Hydrocarbon Reservoir Characteristics Of Buried Hills In The Liaoxi Low Uplift

The reservoirs of Liaoxi low uplift in the Bohai Sea have excellent exploration prospects.However,the basic study of geological reservoirs is not systematic.Considering this,taking the Mesozoic volcanic rocks in the JZ20-2 block,Paleozoic carbonate rocks in SZ36-1 block and JZ25-1S block of the Archean metamorphic rocks which are situated at Liaoxi low uplift as three sets of stratum as the main research objects,based on previous research results,making use of related geology theories and making studies of the "Lithology-Logging response-Physical properties-Oil contain ability" relationship,reservoir space characteristics and the mechanism of reservoir development,establishing the reservoir classification criteria and combining the main buried hill reservoirs' Reservoir profile,then evaluating the reservoir level of the Liaoxi low buried hill and dividing the reservoir zoning.Volcanic rocks reservoirs are the best in volcanic breccia,basalts are the second,and tuff is the worst.The carbonate reservoirs are the best in limestone,the dolomite is slightly worse.The metamorphic rocks are mainly showed that metamorphic granite and fractured rocks are better reservoirs.Buried hill reservoir storage space is complex,three sets of strata are all including cracks,intergranular dissolution pores and intra-crystal pores.The volcanic rocks are mainly composed of fractured-porosity composite reservoirs.The carbonate rocks are mainly fractured-porosity,which can be seen as simple pore-type reservoirs.The metamorphic rocks are mainly fractured-pores complex reservoirs.Otherwise,different types of reservoirs can be distinguished by using the conventional porosity logging response characteristics and imaging logging characteristics.Under the influences of surface weathering dissolution,organic acid dissolution and tectonic action,the secondary pores,cracks which can be found in weathering crust,seepage subsurface flow zone and inner fault zone,these reservoir properties are better.From all of the influences,the contribution of tectonic action is the biggest one.Lithology,formation depth and paleomorphology and other factors can also affect the reservoir's development.The reservoir's development levels of the three blocks are very heterogeneous,but generally better.In the vertical: weathering crust developments level ? reservoir,subsurface flow-seepage zone is level ? reservoir,from this,finds that buried hill below 200 m from the top of this reservoir is a favorable exploration area;occasionally,insider fracture zone grows level ? reservoir,therefore,fracture adjacent area is this class reservoirs' exploration target.On the plane: The reservoir conditions of the metamorphic rocks and volcanic reservoirs in the north of Liaoxi low uplifit are better than those in the carbonate reservoirs in the south.