Seismic-Acoustic Petrophysical Characteristics of North Amer Area, ' Gulf of Suez-Egypt.

Abstract

An advantage of logs is that they usually cover the entire interval of

• interest with a suitable sampling rate providing exceptional detail. Logs can often be obtained in conditions where coring is impossible and they are cheaper. A combination of cored section and log data gives an excellent basis of information. From well log data, we are able to derive reservoir properties such as lithology, porosity and fluids, as well as elastic rock properties, which are functions of velocity and density. This petrophysics provides a critical link between reservoir rocks and fluids and their seismic response. However, the value we get from wellbore data is directly dependant upon the quality of the log data and our ability to interpret and understanding the formation being measured.

When properly employed, well logs and their interpretation results are important sources of data for design, implementation, and control of reservoir simulation models. Because of their excellent vertical detail and depth control, well logs can delineate "reservoir units" of continuous and similar petrophysical characteristics, thereby providing the basis for vertical zonation and for well-to-well correlations. Most importantly, logs provide accurate values of in-situ hydrocarbon and water saturation, and porosity, for each unit over the entire interval of interest in reservoir evaluation.

Unfortunately, in many cases, the lack of logging data makes the determination of these parameters difficult and incorrect. For example, most wells, however, do not have well velocity survey, neutron and density logs usually required for determining porosity, velocity, elastic modulus, seismic impedance, reflectivity and creating synthetic seismograms. The cost of cores, on the other hand, is very expensive and sometimes impossible due to safety reasons or because of formation conditions. For these reasons, extensive coring is usually not done, even in exploration wells.