Study of Evolution,Distribution and Sedimentary Model of Gaotaizi Reservoir in Daqing Placanticline
[Objective]A systematic study of the sedimentary evolution and reservoir heterogeneity of the Gaotaizi reservoir in the Daqing placanticline was conducted to clarify the strata series combinations and deposition sequences for tertiary oil recovery development,and to guide the overall planning and deployment of tertiary oil recovery from the reservoir.[Methods]Beginning with a description of 11 cores from wells in the placanticline,the sedimentary en-vironments for different horizons and locations were determined.The evolutions of the sedimentary sequences along the north/south and east/west sections were assessed to arrive at sedimentation models.The heterogeneous properties of the sand bodies were determined from the microfacies in the different sand body units.[Results and Conclu-sions]It was found that the Gaotaizi reservoir comprises a lacustrine regression/accumulation/regression sequence set developed on an overall lacustrine regression background.The unit boundaries were determined for lake shoreline,in-ner and outer front,and outer front pinch-out line.Three delta sedimentary model types,together with six subtypes,are evident:a river-controlled branch model;a wave-controlled sheet model;and a flow-controlled lumpy-sediment model.It is clear that the second and third types occur in the Gaotaizi reservoir.The third type is subdivided into ⅢA,ⅢB and ⅢC.The distributions indicate that the optimal sand body combinations are present in the Lamadian and Sazhong oilfields(combinations of three or four sets),and the Sabei and Sanan oilfields(combinations of one,two or three sets).A polymer injection field test at the Lamadian 182 block produced uniform 10.4％stage-enhanced oil recovery,indicating favorable development potential.
Daqing placanticlineGaotaizi reservoircharacteristics of evolutionary distributiondepositional modelreservoir type
万方数据
维普
