A 3Y4 Type Growth Curve Improvement Model and Its Validation

Although yield increase curves have high theoretical significance and practical value, the 3Y4 yield increase curve among them is not satisfactory for prediction compared with the two curves 3Y1 and 3W that have been formally written into the standard. In recent years, some scholars have proposed an improved 3Y4 yield increase curve (referred to as 3Y4-1), which has improved the prediction accuracy, but the prediction error is still large at the early stage of development and overall. In order to further improve the prediction accuracy of 3Y4 production enhancement curve and expand its applicability, an improved production enhancement curve model (referred to as 3Y4-2) is established by expanding the primary function of cumulative production and development time into a quadratic time logarithmic function on the basis of the advantages of 3Y4-1 production enhancement curve. Through the comparison and validation of the actual production dynamics of two fields, the results show that the mean values of the overall prediction errors of cumulative production and water content of 3Y4-2 production enhancement curve are less than 1.5% and 15%, respectively. In addition, the model has generalized properties, covering both 3Y4 and 3Y4-1 production enhancement curves, and can be applied to the prediction and planning of field production dynamics with a certain degree of improvement in prediction accuracy and applicability compared with the previous two models. The reason for the slightly worse prediction effect of the validation example 2 compared with example 1 is that the Pinghu oilfield is a condensate reservoir with complex oil-gas-water relationship and strong nonlinearity of the actual data, and the applicability of the method in such reservoirs needs to be further demonstrated in the later research work. The applicability of this method in such reservoirs needs to be further demonstrated in later research work. The research results of this paper have a certain role in promoting theoretical research and practical application of production enhancement curves.