Study On Relationship Between Overpressure And Deep Hydrocarbon Accumulation In Dongpu Depression

Based on the tectonic evolution history of the Dongpu depression,this paper focuses on the distribution of the overpressure system in the Dongpu depression and its influence on deep hydrocarbon accumulation.Based on the measured temperature and pressure data,combined with sonic logging and seismic data,the current pressure space distribution characteristics of different deep layers are studied.The formation pressure in this area has obvious zoning and cyclic characteristics.Strong overpressure is significant.The deep overpressure formation mechanism in Wendong area is systematically analyzed.The increase of pressure is mainly due to the hydrocarbon generation of organic matter,especially the action of gas,which is not related to the under-compaction of mudstone.The reservoir overpressure is formed by oil and gas charging.The sealing action of the salt rock formation and the fault block makes the overpressure well preserved.The improvement of reservoir performance is mainly manifested in: pore preservation,dissolution,and crack development.Under the same geological conditions,the higher the pressure,the corresponding oil-bearing property is improved.Through the analysis of the accumulation period and the migration and release,the control effect of overpressure on hydrocarbon accumulation is discussed.Overpressure promotes the opening of the micro-cracks of the formation,providing oil and gas migration channels;strong overpressure drives the oil and gas to move up along the activation fault.Oil and gas accumulation has two types of accumulation modes: overpressure and overpressure.