Division And Application Of Reservoir Flow Units In Qian 146 Block

Qian 146 block is located in northeast of Changling sag, Center depression region in south of Songliao Basin, expressing a nose like structure with a north leaning part and a south tilting part. Going though decades of production phases, now, the water ration is approximately up to 85%. Thus, the performance on research of reservoir flow units is vital to finding out the distribution of remaining oil and stabilizing production.On the basis of better learning about methods and measures of reservoir flow units division, we propose an approach of cluster analysis with multi-parameters applied in this region according to practical geology characteristic and production situation, with the purpose of full utilization of predecessors'research results and abundant logging materials. We divide into A, B, C, D, E five types of reservoir flow units in this region integrating with sedimentary microfacies type, accumulative thickness of sandstone, ratio of sandstone thickness and strata thickness, mud content, porosity, permeability, original oil saturation, storage coefficient, filtrating coefficient nine parameters.There is distinct difference among reservoir quality corresponding to the five reservoir flow units. We consider the reservoirs corresponding to A, B, C types reservoir flow units are the fine reservoir patterns. Furthermore, A type reservoir flow unit has the best reservoir quality, B type reservoir flow unit is the second one, C type reservoir flow unit has medium reservoir quality. The other reservoirs corresponding to D, E types reservoir flow units is commonly thought to be the invalid reservoir patterns. In plane, A, B, C types reservoir flow units distribute mainly in 39th, 40th, 42nd layers, D, E types reservoir flow units ordinarily distribute in 38th, 41st layers. We observe that, during analysis to influential factors of reservoir flow units, sedimentation is the chief controlling factor to reservoir flow units'types and their distribution. This function is mainly exhibited in aspects of thickness of sandstone, extent of distribution, connectivity behavior, development of barrier and interlayer, cycle rhythm of sandstone. Blockoff activity of fault and alteration of physical property are also the predominant affecting change and distribution of reservoir flow units.Correlationship resulting from statistics of reservoir flow units and production data in this region, reveals that A type reservoir flow unit is the best reservoir for petroleum to store, B type reservoir flow unit is the secondary, C type reservoir flow unit is a fine reservoir to petroleum storage, D, E types reservoir flow unit is almost have no petroleum storage ability. This petroleum storage characteristic show clearly object for remaining oil prediction, otherwise, under the influence of blockoff activity of fault, water injection impression of injection well and variation of vadose characteristic when reservoir flow units change, remaining oil in this region primarily situates in the fault boundary, no effective zones of injection well in the same reservoir flow unit, the boundary where reservoir flow unit changes. With the effect of commingled formation production, remaining oil in each layer of this region possesses succession and mainly locates in south, northwest and northern faults vicinity. Overall, 39th, 40th layers as the major reservoirs have large scale and abundant square areas of remaining oil in south, northwest and northern faults vicinity. 42nd layer is the secondary, 38th, 41st layers have an finite extent of remaining oil in south, northwest and northern faults vicinity.