Abstract: A method for determining an earth formation property from nuclear magnetic resonance measurements includes applying suppression functions to spin echoes in at least one burst measurement set to produce a modified burst data set, the suppression functions to suppress contribution of spin echoes having non-negligible polarization correction; inverting the modified burst data set and at least one standard spin echo measurement set to produce a nuclear magnetic resonance parameter distribution, the at least one standard spin echo measurement set and the at least one burst measurement set being acquired on an earth formation sample; and computing the earth formation property from the nuclear magnetic resonance parameter distribution. The nuclear magnetic resonance parameter includes at least one selected from longitudinal relaxation time, transverse relaxation time, a ratio of longitudinal relaxation time to transverse relaxation time, and diffusion constant.

Abstract: A method for quantifying permeability of a vuggy reservoir includes determining a permeability modeled with matrix porosity (K0) of the reservoir, determining a vug porosity (&PHgr;vug) of the reservoir, and quantifying permeability (K) of the reservoir as follows: K=aK0·bc&PHgr;wg, where a, b, and c are constants.

Abstract: The present invention provides methods and apparatus for determining flow velocity within a formation utilizing nuclear magnetic resonance (NMR) techniques in which the shape of the resonance region is restricted so that sensitivity to radial flow or vertical flow is obtained (or both when more than one NMR tool is used). Flow velocity using these NMR tools is determined using decay amplitude, frequency displacement or stimulated echoes (where the spins are stored along the magnetic field instead of the transverse plane to exploit echo decays and frequency displacements) based on the application of adiabatic pulses. Based on the described NMR measurement of flow velocity, additional wellbore parameters may be obtained such as a direct measurement of permeability, an assessment of drilling damage to the wellbore, formation pressure, invasion rate of the mud filtrate or the migration of fine mud particles during sampling operations.

Abstract: Methods and apparatus are disclosed for minimizing or eliminating an undesired axial electric current induced along a subsurface borehole in the process of subsurface measurements with transmitter and/or receiver antennas which are substantially time varying magnetic dipoles with their dipole moments aligned at an angle to the axis of the borehole. Some antennas are disposed within the borehole on instruments having a non-conductive support member. One instrument includes a conductive all-metal body with an antenna adapted for induction frequencies. Antenna shields adapted for controlled current flow are also provided with an all-metal instrument. Methods include providing an alternate path for the current along the instrument body. Another method includes emitting a controlled current to counter the undesired current. Another method corrects for the effect of the current using a superposition technique.

Abstract: A method for obtaining quantitative characteristics of an area of investigation includes measuring characteristics of the area of investigation in a first dimension, coordinating the measured characteristics with an index of a second dimension, the coordinating enabling an identification of a trend of the measured characteristics, and extrapolating using the trend in the second dimension to obtain quantitative characteristics of the area of investigation. An apparatus configured for use in a drill hole environment includes a clock configured to receive data from the depth meter and a processor configured to correlate clock data and depth data to provide a time after bit measure associated with a plurality of measurements of the measurements taken by the tool whereby the measurements taken at different depths are useful as compared to measurements taken independent of the time after bit measurements.

Abstract: A method for detecting hydrocarbon-bearing zones in a formation penetrated by a wellbore includes acquiring at least two nuclear magnetic resonance measurements, each of the at least two nuclear magnetic resonance measurements acquired from a volume of investigation at a different radial depth from the wellbore; and determining whether the formation bears hydrocarbons by comparing the at least two nuclear magnetic resonance measurements. A method for detecting fines invasion in a formation surrounding a wellbore includes acquiring at least two nuclear magnetic resonance measurements, each of the at least two nuclear magnetic resonance measurements acquired from a volume of investigation at a different radial depth from the wellbore; and determining whether the fines invasion has occurred by comparing the at least two nuclear magnetic resonance measurements.

