- Industry: Oil & gas
- Number of terms: 8814
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A method for the measurement of fluid saturations in a core sample by distillation extraction. The water in the sample is vaporized by boiling solvent, then condensed and collected in a calibrated trap. This gives the volume of water in the sample. The solvent is also condensed, then flows back over the sample and extracts the oil. Extraction continues for a minimum of two days until the extracted solvent is clean or the sample shows no more fluorescence. The weight of the sample is measured before and after extraction. Then the volume of oil is calculated from the loss in weight of the sample minus the weight of the water removed from it. Saturations are calculated from the volumes.
Industry:Oil & gas
A method for rotating axes of a plot such that the eigenvectors remain orthogonal as they are rotated. These rotations are used in principal component analysis so that the axes are rotated to a position in which the sum of the variances of the loadings is the maximum possible.
Industry:Oil & gas
A method for quantifying well and reservoir parameters such as permeability, skin, fracture half-length, dual-porosity parameters, and others, by comparing the pressure change and its derivative of the acquired data to reservoir model curve families, called type curves. When a match is found between data and a type curve, the parameters that characterize the behavior of the model providing a match are thereby determined. <br><br>Originally, type-curve analysis was done manually using only the pressure change. With the introduction of the pressure derivative, the analysis requires matching both pressure change and its derivative. Computer-assisted matching permits rigorous accounting for superposition in time due to flow-rate variations before and even during (in the case of drawdown analysis) the transient data acquisition, as well as providing a continuum of solutions instead of a type-curve family derived from discrete values for the governing parameters.
Industry:Oil & gas
A method for obtaining quantitative mineralogical analysis of a rock sample by measuring the effect of midrange infrared radiation transmitted through the sample.
Industry:Oil & gas
A method for determining the effective properties of random fields, commonly abbreviated EMT. Originally developed to estimate transport coefficients, this theory is based on the idea of replacing the inhomogeneous medium by an equivalent homogenous medium such that the fluctuations induced by restoring the heterogeneity average to zero. <br><br>EMT is used to upscale parameters such as permeability for use in coarse-grained reservoir simulation studies. This use is controversial in reservoirs that are not homogeneous. <br><br>Reference<br><br>Kilpatrick S: 鈥淧ercolation and conduction,鈥?Reviews of Modern Physics 45 (1973): 574-614. <br><br>Mansoori J: "A Review of Basic Upscaling Procedures: Advantages and Disadvantages," in Yarus JM and Chambers RL (eds): 鈥淪tochastic Modeling and Geostatistics,鈥?AAPG Computer Applications in Geology , no. 3. AAPG, Tulsa, Oklahoma, USA, 1994.
Industry:Oil & gas
A method for desaturating a core sample by placing one end in capillary contact with a porous plate and applying gas or oil under pressure to the remaining surfaces. The liquid in the original fully saturated sample is expelled through the porous plate. At different pressure stages, the sample is weighed to determine the loss of liquid, and the gas or oil pressure increased. Desaturation continues until no more weight loss is observed, at which time the sample is at irreducible water saturation. Core samples are desaturated to measure, for example, capillary pressure, irreducible water saturation, resistivity index or nuclear magnetic resonance response.
Industry:Oil & gas
A method for detecting patterns of points in binary data sets. Data pairs on a plot are assigned slopes and offsets and then replotted in slope and offset space. The method has been used on wireline curve data and on image data, where dips and azimuths are used. The Hough transform can be used to obtain the Buckles number. <br><br>Reference:<br><br>Hough PVC: 鈥淎 Method and Means for Recognizing Complex Patterns,鈥?U. S. Patent No. 3,069,064, 1962.
Industry:Oil & gas
A method for characterization of heavy oils based on fractionation, whereby a heavy oil sample is separated into smaller quantities or fractions, with each fraction having a different composition. Fractionation is based on the solubility of hydrocarbon components in various solvents used in this test. Each fraction consists of a solubility class containing a range of different molecular-weight species. In this method, the crude oil is fractionated to four solubility classes, referred to collectively as SARA: saturates, aromatics, resins, and asphaltenes. Saturates are generally iso- and cyclo-paraffins, while aromatics, resins, and asphaltenes form a continuum of molecules with increasing molecular weight, aromaticity, and heteroatom contents. Asphaltenes may also contain metals such as nickel and vanadium. <br>This method is sometimes referred to as Asphaltene/Wax/Hydrate Deposition analysis.
Industry:Oil & gas
A method for constructing a gridded reservoir model by iterative trial and error. The grid is initially populated randomly with a characteristic (such as facies) so that some property (such as a net/gross ratio) is correct. Then the grids are randomly swapped so that the property is preserved but another property (such as total length) is improved.
Industry:Oil & gas
A method of determining injection-flow profiles by monitoring the reduction in tracer material as it moves down the well. A slug of radioactive tracer is added to the injection fluid. As the slug moves down the well, several gamma ray logs are recorded at well-defined time intervals. The position of the slug is seen as a large gamma ray peak whose size is proportional to the flow rate. A reduction in the size of the peak indicates a loss of fluid into the formation. Fluid velocity can be calculated from the time interval and the distance the peak has moved using timed-slug analysis. Tracer-loss measurements produce a type of radioactive-tracer log, used mainly to give a general idea of fluid flow in low flow-rate wells. <br><br>In very low flow-rate wells, an alternative technique has been used in which the gamma ray detector is held stationary at some depth until the slug has passed. The detector is then moved down to another depth to observe the slug again. With these data, it is possible to make quantitative estimates of fluid flow.
Industry:Oil & gas
