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.

Abstract: A method is disclosed for assessing connectivity between sections in a hydrocarbon reservoir. Samples of hydrocarbons are collected over different depths in at least one wellbore. Fluorescence intensity determines the actual heavy end concentrations of hydrocarbons for the corresponding COLLECT GAS CONDENSATE different depths. Estimated heavy end concentrations of hydrocarbons for corresponding different depths are determined and the actual heavy end concentrations of hydrocarbons are compared with the estimated heavy end concentrations to assess connectivity between sections of the hydrocarbon reservoir.

Abstract: The present disclosure relates to apparatuses and methods to detect a fluid contamination level of a fluid sample. The method may comprise providing a fluid sample downhole from a subterranean formation, applying a reactant to the fluid sample to create a combined fluid, observing the combined fluid, and determining if contaminants are present within the fluid sample based upon the observing the combined fluid.

Abstract: An improved method that performs downhole fluid analysis of the fluid properties of a reservoir of interest and that characterizes the reservoir of interest based upon such downhole fluid analysis.

Abstract: A method for performing a field operation within a geologic basin having rock formations and a reservoir that includes fluids includes generating, by forward modeling using a petroleum system model (PSM), an estimate of a fluid property distribution of a fluid within the reservoir of the geologic basin. The method further includes detecting, from fluid samples, a fluid property gradient within the geologic basin. The fluid samples are extracted from within at least one wellbore drilled through the rock formations. The method further includes, comparing the estimate of the fluid property distribution with the detected fluid property gradient to generate a comparison result, iteratively adjusting, based on the comparison result, the PSM to generate an adjusted PSM, and performing, based on the adjusted PSM, the field operation within the geologic basin.

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 methodology that performs fluid sampling within a wellbore traversing a reservoir and fluid analysis on the fluid sample(s) to determine properties (including asphaltene concentration) of the fluid sample(s). At least one model is used to predict asphaltene concentration as a function of location in the reservoir. The predicted asphaltene concentrations are compared with corresponding concentrations measured by the fluid analysis to identify if the asphaltene of the fluid sample(s) corresponds to a particular asphaltene type (e.g., asphaltene clusters common in heavy oil). If so, a viscosity model is used to derive viscosity of the reservoir fluids as a function of location in the reservoir. The viscosity model allows for gradients in the viscosity of the reservoir fluids as a function of depth. The results of the viscosity model (and/or parts thereof) can be used in reservoir understanding workflows and in reservoir simulation.

Abstract: A gas separation and detection tool for performing in situ analysis of borehole fluid is described. The tool comprises a sampling chamber for a downhole fluid. The sample chamber comprises a detector cell with an opening. The tool also comprises a gas separation module for taking a gas from the downhole fluid. The gas separation module comprises a membrane located in the opening, a support for holding the membrane, and a sealant applied between the housing and the membrane or support. Moreover, the tool comprises a gas detector for sensing the gas.

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: 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: Methods and systems to characterize a fluid in a reservoir to determine if the fluid is in one of equilibrium or non-equilibrium in terms of one of gravity, solvency power, entropy effect or some combination thereof. The method includes acquiring tool data at each depth for each fluid sample of at least two fluid samples wherein each fluid sample is at a different depth and communicating the tool data to a processor. Determining formation properties of each fluid sample to obtain formation property data and determining fluid properties for each fluid sample to obtain fluid property data. Selecting a mathematical model based on one of gravity, solvency power or entropy, in view of a fluid property, using one of tool data, formation property data, fluid property data, known fluid reservoir data or some combination thereof, to predict if the fluid is in an equilibrium distribution or a non-equilibrium distribution.

Abstract: Methods of and apparatus to estimate one or more volumes of one or more components of a fluid in a sample chamber of a downhole tool are described. An example method includes obtaining a sample chamber volume measurement, a flowline volume measurement and a supplemental volume measurement. The example method includes drawing the fluid into the sample chamber until the sample chamber is substantially full and measuring a characteristic of the fluid in the sample chamber at a first time to obtain a first characteristic measurement. The example method also includes adding a supplemental volume corresponding to the supplemental volume measurement to over-pressurize the sample chamber after measuring the characteristic at the first time and measuring the characteristic of the fluid in the sample chamber at a second time to obtain a second characteristic measurement. The second time is after the sample chamber is over-pressurized.

Abstract: A method and system for characterizing formation fluids contaminated with drilling mud that compensates for the presence of such drilling mud. The operations that characterize formation fluids contaminated with drilling mud can be carried out in real-time. The operations also characterize a wide array of fluid properties of petroleum samples contaminated with drilling mud in a manner that compensates for the presence of drilling mud. The operations characterize the viscosity and density of petroleum samples contaminated with drilling mud at formation conditions in a manner that compensates for differences between formation conditions and flowline measurement conditions. The operations also derive live fluid density unaffected by contamination of mud filtrate based on a scaling coefficient dependent on measured gas-oil ratio of the formation fluid.

Abstract: A method for downhole fluid analysis is disclosed. The method includes positioning a downhole fluid sampling tool at first and second locations; extracting and compositionally analyzing samples of reservoir fluid while positioned at the first and second locations; comparing analysis results; and repositioning the tool to a third location depending on the results of the comparison. The compositional analysis can be performed using downhole gas chromatography and mass spectrometry systems and preferably can identify subtle non-homogeneities such as biomarkers. The fluid extraction can be performed using a focuses dual-flowline type sampling probe.

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: 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: Methods and devices for mixing a first fluid with a second fluid downhole include a chamber having a first end, a second end and an opening for fluid to flow there through. A top surface of a piston is capable of contacting the second end of the chamber. The piston is located at a first position within the chamber based upon characteristics of a second fluid. A fluid delivery system supplies the first fluid and supplies a second fluid through a first opening of the chamber, wherein the second fluid is at a pressure that moves the piston approximate to the second end of the chamber. The piston includes an agitator mixing device that is attached to a bottom surface of the piston, wherein mixing of the first fluid with the second fluid primarily occurs upon movement of the piston by actuating device.

Abstract: Methods and devices for mixing a first fluid with a second fluid downhole include a chamber having a first end, a second end and an opening for fluid to flow there through. A top surface of a perforated piston is capable of contacting the second end and a top surface of a piston is capable of contacting a bottom surface of the perforated piston. The perforated piston is located at a first position within the chamber based upon characteristics of a first fluid. A first fluid delivery system supplies the first fluid and a second fluid delivery system supplies a second fluid to the chamber, wherein the second fluid is at a pressure that moves the piston approximate to the first end. An actuating device applies a force against the bottom surface of the piston to inject the fluids through channels of the perforated piston to produce spray droplets.

Abstract: A method for analyzing fluid withdrawn from a subsurface formation includes disposing the withdrawn fluid in a chamber and maintaining the fluid in the chamber substantially at a same temperature and pressure as exists in the subsurface formation. Electric current is passed through the fluid in the chamber using at least one electrode made from a selected metal, the electric current comprising direct current and alternating current of frequency sufficient to determine at least one of (i) resistance of the fluid sample in the chamber directly and (ii) from the direct current determine a polarization resistance of the at least one electrode.

Abstract: Methods of calibrating a fluid analyzer for use in a wellbore are described. An example method of generating calibration data for a fluid analyzer for use in a downhole tool involves lowering a downhole tool including a fluid analyzer to a location in a wellbore, measuring, via the fluid analyzer, a characteristic value of a calibration fluid or a vacuum while the fluid analyzer is at the location, obtaining an expected characteristic value for the calibration fluid or the vacuum at the location, and comparing the measured characteristic value to the expected characteristic value to generate a calibration value for the fluid.