- Industry: Oil & gas
- Number of terms: 8814
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Relating to two or more logging measurements that have the same resolution. The term normally refers to vertical resolution, but could also be used for azimuthal or radial resolution.
Industry:Oil & gas
Relating to being held against, or taken from, the side of the borehole. The term also describes a measurement that must be made by pressing the sonde against the side of the borehole in order to minimize borehole effects, as, for example, a sidewall epithermal neutron log.
Industry:Oil & gas
Relating to a formation or interval containing gas, either dissolved in the formation fluid or as free gas. The term is occasionally used to describe wellbore fluids containing dissolved gas.
Industry:Oil & gas
Related to any aspect of logging that employs an electrical cable to lower tools into the borehole and to transmit data. Wireline logging is distinct from measurements-while-drilling (MWD) and mud logging.
Industry:Oil & gas
Related to a wireline log of formation resistivity based on the principle of inducing alternating current loops in the formation and measuring the resultant signal in a receiver. In the simplest device, an alternating current of medium frequency (10?s of kHz) is passed through a transmitter coil, thereby inducing an alternating magnetic field in the formation. This field creates current loops in the formation. The loops produce their own magnetic field, which induce a current when they cross the receiver coil. This signal is proportional to the conductivity of the formation, with contributions from different regions of the formation summing approximately in conductivity. As a result, the induction log is most accurate at high conductivities and with resistive invasion. However, below about 1 ohm-m skin effect becomes important. <br><br>Practical induction-logging tools use arrays of several coils, designed to achieve a specific focusing and depth of investigation. These arrays are either hardwired, such as the 6FF40, 5FF40 and others, or consist of several simple arrays that are combined in software (an array induction). For many years, the most common induction log was the 6FF40. This was often combined with the medium induction and a shallow laterolog or microresistivity log so as to correct for the effect of invasion, assuming a step profile. Induction logs also need borehole correction and shoulder-bed correction. In older tools, this was accomplished through multiple correction charts, while modern tools include software for this purpose. <br><br>H. G. Doll introduced the first practical induction-logging technique in 1949. See Doll HG: Introduction to Induction logging and Application to Logging of Wells Drilled with Oil Base Mud Journal of Petroleum Technology 1, no. 6 (June 1949): 148-162.
Industry:Oil & gas
Referring to the volume of liquid measured in the filtration tests performed according to API specifications, in units of cm<sup>3</sup>/30 minutes. Although applied to water mud, in which the liquid is truly water, the term is sometimes applied to oil mud, in which the liquid is oil.
Industry:Oil & gas
Referring to the varying degrees of inability to move or remove the drillstring from the wellbore. At one extreme, it might be possible to rotate the pipe or lower it back into the wellbore, or it might refer to an inability to move the drillstring vertically in the well, though rotation might be possible. At the other extreme, it reflects the inability to move the drillstring in any manner. Usually, even if the stuck condition starts with the possibility of limited pipe rotation or vertical movement, it will degrade to the inability to move the pipe at all.
Industry:Oil & gas
Referring to the flow of two immiscible fluids, oil and water, oil and gas, or gas and water.
Industry:Oil & gas
Referring to the description of different regimes for the simultaneous flow of gas and liquid in vertical pipes introduced by Y. Taitel and A. Dukler in 1980. The results are shown in the form a crossplot or map with the superficial gas velocity, v<sub>gs</sub>, on the x-axis and the superficial liquid velocity, v<sub>ls</sub>, on the y-axis. Different maps are constructed for different pipe sizes and fluid properties. The Taitel-Dukler map defines the transition between different flow regimes more closely than other models. Taitel and Dukler also described flow transitions in horizontal pipes. <br><br>Reference:<br>Taitel Y, Barnea D and Dukler AE: 鈥淢odelling Flow Pattern Transitions for Steady Upward Gas-Liquid Flow in Vertical Tubes,鈥?AIChE Journal 26, no. 6 (May 1980): 345-354.
Industry:Oil & gas
Referring to the condition that occurs when the kelly is all the way down, so drilling progress cannot continue. A connection must be made, which has the effect of raising the kelly up by the length of the new joint of drillpipe added, so drilling can resume.
Industry:Oil & gas
