8. Conclusions

A common technique for brittleness estimation based on seismic elastic properties has been discussed. The existing method of brittleness average was tested and compared with new attributes (SQp) to indicate the existence of fracture density on a fractured basement reservoir environment in the Malaysian Basin. The results show that SQp attribute coincides with brittleness average and fracture density either on well log data or core data, while the SQs attribute is consistent with neutron porosity-density log which can be used to indicate the hydrocarbon column in the fractured basement reservoir.

Furthermore, the test of SQp and SQs attributes on conventional reservoir shows that those attributes are able to discriminate the lithological and fluid effects optimally. The lithology changes are indicated in the SQp log, which is similar to gamma ray log responses, while the fluid types are distinguished in the SQs log, which is similar to the resistivity log.

One of the advantages of using SQp and SQs attributes for reservoir characterization either in conventional or unconventional reservoir is that the attribute can be not only derived limited on well log domain but also applied three-dimensionally on seismic data. There are two options to get the SQp and SQs from seismic data: based on AVO analysis method and seismic inversion workflow. In the AVO method approach, the anomaly of hydrocarbon reservoir is indicated strongly in the SQp and SQs compared to the conventional AVO analysis using intercept and gradient crossplot method. The application of SQp and SQs attributes through inversion result also gives a strong indicator of lithology and fluid. Due to the similarity of SQp-SQs attributes with petrophysical properties, it is possible to use SQp and SQs attributes for petrophysical property prediction from elastic properties. This will become our future work.
