Effects Of Hydrocarbon Emplacement To The Evolution Of Diagenesis And Secondary Pores Of ES Reservoirs In Linnan Subsag

Linnan Subsag is chose to be the research area in the paper. It is analyzed that the main diagenesis of Es reservoirs concludes compaction, cementation, dissolution, metasomatism and conversion of several clay minerals. Based on analysis of numbers of thin section, it is indicated that the secondary pore is dominant in Es reservoirs of this area. The main cause of secondary pore is dissolution of feldspar and carbonate minerals. The diagenesis stages are diparted according to the specific situation of this area and pore-evolution process and the previous results.Geochemical progress of diagenesis evolution of quartz, feldspar, carbonate minerals and clay minerals is analyzed. It is indicated that the diagenesis environment may be changed as the hydrocarbon filling. According to the research of diagenesis evolution under different oil bearing grade, it is-suggested that hydrocarbon emplacement affects the diagenesis evolution in three areas:cushion the compaction of reservoirs, inhibition of quartz and illite cementation, transformation deep dissolution.Based on the homogenization temperature of a large number of saline inclusions and structural history, it is considered that charging time related to the structural position:in the center of the subsag there are two periods which is Dongying and Guantao-Minghuazhen Period, and at the edge of the subsag there is only Guantao-Minghuazhen Period. The latter is the main period in both structural positions. The fluid salinity can be calculated using the ice point temperature, which fall a little as the oil bearing grade increases, and this further confirmed the influence of hydrocarbon emplacement to diagenesis.Quantitative research between oil saturation and porosity gets the conclusion that:(1) between secondary porosity and oil bearing grade, the secondary porosity increases when the oil bearing grade increasing as oil bearing grade under or equal to immersion, little decreases when oil bearing grade reach oil-rich. (2) The total porosity is generally positive correlated with oil bearing grade, which increases as the oil bearing grade increased.