Study On Evaluation Technology Of Main Controlling Factors For Productivity Of Volumetric Fractured Horizontal Well In Tight Reservoir

Chang 7 reservoir in X block in southwest Ordos Basin belongs to a typical tight sandstone reservoir,and volume fractured horizontal well is used as the main development technology.After years of development practice,fractured horizontal Wells in the research area have the problems of great difference in development effect and unknown main control factors of productivity,and the situation of stable production in the oilfield is severe.Therefore,the production dynamic model of fractured horizontal Wells in the study area is divided,the relationship between various factors and productivity is defined,the main control factors of productivity of volumetric fractured horizontal Wells in tight reservoirs are evaluated,and an appropriate productivity prediction method is established,which has guiding significance for the deployment and development adjustment of new Wells in the later stage of the study area.Paper according to the X area geology,development and engineering data,by means of statistical analysis,according to the first-timer and tired production levels two parameters,establish the standard of fracturing production performance of horizontal well pattern in the study area,on the basis of the study area between natural energy development of fracturing horizontal Wells are divided into the following three models: high bond type and stable yield,high diminishing first-timer,continuous low yield.According to the above three production dynamic modes,the production decline curves with time are fitted respectively.The productivity of horizontal Wells in quasi-natural energy development in the study area conforms to the hyperbolic decline law,and the oil field production declines rapidly.Combined with the production performance analysis of typical fractured horizontal Wells,15 productivity influencing factors were optimized from three aspects of geology,engineering and development,and a set of comprehensive productivity evaluation system for fractured horizontal Wells in tight reservoirs was established.On this basis,in view of 66 fractured horizontal Wells in X area,statistical analysis methods such as partial correlation analysis method and grey correlation method were successively used to determine the main controlling factors of initial and cumulative production levels in the study area,and an effective comprehensive evaluation method of main controlling factors of productivity was formed.The evaluation ranking result of the main controlling factors of primary production level in X zone are as follows: fracture density > horizontal section length > intensity of sand > using fluid strength > flowback rate.Based on the evaluation results of the main production control factors and the decline law of the three production dynamic modes,the productivity prediction model of the fractured horizontal well in the study area was established,and the prediction error of the initial production level could be controlled within 7.8%.This paper realizes the effective prediction of the development productivity of volume fractured horizontal Wells in tight oil reservoirs,which solved the problems of unclear main controlling factors and difficult productivity prediction in the study area,and provided a theoretical basis for the subsequent deployment and development adjustment of new Wells in tight oil reservoirs in Ordos Basin.