Sedimentary Microfacies And Geological Modeling Research Of Member K₂qn³in Old Area In Jilin Qian'an Oilfield

Currently,the old area in Jilin Qian'an Oilfield has entered the mid-to-late stage of development.The study of early sedimentary reservoir can't meet the demand of today's development.The formation of Member K₂qn³in old area in Jilin Qian'an Oilfield is taken as the research object.The research of stratigraphic division and correlation,sedimentary microfacies distribution,facies-controlled single sand body characterization,and 3D geological modeling are studied by using core data,logging data and seismic data of study area.2 long-term base level cycles have been developed in Member K₂qn³in study area,which are internally divided into 12 sand groups,42sublayers,and 18 single layers,for a total of 52 sedimentary units.The source supply during K₂qn³period in study area is mainly from Baokang river system in the southwest of Songliao Basin.The delta front subfacies are developed in study area in K₂qn³period,which can be subdivided into underwater distributary channel,underwater natural levee,distal bar,and underwater interdistributary bay microfacies,according to sedimentary facies marks and logging facies templates.Along with the descent-rise-descent change of the lake level,the plane morphology of underwater distributary channel shows the change of bifurcated shape–reticulated shape-bifurcated shape–curved shape.The composite sand bodies in Member K₂qn³in study area can be divided into 4 types.Based on the vertical and horizontal division marks,7 spatial contact relationships of the single sand bodies models are summarized.Quantitative parameter characterizations of the single sand body at stratified levels shows that the width,thickness,and width-to-thickness ratio of the single sand body are related to the lake level changes.The 3D geological model of Member K₂qn³in old area in Jilin Qian'an Oilfield is established,including the structural model and sedimentary microfacies model.The sand body model and reservoir parameter model are established by using the facies-controlled principle.The geological reserves of Member K₂qn³in old area in Jilin Qian'an Oilfield are calculated.4 modes of single sand body and remaining oil distribution are established based on the combination of single sand body distribution and production data,which deepen the study of single sand body description and reservoir description,provide the basis for well patterns adjusting and perforating fracturing in study area.