It was drilled with an 8.500” bit in a vertical hole (maximum 3-degree deviation) over the image log interval.

Methodology: Field data files are first to read into the computer using a module called Data Load (Geo frame Software). Normally both methods of speed correction are used in BorEid. Optionally, a program called BorScale is run to calibrate the image data response to that of a shallow log such as an RLA2 (resistivity curve). The BorNor is used to dynamically normalize the images to enhance the image contrast. Interactive interpretation of the images is done in BorView. Image logs are displayed using bright colours for resistive units and lower resistivity conductive units are displayed using dark colours in Borview. Interpretation typically started with hand picking dips using sinusoid techniques on oriented images presented at 1:20 or 1:10 scale, so that the geological features are easily visualized. Once dips have been picked they have to be classified into bed boundaries and fractures. The structural dip data is imported into the Bortex software and the heterogeneity analysis of reservoirs from borehole images is carried out by the software used to extract heterogeneities and layer details from images. The FMI images are used to examine the internal organization or rock fabric of the beds or reservoir units in conjunction with open-hole logs. In addition to formation heterogeneities, the software also computed connections for the connected-conductive heterogeneities of a formation (Fig. 2).

Structural dip as input data for heterogeneity analysis: Bedding planes are successions of resistive/conductive planar features in the image logs reflecting variations in the lithological characteristics of the formation across the borehole.

Image for - Characterization of Reservoir by Using Geological, Reservoir and Core Data
Fig. 3(a-b): Statistical plots of bedding dips indicating an average dip of (a) 26 degrees S36W and strike N54W-S54E and (b) Statistical plots for dips of all open fractures in the Asmari formation

Average dip inclination of 26 degrees is the most representative of the whole interval of Asmari formation and statistical plots for dips of all open fractures in the Asmari formation

The dips of these features are used to determine the structural dip in the given borehole. Bed boundaries are almost uniformly distributed throughout the logged interval. The structural dip is 26 degrees toward S36W. The inclinations of dip are generally low and vary between 14-44 degrees. Dip classification based on a geological logic has the advantage of providing a direct representation of structural origin. The structural dip data is an input for permeability analysis software and helped in understanding the reservoir structure, identifying and evaluating sedimentary features and fractures, visualising the rock texture and complementing coring programs (Fig. 3a).