Abstract: The total porosity of said formation, a fractional volume of the shale, and a resistivity of the shale are determined in a laminated reservoir including sands that may have dispersed shales therein. A tensor petrophysical model determines the laminar shale volume and laminar sand conductivity from vertical and horizontal conductivities derived from multi-component induction log data. The volume of dispersed shale and the total and effective porosities of the laminar sand fraction are determined using a Thomas-Stieber-Juhasz approach. Removal of laminar shale conductivity and porosity effects reduces the laminated shaly sand problem to a single dispersed shaly sand model to which the Waxman-Smits equation can be applied.

Abstract: A logging-while-drilling density sensor includes a gamma ray source and at least two NaI detectors spaced apart from the source for determining measurements indicative of the formation density. A magnetometer on the drill collar measures the relative azimuth of the NaI detectors. An acoustic caliper is used for making standoff measurements of the NaI detectors. Measurements made by the detectors are partitioned into spatial bins defined by standoff and azimuth. Within each azimuthal sector, the density measurements are compensated for standoff to provide a single density measurement for the sector. The azimuthal sectors are combined in such a way as to provide a compensated azimuthal geosteering density. The method of the invention may also be used with neutron porosity logging devices.

Abstract: High Definition Induction Logging (HDIL) tools can provide reliable information about the vertical and radial variations of resistivity structure in isotropic media. The focusing technique provides quantitative information about the resistivity variation and qualitative information about invasion at the well site. This type of logging tool utilizes transmitter-receiver arrays coaxial with the borehole and thus cannot provide information about anisotropy in vertical wells. This greatly limits the application of array induction tools in the characterization of reservoirs with finely laminated sand/shale sequences. A multi-component induction tool, 3DEX™, has been developed by Baker Atlas and Royal Dutch Shell. It provides the much needed ability to detect anisotropy for sand-shale laminated reservoirs. Data from such a logging tool are inverted to give an estimate of vertical and horizontal resistivity in a vertical borehole.

Abstract: A fuel composition of improved lubricity comprises a lubricity-increasing amount of a lubricity aid dissolved in low sulfur diesel fuel and spark ignition fuels. The lubricity aid is an alkanolamide of a fatty acid, an alkanolamide of a modified fatty acid or a mixture thereof. If the lubricity aid is other than an alkanolamide of an aryl-substituted fatty acid, the composition further necessarily comprises a haze-inhibiting amount of a dehazer. The lubricity of such fuels may be enhanced without acceptably increasing the tendency of the fuel to become hazy upon contact with water.

Abstract: A cooling system in which an electronic or other component is cooled by using one or more solid sources of liquid vapor (such as hydrates or desiccants that desorb water at comparatively low temperature) in conjunction with one or more high-temperature vapor sorbents or desiccants that effectively transfer heat from the component to the fluid in the wellbore. Solid sources of water are more convenient to use than a container of liquid water (which is prone to spillage or leakage when tipped) and they can contain large amounts of water. For example, the hydrate Disodium Hydrogen Phosphate Dodecahydrate (DHPD) contains over 90% water by volume. The latent heats associated with phase changes and dehydration of a hydrate can provide substantial cooling capacity per unit volume of hydrate, which is particularly important in those applications where space is limited.

Abstract: The present invention provides a semi-passive two-way borehole communication system and method. The system includes a surface source signal generator for generating an acoustic signal. The acoustic source signal is transmitted downhole, and a downhole controllable reflector reflects a portion of the source signal back toward the surface. The reflector is controlled such that an echo signal is created, which contains information to be carried to the surface. A surface receiver is used to detect the echo signal, and a surface controller is used to decode the echo signal.

Abstract: The excitation and/or refocusing pulses used in a CPMG sequence have a nonlinear phase and an envelope with no zero crossings and a corresponding frequency spectrum with sidelobes suppressed. As a result of this, peak power requirements are reduced. Pulse shaping is used for reducing the peak power requirements of a NMR logging tool.

Abstract: A method and apparatus for maintaining the single phase integrity of a deep well formation sample that is removed to the surface comprises a vacuum jacket insulated single working cylinder divided by two free pistons into three variable volume chambers. The intermediate chamber is pre-charged with a fixed quantity of high pressure gas. Wellbore fluid freely admitted to one end chamber bears against one free piston to further compress the gas. The formation sample is pumped into the other end chamber to first, displace the wellbore fluid from the first end chamber and, sequentially, to further compress the gas to preserve the sample phase state upon removal to the surface.

Abstract: A fast, efficient and accurate pseudo 2-D inversion scheme for resistivity determination of an anisotropic formation uses data from a tool (3DEX) comprising three transmitters and three corresponding receivers sampling the formation in a plurality of spatial directions. An initial model of the formation including invasion zones is obtained using a conventional multifrequency and/or multispacing logging tool. A pseudo 2-D inversion scheme combines an accurate full 2-D forward solution of the synthetic responses of the earth model with a 1-D approximation of the sensitivity matrix of the horizontally layered anisotropic background model. The timesaving compared to a regular 2-D inversion scheme can be tremendous. The applicability of this scheme is important in cases when borehole and near-zone effects do not allow an interpretation based on 1-D inversion.