Abstract: In a method for a well logging data presentation, data sets are identified from well logging data. Each data set is assigned a unique identifier. A presentation template, which defines a presentation for the well logging data, is configured. The presentation for the logging data may be in the form of a display and/or a hard copy. The presentation template includes definitions of a number of component presentations. Each component presentation includes a corresponding component template. Each component template includes a pointer pointing to a source for one of the data sets and defines a structure for the component's presentation. A graphical presentation program generates the presentation, responsive to reading the presentation template, component templates and data sets. The presentation can be viewed and changed while data is still being acquired.

Abstract: An electromagnetic tomography system for determining properties of geological formation penetrated by at least one borehole lined with a conductive tubular includes a transmitter disposed in a first borehole and adapted to induce a magnetic field, a first receiver disposed in the first borehole and adapted to detect a magnetic field induced in the conductive tubular by the transmitter, and a second receiver adapted to detect a magnetic field induced in the geological formation by the transmitter.

Abstract: A method for tool path identification in formation evaluation includes obtaining measurements of formation properties in azimuthal sectors for each of a plurality of depth levels; calculating quality factors from the measurements; identifying a centroid or maximum of the quality factors among the measurements in each of the azimuthal sectors for each depth level; and associating the centroid or maximum of the quality factors at each depth level along a borehole to form the tool path. Calculating the quality factors may include parameterizing the measurements according to at least one factor selected from a spine factor, a rib factor, and a volumetric photoelectric factor. A method for determining corrected measurements for formation properties includes identifying a tool path from measurements taken in azimuthal sectors at each depth level along a borehole; and calculating a corrected measurement at the each depth level by averaging measurements in the azimuthal sectors adjacent the tool path.

Abstract: An apparatus and a method for controlling oilfield production to improve efficiency includes a remote sensing unit that is placed within a subsurface formation, an antenna structure for communicating with the remote sensing unit, a casing joint having nonconductive “windows” for allowing a internally located antenna to communicate with the remote sensing unit, and a system for obtaining subsurface formation data and for producing the formation data to a central location for subsequent analysis. The remote sensing unit is placed sufficiently far from the wellbore to reduce or eliminate effects that the wellbore might have on formation data samples taken by the remote sensing unit. The remote sensing unit is an active device with the capability of responding to control commands by determining certain subsurface formation characteristics such as pressure or temperature, and transmitting corresponding data values to a wellbore tool.

Abstract: Methods and apparatus for making subsurface measurements with reduced or eliminated borehole effects. Antenna and electrode configurations address the undesired axial electric currents that are induced along the borehole when antennas with tilted or transverse axes are used to make electromagnetic measurements. Current and measure electrodes are used in combination with antennas to limit the flow of undesired axial borehole currents. Embodiments use passive, active, or semi-active electrodes to limit the undesired current flow.

Abstract: The invention refers to antenna configurations for electromagnetic logging tools. The antennas have one or more electrical conductors disposed on a dielectric substrate wrapped around a core or disposed directly on the core. The conductor or conductors are arranged such that the antenna has a first magnetic dipole moment substantially perpendicular to a longitudinal axis of the core. The invention also refers to antennas adapted for mutual balancing using interleaved conductive paths or disks to alter the magnetic dipole moments to mutually balance the antenna system.

Abstract: A sample module is provided for use in a downhole tool to obtain fluid from a subsurface formation penetrated by a wellbore. The sample module includes a sample chamber carried by the module for collecting a sample of formation fluid obtained from the formation via the downhole tool, and a validation chamber carried by the module for collecting a substantially smaller sample of formation fluid than the sample chamber. The validation chamber is removable from the sample module at the surface without disturbing the sample chamber. A sample chamber is also provided that includes a subtantially cylindrical body capable of safely withstanding heating at the surface, following collection of a formation fluid sample via the downhole tool and withdrawal of the sample chamber from the wellbore, to temperatures necessary to promote recombination of the sample components wihtin the chambers. Additionally, the body is equipped so as to be certified for transportation.

