GAS CHIMNEY DETECTION AND RESERVOIR ROCK GENETIC TYPES USING SEISMIC DATA AND LOG CURVE SHAPES: BALTIM FIELD, MEDITERRANEAN SEA.

Abstract

In this work, the detection of gas chimney and associated structures as preferential hydrocarbon migration pathways from the pre-Messinian kitchen section to the Plio Pleistocene reservoirs was testified by the numerous DHIs within the upper Pliocene Pleistocene reservoirs that are in contact with the boundaries of the gas chimneys. In addition, geochemical analysis on gas samples from targets drilled in the upper Pliocene Pleistocene indicates the presence of thermogenic gas clearly generated by pre-Messinian units. In addition to direct hydrocarbon gas indicators, gas chimney presence has been used in defining the most promising areas inside the exploratory blocks. This approach has been mainly tested in the exploration of the Plio-Pleistocene interval. Areas interested by gas chimneys are obviously not defective as regard the presence of an efficient hydrocarbon generating system. The log curve shapes technique is very useful in identifying the paleo depositional history of the main reservoir in Baltim area and also to identify the sand zone which is impregnate with huge amounts of gases. According to the present work, one can recommend to drill the Lower Pliocene channels in the down thrown of the main fault due to the gases migrated from the gas chimneys in the south to the north until the main fault which it considered as the seal.