Abstract: Data are acquired using multi-array logging tool in a borehole having an angle of inclination to a normal to the bedding plane of earth formations. The multi-array measurements are filtered using angle dependent filters to give a filtered curve corresponding to a target one of the multi-array measurements using angle dependent filters. Correlation coefficients are determined for a set of possible dip angles and a relative dip angle is estimated from the correlation coefficients. This dip angle estimate together with bed boundaries obtained from the multi-array measurements are used for inverting multi-component measurements alone or jointly with multi-array measurements to refine the relative dip angle interpretation and give horizontal and vertical formation resistivity.

Abstract: An improved screen basket for use with a centrifuge includes two adjoining screen sections. The first screen section is formed from a wear resistant material and is located proximate to the point at which slurry is introduced into the basket. The length of the first screen section is chosen so that the majority of potential wear caused by the abrasive slurry occurs within the first section of the basket. The second screen section is preferably formed from less expensive materials, such as steel wedge wire. The second screen section smoothly joins the first screen section and provides for further dewatering or separation of the accelerated slurry so that a dry cake is produced by the centrifuge.

Abstract: Shoulder corrections are applied to measurements obtained from a multi-component electromagnetic logging tool. An anisotropic resistivity model is obtained using the shoulder corrected data. The process is iterated until a good match is obtained between the shoulder corrected data and the model output.

Abstract: A communication protocol based upon the Asymmetric Digital Subscriber Line (ADSL) protocol developed for telephone communications is used for two way transmission of data between a downhole logging device and a surface device. The total available bandwidth for a pair of conductors is determined by the length of the conductors and the choice of conductors (operational mode) of a conventional 7 conductor wireline. The available bandwidth is partitioned into channels with a bandwidth of 4.3125 kHz, each of the channels carrying a portion of the data. A contiguous subset of the channels is used for downward communication and another subset is used for upward communication. The bit loading is dynamically determined based upon monitoring of the noise level. Optionally, more than one mode of the 7 conductor wireline may be used.

Abstract: Measurements from many logging instruments such as Gamma ray counts from a pulsed neutron instrument, and amplitudes of spin-echo signals from a NMR instrument, typically have a spectrum that contains a plurality of exponentially decaying components. The slowest decaying component is obtained by fitting a single exponential over the tail end of the data and selecting a beginning for the fitting window that minimizes the product of the chi-square and the standard error of the fit. The single determined component may be subtracted from the data and the process repeated to give additional components. The determined components are indicative of thermal neutron capture cross-sections (in the case of a pulsed neutron instrument) and of the distribution of relaxation times and fluids within the pores of a rock in the case of a NMR instrument.

Abstract: Measurements from many logging instruments such as Gamma ray counts from a pulsed neutron instrument, typically have a spectrum that contains a plurality of exponentially decaying components. The slowest decaying component is obtained by fitting a single exponential over the tail end of the data and selecting a beginning for the fitting window that minimizes the product of the chi-square and the standard error of the fit. The single determined component may be subtracted from the data and the process repeated to give additional components. The determined components are indicative of thermal neutron capture cross-sections.

Abstract: An NMR apparatus includes permanent magnets oppositely polarized in the axial direction and suitably arranged along the axis of the apparatus to produce a nearly radial static magnetic field in a toroidal examination region within the rock formation surrounding the wellbore. A first coil is wound around a cylindrical annulus core coaxial with the magnets, the core including high magnetic permeability material. The first coil produces pulsed RF magnetic fields oriented parallel to the axis of the apparatus and thus perpendicular to the static magnetic field in the toroidal examination region. This reorients certain nuclear spins and the bulk magnetization of the formation within the examination region resulting from them. The first coil picks up on component of the spin-echo signals of the precessing nucleii.

Abstract: Determination of the rate of penetration (ROP) of drilling has usually been based upon surface measurements and may not be an accurate representation of the actual ROP. This can cause problems in Logging While Drilling (LWD). Because of the lack of a high-speed surface-to-downhole communication while drilling, a conventional method of measuring ROP at the surface does not provide a solution to this problem. However, the instantaneous ROP can be derived downhole with a certain degree of accuracy by utilizing an accelerometer placed in (or near) the tool to measure acceleration in the axial direction. When three-component accelerometers are used, the method may be used to determine the true vertical depth of the borehole.

Abstract: The present invention provides an apparatus and method for minimizing movement of a drill string during MWD with vibration-sensitive instruments comprising conveying a drill string into a borehole with a sensor mounted on the drill string for sensing a parameter of interest of a formation. A clocked controller is disposed on the drill string for controlling timing of the sensor; and a second clocked controller is disposed at a surface location. During drilling operations, the clocked controllers are synchronized such that the surface controller is performing certain tasks in timed sequence with the sensor even though the surface controller is not connected to the sensor.

Abstract: A minimum volume apparatus and method is provided including a tool for obtaining at least one parameter of interest of a subterranean formation in-situ, the tool comprising a carrier member, a selectively extendable member mounted on the carrier for isolating a portion of annulus, a port exposable to formation fluid in the isolated annulus space, a piston integrally disposed within the extendable member for urging the fluid into the port, and a sensor operatively associated with the port for detecting at least one parameter of interest of the fluid.

Abstract: Measurements are made with a multicomponent induction logging tool in earth formations in a borehole inclined to earth formations. A combination of principal component measurements is used to determine the horizontal resistivity of the earth formations. The determined horizontal resistivities are used in a model for inversion of other components of the data to obtain the vertical formations resistivities. When multifrequency measurements are available, frequency focusing is used.