- Branża: Oil & gas
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The act of forcing a device called a pig through a pipeline for the purposes of displacing or separating fluids, and cleaning or inspecting the line.
Industry:Oil & gas
The act of determining values for grid elements on a map. The grid element values are chosen from nearby data points. Methods are deterministic and use linear and nonlinear interpolation methods, or may be statistical and use geostatistical approaches such as kriging. Gridding is usually applied to one characteristic per map, such as structure, thickness, porosity, permeability or saturation.
Industry:Oil & gas
The act of adjusting a model of a reservoir until it closely reproduces the past behavior of a reservoir. The historical production and pressures are matched as closely as possible. The accuracy of the history matching depends on the quality of the reservoir model and the quality and quantity of pressure and production data. Once a model has been history matched, it can be used to simulate future reservoir behavior with a higher degree of confidence, particularly if the adjustments are constrained by known geological properties in the reservoir.
Industry:Oil & gas
The accumulation or buildup of material, such as sand, fill or scale, within a wellbore, to the extent that the flow of fluids or passage of tools or downhole equipment is severely obstructed. In extreme cases, the wellbore can become completely plugged or bridged-off, requiring some remedial action before normal circulation or production can be resumed.
Industry:Oil & gas
The abnormal behavior in a buildup curve caused by phase redistribution in a wellbore. This behavior is most noticeable in oil wells producing a substantial amount of gas and having a substantial skin effect. Analysis of buildup curves for wells exhibiting this behavior can be difficult or impossible because the "hump" obscures the reservoir response.
Industry:Oil & gas
The accumulation of smaller tracts of land, the sum total acreage of which are required for a governmental agency to grant a well permit or assign a production quota or allowable to an operator.
Industry:Oil & gas
The ability, or measurement of a rock's ability, to transmit fluids, typically measured in darcies or millidarcies. The term was basically defined by Henry Darcy, who showed that the common mathematics of heat transfer could be modified to adequately describe fluid flow in porous media. Formations that transmit fluids readily, such as sandstones, are described as permeable and tend to have many large, well-connected pores. Impermeable formations, such as shales and siltstones, tend to be finer grained or of a mixed grain size, with smaller, fewer, or less interconnected pores. Absolute permeability is the measurement of the permeability conducted when a single fluid, or phase, is present in the rock. Effective permeability is the ability to preferentially flow or transmit a particular fluid through a rock when other immiscible fluids are present in the reservoir (for example, effective permeability of gas in a gas-water reservoir). The relative saturations of the fluids as well as the nature of the reservoir affect the effective permeability. Relative permeability is the ratio of effective permeability of a particular fluid at a particular saturation to absolute permeability of that fluid at total saturation. If a single fluid is present in a rock, its relative permeability is 1. 0. Calculation of relative permeability allows for comparison of the different abilities of fluids to flow in the presence of each other, since the presence of more than one fluid generally inhibits flow.
Industry:Oil & gas
The ability of the formation to resist electrical conduction, as derived from the change in position of the peaks of an electromagnetic wave generated in a propagation resistivity measurement. At the frequencies used, the phase shift depends mainly on the resistivity of the material with a small dependence on dielectric permittivity, particularly at high resistivity. Common practice is to transform the phase shift to resistivity assuming that the dielectric permittivity is related to resistivity by a simple algorithm. The transform also depends on transmitter/receiver spacings and tool design. For a 2-MHz measurement, a typical measurement range is 0. 2 to 200 ohm-m. Above 200 ohm-m, the dielectric effects become too variable and it is preferable to use the dielectric resistivity.
Industry:Oil & gas
The ability of fluid to move through a rock, as measured by the reduction in amplitude or increase in slowness of the acoustic Stoneley wave generated in the borehole. The velocity and amplitude of the Stoneley wave are reduced by the presence of mobile fluids in the formation. Physically, the effect can be seen as a coupling of the Stoneley energy into a formation wave known as the slow wave, as predicted by the Biot theory. The amount of reduction is a complicated function of this mobility (or permeability divided by viscosity), the properties of the borehole fluid, the pore fluid and the mudcake, the elastic properties of the rock and the frequency. Since all these factors are measured or estimated from logs, it is possible to determine formation mobility. In practice, the mobility needs to be reasonably high for the method to be accurate.
Industry:Oil & gas
