Study Of Reservoir Evaluation Of Chang6、Chang2 Of Resiwan Area Of Zichang Oilfield

This paper taking reservoir of Chang6、Chang2 of Resiwan area of Zichang Oilfield asthe research object,by the drilling,core,logging,production performance data as the basis,toresearch the stratum,structure,sedimentary facies,reservoir space,diagenesis,reservoircharacteristics and aelotropy of sudy area. Besides make a comprehensive evaluation of thereservoir of Chang6、Chang2 of Resiwan area of Zichang Oilfield.And research showsthat:The structure background is a gently West dipping monoclinic,and the gradient is8.5～10.7m/km. Besides,no fracture;Chang 2 formation belongs to braided river sedimentaryand Chang 6 formation belongs to the delta plain subfacies deposition.Both braided channelsand body of Chang 2 and delta distributary channel sand body of Chang 6 are the mostfavorable area of reservoir;Chang 2 formation mainly is fine-grained arkose,The main mineralcomposition of the sandstone is feldspar,and the average content is 54.29%.Sorting ofsandstone is moderate to good.Contact relationship mainly is point and line contact.Roundnessis subangular pore.Cementation style mainly is membrane-pore and increase～porecementation.Maturity of sediment structure is highly but the mineral maturity is low. Chang 6formation also mainly is fine-grained arkose,The main mineral composition of the sandstone isfeldspar,and the average content is 58.02%.Sorting of sandstone is moderate.Contactrelationship mainly is point-line contact.Roundness is subrounded.Cementation style mainlyis membrane-pore cementation;The main diagenesis of reservoir:compaction,pressure solutionand cementation play a destructive role for the reservoir pore,but dissolution plays anenlargement role for reservoir pore.Both sandstone reservoir of Chang 2 and Chang are in themiddle diagenetic stage;The average porosity of Chang 2 reservoir is 11.73%,The averagepermeability of Chang 2 reservoir is 11.45×10-3μm2 The average porosity of Chang 6 reservoiris 11.73%,The average permeability of Chang 6 reservoir is 0.46×10-3μm;The reservoirevaluation according to the clastic reservoir classification and evaluation standard of Mesozoicof Erdos basin,besides,combined with the mercury injection curves to classify the reservoir ofthe study area:Sandstone reservoir of Chang 2,Chang 6 are divided into low permeability layer(Class Ⅱb), extra low permeability layer (Class Ⅲ),super low permeability layer(Class Ⅳ) anddense layer(Class V) four categories.what’s more,the reservoirs of class Ⅱb which are mainlydistributed in the Chagn 2 channel sands are better.