Abstract: A drill string includes drill pipe and a modular fracturing sub. A processor can control the drill string to drill a wellbore to some desired depth. The drill string is positioned at a desired location in the wellbore and a section of the wellbore is hydraulically isolated, forming a cavity. Existing fluid may be evacuated from the cavity and fracturing fluid injected into the cavity until a desired level of fracturing is attained. Retrievable packers are used for the hydraulic isolation. A pump evacuates the existing fluid via ports in the fracturing sub. The ports may also be used when injecting fracturing fluid. Seismic sensors may be distributed along the drill string to monitor fracture growth. Logging-while-drilling tools may be integrated into the drill string. Fluid from the lower portion of the wellbore is blocked by a lower sealing unit on a bottomhole assembly.

Abstract: For a given medium, a property may be inferred based on nuclear magnetic resonance (NMR) data. NMR data that includes two or more different NMR signals are used. Differences between any particular two of the two or more different NMR decays are computed and a distribution is produced based on the computed differences. The property of the medium may be inferred using the produced distribution. The produced distribution features the change in a parameter. The NMR distributions may be T2 distributions, T1 distributions, diffusion, or any other type of NMR data. The NMR data may be acquired: at different times, for different levels of invasion, before and after water flooding, or for different saturation states. The inferred property may pertain to the oil and gas industry, material analysis, medicine, pharmaceuticals, the process industry, or the food industry. For example, the inferred property may be the porosity of a subsurface formation.

Abstract: A permanent monitoring tool is provided and disposed in a wellbore. Measurements are made at different times using the permanent monitoring tool on a region of a formation penetrated by the wellbore. One or more properties of the formation are inferred at one or more depths of investigation within the region using the measurements. Any changes in the one or more inferred formation properties are determined and one or more reservoir management decisions are made based on the determined changes. The well may be an observation well, an injector well, or a production well. The permanent monitoring tool may be a magnetic resonance tool or an electromagnetic tool. The measurements may be stacked to improve the signal-to-noise ratio of the signal. Different depths of investigation may be selected using antenna arrays of different lengths. The inferred properties may be saturation or resistivity. Conductive or non-conductive casing may be used.

Abstract: A NMR logging tool is provided and disposed in a wellbore at some desired depth. Packers are provided and actuated to hydraulically isolate a section of the wellbore and form a cavity between the NMR logging tool and the wall of the isolated section of the wellbore. The cavity is evacuated until a first desired pressure within the cavity is attained. Fluid is injected into the cavity until a second desired pressure within the cavity is attained. A plurality of NMR measurements is made on the region of the formation, each of the plurality of measurements being made at different times. Formation properties are inferred using the measurements. A baseline NMR measurement may be made when a first desired pressure is attained. A time-zero NMR measurement may be made when a second desired pressure is attained. Similar measurements may be made in a laboratory on a sample.

Abstract: A NMR logging tool is provided and disposed at some desired depth in a wellbore penetrating a subsurface formation. A first set of NMR measurements is made over a desired depth range and depth of investigation, wherein the first set of NMR measurements includes a first NMR signal intensity. Supercritical carbon dioxide is injected into the formation and a second set of NMR measurements is made over the desired depth range and depth of investigation, wherein the second set of NMR measurements includes a second NMR signal intensity. The first NMR signal intensity is compared to the second NMR signal intensity and one or more properties of the formation are inferred using the compared NMR measurements. A magnetic field gradient that varies a static magnetic field along a desired spatial dimension of a region of investigation may be provided to map a rate of fluid movement.

Abstract: A NMR logging tool is provided and disposed at some desired depth in a wellbore penetrating a subsurface formation. A first set of NMR measurements is made over a desired depth range and depth of investigation, wherein the first set of NMR measurements includes a first NMR signal intensity. Supercritical carbon dioxide is injected into the formation and a second set of NMR measurements is made over the desired depth range and depth of investigation, wherein the second set of NMR measurements includes a second NMR signal intensity. The first NMR signal intensity is compared to the second NMR signal intensity and one or more properties of the formation are inferred using the compared NMR measurements. A magnetic field gradient that varies a static magnetic field along a desired spatial dimension of a region of investigation may be provided to map a rate of fluid movement.

