THE DISCUSSION ABOUT THE ACCUMULATION OF GAS IN MIOCENE IN GUMAN TECTONIC BELT OF YE CHENG SAG

The main layer of Guman tectonic belt is the neogene of Miocene. According to the train of thought for structural reservoirs,there was no breakthrough in the 1980 s. Now we think there are no structure traps in the area through the research of seismic in recent years. Through the analysis of oil and gas source,sedimentary system and the tectonic background,lithologic reservoirs of Miocene are likely formed in the area. We analyze the main control factors of lithologic reservoir deeply in order to guide the exploration in the area better. Firstly,the research on the surface oil output state shows that the main source rock is Permian shale and the source is sufficient. Secondly,the reservoir is sandstone and siltstone,with low permeability and,low porosity,which is located in underwater channel of fan delta. The cover for reservoir is mudstone and sandy mudstone which is interacted with the reservoir. The trap types is updip lithologic trap under the background of structure. The vertical fracture that links with oil and lateral reservoir sand composes stereo channel system for oil and gas.Therefore,Guman tectonic belt is in good accumulation condition and it has considerable exploration potential. It is more realistic exploration replacement area since Kekeya gas field discovered.