Abstract: Method of drilling a well, including one method comprising determining a first value indicative of a relative position of a geological bed boundary with respect to a drilling assembly, determining a second value indicative of an optical property of a formation fluid proximate the drilling assembly, and controlling a well trajectory based on the first and second value.

Abstract: Various implementations directed to analyzing a reservoir using fluid analysis are provided. In one implementation, a method may include determining mud gas logging (MGL) data based on drilling mud associated with a wellbore traversing a reservoir of interest. The method may also include determining first downhole fluid analysis (DFA) data based on a first reservoir fluid sample obtained at a first measurement station in the wellbore. The method may further include determining predicted DFA data for the wellbore based on the first DFA data. The method may additionally include determining second DFA data based on a second reservoir fluid sample obtained at a second measurement station in the wellbore. The method may further include analyzing the reservoir based on a comparison of the MGL data and a comparison of the second DFA data to the predicted DFA data.

Abstract: Integrated formation modeling systems and methods are described. An example method of performing seismic analysis of a subterranean formation includes obtaining seismic data of the formation, obtaining fluid from the formation and analyzing at least some of the fluid to determine a fluid parameter. The example method additionally includes generating a model of the formation based at least on the seismic data and modifying the model based on the fluid parameter.

Abstract: The present disclosure relates to a method for characterizing a hydrocarbon reservoir of interest traversed by at least one wellbore that includes (a) using a numerical model to simulate over geological time a non-equilibrium concentration of an asphaltene component as a function of location within the wellbore, (b) analyzing fluid samples acquired from at least one wellbore that traverses the reservoir of interest to measure concentration of the asphaltene component as a function of location within the wellbore, (c) comparing the non-equilibrium concentration of the asphaltene component as a function of location within the wellbore resulting from the simulation of (a) to the concentration of the asphaltene component as a function of location within the wellbore as measured in (b), and characterizing the reservoir of interest based upon the comparing of (c).

Abstract: Upper and lower asphaltene weight fractions of fluid proximate ends of an oil column are obtained based on measured OD. Upper and lower maltene partial densities are obtained based on the asphaltene weight fractions. A maltene partial density distribution is obtained utilizing the maltene partial densities and a predetermined diffusion model. An asphaltene partial density distribution is obtained based on the maltene partial density distribution and an estimated mass density gradient. An asphaltene weight percentage is obtained based on the asphaltene partial density distribution and the mass density gradient. The asphaltene weight percentage distribution is converted to an OD distribution utilizing a predetermined correlation. An optimization then reduces differences between the OD distribution and the measured OD data to within a predetermined range to refine a biodegradation time of the predetermined diffusion model. A viscosity distribution may be obtained based on the optimized OD distribution.

Abstract: A method for determining reservoir architecture using modeling of a non-equilibrium distribution of at least one analyte in reservoir fluids. The analyte(s) of the analysis preferably has (have) significant compositional variation in the reservoir. For example, the analyte can be a later charging single gas component (such as methane, carbon dioxide, or hydrogen sulfide) in a multi-component fluid system. In this case, the model can assume that the components of the early charge are in a stationary state or in equilibrium, whereas the later charge is in a state of non-equilibrium. The non-equilibrium distribution of the analyte(s) derived from the model is compared to the distribution of the analyte(s) derived from downhole or laboratory fluid analysis of reservoir fluid, and the architecture of the reservoir is determined based upon such comparison.

Abstract: Fluid analysis measurements may be performed during withdrawal of a downhole tool to the surface. Fluid may be collected within a fluid analysis system of the downhole tool and the collected fluid may be exposed to the wellbore pressure during withdrawal of the downhole tool. Measurements for the collected fluid, such as optical density, the gas oil ratio, fluid density, fluid viscosity, fluorescence, temperature, and pressure, among other, may be recorded continuously or at intervals as the downhole tool is brought to the surface. The measurements may be employed to determine properties of the collected fluid, such as the saturation pressure and the asphaltene onset pressure.

Abstract: Method of drilling a well, including one method comprising determining a first value indicative of a relative position of a geological bed boundary with respect to a drilling assembly, determining a second value indicative of an optical property of a formation fluid proximate the drilling assembly, and controlling a well trajectory based on the first and second value.

Abstract: A downhole tool, surface equipment, and/or remote equipment are utilized to obtain data associated with a subterranean hydrocarbon reservoir, fluid contained therein, and/or fluid obtained therefrom. At least one condition indicating that a density inversion exists in the fluid contained in the reservoir is identified from the data. Molecular sizes of fluid components contained within the reservoir are estimated from the data. A model of the density inversion is generated based on the data and molecular sizes. The density inversion model is utilized to estimate the density inversion amount and depth and time elapsed since the density inversion began to form within the reservoir. A model of a gravity-induced current of the density inversion is generated based on the data and the density inversion amount, depth, and elapsed time.

Abstract: A methodology for reservoir understanding that performs investigation of asphaltene instability as a function of location in a reservoir of interest. In the preferred embodiment, results derived as part of the investigation of asphaltene instability are used as a workflow decision point for selectively performing additional analysis of reservoir fluids. The additional analysis of reservoir fluids can verify the presence of asphaltene flocculation onset conditions and/or determine the presence and location of phase-separated bitumen in the reservoir of interest.