Abstract: An acoustic logging tool is disposed in a wellbore during an acidizing operation. Measurements are made using the acoustic logging tool on a region of a formation penetrated by the wellbore and being subjected to the acidizing operation. An acoustic anisotropic property of the formation is inferred at one or more depths of investigation within the region using the measurements, and a wormhole porosity and/or an orientation of one or more wormholes resulting from the acidizing operation is determined. Acidizing operation management decisions may be made based on the determined wormhole porosity and/or orientations of the wormholes. An acidizing operation management decision may be to maintain, increase, or decrease an acid injection rate. Measurements made may include the velocity of an acoustic wave propagating through the formation and the acoustic anisotropic properties of fast waves and slow waves. The acoustic anisotropic properties of the formation generally depend on rock stiffness.

Abstract: A downhole tool to make one or more downhole measurements of laser-induced vaporization and/or pyrolysis of hydrocarbons is provided and disposed at a desired location within a wellbore. A tool head of the downhole tool is brought into sealing engagement with the wellbore wall. The fluid within an interior region enclosed by the tool head and the wellbore wall is evacuated and a measurement spot is irradiated with a laser to generate volatile hydrocarbons and/or pyrolytic hydrocarbons. Measurements are made on the volatile hydrocarbons and/or pyrolytic hydrocarbons and one or more formation properties are inferred based on the measurements. A low level of laser radiation intensity, irradiating some or all of the wellbore wall enclosing the interior region, may be used to prevent measurement contamination, and both medium power and high power levels of laser radiation may be used to first vaporize and then pyrolyze the hydrocarbons.

Abstract: A mineralogy composition of a formation of interest is determined using core samples or downhole measurements. A dry permittivity is determined for each identified mineral. A volumetric mixing law is employed using the determined mineralogy composition and the determined dry permitivities. An effective matrix permittivity is determined using results from the volumetric mixing law. Dielectric dispersion measurements of the subject formation are acquired using the core samples or the downhole measurements. A dielectric petrophysical model is produced using the dielectric dispersion measurements and the effective matrix permittivity. A water saturation is estimated based on the dielectric petrophysical model. Nuclear magnetic resonance (NMR) T2 measurements having short echo spacings are acquired. A NMR petrophysical model is generated based on the NMR T2 measurements. A total porosity is determined based on the generated NMR petrophysical model.

Abstract: Sealing particles are used to stop or reduce undesired fluid loss. The sealing particles may be swellable or have effective cross-sectional areas greater than five square millimeters or are both swellable and have effective cross-sectional areas greater than five square millimeters. The sealing particles are disposed in one or more locations in which there is undesired fluid flow and, once lodged therein, stop or at least reduce the undesired fluid loss. A tubular having a bypass flow path may be used to deploy the sealing particles. The bypass flow path may use a biased or unbiased sleeve that is selectably movable to expose or block exit ports in the tubular. A retrievable sealing disk may be deployed to move the sleeve. The sealing particles may be made of a bi-stable material with extenders and may be actuated using swellable material. The sealing particles may extend in multiple dimensions.

Abstract: According to some embodiments, a borehole deployable apparatus is described that can be used to generate strong vibrations in a subterranean rock formation. In some embodiments, the apparatus accelerates a mass using mechanisms built into the tool and causes the mass to strike the borehole wall. The mechanisms can control the mass acceleration, and the frequency of strikes. In some embodiments, the apparatus is designed for use in the field of petroleum recovery where the vibrations are used to create or re-establish a flow rate for the fluids in the formation.

Abstract: Downhole gravity measurements are used to monitor the volumetric sweep of CO2 and estimate the fingering phenomenon if any. The gravity measurements have been found to be effective due to the high density contrast between CO2 and brine or oil which provides better and higher sensitivity. An analytical forward model is used to determine the location and shape characteristics of the flooding front. A strategy to monitor the movement of the CO2 flooding front and to predict the fingering phenomenon is used to provide a warning tool to improve the sweep efficiency, according to some embodiments.

Abstract: Systems and methods are described for controlling the location where a fracture initiates and the fracture direction at the initiation point. A mechanical device is positioned in a main wellbore or partially or fully in a side hole off of the main wellbore. The mechanical device is actuated so as to contact the formation walls and induce stress in the formation. According to some embodiments, fractures are also initiated using the mechanical device. A hydraulic fracturing process is then carried out to fracture and/or propagate fractures in locations and/or directions according to the actuation of the mechanical device.

