Study On Sedimentary Facies And Diagenesis In Putaohua Oil Layer In Gulong Oilfield

Gulong oilfield is located in Daqing oilfield of Datong District, Heilongjiang Province,and belongs to exploration and development blocks of ninth factory of Daqing Oilfield.Along with the more practical exploration and development work in the study area,the problems of Gulong oilfield Putaohua Reservoir such as the rapidly changing of lithology in vertical and horizontal,instability of reservoir distribution in space,complexity of sand deposition and the relationship between oil and water are gradually exposed.So existing level of awareness of work area for four blocks(Bayanchagan, Longnan, Talaha and Changjiaweizi)of the reservoir can not meet the actual needs of exploration,development and production. And sedimentary facies and diagenesis is of importance for exploration,development and actual production,it is necessary for a further study of deposition phase and diagenesis of the block.This paper makes use of data of layer of interest in studying area such as well logs,drilling,lithology, sandstone thickness.combined with logging data and seismic data,established a log-sedimentary facies mode, and the types of sedimentary facies in study area is divided into 1 phase,1 subfacies and 4 microfacies.Based on the logging feature combinations and logging lithofacies,and analyze single well sedimentary facies and combining well sedimentary facies,and make seismic attributes as an important basis.Comprehensively analyse the horizontal distribution of microfacies characteristics of Putaohua Reservoir in Gulong oilfield.The results showed that during the deposition,the layer of interest in study area are controlled by lake-river-delta system,mainly developed mouth bar, distributary channel, distributary bay and sheet sand microfacies.Diagenesis in study area for the purpose of secondary porosity plays a crucial role.Diagenesis in Putaohua layer Gulong oilfield are mechanical compaction, dissolution and dissolution, cementation and metasomatism, secondary growth of quartz and feldspar.This paper mainly based on the conversion of clay minerals,and divided the main diagenetic stage of the layer of interest in the study area into sub-stages A1 and A2 in mid-diagenetic stage;and base on the study above,the horizontal distribution of secondary porosity zones were integrated forecast.This paper analyzed the influences of characteristics of reservoir rock physical and pore characteristics, sedimentary facies, diagenesis and shielding fault conditions on reservoir water distribution.Optimized 6 favorable blocks, wherein 3 class I favorable blocks,1 class II favorable block,2 class III favorable blocks,and optimized 3 favorable wells.