Abstract: The present disclosure relates to a method to estimate a subsurface formation property. A downhole logging tool is provided and disposed in a wellbore. Multiple measurements of various measurement types are obtained at various depths of investigation using the downhole logging tool. The multiple measurements may include natural gamma ray measurements, density measurements, resistivity measurements, nuclear measurements, and nuclear magnetic resonance measurements. The signal-to-noise ratio of the measured signals is increased using, for example, lateral stacking and multi-shell inversion. The subsurface formation property is estimated using the increased signal-to-noise ratio signals. The subsurface formation property may include porosity, adsorbed gas volume, free gas volume, bound water volume, free water volume, oil volume, and kerogen volume. A fluid analysis may be performed using a multi-dimensional nuclear magnetic resonance technique.

Abstract: A method and system for performing speed correction on nuclear magnetic resonance logging data is provided. The speed correction performed can be done on a representation of echo data received by a logging tool, and then additively applied to the echo data. Such a process can reduce or remove the amplification of noise in the echo data that is common in conventional methods of speed correction.

Abstract: The present disclosure relates to a method to determine the capture cross-section of a subsurface formation at a desired depth in the formation. A database of Sigma values for known lithologies, porosities, and salinities is provided, and multiple Sigma measurements are obtained from a downhole logging tool. Within the database, Sigma values are interpolated to determine the respective depths of investigation of the multiple Sigma measurements. A monotonic function is fitted to the multiple Sigma measurements at the determined depths of investigation, and the capture cross-section of the subsurface formation at any desired depth in the formation is determined using the fitted function. Similarly, a system to determine the capture cross-section of a subsurface formation at a desired depth in the formation and/or a depth of invasion of drilling fluids is also disclosed.

Abstract: The present disclosure relates to a method to determine a characteristic of a subsurface formation using a downhole logging tool. A downhole logging tool having the ability to make substantially concurrent disparate measurements on the subsurface formation is provided and substantially concurrent disparate measurements on the formation using the downhole logging tool are made. Those measurements are used to solve a system of equations simultaneously and the solution to the system of equations is used to determine the characteristic of the subsurface formation.

Abstract: A method for determining a formation type within a wellbore includes forming the wellbore such that the wellbore intersects fractures within a formation. Hydrocarbons are produced from the formation. An induction tool is disposed into the wellbore after producing the hydrocarbons. A resistivity of a portion of the formation is measured with the induction tool. The resistivity of the portion of the formation is compared with a known formation type. The formation type of the portion of the formation is determined based on the resistivity. A characteristic of the formation type is output.

Abstract: A logging tool having a plurality of different sensor types having close spacings mounted on an articulated or extendible pad, a sleeve, a mandrel, a stabilizer, or some combination of those is provided and used to make measurements in a wellbore in a single logging run. Those measurements are used to create images of the wellbore and the images are used to deduce the local geology, optimize well placement, perform geomechanical investigation, optimize drilling operations, and perform formation evaluation. The logging tool includes a processor capable of making those measurements, creating those images, performing those operations, and making those determinations. The plurality of different sensors may be one or more resistivity sensors, dielectric sensors, acoustic sensors, ultrasonic sensors, caliper sensors, nuclear magnetic resonance sensors, natural spectral gamma ray sensors, spectroscopic sensors, cross-section capture sensors, and nuclear sensors, and they may be “plug-and-play” sensors.

Abstract: A method for determining fluids in a formation. The method includes obtaining open hole measurements for a borehole in the formation; identifying points in the borehole from which to obtain pressure measurements using the open hole measurements; obtaining pressure measurements at the identified points in the borehole; applying an excess pressure technique to the pressure measurements to identify a plurality of pressure compartments in the borehole; characterizing fluid in each of the plurality of compartments; and developing a drilling plan based on characterization of fluids in each of the plurality of compartments.

Abstract: A method and system for performing speed correction on nuclear magnetic resonance logging data is provided. The speed correction performed can be done on a representation of echo data received by a logging tool, and then additively applied to the echo data. Such a process can reduce or remove the amplification of noise in the echo data that is common in conventional methods of speed correction.

Abstract: A method for analyzing a formation, that includes plotting resistivity data points on a resistivity graph to obtain plotted resistivity data points, and selecting a first shale point on the resistivity graph based on the plotted resistivity data points. The first shale point represents a resistivity anisotropy of shale in the formation. The method further includes generating, for each of a plurality of shale fraction values, a first shale fraction curve on the resistivity graph based on the shale fraction value and the first shale point, and generating, for each of a plurality of sand resistivity values, a first sand resistivity curve on the resistivity graph based on the sand resistivity value and the first shale point. A hydrocarbon yielding region in the formation is identified based on the first sand resistivity curves and the first shale fraction curves.

Abstract: A method for determining oil viscosity and continuous gas-oil-ratio (GOR) from nuclear magnetic resonance logs (NMR). The method includes obtaining a set of NMR data of a portion of the subterranean formation from inside the wellbore without acquiring formation fluid sample; isolating a quantitative reservoir fluid information associated with oil from oil based mud (OBM) using radial profiling of the set of NMR data, wherein the OBM is used for extracting fluid from the underground reservoir; determining GOR related information associated with the portion of the subterranean formation from the quantitative reservoir fluid information associated with oil, wherein the GOR related information is determined based on a predetermined model; and performing operations for the oilfield based on the GOR related information.

