Current situation of researching tight oil exploration

Based on a thorough literature investigation,this paper summarizes the current situation of researching tight oil exploration.Tight oil and shale oil are different,so we should distinguish them in the research.The formation of tight oil required the following conditions:wide distribution of tight reservoir,high quality source rock with moderate maturation and close contact between tight reservoir and source rock.Tight oil are mainly developed in fine sandstone,siltstone,argillaceous siltstone which deposited in the environment of delta and gravity flow and dolomite and marl in semideep-deep lake facies,the reservoir physical characters of tight oil are worse and nano — pore throat of grain micropore,inter-crystalline pore and microcrack play an important role in reservoir space of it.Unlike conventional reservoir,tight oil reservoir has the following characteristics:the source- reservoir- cap are closely adjacent,the influence of structural traps are small,trap boundaries is indefinite.Oil in the migration process is mainly affected by the pressure of the hydrocarbon expulsion and filling in a non-Darcy flow.The reservoir has no unified interface of oil,gas and water and pressure systems,also the distribution regularity of oil,gas and water is poor.The tight oil resource estimation study are relatively weak,now we mainly use basin simulation,statistical method and analog study to evaluate the tight oil resource extent.