| In Y Oil-field of the Middle East,the geometry,connectivity and reservoir property of the comprehensive Carbonate reservoir is very complex.On the basis of fully studying the oldexploratory well data,the carbonate reservoir characterization techniques are researched and applied in this dissertation.Guided by the theory of Sequence Stratigraphy and controlled by regional standard layers,the early Cretaceous formation layering and correlation of five exploratory wells are carried out in this dissertation.Sarvax group is divided into Seven4th-grade sequences,which are upward-coarsening reverse cycle,to be further divided into sixteen layers.Fahliyan group is divided into four4th-grade sequences,to be further divided into nine layers.On the basis of the isochronous stratigraphic framework,the structure contour maps are made.The structure is a low-dip anticline along north-south distribution.Combined with regional geological background and the coring data and logging curves,the study of sedimentary facies suggests that Sarvak and Fahliyan groups are shallow water carbonate platform sedimentary reservoir with mainly chalky limestone and argillaceous limestone.The main sedimentary sub-facies are platform edge reef(shoal),platform fore slope facies,platform shoal facies,wherein,beach and shallow sub-facies constituted the main reservoir of Sarvak group and Fahliyan group.Sedimentary characteristics determines that the continuity of the Fahliyan reservoir is better than that of Sarvak group.By using wire-line logging data,combined with core analysis,mud logging,production test data,this dissertation carries out the studies on the relationship of four properties and the interpretation model of reservoir parameter,then establishes the standard of identifying oil-water layer and division of effective thickness,determines the parameters of reserves.Based on core observation,FMI imaging logging data and structure stress analysis,it's considered that there is mainly porous type of reservoir in the oilfield.In the form of micro-fracture,three types of fracture mainly develop,such as structural fracture,diagenetic fracture and weathering crack.Innovatively applying Monte Carlo method to interpret fracture with conventional logging curves,and establishing the model of development degree of fractures,which can improve the precision of identifying fracture with conventional logging data.Based on analysis of main geological factors that control the crack and fracture development,Fracman and 3D-Move software are used for prediction and research on the distribution offractures lateral and vertical.The main fracture trends are E-W,NE-SW,N-S.The lateral distribution of micro-crack and micro-fracture is mainly controlled by structurestress,and the vertical variation is mainly controlled by lithology.The existing of micro-fractures effectively improves the reservoir permeability.In this dissertation,through the Interactive Petrophysics(IP)advanced interpretation software,an attempt is made,successfully,to determine the oil-water contact(OWC)of the complex carbonate reservoir in Y Oilfield by using capillary pressure data.Firstly,the function of water saturation(Sw)and height H(above free-water-level)was fit by the capillary pressure(PC)curves.Combined with the Sw profile,in which,water saturation(Sw)is computed and interpreted through conventional logs,the free water level depth is calculated through the best fitting method,and further,the oil-water contact(OWC)is calculated and determined.From the analysis of reservoir profile and characteristics,it shows that Sarvak reservoir is the layered massive reservoir with edge and bottom water,which is overall with oil above water,and the water-up-to(WUT)gradually ascends from north to south.Fahliyan reservoir is the layered reservoir,which has three sets of oil-water contacts.On the basis of the above researches,the 3D geological model of the reservoir is established in Y oilfield,which is tested,verified and improved by the application of new wells' data. |
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