×

System and method for real-time management of formation fluid sampling with a guarded probe

  • US 7,757,760 B2
  • Filed: 09/22/2006
  • Issued: 07/20/2010
  • Est. Priority Date: 09/22/2006
  • Status: Active Grant
First Claim
Patent Images

1. A method, comprising:

  • conveying a wellbore tool in a wellbore extending into an earth formation, wherein;

    the wellbore tool comprises a fluid sampling device;

    the fluid sampling device comprises;

    an inner probe configured to withdraw a first fluid sample from the formation; and

    an outer probe surrounding the inner probe and configured to withdraw a second fluid sample from the formation;

    urging the fluid sampling device into contact with a wall of the wellbore;

    withdrawing the first and the second fluid samples from the formation while;

    maintaining the inner probe at a first pressure; and

    maintaining the outer probe at a second pressure, wherein the first pressure is higher than the second pressure;

    determining a first contamination amount of the first fluid sample using an optical fluid analysis (OFA) sensor;

    determining a second contamination amount of the second fluid sample using the OFA sensor;

    determining in real-time a difference between the first and second contamination amounts;

    confirming correct operation of the fluid sampling device by determining in real-time a maximum of the difference between the first and second contamination amounts;

    extrapolating future values for the difference between the first and second contamination amounts by;

    normalizing the first and second contamination amounts using initial values of the first and second contamination amounts determined upon commencement of withdrawing the first and second fluid samples; and

    fitting to a power-law model the determined difference between the first and second contamination amounts;

    determining from the extrapolated future values a time at which the difference between the first and second contamination amounts will reach a minimum;

    continuing withdrawing of the first and second fluid samples until reaching the determined time; and

    theninitiating collection of a portion of the first fluid sample.

View all claims
  • 1 Assignment
Timeline View
Assignment View
    ×
    ×