A Study On Sandstone Reservoir Flow Unit Of B48Fault-Block Oilfield

On the basis of the deep analysis for the present research situation at home andabroad, taking the48Fault-Block sandstone reservoir as studying object，research thereservoir flow unit which include control factors, division method, remaining oildistribution, production decline law and so on.Firstly, study the control factors of reservoir flow unit. The research shows that themain control factors of reservoir flow unit include the sedimentation that focus onreservoir rhythmic patterns, interlayer distribution, rock pore structure, stratificationstructure; the tectonic processes that focus on the sealing of fault, the development offracture; the fluid physical properties that focus on crude oil properties and developmentengineering factors that focus on development measures, well spacing density, recoveryrate, injection-production schemes et cetera.Secondly, classify the parameters which describe of the reservoir flow unit andmainly include the sedimentary characteristics parameter，reservoir macro-characteristicparameter, reservoir pore micro-structure characteristic parameter, fluid physicalproperties parameter, induction number; By analyzing the source and correlation degree ofparameters, and combining with the parameter selection principle, select9parameterswhich include porosity and permeability to divide the study region of reservoir flow unit.On the basis of adherencing to the classification principle of reservoir flow unit，usingSPSS software for cluster analysis, classify the reservoir flow unit of study region intoclass A, class B and class C. The seepage ability and reservoir capacity of class A is thebest, and the class B take second place, class C is the worst. Verify the rationality ofreservoir flow unit division by using early productivity, situation of producing fluid andabsorbing capacity. Results shows that this division scheme is more reasonable, andaccords with the physical significance of reservoir flow unit.Once more, taking the reservoir flow unit as unit and using volumetric method tocalculate the geologic reserve, from class A to class C were34.487×10~4t、47.563×10~4t、37.724×10~4t, respectively. The producing degree of different types of reservoir flow unitexists great difference, the degree of reserve recovery is decreased gradually from class A to class C. Using four method to predict the recovery ratio of study region, from theclass A to class C respectively are18.5%,16.7%,14.5%. Residual oil distribution law areclosely linked with the spatial distribution of reservoir flow unit; and propose the policy oftapping the potential of residual oil.Finally, using the software fitting analysis the decline type of production for reservoirflow unit, it is mainly to exponential decline, followed by the hyperbolic decline, and thedecline type may be changed by the change of development method. Through thederivation of equation of decline factors, six factors have influence on the productiondecline rate of flow unit. Analysised the factors on the impact of production decline by themethod of regular-crossed trial, class A is mainly based on the influence of water ratio andoil-water fluidity, class B and class C is mainly based on the influence of the size ofoil-water fluidity and the effective yield oil thickness of oil layer. At the same time,propose the corresponding palliation measures according to the degree of influence.