- Settore: Oil & gas
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The change in direction of rotation that occurs when a spinner flowmeter tool is moving in the same direction, but faster, than the fluid. When the tool is stationary, moving against the fluid flow, or moving in the same direction but slower than the flow, it will rotate in one direction, perhaps clockwise. However, if it moves in the same direction, but faster than the fluid, it will rotate counterclockwise. This may happen at the bottom of a producing well, and, unless identified, can lead to a false interpretation.
Industry:Oil & gas
The change in a pulsed neutron capture measurement produced by acidizing a carbonate formation. Acidizing tends to increase the porosity as well as leave chlorides in the formation, thereby increasing the capture cross section. Both of these results affect the formation thermal decay time and must be taken into account in the interpretation.
Industry:Oil & gas
The cement slurry remaining in the wellbore following a cement squeeze in which the objective is to squeeze slurry into the perforations and behind the casing or liner. The volume of slurry required to effect a successful squeeze is often difficult to estimate. In most cases, an excess allowance is made since a shortage of slurry would result in failure of the operation. Removal of the excess cement slurry before it sets has been a key objective in the development of modern cement-squeeze techniques.
Industry:Oil & gas
The careful application of pump pressure to force a treatment fluid or slurry into a planned treatment zone. In most cases, a squeeze treatment will be performed at downhole injection pressure below that of the formation fracture pressure. In high-pressure squeeze operations, performed above the formation fracture pressure, the response of the formation and the injection of treatment fluid may be difficult to predict.
Industry:Oil & gas
The calculated flow area provided by perforations across a specific zone of interest. The resulting value is used to calculate pressure drops and fluid-flow performance.
Industry:Oil & gas
The barrel of the sucker rod pump. The plunger travels up and down in the cylinder. The plunger and the barrel operate as a piston mechanism to lift reservoir fluids into the subsurface pump. A cylinder is also known as a pump barrel.
Industry:Oil & gas
The axis along which the data in n-dimensional space is primarily distributed. In two dimensions, the first principal axis is the semimajor axis of the ellipse that best fits the data set. Multiple principal axes are always orthogonal. Data are sometimes rearranged to be in principal component space before further analysis (such as cluster analysis) is performed. Analysis on data that have been transformed into principal component space is referred to as principal component analysis, or PCA.
Industry:Oil & gas
The average value of a set of measurements, calculated by taking the logarithms of the measurements, finding the arithmetic average of the logarithms and then taking the antilogarithm of the average.
Industry:Oil & gas
The average reading of the spontaneous potential (SP) log opposite the shale layers in a well. Opposite shales, the SP is relatively constant and changes only slowly with depth. This is the shale baseline. The log is normally adjusted by the logging engineer to read near zero at the baseline. Sharp shifts in the baseline can sometimes be observed, for example when two permeable beds with different formation water salinities are separated by a shale that is not a perfect cationic membrane, or when the formation water salinity changes within a permeable bed.
Industry:Oil & gas
The assignment of values to points intermediate to two data points. Linear interpolation plots values along a straight line between the values of the two nearest data points. Other interpolation techniques involve other functions. Interpolation is used to fill in missing data in well logs and other data sets. It may also be used to assign values to grid elements in maps.
Industry:Oil & gas
