Reservoir Architecture Characterization Of The 1^st Sand Group Of Es2 In The Second Area Of Shengtuo Oilfield

Shengtuo Oilfield,a large-scale integrated oilfield put into production in the early stage in China,has experienced water injection development for more than half a century.At present,its comprehensive water cut is up to more than 97%entering the stage of extremely high water and it occurs problems of water injection channeling along the high permeability zone and severe imbalance of displacement.All these result in the recovery ratio decline significantly.Therefore,the fine characterization of reservoir architecture is of great significance to enhance oil recovery in the later stage of oilfield development.This thesis with the support of rich core,seismic,logging and dynamic data and the instruction of outcrop and modern deposition describes reservoir architecture for braided river and shallow lake beach-bar of 2^nd member of Shahejie Formation?Es2?in the second area of Shengtuo Oilfield.Then explain template of architectures are built and vertical stages for target stratum are divided.Under the constraint of quantitative scale,the multi-well fitting method is adopted to dissect multiple hierarchical architecture of research area.And it's the next step to use dynamic data to verify and establish the architural models of braided river and shallow lake beach-bar.Finally 3D model shows the spatial distribution of reservoir architecture.The conclusions of this study are as follow.?1?There are two types of sedimentary facies in the research area.The top is braided river and the bottom is shallow lake beach-bar.The overall decline of lake level in the Es2s1 sand group leads to the change from the underwater shallow lake to the exposed surface water environment.The enhance of fluvial action advances braided river to the lake basin.The conversion between shallow lake beach-bar and braided river dues to the frequent changes of long-term,medium,short and ultrashort datum level cycle.?2?The seven-level architecture of braided river includes brained belt and floodplain.The eight-level architecture covers channel bar,braided channel and overbank.Both the accretion and falling mud layer in the channel bar constitute the nine-level architecture.The components of seven-level architecture in beach-bar are beach-bar complex and mud of shallow lake.And the eight-level architecture includes beach sand and bar sand.The nine-level architecture is consist of accretion and falling mud layer in the bar sand.?3?In the braided river reservoir,braided belt distributes in a continuous thick-layer along the paleocurrent direction.The channel bar is rhomboid with its long axis paralleling to the paleocurrent direction.The interlaced braided channels cut down to the bottom of the channel bar.And the narrow banded over bank is distributed in the boundary of braided belt while the mud of floodplain is an essential interlayer.In the inner channel bar,there are 2-3 periods of topset inner accretion with falling mud layer developing partially.?4?In the beach-bar reservoir,beach-bar complex parallels offshore with the continuous and semi continuous distribution.Bar sand is long spherical with its long axis paralleling to the lake shoreline.Beach sand is associated with bar sand or isolated in the mud and shallow lake mud is an important interlayer in vertical and lateral direction.The interior of bar sand develops 1-3 periods of covered accretion while falling mud layer is preserved nicely.?5?The established reservoir architecture model adopts the surface-based deterministic modeling method in order to reflect the spatial distribution of the underground architecture appropriately.