Abstract:

Geotemperature and pressure have a great controlling function on hydrocarbon generation, migration and accumulation. The characteristics of geotemperaturepressure system in Zhuyi Depression, Pearl River Mouth Basin are underresearched. By theory of geotemperaturepressure system, the geotemperature, formation pressure and geotemperaturepressure system in three typical sags are characterized and their relationship with hydrocarbon distribution is explored based on measured data. Research shows that Zhuyi Depression is characterized by rising geothermal gradient from top to bottom and rising overpressure extent with Enping Formation developing slight overpressure and Wenchang Formation developing moderate overpressure. Overpressure composite geotemperaturepressure system develops in Zhuyi Depression, namely normal geotemperaturepressure system of shallow layers and overpressure system of deep layers. So far the reservoirs discovered in Zhuyi Depression are mainly fault reservoirs distributed in shallow and middle layers. However, it is highly possible that overpressure lithological reservoirs are developed in deep layers, which is predicted according to the basic characteristics of overpressure composite geotemperaturepressure system. Finding out the characteristics of geotemperaturepressure system is quite instructive in predicting hydrocarbon distribution and making exploration deployment in Zhuyi Depression.

Key words: Pearl River Mouth Basin, Zhuyi Depression, geotemperature, pressure, geotemperaturepressuresystem