EIGHT MAJOR DEPOSITIONAL PROCESSES OF CLASTIC ROCKS AND THEIR PETROLEUM RESERVOIR CHARACTERIZATION

Comprehensive evaluation, modeling and prediction of petroleum reservoir are always concerned in the oil-and-gas field exploration and development. Moreover, study of reservoir characteristics is related to analysis of depositional facies or microfacies. It revolves occurrence of residual petroleum and sweep efficiency or conformance factor of injectant to find new reservoirs and enhance oil recovery during the stage of reservoir management and development in maturing oil fields, and this is related to the study on reservoirs heterogeneity. The fundamental reason of all these results is the mechanisms forming depositional sandbody-depositional processes. The relationship between depositional process and response of reservoir heterogeneity is for the geologists and petroleum engineers to resolve. Based on the previous research, 8 major depositional processes (vertical accretion, progradation, lateral accretion, overbank accretion, sieve accretion, winnowing accretion, channel filling, and turbidity deposition) have been defined and the sedimentary features, reservoir characteristics, architecture, log and seismic responsibility of the sediments formed mainly by these depositional processes have been described in detail, in order to get a better understanding of reservoir heterogeneity and occurrences of residual petroleum on clastic rocks and to provide basis for analyzing genetic mechanism.