Shallow-water deltaic facies-controlled reservoir prediction study:A case study of the Quantou Formation in the Da'an Area of the Central Depression,Songliao Basin
WANG Yuheng
YU Fusheng
LI Zhongcheng
WANG Xiaokun
XIONG Lianqiao
QI Yili
FENG Zhenming
Abstract：The frontal transition of the delta in the shallow-water lake basin is rapid,with com-plex sedimentary evolution and variable reservoir distribution.Conventional methods such as seismic slicing and well analysis are ineffective in analyzing the sedimentary evolution patterns and reservoir distribution.To enhance the accuracy of reservoir prediction and the precision of sedimentary model characterization in the shallow-water lake basin delta,the sedimentary evo-lution process of the 4th member of Quantou Formation in the Cretaceous of the Da'an area is reconstructed based on 3D seismic inversion,integrating well information,and dissecting and slicing the formations through a dense well network.The study quantitatively characterizes the range of reservoir distribution.The results show that under a sedimentary background of stable tectonics,gentle terrain,and fluctuating lake levels,a shallow-water delta is formed.The delta undergoes sedimentary evolution from early plain deposition of coarse-grained thick sands to later frontal deposition of fine-grained thin sands.Multiple lake-level advances and retreats also occur internally.The sand bodies mainly consist of sand-dam-type composite sedimentary bodies formed by river channel deposition,estuarine dam deposition,and overflow deposition,with width-thickness ratios ranging from 35 to 225.These bodies can form vertically isolated,superimposed,and replacement patterns.With the rise of lake level and reduced water energy,the advancing distance of sand dams decreases,curvature increases,and overflow deposition on both sides gradually disappears.The formations tend to gradually bifurcate at the end,forming a finger-like morphology.Under strong water dynamics,low-curvature branching forms more easily,tending to form an interlaced network morphology at the end.Reservoir quantification prediction in non-well areas or sparsely well areas is achieved through sedimentary facies control and attribute constraints.The accuracy of sand thickness prediction can reach 89.93％,providing new ideas and methods for reservoir prediction in oil and gas exploration.
Keywords：shallow water delta sedimentary modelwaveform indication inversionsedimentary facies control reservoir distributionCentral depression area of Songliao Basin
Publication Date：2024-05-30
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：21( 564-584 )