Abstract: An apparatus for use in a wellbore may include a tool having a first section configured to receive a core and a second section configured to collect a gas escaping from the core. The apparatus may also include a sensor associated to provide signals relating to a property of gas. In one aspect, the second section may be removable and may be pressurized. The apparatus may also include a recorder that records data representative of the signals received from the sensor. The recorder may record data while the tool is retrieved from the wellbore. A method for estimating a parameter of interest of a formation includes retrieving a core from the formation, collecting a gas escaping from the core as the core is retrieved to the surface, and measuring at least one property of gas while the core is retrieved to the surface.

Abstract: A system, method and computer-readable medium for developing an earth formation is disclosed. A tool conveyed in a borehole induces a stress in the earth formation proximate a borehole. A sensor assembly obtains a measurement of a physical property of the borehole at a plurality of azimuthal locations in the borehole. The values of the physical property are indicative of the induced stress in the formation. A processor forms an image of the borehole using the obtained measurements of the physical property, estimates an azimuthal variation with borehole depth of the induced stress in the formation from the formed image, and alters an operational parameter of a device for developing the earth formation using the estimated azimuthal variation with depth of the induced stress in the formation.

Abstract: A system and method for the geomechanical steering of the orientation of a wellbore is disclosed. In one embodiment, any available a priori data regarding the stress characteristics of a region of interest are used to develop a preliminary stress model for the region. A geosteered drilling operation is thereafter commenced, with the trajectory being steered in a direction relative to the stress model of the region. While drilling, real-time data is obtained from conventional down-hole instrumentation. The real-time data is used to refine the stress model for the region, such that the trajectory can be guided on an ongoing basis to achieve an optimal relationship with the measured stress characteristics of the region.

Abstract: Methods and apparatus for collecting a downhole sample are provided. The method may include conveying a sampling tool in a borehole using a first carrier, conveying a sample container in the borehole using a second carrier, and introducing a downhole sample from the sampling tool to the sample container. An apparatus includes a sampling tool disposed on a first carrier, a sample container disposed on a second carrier, wherein the first carrier and the second carrier are independently conveyable in a borehole, and a coupling connectable to the sampling tool and the sample container.

Abstract: A method to correct for a systematic error of a sensor having a plurality of accelerometers configured to measure gravitational acceleration, the method including: rotating the plurality of accelerometers about a first axis; obtaining a first set of calibration measurements from the plurality of accelerometers from the rotation about the first axis; determining a first systematic error for each accelerometer in the plurality using the first set of calibration measurements; and removing the first systematic error from sensor measurements to correct for the systematic error.

Abstract: A method for measuring true vertical depth in a borehole, the method including: measuring gravitational acceleration in the borehole; and determining the true vertical depth from the measurement.

Abstract: A transmitter on an instrument is used to induce currents in an earth formation when it is turned on or off. A Fourier transform is applied to transient measurements made in the receivers. A multifrequency focusing of the transformed data is used for applications like determination of a distance to an interface in the formation, controlling the drilling direction, determination of formation resistivities and formation strike directions.

Abstract: A method for estimating information about a formation, the method including obtaining a first set of radiation data substantially influenced by the formation and non-formation materials; obtaining a second set of radiation data substantially influenced by the non-formation materials; and correcting the first set of radiation data with the second set of radiation data to provide corrected formation radiation data.

Abstract: Apparatus and methods for collecting a downhole sample are provided. The method may include introducing a flowable sealant to a borehole wall portion, modifying a formation system mobility using the flowable sealant, and receiving the downhole sample using a sample receiving port positioned proximate the borehole wall portion. An apparatus includes a formation sampling member having a sample receiving port for receiving the downhole sample, and an inhibitor that includes one or more of an activator and an injector.

Abstract: A method for presenting a formation property to a user includes estimating an initial property of the formation using a tool conveyed in a borehole and estimating a relationship between the tool and the formation based on information received from the tool. The method also includes presenting the user a first output based at least in part on the initial property and presenting a second output based at least in part on the relationship proximate the first output.

Abstract: Apparatus and methods for collecting a downhole sample are provided. The method may include monitoring a flow path parameter, introducing a sealant to a borehole wall when the flow path parameter satisfies a first predetermined condition, and collecting a downhole sample when the flow path parameter satisfies a second predetermined condition. An apparatus may include a formation sampling tool having a flow path, an inhibitor coupled to the formation sampling tool, a sampler coupled to the formation sampling tool, and a selector that selects one or more of the inhibitor and the sampler when a parameter of the flow path satisfies a predetermined condition.

