Research On Flow Field Transformation Of Sand Reservoir In Extra-high Water Cut Period

At present,many oil fields in China have entered the extra-high water cut stage.In order to stabilize production and increase efficiency,it is urgent to extract and tap the remaining oil of these fields.By studying the oil-water flow law in the underground during extra-high water cut period,the distribution of remaining oil can be predicted and determined.The study of flow field can provide scientific guidance effectively for the next step of production adjustment,so the study is particularly important at present.In view of the situation of the extra-high water cut in the typical sand reservoir,this paper analyzes the factors of affecting the flow field and uses logic analysis to screen out two main factors.The two main influencing factors are analyzed in detail,and the modified flow field intensity formula is characterized by fuzzy comprehensive evaluation method and subjective and objective weighting method,and its actual reservoir meaning is explained,and the sensitivity of the newly characterized flow field intensity is studied in detail from the static influencing factors and dynamic influencing factors.Based on the characterized parameters,the evaluation index and zoning method of the flow field intensity in the reservoir are proposed.It is found that the average flow field intensity can reflect the current production ability,and the variation coefficient of flow field intensity can better reflect the cumulative production of the reservoir.The distribution law of flow field intensity is conducive to the further application in the reservoir,which is of great guiding significance for the adjustment and potential tapping of the reservoir during high water cut period.The flow field transformation analysis of well pattern adjustment in different rhythmic formation was carried out during the extra-high water cut period,and the law of flow field transformation was obtained.It was found that there was a large amount of remaining oil in the area with low flow field intensity.If it was produced according to the original production mode,the remaining oil will be difficult to extract.The change of the oil-water relative permeability curve caused by the long-term flushing by the injected water can affect on the flow field,which is fundamentally explored.Finally,the flow field transformation in the reservoir with bottom and edge water respectively carries out the analysis,and the characteristic law of residual oil and flow field intensity distribution were studied through the practice of the mine.The relevant laws were verified and relevant suggestions for enhancing oil recovery were given.