ROCK PHYSICS MODELING AND SEISMIC INVERSION APPLICATIONS FOR THE GAS-BEARING SAND CHARACTERIZATION, SIMIAN FIELD, MEDITERRANEAN SEA, EGYPT.

Abstract

From a general point of view, the objective of Reservoir Characterization techniques is to interpret seismic amplitudes in terms of reservoir properties, such as porosity and lithology, and also, when possible, to infer fluid content. All the techniques we used during this study help us to answer our questions about the area such as: Given a anomaly of seismic amplitudes, such as high energy event, and we conclude that it corresponds to an hydrocarbon accumulation, this done by combining multi-discipline workflow which enable us to enlarge our knowledge from rock physics modelling to verify main contributor of such high anomaly which is because of gas reservoir, beside using seismic information to know about the extension of a sand reservoir in our area. This thesis set out to justify the process of seismic inversion by comparing the different post-stack seismic data algorithm and discovering the potential of quantitative interpretation of pre-stack data using angle stack. It has shown that pre-stack inversion can help improve the detail with which a gas field is evaluated. By presenting a greater number of rock properties into the area the Simian field become a lot more flexible in terms of how the interpretation can be approached. A dedicated rock physics study using variety of attribute allows detailed analysis of the measured data with which to build the inverted volume around also building rock physics templet which help to predict properties in an investigated area and shows what potential the field has undergoing an angle stack inversion. Merging the findings from this study with sufficient well control, an appropriate wavelet and an initial model the rock physics study is generalized volume wide with the opportunity to feat any ideal attribute to best represent the separation between data. In the case of the Simian field there is to many attributes which gave way to the optimum possibility of defining quantitative gas sand analysis over the volume. This is a level above conventional interpretation which is limited to the spatial distribution of amplitudes to decipher the geology. By performing fluid replacement for the desired zone of interest, it has been demonstrated that it is possible to predict the signature of each case and to see just how the clean sands and the gas sands are distributed. This allows a detail of geological information to be available that it was not previously possible to extract. On this root then, angle stack inversion is an achieve and should not fail to help in the interpretation, development and production of any field. This study has, however, shown the limitations of a method which seems to offer so much. The process is one that needs firm basics in the form of a reliable wavelet, appropriately wire-line logged wells and a sufficiently initial model. Unfortunately, the