Abstract: A load cell for sensing deformation in a drill collar is provided. The load cell comprises a disc member having one or more arcuate apertures and a deformation sensing element disposed on a side surface of the arcuate apertures. The load cell is capable of sensing such drilling parameters as weight and torque on a drill bit during the drilling operation.

Abstract: Methods and apparatus are disclosed for minimizing or eliminating an undesired axial electric current induced along a subsurface borehole in the process of subsurface measurements with transmitter and/or receiver antennas which are substantially time varying magnetic dipoles with their dipole moments aligned at an angle to the axis of the borehole. Some antennas are disposed within the borehole on instruments having a non-conductive support member. One instrument includes a conductive all-metal body with an antenna adapted for induction frequencies. Antenna shields adapted for controlled current flow are also provided with an all-metal instrument. Methods include providing an alternate path for the current along the instrument body. Another method includes emitting a controlled current to counter the undesired current. Another method corrects for the effect of the current using a superposition technique.

Abstract: A method for supplying a customer with well log data including obtaining wellsite properties from the customer, recommending at least one tool string and analysis software tool combination using the wellsite properties, processing well log data using customer domain information and the least one tool string and analysis software tool combination to obtain processed well log data, viewing the processed well log data using an interactive viewer, manipulating the customer domain information, and updating the processed well log data on the interactive viewer using the manipulated customer domain information.

Abstract: An improved cup packer for use on wellbore tools is disclosed. The open end of the cup packer bore is filled with an elastomer to prevent the intrusion of sand and debris into the space between the cup packer and the wellbore tool on which it is mounted. In an alternative embodiment of the invention, the packer body includes an angularly protruding section at at least one of its ends, wherein the longitudinal dimension of the packer body is at its maximum at its bore. In an additional alternative embodiment of the invention, the open end of the packer is sealed by a screen to prevent the intrusion of sand and debris into the space between the cup packer and the wellbore tool on which it is mounted.

Abstract: A downhole sampling tool and related method are provided. The tool is provided with a main flowline for communicating fluid from the formation through the tool. A main valve is positioned in the main flowline and defines a first portion and a second portion of the main flowline. At least one sample chamber with a slidable piston therein defining a sample cavity and a buffer cavity is also provided. The sample cavity is in selective fluid communication with the first portion of the main flowline via a first flowline and with the second portion of the main flowline via a second flowline. Fluid communication is selectively established between the sample cavity and the first and/or second portions of the main flowline for selectively flushing fluid through the sample cavity and/or collecting samples of the fluid therein. Fluid may also be discharged from the buffer cavity via a third flowline.

Abstract: In a well an instrumentation line can be introduced down the well bore by a control line having at least a portion outside of intermediate casing and set in cement slurry between the intermediate casing and the surrounding rock and reaching to a zone of interest. A primary member accepts the distal end of the control line at the end of the intermediate casing. A secondary member has a terminal control line (sealed at its far end) attached on its outer surface. When in place, the secondary member extends into and through the zone of interest. When the secondary member is lowered through the primary member, its top end is lowered onto the bottom end of the primary member. Couplings engage and angularly orientate so that the top of the terminal control line couples to and seals with the distal end of the control line to form a conduit through which a fibre optic instrumentation line can be threaded.

Abstract: A gravity sensor is disclosed which includes a first mass adapted to free fall when selectively released from an initial position. The mass has optical elements adapted to change a length of an optical path in response to movement of the mass. The sensor output is coupled to a beam splitter. One output of the splitter is coupled substantially optically directly to an interferometer. Another output of the splitter is coupled to the interferometer through an optical delay line. A frequency of the interference pattern is directly related to gravity at the mass. A second such mass having similar optics, optically coupled in series to the first mass and adapted to change the path length in opposed sign, when selectively dropped to cause time coincident movement of the two masses, generates an interference pattern having frequency related to gravity difference.