Abstract: A system and method for determining at least one fluid characteristic of a downhole fluid sample using a downhole tool are provided. In one example, the method includes performing a calibration process that correlates optical and density sensor measurements of a fluid sample in a downhole tool at a plurality of pressures. The calibration process is performed while the fluid sample is not being agitated. At least one unknown value of a density calculation is determined based on the correlated optical sensor measurements and density sensor measurements. A second optical sensor measurement of the fluid sample is obtained while the fluid sample is being agitated. A density of the fluid sample is calculated based on the second optical sensor measurement and the at least one unknown value.

Abstract: A method for deriving VOI for a hydrocarbon-bearing reservoir fluid model based on DFA data (“true fluid model”) versus an “incorrect fluid model” includes calculating first, second and third objective functions that are based on NPV(s) of simulated production by a reservoir simulator with different configurations. For the first objective function, the simulator is configured with the incorrect fluid model and control variables that are optimized to derive a first group of control variable values. For the second objective function, the simulator is configured with the true fluid model and the first group of control variable values. For the third objective function, the simulator is configured with the true fluid model and control variables that are optimized to identify a second group of control variable values. The objective functions can be deterministic, or can include statistics that account for uncertainty. A visualization of such results with uncertainty is also described.

Abstract: A method includes identifying linearly behaving data within obtained data associated with fluid obtained from a subterranean formation. Shrinkage factor is determined based on the linearly behaving data. A function relating GOR data of the obtained fluid with the determined shrinkage factor is determined. A first linear relationship between optical density (OD) data of the obtained fluid and the function is determined. A second linear relationship between density data of the obtained fluid and the function is determined. An oil-based mud (OBM) filtrate contamination property of OBM filtrate within the obtained fluid based on the first linear relationship is determined. A native formation property of native formation fluid within the obtained fluid based on the second linear relationship is determined. A volume fraction of OBM filtrate contamination within the obtained fluid based on the OBM filtrate contamination property and the native formation property is estimated.

Abstract: Various implementations described herein are directed to a method for assessing risks of compartmentalization. In one implementation, the method may include receiving seismic data for a formation of interest; identifying areas in the formation having a dip angle greater than about 30 degrees; performing a plurality of downhole fluid analysis (DFA) within a wellbore around the formation having the dip angle greater than about 30 degrees to identify areas experiencing mass density inversion; and determining the areas experiencing mass density inversion by DFA as having one or more risks of compartmentalization.

Abstract: The present disclosure relates to methods and apparatus for determining a gas-oil ratio based on downhole fluid analysis measurements and calibrated gas-oil ratio parameters. According to certain embodiments, the parameters for calculating the gas-oil ratio may be calibrated using historical data from the reservoir. For example, previously determined gas-oil ratios may be employed to calibrate the parameters to the reservoir. The calibrated parameters may then be employed during sampling operations to determine the gas-oil ratio.

Abstract: A method for predicting asphaltene onset pressure in a reservoir is provided. In one embodiment, the method includes performing downhole fluid analysis of formation fluid via a downhole tool at a measurement station at a first depth in a wellbore and determining an asphaltene gradient for the formation fluid at the measurement station. Asphaltene onset pressure for a second depth in the wellbore may then be predicted based on the downhole fluid analysis and the determined asphaltene gradient. Additional methods, systems, and devices are also disclosed.

Abstract: A method for downhole fluid analysis by optical spectroscopy with photoacoustic detection includes positioning a photoacoustic system within a wellbore, applying a laser pulse to the fluid sample using the pulsed laser system, detecting, by the acoustic sensor, a time-resolved acoustic pulse generated by absorption of the laser pulse by the fluid sample, and determining a property of the fluid sample using the detected time resolved acoustic pulse. The photoacoustic system includes a pulsed laser system and an acoustic sensor.

Abstract: A wellbore tool for determining a speed of sound of a fluid sample, such as a hydrocarbon sample or a wellbore fluid, is described herein. The wellbore tool includes a photoacoustic system for analyzing the fluid sample. The photoacoustic system includes a laser system that generates a laser pulse, an interface disposed between the fluid sample and the laser system, and an acoustic detector that receives an acoustic pulse that is generated in response to absorption of the laser pulse. The acoustic pulse is generated when the laser pulse is absorbed by the fluid sample or the interface. This acoustic pulse then moves through the fluid sample and is detected by the acoustic detector. The acoustic pulse is then used to determine a speed of sound of the fluid sample.

Abstract: A method of evaluating a gradient of a composition of materials in a petroleum reservoir, comprising sampling fluids from a well in the petroleum reservoir in a logging operation, measuring an amount of contamination in the sampled fluids, measuring the composition of the sampling fluids using a downhole fluid analysis, measuring an asphaltene content of the sampling fluids at different depths; and fitting the asphaltene content of the sampling fluids at the different depths to a simplified equation of state during the logging operation to determine the gradient of the composition of the materials in the petroleum reservoir.

Abstract: The present disclosure relates to methods and systems for developing an equation of state model for petroleum fluids. In one embodiment, formation fluid from a plurality of depths within a wellbore may be analyzed to determine a change in a gas oil ratio with respect to depth. The change in the gas oil ratio may be employed to determine a ratio of solubility and entropy terms to a gravity term. The resulting ratio can be used to develop the equation of state model.