Abstract: A method and system for determining fluid contamination. The method may comprise monitoring a fluid sample, wherein the fluid sample comprises a reservoir fluid contaminated with a well fluid, and obtaining input parameters, wherein the input parameters comprise fluid properties obtained from measurement of the fluid sample and mud filtrate composition. The method may further comprise representing a mud composition as a Gaussian distribution, selecting a plurality of input data during a pumpout, determining calculated fluid properties of the reservoir fluid using an equation of state filtrate analysis, and further obtaining updated values of iterative parameters for use in a mole fraction distribution function.

Abstract: Systems and techniques for determining properties of a formation comprising are disclosed. A test tool attached to test string comprising a fluid conduit is deployed to a test position within a wellbore. The deployment includes hydraulically isolating a portion of the wellbore proximate the test tool to form an isolation zone containing the test position. A fluid inflow test is performed within the isolation zone and an initial formation property and a fluid property are determined based on the fluid inflow test. A fluid injection test is performed within the isolation zone including applying an injection fluid through the test string into the isolation zone, wherein the flow rate or pressure of the injection fluid application is determined based, at least in part, on the at least one of the formation property and fluid property, The fluid injection test further includes measuring pressure within the isolation zone to determine a pressure transient associated with the injection of the injection fluid.

Abstract: A method includes forming a first sealed connection volume between a formation and a first pressure sensor in a borehole and forming a second sealed connection volume between the formation and a second pressure sensor. The second sealed connection volume surrounds the first sealed connection volume. The method further includes lowering a second sealed connection volume pressure to be less than a borehole pressure and acquiring a first measurement using the first pressure sensor before lowering the pressure of the second sealed connection volume, wherein lowering the pressure comprises lowering the pressure to a first lowered outer volume pressure during a first interval. The method further includes acquiring a second measurement using the first pressure sensor, and, in response to a determination that a measurement pattern shows a trend to a formation pressure value, generating a formation property prediction based on the second measurement.

Abstract: Disclosed are methods and systems for determination of fluid contamination of a fluid sample from a downhole fluid sampling tool. A method may comprise obtaining a fluid sample, obtaining input parameters, wherein the input parameters comprise fluid properties obtained from measurement of the fluid sample and mud filtrate composition, obtaining initial values of iterative parameters, determining component mole fractions of the reservoir fluid using the initial values of the iterative parameters in a mole fraction distribution function, determining calculated fluid properties of the reservoir fluid using equation of state flash calculating, and repeating steps of determining component mole fractions and determining calculated fluid properties and further obtaining updated values of the iterative parameters for use in the mole fraction distribution function until a comparison of one or more of the calculated fluid properties with one or more of the input parameters is within a tolerance error.

Abstract: Disclosed herein are methods and systems for fluid characterization of fluid samples from a downhole fluid sampling tool. A fluid characterization method may include obtaining a fluid sample of a reservoir fluid; analyzing the fluid sample to derive input parameters, wherein the input parameters comprise fluid properties obtained from measurement of the fluid sample; determining component mole fractions of the fluid sample using a mole fraction distribution function; and determining calculated fluid properties using equation of state flash calculating.

Abstract: Systems, devices, and techniques for determining downhole fluid contamination are disclosed. In one or more embodiments, phase-related properties are measured for a reservoir fluid having a determined composition. An equation-of-state (EOS) is tuned based, at least in part, on the measured phase-related properties and the tuned EOS is applied to estimate fluid property values for a reference fluid over specified ranges of at least two thermodynamic properties. Contaminant reference data are generated that correlate the estimated fluid property values for the reference fluid with respective contaminant levels. Within a wellbore, a fluid sample is analyzed to determining a fluid property values. A contaminant level is identified that corresponds within the contaminant reference data to the determined fluid property value of the fluid sample.