| Most of China’s oil fields have entered the stage of high(ultra-high)water cut in the middle and late stage of development.Due to the complexity of sand body internal structure and insufficient understanding of sand body connectivity,it is difficult to tap the remaining oil potential and the contradiction between injection and production is large.This paper takes sheng1 area of Shengtuo oilfield as the research object,aiming at the frequent breach and bifurcation of distributary channel in delta sedimentary system of Sha 2 member 1 sand group,which leads to subsidence On the basis of fine division and correlation of reservoirs,sedimentary microfacies,distributary channel reservoir structural style and connectivity were studied.The following achievements and understandings have been made in this paper:(1)The 1 sand formation of the second member of Shahejie Formation in the study area is divided into 2 layers and 7 rhythmic layers.Under the guidance of equal elevation and phase transformation contrast model,the 1 small layer 2 and 3 rhythm layers are further subdivided into 3 and 4 single sand bodies according to the shape and structure characteristics of sand body;(2)The distribution characteristics of rhythmic layer and single sand body are revealed.1-11 and 1-14 channel sandbodies are distributed in a small range,and they are distributed in NWSE direction in the northwest;1-13 channel sandbodies are generally narrow and mainly separated by Bay on the plane.From 1 to 12,the distributary channel sandbodies gradually migrate to the west of the study area.On the profile,the individual sandbodies are overlapped and connected,while laterally,they are mainly connected by short distance interval and main body;(3)It is proposed that the typical delta plain distributary channel deposits are developed in the target strata of the study area.The single sand body is thin,and the sand body is distributed in a zonal manner,and the profile has the characteristics of bank overflow sedimentation channel channel overflow deposit river channel;(4)the connection patterns of different rhythmic layers and single sandbodies are proposed,which mainly include unconnected type,weakly connected type superimposed on the edge of distributary channel and main connection of distributary channel On the plane,there are three types of sand body contact structures,i.e.,bay segmentation and disconnection type,interval connection type(sand and mud)and flaky connected type. |
