Abstract:
The present disclosure relates to determining hydrogen indexes of downhole fluids using fluid composition data. In certain embodiments, the type of the fluid, such as gas, water, or oil, may be determined downhole and used to select a method for determining the hydrogen index of the fluid. The selected method may then be employed while the tool is downhole to calculate the hydrogen index of the fluid.
Abstract:
A downhole tool is conveyed within a borehole extending into a subterranean formation. Fluid is drawn from the subterranean formation into the downhole tool, wherein the fluid comprises heavy oil. Fluorescence intensity of the drawn fluid is measured via a sensor of the downhole tool, and asphaltene content of the drawn fluid is estimated based on the measured fluorescence intensity.
Abstract:
A method for monitoring oil based mud filtrate contamination is provided including steps of analytically dividing a fluid stream into two parts, determining a gas/oil ratio for a native fluid determining an apparent gas/oil ratio for the contaminated fluid and determining on a volume fraction, an oil based contamination level based upon the gas/oil ratio for the native fluid and the apparent gas/oil ratio for the contaminated fluid.
Abstract:
Embodiments of the disclosure can include systems, methods, and devices for determining saturation pressure of an uncontaminated fluid. Downhole saturation pressure measurements and downhole OBM filtrate contamination of a contaminated fluid may be obtained and a relationship may be determined between the saturation pressure measurements and OBM filtrate contamination. The relationship may be extrapolated to zero OBM filtrate contamination to determine the saturation pressure of the uncontaminated fluid. In some embodiments, OBM filtrate contamination may be determined from downhole saturation pressure measurements during pumpout of a fluid.
Abstract:
Methods for obtaining in-situ, multi-temperature measurements of fluid properties, such as saturation pressure and asphaltene onset pressure include obtaining a sample of formation fluid using a downhole acquisition tool positioned in a wellbore in a geological formation. The downhole acquisition tool may be stationed at a first depth in the wellbore that has an ambient first temperature. While stationed at the first depth, the downhole acquisition tool may test a first fluid property of the sample to obtain a first measurement point at approximately the first temperature. The downhole acquisition tool may be moved to a subsequent station at a new depth with an ambient second temperature, and another measurement point obtained at approximately the second temperature. From the measurement points, a temperature-dependent relationship of the first fluid property of the first formation fluid may be determined.
Abstract:
Disclosed are methods and apparatus pertaining to processing in-situ, real-time data associated with fluid obtained by a downhole sampling tool. The processing includes generating a population of values for Ĉ, where each value of Ĉ is an estimated value of a fluid property for native formation fluid within the obtained fluid. The obtained data is iteratively fit to a predetermined model in linear space. The model relates the fluid property to pumpout volume or time. Each iterative fitting utilizes a different one of the values for Ĉ. A value Ĉ* is identified as the one of the values Ĉ that minimizes model fit error in linear space based on the iterative fitting. Selected values Ĉ that are near Ĉ* are then assessed to determine which one has a minimum integral error of nonlinearity in logarithmic space.
Abstract:
Systems and methods for identifying a likelihood that a reservoir of a geological formation received a secondary charge of hydrocarbons of relatively very different thermal maturity of composition are provided. One method includes positioning a downhole acquisition tool in a wellbore in a geological formation and testing one or more fluid properties of the formation fluid. Data processing circuitry may identify whether a relationship of the one or more fluid properties exceeds a first threshold that indicates likely asphaltene instability. When this is the case, data processing circuitry may be used to model the geological formation using a realization scenario in which multiple charges of hydrocarbons of substantially different thermal maturity or substantially different composition, or both, filled a reservoir of the geological formation over geologic time.
Abstract:
Systems and methods for identifying a likelihood that a reservoir of a geological formation received a secondary charge of hydrocarbons of relatively very different thermal maturity of composition are provided. One method includes positioning a downhole acquisition tool in a wellbore in a geological formation and testing one or more fluid properties of the formation fluid. Data processing circuitry may identify whether a relationship of the one or more fluid properties exceeds a first threshold that indicates likely asphaltene instability. When this is the case, data processing circuitry may be used to model the geological formation using a realization scenario in which multiple charges of hydrocarbons of substantially different thermal maturity or substantially different composition, or both, filled a reservoir of the geological formation over geologic time.
Abstract:
A method includes operating a downhole acquisition tool in a wellbore in a geological formation. The wellbore or the geological formation, or both, contains first fluid that includes a native reservoir fluid of the geological formation and a contaminant. The method also includes receiving a portion of the first fluid into the downhole acquisition tool and determining a plurality of properties of the portion of the first fluid using the downhole acquisition tool. The plurality of properties includes a mass fraction of a component of the portion of the first fluid and a density of the portion of the first fluid. The method also includes using the processor to estimate a volume fraction of the contaminant in the portion of the first fluid based at least in part on a composition mass fraction function that depends at least on the mass fraction of the component in the portion of the first fluid and the density of the portion of the first fluid.
Abstract:
A method, apparatus, and program product model address a modeling gap existing between basin and reservoir modeling through the use of a Reservoir Fluid Geodynamics (RFG) model usable for simulations conducted at a relatively fine spatial resolution and over a geological timescale.