A series of techniques that use geostatistical methods to determine fluid and contaminant flow in the subsurface.

An example used for comparison. In oil and gas exploration, geoscientists and engineers compare new prospects and fields with fields and surface exposures thought to be similar in depositional environment and reservoir character to guide predictions.

A mathematical method of finding a central value for a group of data. It is most often referred to as the average but also as the mean.

The study of ideas that enable computers to do the things that make people seem intelligent.

The angle that characterizes a direction or vector relative to a reference direction (usually True North) on a horizontal plane.

An inference or deduction made using Bayes' theorem

A method of updating distributions that requires that prior distributions of the required geological characteristics are defined and that calculation of the posterior distributions be based on an exact stochastic model.

A probability based on Bayes' theorem of interdependent events occurring interdependently.

Analysis of two data sets that determines whether or not the data are related and describes the best relationship between them.

One of a number of possible distributions that may occur when the results of events are plotted

The development of a reservoir model by the use of objects. Reservoir models may be developed by adding together a series of objects (such as channel belts) in a fashion that honors the well data (logs, cores, etc.) and satisfies all the geostatistical requirements of the model. Such models may be used to simulate the behavior of the fluids in a reservoir.

A grid pattern laid over a representation of fractures. The number of boxes that contain a fracture is counted and plotted against the box size on logarithmic scales. The slope of the line is equal to minus the fractal dimension. This is sometimes referred to as the box 'dimension.'

A system for color-coding three-dimensional information.

The motion of atoms and molecules in fluids due to the temperature of the fluid

A conventional method of mapping reservoir parameters in two dimensions, x and y.

A group of data points having similar characteristics.

The act of determining clusters from data sets.

Mathematical techniques for summarizing large amounts of multidimensional data into groups.

A map that displays the degree of correlation between wells as a vector that points from one well to another, the length of the vector being related to the degree of correlation from a correlogram.

A form of kriging that involves multiple variables.

The productive segment of an oil or gas field that is not in fluid communication with the remainder of the field.

The geological segmentation of once continuous reservoirs into isolated compartments.

A hypothetical model characterizing strata, generally strata deposited in one or a related set of environments.

A geostatistical tool that yields a quantitative measure of the error in a map.

A projection of data from the apex of a cone in a three-dimensional plot onto a surface at the base of the cone.

To compare and fix measured depths with known features on baseline logs of the wellbore tubulars and the surrounding formation.

A positive relationship between data samples that implies a connection or a relationship between them.

A graphical representation of the degree of agreement between segments of curves being correlated between different wells.

A two-dimensional plot with one variable scaled in the vertical (Y) direction and the other in the horizontal (X) axis.

The total amount of oil and gas recovered from a reservoir as of a particular time in the life of the field.

A succession of strata deposited during a single cycle of deposition.

A standard unit of measure of permeability.

The practice of ensuring that all measurements taken in a borehole are matched to the 'base depth,' normally the depth determined with the resistivity log.

The practice of shifting depths of various data sets to a measurement that is known to be on depth.

Logs that have been calculated from other logs to find the rate at which a log is changing with depth

The use of deterministic methods to solve problems or find solutions to data sets.

Techniques that use equations or algorithms that have been previously developed for similar situations.

The angle at which a wellbore diverges from vertical.

The angle between a planar feature, such as a sedimentary bed or a fault, and a horizontal plane.

A fault whose primary movement is in the dip direction.

Variograms and semivariograms that have a directional component in addition to the normal distance component.

The variation in the values of a one-dimensional data set.

A region characterized by a specific feature.

A region of magnetic polarity within a ferromagnetic body.

The set of values assigned to the independent variables of a function.

A structure made up of a number of superposed domains, usually of different size or wavelength.

A method for determining the effective properties of random fields, commonly abbreviated EMT.

The vector that best represents the trend of data in multiple dimensions

Pertaining to analysis that includes equations or formulae that were derived purely from data analysis and were not derived from a theoretical basis.

A discontinuous parabola kernel that is used in contouring areal density of data points in a crossplot.

A data value that is not correct.

The difference between a data value and the value predicted by statistical distribution or other mathematical algorithm

A dimension in Euclidian space

The distance between two points in Euclidian space.

Global sea level, which changes in response to changes in the volume of ocean water and the volume of ocean basins.

The results of extrapolating from a known data point to points away from measurements.

A computer system that uses a rule-based algorithm to provide expertise on a given subject.

The characteristics of a rock unit that reflect its origin and permit its differentiation from other rock units around it.

The act of modeling a reservoir using knowledge of the facies that make up the reservoir and the depositional environments that the facies represent.

Devices for selecting or excluding data from a data stream or data set.

A variogram or semivariogram is said to have been fitted after the best possible model has been applied to it.

A surface exhibiting evidence of an abrupt increase in water depth, separating younger from older strata.

A model of a reservoir in which the steady-state flow and the advective transport are described in two or three dimensions by a computer program

The dynamic simulation of fluids through a reservoir model over time.

The movement of fluid through pores and fractures within permeable rocks in a reservoir.

A mathematical algorithm designed by geometrician and physicist Baron J.B.J. Fourier to determine the frequency distribution within a wave pattern as a series of sine waves

A special mathematical geometry with properties that reproduce a pattern over a range of scales.

Analysis of a geometrical system using fractal mathematics.

Networks that are described using the mathematics of fractals

Patterns in multiple fractures that intersect with each other.

An algorithm built on a Markov-type hypothesis, whereby collocated secondary information is assumed to screen out secondary data from farther away.

A parametric approach to stochastic imaging or simulation of a reservoir.

Techniques that are applied to reservoir characterization using various statistical approaches to estimate the geological characteristics of formations at a distance from known points, such as within wellbores.

The process of generating models of the subsurface using geostatistical methods.

The study of samples of data from a complete data set (or population) to attempt to estimate the behavior of the population.

A diagram that displays multivariate data.

A mathematical procedure used to improve computer usage in simulated annealing runs.

The act of determining values for grid elements on a map.

A computational procedure incorporated in methods for determining the values to be assigned to grid elements on a map.

A particular frequency at which a data set has a resonance, or the frequency has special significance.

A set of data values related by some function of frequencies and capable of being represented by sine and cosine functions.

A method of cluster analysis in which the distance between every pair of data points is determined and the relative distances displayed on a dendogram.

A systems tract bounded below by a downlap surface and above by a sequence boundary, commonly abbreviated as HST.

The act of adjusting a model of a reservoir until it closely reproduces the past behavior of a reservoir.

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.

An approach to stochastic imaging or simulation of a reservoir that is nonparametric.

Models of reservoirs built using indicator (nonparametric) methods.

The study, collection and management of information, especially with respect to computer technology.

The assignment of values to points intermediate to two data points.

The gas stored in the pore space of a reservoir rock.

Mathematical techniques that require an algorithm or equation to be repeated until a condition is met.

A clustering technique that begins with the assignment of the number of clusters to be found.

A curve used to generate a certain type of fractal geometry.

The weights assigned to control points in kriging operations to minimize the variance, thus eliminating systematic estimation errors.

A measure of a curve describing the statistical frequency distribution in the region about its mode; the relative 'peakedness' of the distribution.

A highly simplified description of a geological scenario. Although sometimes used for 'quick and dirty' simulation models, this description is often not appropriate for detailed or accurate work.

To continuously measure formation properties with electrically powered instruments to infer properties and make decisions about drilling and production operations.

A plot of the longitudinal component of the dip vector computed from a dipmeter.

A systems tract overlying a sequence boundary and overlain by a transgressive surface.