A Study on the Sedimentary Evolution of Meandering Rivers in the Jurassic J3ak Layers of K Oilfield

Within the Jurassic J3ak interval of the southern area of the K Oilfield, meandering river deposits are prominently developed, exhibiting complex and variable depositional characteristics. This study employs a combination of core descriptions, detailed well logging interpretation, and seismic attribute extraction and analysis to successfully establish a depositional model for the KK Oilfield’s meandering river system. The results reveal that the channel morphology of the meandering rivers evolves into diverse flow patterns in response to fluctuations in water levels, and the spatial distribution of the sediments shows significant variations. Specifically, the meandering river deposits in the area can be subdivided into four subfacies: channel-retention deposits, shoreface deposits, levee deposits, and overbank deposits. Among these, reservoirs corresponding to shoreface and channel-retention deposits exhibit higher productivity, while those associated with levee and overbank deposits demonstrate lower production performance. This study not only elucidates the internal evolution of the meandering river deposits but also provides robust geological evidence for further development of residual oil and for implementing lateral expansion strategies.