Fine Characterization Of Delta Facies Reservoir Of Abu Gabra Formation In Neem Oilfield, Sudan

Neem field is located in the northeastern part of Muglad Basin in the Sudan,and the eastern uplift belt of Kaikang trough,the total area is about 320km2.Two main boundary faults which have opposite fault dip control this uplift belt.Based on the data of seismic,core and logging,this paper studied the reservoir fine characterization of Abu Gabra in the study area.Based on the theory of "high-resolution sequence stratigraphy" and "sedimentology",the fine stratigraphic division and comparison of the Abu Gabra group in Neem Oilfield were carried out by using the idea of "point-line-face-body".Identified a set of the main mark layer AG-4 layer and two sets of auxiliary marking layer AG-1,AG-5 layer;And the horizontal stratigraphic comparison was carried out by three-dimensional tracing of the marker layer.The Abu Gabra group was divided into eight sand groups,44 small layers.A total of 133 faults were identified by coherence slices and along the seismic amplitude attribute extraction method;the F150 and F009 faults divide the study area into three structural units: the southwest fault zone,the central tectonic belt and the northeast fault zone.Based on the stratified data,the top contours of the Abu Gabra group are plotted,Thus identifying the structural highs and the type of traps——fault traps and stratigraphic traps.The sedimentary facies identification indicates that the Abu Gabra Formation is mainly developed in the delta front and the front delta subfacies,which can identify the underwater distributary channel,Mouth bar,distal bar,interchannel,prodelta mud microfacies.A compreh-ensive analysis of FMI and seismic inversion data shows that the Abu Gabra source comes from the northeast direction of the work area.On this basis,the facies features of the sediment-ary microfacies are identified,and the sedimentary facies model of the Abu Gabra formation is established--Bird foot delta deposition.The reservoir types of the Abu Gabra Formation are mainly siltstone,coarse sandstone,a-nd conglomerate.The comprehensive interpretation of core and well shows that the reservoir properties of Abu Gabra group have the characteristics of middle and high porosity and high permeability.In the development of the former delta mudstone,the Abu Gabra Formation is divided into seven independent reservoirs in the vertical direction.The small fault and the interlayer —interchannel makes the direction of the seepage within the layer has changed,so that the reservoir heterogeneity of the Abu Gabra Formation in the study area is obvious.Base-d on the above analysis,it is deduced that AG-3,AG-4,AG-5 and AG-6 in Neem belong to favorable reservoir area.