Study On The Change Rule Of Development Index And Influence Factors In PX Field

The oilfield has entered the middle and high water cut stage,and the development contradiction has further intensified.This article takes the PX oilfield as the research object,and starts from the three perspectives of theoretical analysis,development experience summary of similar reservoirs,and actual development laws of the oilfield.The evaluation and analysis of the four aspects are mainly done as follows:(1)Establish normalization curves of water cut and recovery degree of 7 adjacent reservoirs in the same tectonic zone by linear interpolation,weighted average and other methods from the perspective of development experience,and derive the theoretical water cut change law based on the data of the PX oilfield phase permeability curve to establish the basis for the evaluation of the water change law and other indicators of the PX oil field;the displacement process curve method is used to determine the entire process and the staged water cut change pattern function of the PX oil field.Impact of well pattern infill adjustment during development on water cut and water cut rise.The results show that the water content is reduced by 20 percentage points in the short-term encryption,the degree of water flood control is improved,and the development effect is greatly improved;the scale of the second encryption is small,and reducing the water content by 5 percentage point.(2)In the low water cut stage,based on the typical characteristics of the initial stage of PX oilfield development,the empirical formula is used to predict the recovery rate under the conditions of the well pattern in the early stage of development;in the middle and high water cut stages,the actual development curve and theoretical analysis are combined to further determined the reason for the large difference in the recovery prediction of different water flooding law curves.The water rise rate in the later stages of the different water drive law curves is different,and the water rise rate law in the later stage of the water drive law curve and the water rise rate in the middle and high water cut periods of the oil field are proposed.The combined selection method uses the methods of inflection point recognition,segment prediction,and correction of Tong’s plate to predict and evaluate the recovery rates under the conditions of primary encryption,secondary encryption,and secondary non-uniform encryption,respectively,and quantify the effect of well pattern infill adjustment on recovery factor,the results show that the higher the water cut,the smaller the value of well pattern infill improvement.(3)Determine the theoretical change law of water content and recovery degree based onthe phase permeability curve.Based on the injection-production balance,deduce the change law of theoretical water retention rate based entirely on the phase permeability curve.The dimensionless injection curve-production curve and the water drive law curve were combined together to establish the prediction method of the water retention rate and water drive index based on the displacement law,and the water retention rate evaluation board was established based on the actual displacement law;Considering the influence of multiple factors and the instability of the actual data,the rank correlation coefficient method is used to analyze indexes such as fluid production rate,oil production rate,well pattern density,injection-production ratio,and oil-water well ratio.Correlation of water storage rate,the results show that: the liquid extraction rate and well pattern density have the greatest effect on the water injection effect.(4)On the basis of previous studies,A systematic approach about the formation of PX oilfield theoretical production decline type judgment,decline trend stability analysis,oilfield actual decline type discrimination,decline type correction,production index prediction and evaluation,and analysis of decline factor influencing factors were formed.The results show that the theoretical decline types of basic well pattern,primary infill well pattern,and secondary infill well pattern are hyperbolic decrease,which is consistent with the actual decrease law;local infill well patterns belong to harmonic decrease.Moisture content,fluid recovery rate and injection-production ratio have a greater impact on the decline in production of PX oilfields,and well pattern intensification has significantly slowed the decline in production across the region in the short term.