Frederic Lefeuvre

Fracture Related Anisotropy Detection And Analysis: “And If the P-waves Were Enough? ”

o use the P waves associated to the S waves for fracture related anisotropy detection The two techniques we used are based on seismic attributes. Seismic attributes analysis. We show the P waves are able to detect the effects on the are estimated parameters computed from the seismic data volume which may bring wave propagation using a statistical approach with general seismic attributes at the reservoir level, as well as on the using the 3D AVO attributes. The technique appeals to any of physical properties aspect. The most commonly known attribute is the amplitude. tttributes and is based on learning and recognition process. The second technique, They might be used as stand alone tools for an interpreter, like the he (Amplitude Versus Offset and Versus the offset (angle of incidence) when we perform an AVO analysis or they might be simultaneously the the offset and the azimuth. They are used with combined through statistical operations (learning and recognition process) to create learning nor recognition process, only with interpretation. The P waves need new attributes which are automatically interpreted. o be calibrated with the S waves to really go to the fracture level and we show heir potential to extant locally known information from the S waves to large areas especially 3D data). This should have a tremendous impact on the design of future Statistical approach of the attributes acquisition but we suggest that most of the already recorded 3D P wave lata should be analyzed and interpreted again if anisotropy analysis is important. A statistical approach of reservoir properties estimation can be performed through direct analysis of the seismic signatures. It allows an automatic interpretation of the seismic data with a large set of different seismic attributes. The

Sand-shale ratio and sandy reservoir properties estimation from seismic attributes: An integrated study

Total and Unocal estimated sand-shale ratios in gas reservoirs from the upper Tertiary clastics of Myanmar. They separately used deterministic pre-stack and statistical post-stack seismic attribute analysis calibrated at two wells to objectively extrapolate the lithologies and reservoir properties several kilometers away from the wells. The two approaches were then integrated and lead to a unique distribution of the sands and shales in the reservoir which fit in the known regional geological model. For the sands, the fluid distributions (gas and brine) were also estimated as well as the porosity, water saturation, thickness and clay content of the sands. This was made possible by using precise elastic modeling based on the Biot-Gassmann equation in order to integrate the effects of reservoir properties on seismic signatures.

Characterizing fractured reservoir by multicomponent reflection data and VSPs in the Paris basin

We process and interpret nine-component (9C, three component recordings of two horizontal and one vertical sources) surface seismic data and two nearby VSPs to characterize the fractured carbonate reservoir in the Dogger Formation in the Paris Basin. This is achieved by analysing differential changes in the various attributes of the vector wavefield: velocity ratios, polarizations, amplitudes and differential travel times. Careful processing is required to preserve and recover these attributes which have diagnostic anomalies associated with the Dogger formation. The interval shear-anisotropy within the Dogger shows an average of 4% with significant lateral variations, which might be interpreted as lateral changes in porosity and permeability. The differential shear-wave amplitude from the top of the Dogger shows an overall dimming. The shear-wave polarization section reveals detailed internal layering, up to six intervals, within the Dogger, which is not visible in the P-wave section. The information inferred from these wavefield attributes can be broadly correlated with the reservoir properties at the inter-well scale in Duval but with more detailed lateral variations.

Propagator matrix and layer stripping methods: A aomparison of shear‐wave birefringence detection on two data sets from railroad gap and Lost Hills fields

This paper compares two methods. the propagator matrix and layer stripping methods, for measuring shear-wave birefringence and its variation with depth. The comparison is done on two near offset S-wave VSPs from the southwest San Joaquin basin of California. The layer stripping method, which works from the surface by removing birefringence effects as soon as they change, is compared to the propagator matrix method, which works between two given depths without any need for information from the shallower depths. The two methods require S-wave VSPs obtained with two different horizontal source polarizations. The comparison is performed on data sets from the Railroad Gap and Lost Hills fields in California. The results of the two methods are in close agreement, especially when birefringence is large (3% to 7%). Interesting differences in results illustrate advantages and disadvantages of each method.