Abstract:

For the tim ing of hydrocarbon charging in shallow reservoirs，methods such as traditional geological analysis，fluid inclusions in reservoirs and illite dating have obvious shortages.Based on the interactions between hydrocarbons，water and m inerals，this paper puts forward a newmethod to determ ine hydrocarbon charging time of shallow reservoirs by differences of diagenetic characteristics of reservoir rocks.Taking the A oilfield in Kazakhstan as an example，the hydrocarbon charging time for theMˉⅡoil layer is determ ined in this way.The time of bulk hydrocarbon charging can be determ ined through the analyses of differences of content of certain m inerals and in combination with diagenetic evolutionary sequence and burial thermal history.On the basis of poolˉform ing element analysis，hydrocarbon charging direction can be traced and hydrocarbon charging process can be identified with references to the trend of relative content of diagenetic m inerals.

Key words: diagenetic characteristics of reservoirs, hydrocarbon charging time, diagenetic evolution, shallow oil/gas pool