Abstract: An anchor is placed in a wellbore to convey loads into a wellbore. The anchor is placed at some desired location in a wellbore and installed at that location using, for example, arms that penetrate into the formation surrounding the anchor. A line extends from the surface, wraps around a pulley in the anchor and attaches to the downhole end of the load. Tension is applied at the surface to the line to pull the load to a desired location in the wellbore. Optionally, the same or a second line can be attached to the uphole end of the load to reposition or retrieve the load. Alternatively, a powered anchor has a line drive device and a spool. A portion of a line extends from the anchor to the load. The line is spooled onto the spool by the line drive device, thereby pulling the load into the wellbore.

Abstract: Methods are provided for separating oil and water signals in multidimensional nuclear magnetic resonance (NMR) maps. In one embodiment, separate multidimensional NMR maps are provided for oil and water content. In another embodiment, an oil-water boundary and a water-gas boundary are generated on a D-T2 map. The boundaries may be curved boundaries or lines.

Abstract: The wettability of a formation may be estimated using a multi-frequency dielectric measurement tool. Multi-frequency dielectric dispersion measurements are made using the multi-frequency dielectric measurement tool on a sample. The bulk density and the total porosity of the sample are also otherwise acquired. The bulk density, matrix permittivity, total porosity, and multi-frequency dielectric dispersion measurements are input into a petrophysical dielectric model and the petrophysical dielectric model is applied to obtain inversion results. A wettability state of the sample is determined using the inversion results and one or more reservoir management decisions are made based on the determined wettability state of the sample. A non-transitory, computer-readable storage medium may be provided that has stored on it one or more programs that provide instructions.

Abstract: Systems and methods are described for calculating pore pressure in a porous formation such as shale gas having substantially disconnected pore spaces. In some described examples, an NMR logging tool with at least two depths of investigation (DOIs) is used. The deeper DOI can be used to sample the shale gas that has not been perturbed by the drilling process, for example, and contains the gas at connate pressure. The shallow DOI can be used to sample shale gas that has been perturbed, and has lost at least part of its gas content. The micro cracks that have been formed in the shallow location (closer to the borehole) allow for injection of gas into the formation at known pressures while measuring the NMR response. The connate pore pressure can then be calculated for the deeper location based on the NMR response to the known pressure increase.

Abstract: A sample that includes formation content from a subsurface formation and other sample constituents is obtained while the sample is in close proximity to the subsurface formation. While downhole, the formation content is separated from the other sample constituents by passing the sample through an oil-wet porous plate, a water-wet porous plate, or through both plates, and analyzed. Various petrophysical properties of the formation content may be determined. To further separate the formation content, one may pass the sample through a mesh, pass the sample into an expansion chamber, or draw the sample into a chamber using a moveable piston. The formation content may be analyzed downhole using, for example, a mass spectrometer, FTIR, or chromatograph. The hydrocarbon contribution from oil based drilling fluid can be accounted for. Alternatively, a capsule may be charged with “live” formation content and conveyed uphole to be analyzed.

Abstract: An open ended coaxial probe is disclosed that can be used to measure the dielectric properties of solids. According to some embodiments, the probe is specially designed to make good contact with solids having flat or non-flat surfaces. This design relies on forcing a good contact between the solid surface with both the center conductor and outer conductor of the coaxial probe. A method is also described in which the coaxial probe is used to monitor the dielectric permittivity of cylindrical samples such as rock cores drilled from a well. Also described are methods of using the coaxial probe to provide a continuous log of the dielectric permittivity of a rock core.

Abstract: An apparatus and related methods are described for detecting features of a reservoir surrounding a borehole, the apparatus being capable of emitting an electromagnetic wave signal and receiving a signal representing a response of the reservoir to the electromagnetic wave signal, wherein the emitted signal is a broadband signal selected from within the range of 1 Hz to 1000 Ghz and the received signal includes a directional characteristic to provide an azimuthal determination of the direction of a discontinuity within the formation as the discontinuity reflects or scatters at least part of the broadband signal; azimuthally scanning the surrounding formation; and inverting the received signal for deriving at least a distance of the reflecting discontinuity from the borehole using simultaneous inversion of the reflected or scattered wavefield at multiple frequencies.