- Industry: Oil & gas
- Number of terms: 8814
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A technique for measuring a signal that is broadcast from a transmitter or source located in one well, to a receiver array placed in a neighboring well. This technique is used to create a display of formation properties such as acoustic velocity and attenuation, seismic reflectivity, or electromagnetic resistivity in the area between wells. The reservoir-scale data acquired with this technique can be used to bridge the gap between wellbore measurements and surface measurements.
Industry:Oil & gas
A technique for interpreting the results from a spinner flowmeter using two logging runs over the zone of interest, one up and one down. If the two passes are run at the same cable speed, they will overlay below the perforations, where there is no flow. If they were not run at the same speed, the curves are shifted to overlay. Elsewhere, the separation between the curves gives the relative contribution of each zone. Viscosity changes should have a small effect, since they will have the same influence on both passes. <br><br>The technique is applicable when the flow is single-phase, or else multiphase with a sufficiently homogeneous-flow regime, such as with emulsion or dispersed bubble flow.
Industry:Oil & gas
A technique for interpreting the results from a spinner flowmeter using several logging runs of the flowmeter over the zone of interest at different speeds, both up and down. Spinner speed is a nearly linear function of the effective velocity of the fluid. Although this function can be measured on surface, it varies with the fluid and is most reliably determined in situ. After several passes are made, the function can be calibrated and the spinner speed converted into flow rate. <br><br>The technique is applicable when the flow is single phase, or else multiphase with a sufficiently homogeneous flow regime such as with emulsion or dispersed bubble flow.
Industry:Oil & gas
A technique for interpreting the results from a spinner flowmeter using only one logging run over the zone of interest. Spinner speed is related to fluid velocity using laboratory-determined values for threshold velocity and spinner response. The single-pass method is generally considered inferior to the in-situ multipass or two-pass method. However, in highly deviated and horizontal wells, where the logging tools must be deployed using coiled tubing or a tractor, the cost of an additional pass is high. Single-pass interpretation, with improved spinner characterization, has therefore become more common in recent years.
Industry:Oil & gas
A technique for improving the accuracy of injection profiles measured using the velocity-shot method. In the normal velocity-shot method, the flow velocity is determined by the time of flight of a radioactive slug between two detectors or between ejector and detector. Since the distance involved may be several feet, the vertical resolution is low. The interval method consists of making overlapping measurements from which a higher resolution injection profile may be determined.
Industry:Oil & gas
A technique for imaging a core by scanning it with a highly focused source of X-rays and recording the attenuated X-rays on the other side. The source and detector are rotated and moved along the core. The measurements are combined mathematically to give a full core image.
Industry:Oil & gas
A technique for imaging a core by moving a core between a source of X-rays and a fluorescent screen. The image on the screen is intensified and recorded by a video camera.
Industry:Oil & gas
A technique for imaging a core by moving a source of X-rays along a core and recording the attenuated X-rays on the other side on a suitable photographic film.
Industry:Oil & gas
A technique for focusing an electrode device based on maintaining a spherical equipotential surface centered at the main current electrode. Unlike the laterolog, which tries to maintain equipotential lines parallel to the sonde, spherical focusing tries to maintain the spherical equipotential lines that would exist in a homogeneous formation with no borehole. This is achieved with a particular arrangement of current-emitting electrode, current-return electrodes and monitor electrodes. This arrangement creates two spherical equipotential spheres with a constant voltage drop between them. The resistivity is determined from the current flowing between the spheres and the voltage drop. The depth of investigation is determined by the radii of the two spheres. Spherical focusing is used to produce shallow-reading resistivity logs and the pad-based microspherical log.
Industry:Oil & gas
A technique for estimating the cation-exchange capacity of a sample by measuring the conductivity of the sample during titration. The technique includes crushing a core sample and mixing it for some time in a solution like barium acetate, during which all the cation-exchange sites are replaced by barium (Ba<sup>++</sup>) ions. The solution is then titrated with another solution, such as MgSO<sub>4</sub>, while observing the change in conductivity as the magnesium (Mg<sup>++</sup>) ions replace the Ba<sup>++</sup> ions. For several reasons, but mainly because the sample must be crushed, the measured cation-exchange capacity may differ from that which affects the in situ electrical properties of the rock.
Industry:Oil & gas
