Study On Reservoir Heterogeneity In The Sixth Sand Group Of Guantao Formation In Zhong 1 Area Of Gudao Oilfield

Reservoir heterogeneity is the major factor to influence on the seepage and driving of petroleum and plays an important role in the distribution of remaining-oil. The layer of the sixth sands group of Guantao formation in Zhong 1 area of Gudao oilfield developed braided river deposit, reservoir sand body varies fast horizontally, and heterogeneity is serious. Since Gudao oilfield came into the stage of high watered, the oil layer watered seriously, remaining oil is scattered. The thesis is focused on the reservoir of the sixth sands group of Guantao formation, developed the research of sedimentary microfacies, calculated reservoir heterogeneous synthetic index by using log interpretation parameters, and researched reservoir characterizations in the three sides of in-layer, interlayer and plane heterogeneity. On the basis of these studies, the relation between reservoir heterogeneous and remaining oil is analyzed.Following achievements have been obtained in this thesis: firstly, the layer of the sixth sands group of Guantao formation is divided five beds, and built up stratigraphic framework. Secondly, pointed out the styles and characters of sediment microfacies, and established the model of sedimentary microfacies. Thirdly, the research of in-layer heterogeneity model indicated that the reservoir is mainly with the two styles, intricacy positive rhythm and simple positive rhythm, and summarized characters, genesis and spatial distribution of three different interbeds. Fourthly, the research of interlayer heterogeneity model pointed out that physical property parameters are different greatly between main reservoir and non-essential reservoir; barrier wholly developed. Fifthly, by adopting heterogeneous synthetic index, reservoir heterogeneous is characterized quantitatively, then, obtaining conclusions that in-layer heterogeneity is middle, interlayer heterogeneity is stronger and the degree of reservoir plane heterogeneity is mainly middle to stronger. Sixthly, sedimentary microfacies are the most important factor to impact reservoir heterogeneity, the affection of diagenesis is little. Finally, microfacies is the most important factor to control the distribution of remaining oil, in the plane, remaining oil mostly distributed in the zone where reservoir heterogeneity is from middle to stronger, and in-layer remaining oil mostly distributed in the top of positive rhythm or the reservoir which is controlled by interbed and is not swept by injected water; in the view of interlayer, remaining oil mostly distributes in the main layer which is focus of exploitation.According to the results of reservoir heterogeneity research, the enrichment regions of remaining oil distribution are concerned and the wells are proposed, the application of this theses can be used in other similar oilfields, and have a guidance to improve developed effect and increasing ultimate recovery of Gudao oilfield.