Different configurational orders of sand bodies and interlayers in lacustrine nearshore sand bar reservoirs frequently interact,causing complicated genesis and distribution of argillaceous sediments,as well as other i...Different configurational orders of sand bodies and interlayers in lacustrine nearshore sand bar reservoirs frequently interact,causing complicated genesis and distribution of argillaceous sediments,as well as other issues.This paper investigates the spatial configuration of sand and mud in the sand bar reservoir,and analyzes its internal structure.Modern sand bar deposits in the Xiashan Lake,Shandong Province,China,were analyzed and compared with the sand bar reservoirs of the Member 2 of the Paleogene Shahejie Formation in the Banqiao Sag,China.The configurational mode of sand bar deposits was explored from the perspective of the spatial distribution and composition relationships between sand and mud.Based on the alternate deposition characteristics of sand and mud in the longitudinal direction,lacustrine nearshore sand bars can be divided into three sedimentary combination patterns:thin-sand and thin-mud interbed pattern,thick-mud thick-sand pattern,and thin-mud thick-sand pattern.Their mud components manifest as the deposition of fine-grained lithofacies of multiple genetic types.These include(semi-)deep lacustrine mud,sand and mud interbedded beach,argillaceous sediments in the water retention area behind the bar,and fall-silt seams that resulted from flood discharge.By summarizing the specific developmental locations and sequential relationships of each fine-grained argillaceous facies in modern sand bar deposits,a depositional process-based argillaceous sediment composition model is proposed.Based on this,this paper discusses the spatial configuration of sand bodies and argillaceous sediments in sand bar reservoirs,and introduces the typical stratigraphic structures of sand bars in two environments,i.e.,vertical superposition and lateral migration.In lacustrine nearshore sand bar reservoirs,the deposition and preservation degrees of mud mainly depend on three factors:accommodation space change,frequency of base-level cycles,and exposure-erosion time.These in turn influence the continuity and relative contents of sand and mud in reservoirs.The distribution of argillaceous sediments forms different orders of interlayers,which affects the heterogeneity and fluid percolation of sand bar reservoirs.Clarifying the space-matching relationship of sand and mud in sand bar deposits provides geological models and information parameters for the refined characterization and modeling of the internal configuration of sand bar reservoirs.Furthermore,this work offers guidance for the optimal adjustment of reservoir development strategies or the optimization of reservoir development plans.展开更多
In order to explore the influence of sandstone architecture on waterflooding mechanisms using the architecture method,and taking as an example the M-I layer of the Kumkol oilfield in the South Turgay Basin,Kazakhstan,...In order to explore the influence of sandstone architecture on waterflooding mechanisms using the architecture method,and taking as an example the M-I layer of the Kumkol oilfield in the South Turgay Basin,Kazakhstan,we portrayed the architecture features of different types of sandstones and quantitatively characterized heterogeneities in a single sand body in meandering river facies.Based on the waterflooding characteristics of point bar sand and overbank sand according to waterflooded interpretation results in 367 wells and numerical simulation results of well groups,we finally analyzed the remaining oil potential of the meandering river sandstone and pointed out its development directions at the high water cut stage.The result shows that because lateral accretion shale beds are developed inside single sand bodies,the point bar sand is a semi-connected body.The overbank sand is thin sandstone with poor connectivity,small area and fast lateral changes.The heterogeneity of the overbank sand is stronger than the point bar sand.The sandstone architectures control the waterflooding characteristics.In meandering river sandstones,the bottom of the point bar sand is strongly waterflooded,while the top of the point bar sand and most of the overbank sand are only weakly waterflooded or unflooded.The thickness percentage of unflooded zone and weakly waterflooded zone in point bar sand is 40％,and the remaining oil in its top part is the main direction for future development.展开更多
基金Supported by the National Natural Science Foundation of China(41702359)China National Science and Technology Major Project(2016ZX05033003-003).
文摘Different configurational orders of sand bodies and interlayers in lacustrine nearshore sand bar reservoirs frequently interact,causing complicated genesis and distribution of argillaceous sediments,as well as other issues.This paper investigates the spatial configuration of sand and mud in the sand bar reservoir,and analyzes its internal structure.Modern sand bar deposits in the Xiashan Lake,Shandong Province,China,were analyzed and compared with the sand bar reservoirs of the Member 2 of the Paleogene Shahejie Formation in the Banqiao Sag,China.The configurational mode of sand bar deposits was explored from the perspective of the spatial distribution and composition relationships between sand and mud.Based on the alternate deposition characteristics of sand and mud in the longitudinal direction,lacustrine nearshore sand bars can be divided into three sedimentary combination patterns:thin-sand and thin-mud interbed pattern,thick-mud thick-sand pattern,and thin-mud thick-sand pattern.Their mud components manifest as the deposition of fine-grained lithofacies of multiple genetic types.These include(semi-)deep lacustrine mud,sand and mud interbedded beach,argillaceous sediments in the water retention area behind the bar,and fall-silt seams that resulted from flood discharge.By summarizing the specific developmental locations and sequential relationships of each fine-grained argillaceous facies in modern sand bar deposits,a depositional process-based argillaceous sediment composition model is proposed.Based on this,this paper discusses the spatial configuration of sand bodies and argillaceous sediments in sand bar reservoirs,and introduces the typical stratigraphic structures of sand bars in two environments,i.e.,vertical superposition and lateral migration.In lacustrine nearshore sand bar reservoirs,the deposition and preservation degrees of mud mainly depend on three factors:accommodation space change,frequency of base-level cycles,and exposure-erosion time.These in turn influence the continuity and relative contents of sand and mud in reservoirs.The distribution of argillaceous sediments forms different orders of interlayers,which affects the heterogeneity and fluid percolation of sand bar reservoirs.Clarifying the space-matching relationship of sand and mud in sand bar deposits provides geological models and information parameters for the refined characterization and modeling of the internal configuration of sand bar reservoirs.Furthermore,this work offers guidance for the optimal adjustment of reservoir development strategies or the optimization of reservoir development plans.
基金funded by the Major Program of PetroChina(2011E-2506)
文摘In order to explore the influence of sandstone architecture on waterflooding mechanisms using the architecture method,and taking as an example the M-I layer of the Kumkol oilfield in the South Turgay Basin,Kazakhstan,we portrayed the architecture features of different types of sandstones and quantitatively characterized heterogeneities in a single sand body in meandering river facies.Based on the waterflooding characteristics of point bar sand and overbank sand according to waterflooded interpretation results in 367 wells and numerical simulation results of well groups,we finally analyzed the remaining oil potential of the meandering river sandstone and pointed out its development directions at the high water cut stage.The result shows that because lateral accretion shale beds are developed inside single sand bodies,the point bar sand is a semi-connected body.The overbank sand is thin sandstone with poor connectivity,small area and fast lateral changes.The heterogeneity of the overbank sand is stronger than the point bar sand.The sandstone architectures control the waterflooding characteristics.In meandering river sandstones,the bottom of the point bar sand is strongly waterflooded,while the top of the point bar sand and most of the overbank sand are only weakly waterflooded or unflooded.The thickness percentage of unflooded zone and weakly waterflooded zone in point bar sand is 40％,and the remaining oil in its top part is the main direction for future development.
