Research On Individual Sandbody Identification/Description Method For River-Delta Sedimentary Reservoirs In The Southern Songliao Basin

JiLin QianAn And LingJing Oil Field is characterized as a large river-delta sedimentary reservoir with multiple formations, great thickness and high heterogeneity. As oil production enters into ultrahigh water cut period, the residual oil distributes quite differently in vertical and horizontal directions, resulting in tertiary production techniques have become leading ways to further improve oil recovery for this special stage. From the point of mechanism, the EOR can produce more residual oil that depends on precise descriptions on heterogeneous characteristics of intra-layers. At present, the reservoir descriptions, from sedimentary cells in vertical direction to sedimentary phase in horizontal direction, cannot completely demonstrate the heterogeneity of intra-layers. Although many people, domestic and abroad, have done a lot of research on outdoor geological outcrops and current river sediments, there are still not mature methods and techniques in terms of individual sandbody identification and description.Based on the studies and investigation on relative technical literatures and research results at home and abroad, the paper put forward to the method and criteria of individual sandbody identification and description and established relative process system, which has combined with core data, logging test data of infill drilling well pattern, fine description results and some theories and methods regarding the sediment, formation sequence, geological statistics, layer arrangement analysis and others. The innovative techniques include individual sandbody identification and description methods for river and delta sedimentary reservoirs as well as individual spot/dam identification method for curving river compound sandbody.The research results has been applied to three typical blocks, not only making the method and process more perfect, but also providing practical base for producing more residual oil. Meanwhile, the research has great significance on future structure properties studies of river phase reservoirs.