Microscopic pore structure characteristics of the Chang 7 reservoir in LM wellblock of Xifeng Oilfield

Pore structure determines the seepage characteristics of reservoir fluid and directly influences the development effect of water flooding.The pore structure of Chang 7 reservoir in the studied area is analyzed and studied by using many technical means such as thin sections,scanning electron microscopy,high pressure mercury intrusion,etc.it is shown that the Chang 7 reservoir is of ultra-low porosity,super low permeability and strong diagenesis,in which secondary solution pores are relatively developed.The dissolution of flspar,rock debris and carbonate cements is the important reason for the formation of the secondary pores.Most of the reservoir space is medium and large pores;fine and micro throats are the basic seepage channels.Micro-fracture greatly improves the seepage ability of the reservoir.The Chang 7 reservoir is of complex pore throat characteristic,and the microscopic pore structure characteristic is the important factor caused the difference in the productivity of oil wells.