Abstract: A Petragrid method and apparatus generates grid cell property information that is adapted for use by a computer simulation apparatus which simulates properties of an earth formation located near one or more wellbores. An interpretation workstation includes at least two software programs stored therein: a first program called "Petragrid" and a second simulation program which is responsive to output data produced from the first "Petragrid" program for generating a set of simulation results. The set of simulation results are displayed on a workstation display monitor of the workstation. The first Petragrid software program will: receive well log and seismic data which indicates the location of each layer of a formation near a wellbore, and then grid each layer of the formation, the grid being comprised of a plurality of cells. The first Petragrid software will then generate more accurate data associated with each cell, such as the transmissibility of well fluid through each cell.

Abstract: An automatic, non-artificially extended, fault surface based horizon modeling method and apparatus produces a final faulted horizon model which is a three dimensional representation of a faulted earth formation including all the horizons and all the faults in response to seismic data, well log data, and fault surfaces and relationships data. The horizon modeling apparatus produces the final faulted horizon model by filtering input horizon data and removing bad (wrong-sided) data points.

Abstract: An interpretation workstation based apparatus having an "Auto Fault" software stored therein automatically identifies a plurality of fault cuts in each of a plurality of horizons in a seismic data volume in response to a plurality of predetermined "horizon time structures".

Abstract: A method and associated apparatus for generating time slice maps and/or horizon maps, representative of a time slice or a horizon in an earth formation that is subject to a seismic operation, in response to received seismic data includes the steps of: (a) cross correlating a plurality of seismic traces from the seismic data and a corresponding plurality of quadrature traces associated, respectively, with the plurality of seismic traces to obtain a corresponding plurality of cross correlation functions "Q(.tau.)", (b) obtaining a plurality of particular values from the plurality of cross correlation functions "Q(.tau.)", at least one particular value being obtained from each cross correlation function, and (c) assigning the plurality of particular values to a respective plurality of reflection points on a map, each particular value being assigned to a different one of the reflection points, thereby constructing the time slice map and/or the horizon map.

Abstract: A novel fault framework method and apparatus automatically computes the relationships between intersecting fault surfaces. When faults are loaded into the novel fault framework apparatus, all intersecting fault pairs are determined and the fault fault intersection lines are computed and stored. The intersecting fault pairs are presented and available for automatic calculation of the major/minor and above/below fault pair relationships. The geometry of both intersecting fault surfaces are examined on either side of the fault fault intersection line. This, in combination with the relative size of the faults, is analyzed to compute the major/minor and above/below relationships based on geologic assumptions and knowledge of the origin of the fault surface data. When the relationships between intersecting faults is defined, the minor fault is appropriately truncated.