- Branża: Oil & gas
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The ability of a material to resist electrical conduction. It is the inverse of conductivity and is measured in ohm-m. The resistivity is a property of the material, whereas the resistance also depends on the volume measured. The two are related by a system constant, which in simple cases is the length between the measurement electrodes divided by the area. In the general case, the resistivity is the electric field divided by the current density and depends on the frequency of the applied signal.
Industry:Oil & gas
The ability of a material to conduct electricity. It is the inverse of resistivity and is measured in siemens per meter (S/m) or mho/m. The conductivity is a property of the material, whereas the conductance also depends on the volume measured. The two are related by a system constant, which in simple cases is the length between the measurement electrodes divided by the area. In the most general case, the conductivity is the current density divided by the electric field and depends on the frequency of the applied signal.
Industry:Oil & gas
The ability of a formation to resist electrical conduction, as derived from the reduction in amplitude of the electromagnetic wave generated in a propagation resistivity measurement. At the frequencies used and within the range of measurement, the attenuation depends almost solely on the resistivity, so that the former can be transformed to the latter with 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 50 ohm-m. Above 50 ohm-m, the dependence of attenuation on resistivity is too small to measure accurately.
Industry:Oil & gas
That portion of a dual-porosity reservoir鈥檚 permeability that is associated with the secondary porosity created by open, natural fractures. In many of these reservoirs, fracture permeability can be the major controlling factor of the flow of fluids. <br>
Industry:Oil & gas
That part of the pore space that has a characteristic dimension less than 1 micron. In general, this includes not only very small pores but also the porosity associated with surface roughness. The water in this pore space is part of the capillary-bound water and the small-pore water. Water in micropores is not expected to flow on production. The term is also defined as porosity that cannot be seen at magnifications less than 50x.
Industry:Oil & gas
That period when drilling debris and fluids are still coming out of the formation and perforations. During this time, the skin effect is changing and any well-test results may reflect temporary obstruction to flow that will not be present in later tests.
Industry:Oil & gas
That part of the effect of gas on the neutron porosity measurement that is not explained by differences in hydrogen index. By using the concept of hydrogen index, the only significant contributor to the neutron porosity in a gas zone is the liquid-filled porosity, since the hydrogen indices of gas and matrix are close to zero. However, the resultant liquid-filled porosity is found to be too low. The error comes from treating the gas-filled porosity as matrix. If this matrix is excavated and replaced with gas, the correct response can be predicted.
Industry:Oil & gas
Tests conducted at a series of different flow rates for the purpose of determining well deliverability, typically in gas wells where non-Darcy flow near the well results in a rate-dependent skin effect. Multiple-rate tests are sometimes required by regulatory bodies.
Industry:Oil & gas
Tests in an oil or gas well to determine its flow capacity at specific conditions of reservoir and flowing pressures. The absolute open flow potential (AOFP) can be obtained from these tests, and then the inflow performance relationship (IPR) can be generated. A deliverability test also is called a productivity test.
Industry:Oil & gas
Testing that is accomplished by measuring pressure in the annulus, or by pulling the pump and running a pressure gauge in the hole. The preferred method is usually to measure the pressure in the annulus if no packer is present. This is best done by monitoring the rise in fluid level with an echo-sounding device and calculating the bottomhole pressure by assuming a fluid density. Several excellent devices and associated services are available. Any time a well is shut in gradually, as is the case for pumping wells, some kind of multirate analysis is usually required to obtain acceptable results.
Industry:Oil & gas
