Fine Reservoir Description In Middle-late Stage Of Development In Sha 20 Block,Shanian Oilfield

After long-term development of sha 20 fault block,the contradiction between plane and interlayer gradually increases,the development trend becomes worse,the water cut rises slowly,and the output of sha 20 fault block shows a continuous decreasing trend.Oil field residual oil distribution is not clear,oil-water movement relationship is complex due to the single production layer system and the main way of development is layer by layer back development as well as the long-term water injection development.It is necessary to carry on deeply reservoir description and seepage channel research,and establish a three-dimensional geological model for reservoir numerical simulation of residual oil distribution.Based on geophysical exploration,drilling,coring,logging and some other data,combined with previous research and knowledge,using geological theory and reservoir description method,the micro-structure,single sand body sedimentary microfacies,reservoir heterogeneity,flow unit and dominant seepage channel description of the block were carried out,and a three-dimensional fine geological model of the block was established.And provide a basis for further evaluation of development of the oil reservoir and the distribution of residual oil.Through research,the following main results have been achieved:Firstly,microstructure study is an effective method to identify the distribution of remaining oil.Although this block is a narrow strip reservoir,there is still remaining oil controlled by microstructure;Secondly,reservoir description in the middle and late development period is based on sedimentology theory and combined with dynamic analysis to deepen the understanding of sedimentary microfacies.It still plays an important role in tapping the potential of remaining oil;Thirdly,the experiment shows that the physical parameters of the low permeability reservoirs in this area become worse after long-term water flooding.However,the overall decline is not significant.On the surface,there is no obvious change in reservoir parameters.However,it does not exclude the occurrence of local high physical properties and overall low distribution of cements in reservoirs,which may easily lead to the formation of channeling channels;Fourthly,the geostatistics method can effectively divide the flow units and judge the dominant seepage channels between oil and water wells.The results of the two methods can further provide a foundation for the treatment of single-layer outburst and flat-surface water line tongue intrusion;Fifthly,based on the detailed description of the reservoir,the flow unit is used as the constraint model for the first time,and a geological prediction model that can accurately reflect the distribution of oil,gas and water in the block is established.The results are applied to numerical simulation,and good results are obtained,which provides a technical basis for accurately and effectively describing the distribution of remaining oil in the reservoir in the middle and late stages of development.