Observation and electronscanning of rock slices and core samples in 8th district

Karamay oilfield

have the following characters:1.Complicated petrofabric——coarse and fine matrices

five kinds of grainsupported framworks and four types of grain contact.2.Violent mechanical compaction——grain deformation

intra-grain fissures and false matrices.3.Well developed authigenic minerals——three series of zeolites

calcites and chlorites.Based on the occurrence and origin of the authigenic minerals

the relationship between pore evolution and diagenesis processes

the conglomerate are in immatured and semi-matured diagenesis

mechanical and chemical compaction greatly decreased primary porosity

but the de-analcitization resulted in a large amount of secondary corrosion pores

and then

the chlorite grown inpores apparently blocked the throats

thus reduced the permeability of the conglomerate.Two diagenesis processes are discriminated:the ductile tuffaceous clastic conglomerate with a few secondary corrosion evolved into nonreservoir

where as conglomerates composed of compression-resistant neutral and acidic lava clastics with much more secondary pores

developed into effective reservoir.