Abstract: An apparatus for estimating a property of an earth formation includes: a plurality of sensors configured to estimate at least one property, each of the plurality of sensors located at a known position relative to one another; and a processor in operable communication with the plurality of sensors and configured to estimate uncertainties of the location of the plurality of sensors over a period of time. A method and computer program product for estimating a property of an earth formation is also disclosed.

Abstract: The grain size of a pore-scale geometric model of a clastic earth formation are adjusted so that the NMR relaxation time distribution output of the model matches a measured NMR distribution. Fluid drainage and imbibing can be simulated. Additional properties of the earth formation are predicted using the pore-scale model. The additional properties may be based on additional measurements of properties of a fluid in the formation.

Abstract: A method is disclosed for changing an optical path length through a fluid downhole, comprising interspersing an optically transmissive member into a first optical path through the fluid, thereby creating a second shorter optical path through the fluid. In another embodiment, the method further comprises measuring an intensity of light, I1 transmitted through the first optical path; measuring an intensity of light, I2 transmitted through the second optical path; and estimating an optical property for the second optical path from the ratio, I1/I2. A system is disclosed for changing an optical path length through a fluid downhole, comprising a fluid passage between two optically transmissive windows for the fluid downhole, the fluid passage having a first optical path through the fluid; and an optically transmissive member for insertion into the first optical path, thereby creating a second shorter optical path through the fluid.

Abstract: A method for estimating a property of a portion of an earth formation ahead of a borehole penetrating the formation, the method includes: conveying a logging tool through the borehole; receiving one or more first signals from a previous depth of the logging tool; constructing a model of the earth formation using the one or more first signals; predicting one or more second signals from the portion of the earth formation ahead of the borehole using the model; receiving one or more third signals from the portion of the earth formation ahead of the borehole; calculating a difference between the one or more third signals and the one or more second signals; and estimating the property from the difference.

Abstract: Many reservoirs of interest include heavy oil. In such reservoirs, partly at normal temperatures, many instruments commonly used for formation evaluation may not be able to distinguish between heavy oil and bound water in the formation. Passive or active heating is used to elevate the temperature of the fluids in the formation. At elevated temperatures, distinguishing between heavy oil and bound water is easier. Of particular interest is the increase in the resolvability of the transverse relaxation time T2 of NMR spin echo measurements. Additionally, the dielectric constant and the loss tangents of water and heavy oil show different temperature and frequency dependence.

Abstract: An apparatus for use in a wellbore may include a tool having a first section configured to receive a core and a second section configured to collect a gas escaping from the core. The apparatus may also include a sensor associated to provide signals relating to a property of gas. In one aspect, the second section may be removable and may be pressurized. The apparatus may also include a recorder that records data representative of the signals received from the sensor. The recorder may record data while the tool is retrieved from the wellbore. A method for estimating a parameter of interest of a formation includes retrieving a core from the formation, collecting a gas escaping from the core as the core is retrieved to the surface, and measuring at least one property of gas while the core is retrieved to the surface.

Abstract: A method to correct for a systematic error of a sensor having a plurality of accelerometers configured to measure gravitational acceleration, the method including: rotating the plurality of accelerometers about a first axis; obtaining a first set of calibration measurements from the plurality of accelerometers from the rotation about the first axis; determining a first systematic error for each accelerometer in the plurality using the first set of calibration measurements; and removing the first systematic error from sensor measurements to correct for the systematic error.

Abstract: A transmitter on an instrument is used to induce currents in an earth formation when it is turned on or off. A Fourier transform is applied to transient measurements made in the receivers. A multifrequency focusing of the transformed data is used for applications like determination of a distance to an interface in the formation, controlling the drilling direction, determination of formation resistivities and formation strike directions.

Abstract: Methods and apparatus for collecting a downhole sample are provided. The method may include conveying a sampling tool in a borehole using a first carrier, conveying a sample container in the borehole using a second carrier, and introducing a downhole sample from the sampling tool to the sample container. An apparatus includes a sampling tool disposed on a first carrier, a sample container disposed on a second carrier, wherein the first carrier and the second carrier are independently conveyable in a borehole, and a coupling connectable to the sampling tool and the sample container.