- Отрасли: Oil & gas
- Number of terms: 8814
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A device for measuring the diameter of the internal wall of a casing or tubing using multiple arms. By using a large number of arms, or fingers, the caliper can detect small changes in the wall of the pipe. The main purpose of the measurement is to detect deformations, the buildup of scale or metal loss due to corrosion. Typical multifinger calipers have between about 20 and 80 fingers, the larger numbers being necessary in larger pipes.
Industry:Oil & gas
A device for measuring the density of fluids in a completed well, using a radioactive source of gamma rays and a detector. In most instruments, a <sup>137</sup>Cs (cesium) or <sup>241</sup>Am (americium) source is used to induce Compton scattering, as in the openhole density measurement, except that the device is unfocused. The count rate at the detector then depends primarily on the density of the fluids in the well. In some devices, the fluids pass through an open space in the body of the tool within which the measurement is made. The results then reflect the density of the fluids passing through the tool. In other devices, the source and detector are isolated so that the gamma rays pass outside the tool. The results then reflect some average density of all the fluids within the well. In smaller casings, some formation signal may contaminate the measurement. <br><br>Compared with a gradiomanometer, the nuclear fluid densimeter is a less direct measurement of density, and has a statistical uncertainty and less resolution. On the other hand, it is not affected by well deviation, friction or kinetic effects.
Industry:Oil & gas
A device for measuring the average density of the fluid at different depths in a completed production or injection well to produce a fluid-density log. Knowing the density of the individual phases allows their holdups to be determined, directly in the case of biphasic flow, and in combination with other measurements for triphasic flow. Introduced in the late 1950s, the gradiomanometer measures the pressure difference between two pressure sensors, placed approximately 2 ft (0. 6 m) apart. The pressure difference reflects the average fluid density across the well within that depth interval. <br><br>The resolution is high, around 0. 005 g/cm<sup>3</sup>, but the accuracy can be affected by a friction effect, a kinetic effect and well deviation. The effect of deviation can be corrected, but the sensitivity to holdup is reduced as the deviation increases until it is zero in a horizontal well. <br><br>Note: Gradiomanometer is a mark of Schlumberger. It is now a commonly accepted term for a certain tool that measures differential pressure.
Industry:Oil & gas
A device for measuring in-situ the velocity of fluid flow in a production or injection well in which the total fluid flow is diverted to pass over an impeller, or spinner. Various techniques have been used to achieve this, one of the earliest being the packer flowmeter. In a typical modern device, the diverter consists of a fabric in a metal cage that is collapsed to pass through the tubing and other restrictions. Below the tubing, the cage is opened until an inflatable ring seals against the casing wall. At this point, the up-going production fluids are forced through the diverter and over an impeller. This ensures that the total casing flow is measured, but may also create an extra pressure drop and hence a change in multiphase flow structure. <br>The diverter flowmeter is particularly suitable for low flow rates in vertical or moderately deviated wells. Readings are made with the tool stationary.
Industry:Oil & gas
A device for measuring in situ the velocity of fluid flow in a production or injection well in which the flow is diverted through the spinner by a set of metal vanes, or petals. The vanes are closed while running in the hole, and then opened with the tool stationary at the measurement depth. The petals do not seal completely against each other or against the side of the hole, so that not all the fluid is diverted. A type of diverter flowmeter, the petal basket design has generally been replaced since the late 1980s by the inflatable diverter and other designs.
Industry:Oil & gas
A device for measuring in situ the velocity of fluid flow in a production or injection well in which a packer is inflated between the tool housing and the casing wall, causing the total fluid flow to pass inside the tool and over a spinner. The measurement is made with the tool stationary, after borehole fluids have been pumped to inflate the packer. The packer flowmeter was introduced in the mid-1950s. It is a type of diverter flowmeter, but has generally been replaced by petal basket and inflatable diverter flowmeters.
Industry:Oil & gas
A device for measuring in situ the velocity of fluid flow in a production or injection well based on the torque, or force, produced by the fluid on a stationary impeller. This torque can be related to the effective velocity of flow across the impeller. The torque flowmeter is sometimes used as an alternative to the spinner flowmeter.
Industry:Oil & gas
A device for measuring in situ the velocity of fluid flow in a production or injection well by measuring the transit time of a disturbance between two dielectric sensors a fixed distance apart. The device is a type of crosscorrelation flowmeter that uses several pairs of capacitance, or dielectric, sensors held on an arm to span the borehole.
Industry:Oil & gas
A device for measuring in situ the velocity of fluid flow in a production or injection well based on the speed of rotation of an impeller, or spinner. The spinner can be helical, that is, longer than it is wide, or like a vane, which is similar to a fan blade. In both cases, the speed of rotation is measured and related to the effective velocity of the fluid. Friction and fluid viscosity cause the relationship to be slightly nonlinear at low effective velocities and introduce a threshold velocity below which the spinner does not turn. Results are interpreted using the multipass, two-pass or single-pass methods. <br><br>There are several types of spinner flowmeter. The most common device uses a small vane-like spinner, about 1. 5 in. (3. 8 cm) in diameter, allowing the logging tool to pass through the tubing and other restrictions before reaching the reservoir interval. The small spinner captures only part of the fluid flow in the casing, too little to make it turn in some low flow-rate wells and possibly unrepresentative in multiphase flow settings. Other devices have been designed to capture more of the flow, for example the fullbore spinner and various types of flow-concentrating or diverter spinners, such as the packer flowmeter and the basket flowmeter.
Industry:Oil & gas
A device for measuring fluid velocity in a production well. The device measures the transit time of a disturbance between two sensors separated by a fixed distance. The technology applies to multiphase flow, in which the disturbance is caused, for example, by the passage of a bubble of gas over each sensor. In practice, there will be many bubbles of gas, so it is necessary to record both sensor signals over a time window and compare, or correlate, them. The two signals will correlate best after shifting one of them by a time corresponding to the average transit time of the bubbles. Different sensors may be used, for example a measure of electrical capacitance as in a holdup meter. <br>The crosscorrelation flowmeter gives the velocity of the disturbance. Since this is caused by just one of the phases, it produces a type of phase velocity log.
Industry:Oil & gas
