Research On Gao Ⅱ1-18 Reservoir Characteristics Of L8-JP182 Area

Most of the oil fields in china, which have been explored several years, have already been in the period of high percent of water. In these oil fields, as oil and gas distribution is complex, a detailed study on reservoir characteristics has become the focus of the continuous production, which has an important meaning on the guidance of oil development.Taking the 1-18 layer of Gao II oil group in Lamadian L8-JP182 section for example, this paper has researched on division of sedimentary units and Identification of sedimentary microfacies in experimental purpose layer, under the guidance of the theory of sequence stratigraphy, sedimentology, reservoir geology, combined with sedimentary background of experimental zone, core data, the testing results and logging curve,etc. The GII1-18 layer has been divided into 20 sedimentation unit. and the experimental purpose zone is in the delta front environment, which generates 4 microfacies types in terms of underwater distributary channel, mouth bar, far sand dam, sand sheet.On this basis, this paper has studied the reservoir characteristics and the effecting factors of reservoir features. Then well-logging interpretation model of permeability and oil saturation has been established. the physical properties of the test purpose has been determined as medium porosity and medium permeability.Reservoir physical properties, distribution and heterogeneity are under the control of sedimentary evolution regularity and microfacies types. In vertical direction,physical properties is poor in the period of later water-in cycle and the period of early water-back cycle and the alternative layers is relatively develop with high anisotropy. Conversely physical properties is good in the period of early water-in cycle and the period of later water-back cycle and the alternative layers is relatively undeveloped with low anisotropy. In different microfacies sandbodies,physical properties of underwater distributary channel and mouth bar is developed and physical properties of distal bar is undeveloped with middle-low porosity and low permeation.On the basis of a detailed study on reservoir, the research has comprehensively evaluated test purpose layer and 3 types of reservoir has been divided. Among of them, III type of sandbody is remaining oil enriched area which almost distributes in the areas of the distributary channel, the edge of main shelf blanket sands, the folium of blanket sands and most outer reservoir.Through the reservoir characteristics and evaluation research,the research has determined the potentiality of reservoir distribution laws of remaining oil in high water existing period,which has effective guidance on the study of remaining oil potential and has profound and lasting meaning for oilfield remaining oil exploration and theoretical basis for the sustainable development.