Abstract: The present disclosure relates to a method to estimate a subsurface formation property. A downhole logging tool is provided and disposed in a wellbore. Multiple measurements of various measurement types are obtained at various depths of investigation using the downhole logging tool. The multiple measurements may include natural gamma ray measurements, density measurements, resistivity measurements, nuclear measurements, and nuclear magnetic resonance measurements. The signal-to-noise ratio of the measured signals is increased using, for example, lateral stacking and multi-shell inversion. The subsurface formation property is estimated using the increased signal-to-noise ratio signals. The subsurface formation property may include porosity, adsorbed gas volume, free gas volume, bound water volume, free water volume, oil volume, and kerogen volume. A fluid analysis may be performed using a multi-dimensional nuclear magnetic resonance technique.

Abstract: A method for estimating fluid productivity of a subsurface rock formation from within a wellbore drilled therethrough includes measuring a nuclear magnetic resonance property of the formation at a plurality of lateral depths therein. The measured nuclear magnetic resonance property is used to estimate the fluid productivity.

Abstract: A method for estimating fluid saturation in a formation penetrated by a wellbore from nuclear magnetic resonance measurements made at a plurality of lateral depths into the formation from the wellbore includes estimating a bound water volume, a total porosity and a free water volume at each of the lateral depths from the nuclear magnetic resonance measurements. A minimum water saturation is estimated at each lateral depth from the total porosity, the free water volume and the bound water volume at each lateral depth. A value of water saturation is estimated at each lateral depth from the minimum water saturation at each lateral depth. A relationship between lateral depth and water saturation is determined. Water saturation is estimated at a selected lateral depth greater than the greatest lateral depth of the nuclear magnetic resonance measurements.

Abstract: The present disclosure relates to a method to determine the capture cross-section of a subsurface formation at a desired depth in the formation. A database of Sigma values for known lithologies, porosities, and salinities is provided, and multiple Sigma measurements are obtained from a downhole logging tool. Within the database, Sigma values are interpolated to determine the respective depths of investigation of the multiple Sigma measurements. A monotonic function is fitted to the multiple Sigma measurements at the determined depths of investigation, and the capture cross-section of the subsurface formation at any desired depth in the formation is determined using the fitted function. Similarly, a system to determine the capture cross-section of a subsurface formation at a desired depth in the formation and/or a depth of invasion of drilling fluids is also disclosed.

Abstract: The present disclosure relates to a method to determine a characteristic of a subsurface formation using a downhole logging tool. A downhole logging tool having the ability to make substantially concurrent disparate measurements on the subsurface formation is provided and substantially concurrent disparate measurements on the formation using the downhole logging tool are made. Those measurements are used to solve a system of equations simultaneously and the solution to the system of equations is used to determine the characteristic of the subsurface formation.

Abstract: A technique utilizes the acquisition of data via nuclear magnetic resonance at multiple depths of investigation in a well region. The acquired data is processed to estimate variable fluid mixture densities at different radial depths. The variable fluid mixture densities and a radial response from a density tool, for example, can be used to calculate an effective fluid mixture density and used to interpret density logs. Other logs such as neutron log, induction resistivity log, and dielectric permittivity log can be combined with NMR. For these tools a corresponding effective formation property can be calculated and used to determine other formation characteristics, such as total porosity, total density, dielectric permittivity, electric resistivity, and formation characteristics derivable from these.

Abstract: Methods are disclosed herein that relate to determining a formation type within a wellbore. The wellbore may be formed (e.g., drilled) such that the wellbore intersects fractures within a formation. An induction tool may then be disposed downhole into the wellbore for taking measurements of the formation surrounding the wellbore. These measurements may include a resistivity of the formation based upon horizontal resistivity measurement, a vertical resistivity measurement, and/or an anisotropy measurement. Using any one or all of these measurements then, one may determine a formation type of the formation measured with the induction tool.

Abstract: A method for determining fluids in a formation. The method includes obtaining open hole measurements for a borehole in the formation; identifying points in the borehole from which to obtain pressure measurements using the open hole measurements; obtaining pressure measurements at the identified points in the borehole; applying an excess pressure technique to the pressure measurements to identify a plurality of pressure compartments in the borehole; characterizing fluid in each of the plurality of compartments; and developing a drilling plan based on characterization of fluids in each of the plurality of compartments.

Abstract: A method for estimating fluid productivity of a subsurface rock formation from within a wellbore drilled therethrough includes measuring a nuclear magnetic resonance property of the formation at a plurality of lateral depths therein. The measured nuclear magnetic resonance property is used to estimate the fluid productivity.

Abstract: A method for determining skin factor of a subsurface rock formation from within a wellbore drilled therethrough includes measuring a nuclear magnetic resonance property of the formation at a plurality of lateral depths therein. The measured nuclear magnetic resonance property is used to estimate the skin factor.