PfEFFER Version 2.0

(Petrofacies Evaluation of Formations for Engineering Reservoirs)

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PfEFFER Pro contains three new modules to 1. help integrate and display petrophysical reservoir information, 2. further characterize spatial variation of petrophysical properties, and 3. build a bridge from a petrophysical geological model to a reservoir simulator for testing and refinement and evaluation of options for improved reservoir management.

Flow units are fundamental units in reservoir characterization. They are defined as correlatable and mapable regions in the reservoir that control fluid flow. Their distinction is usually centered on comparing permeability and porosity. Definition of flow units can be further refined utilizing fluid recovery, pressure data or chemical fingerprinting. Often times, particularly in older fields, production is commingled and cannot be used to substantiate flow units. Moreover, the cost of extensive fluid and pressure testing is not economic. Thus, the distinction of flow units often falls back on the use of well logs; if not, well logs remain the central data type for distinction of flow units.

PfEFFER Pro helps to further evaluate flow units by extending wireline log analysis of single wells to multiple wells via cross sections, gridding, mapping, and linking with fluid flow reservoir simulators. Cross sections, in particular, help to distinguish vertical and lateral trends and patterns of irreducible bulk volume water, water saturation, and porosity and in turn are useful in correlating and assessing the distinction of flow units using well logs.

Conversion of Latitude and Longitude to UTM coordinates (LatLngtoUTM)

UTM (Universal Transverse Mercator) is a common projection used for most geographic information system (GIS) applications, land grids and commercial mapping. The LntLngtoUTM module in PfEFFER Pro converts longitude (x) and latitude (y) data to UTM x-y coordinates, in units of meters. UTM x-y coordinates can then be are mapped using orthogonal axes. From a geodetic perspective, Universal Transverse Mercator (UTM) projection represents ellipsoidal positions (latitude and longitude) as grid coordinates (easting and northing) on a cylindrical surface, resulting in a number of zones. Uniform scale factor, false origins and zone size and numbering have been adapted for the Universal Transverse Mercator Projection. Zones are specified for each portion of the earth. In the conversion process, zone number must be provided. The conversion to UTM and meters scale is also the first step toward conducting a simulation.

Cross section (XsecExcl97)

The cross section is an important tool to assess lateral and vertical heterogeneity of a reservoir. The delineation of flow units, requires cross sections to help ascertain their correlation and continuity. Cross sections also help to examine consistency and calibration issues in the analysis of each well. The interactive link between conducting log analysis and construction of cross sections facilitates the definition and refinements of flow units and examination of related information such as perforations. Modules in PfEFFER 2.0 such as Cluster and Mapping also assist in characterization of flow units.

Generation of reservoir parameter information for the fluid flow reservoir simulator (GridforSim)

This module was developed to link the elements of building a petrophysical model and a simulation of the reservoir. Specific goals include 1. reduce complexity in building an input file for a simulation, 2. facilitate interaction with the simulation such that the petrophysical model can be easily modified, effectively bring the engineering and geological disciplines together, and 3. permit iteration of to lead to a refined petrophysical geologic model and fluid flow simulation.

In using the GridforSim module, wells are selected for the eventual reservoir simulation. The reservoir parameters to be included in the simulation are developed for the flow units/layers that comprise the reservoir. Grids are computed for each parameter and saved as sheets in a simulation workbook. PfEFFER helps the user in defining optimum grid size and gridding options. Locations of wells in UTM coordinates are converted to feet as required by some simulators including DOE's Boast 3 black oil simulator. Once grids are generated, wells can be posted on the grid sheet itself to assess the optimization of the grid spacing. Grid and well summary data are also provided for ease as transferring as input data to the reservoir simulator. A mapping option in GridforSim can post wells and show section and township lines computed from the well's spot location.

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Kansas Geological Survey, PfEFFER software
Comments to
Updated August 7, 1998