means of said transducer and simultaneously measuring said volume of said pumping chamber; determining said volume of said pumping chamber when a fluid from said wellbore disposed within said probe at the start of withdrawal of said fluid sample ceases to expand by determining an expansion volume at which said fluid pressure decreases at a different rate with respect to an increase in said volume of said pumping chamber; and determining said volume of said fluid sample by subtracting said expansion volume from a total volume of fluid withdrawn into said pumping chamber. - View Dependent Claims (6, 7)
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Specification