Description Of Paleogene Fractured Sandstone Reservoir With Low Porosity And Low Permeability In Dina 1 Gas Field

In the Dina 1 Gas Field,the Paleogene reservoirs are characterized by large thickness,good development of fractures,and miscellaneous interlayers and intercalations that it is necessary to carry out the works such as fine correlation of layers,evaluation of fracture distribution,research on characteristics of interlayer and intercalation,and comprehensive evaluation of reservoir.They will provide reliable reservoir characterization parameters for future optimization of well site and preparation of development technical policies in the gas field.This study will focus on works related to reservoir description in the Dina 1 Gas Field.By integrating with logs,well logging,core,and dynamic data are used to subdivide the target layer in the study area.A reasonable stratigraphic correlation unit is correlated that it can be divided into layers,thereby establishing an accurate stratigraphic framework.The fractures in the study area are identified and described by core observation and logs.The rock mineral composition is analyzed according to the data of coring well,thereby identifying rock types.The porosity and permeability are analyzed.By using common and casted thin sections,SEM(scanning electronic microscopy),pore structure,cementation type,and structural maturity are analyzed.Based on the above research,comprehensive evaluation of reservoirs is carried out.The result shows that the Paleogene in the Dina 1 Gas Field mainly developed the fan delta plain and fan delta front.The rock types are dominated by siltstone and pebbly siltstone.The fractures in the study area are relatively developed,dominated by high-angle and vertical fractures.The development of fractures has aggravated the heterogeneity of spatial physical properties.Longitudinally,the E2-3s~2 sand layer shows the best physical properties,followed by the E2-3s~1 sand layer,and the E2-3s~3 sand layer is relatively poor.For plane distribution of physical properties,it is better in the southern DN11 well vicinity than that in the northern DN102 vicinity which is relatively homogeneous.Generally,the reservoir is highly heterogeneous,belonging to reservoirs with ultra-low porosity-ultra-low permeability and low porosity-low permeability.