An improved empirical model for production prediction of horizontal wells of Chang7 shale oil in Yanchang Oilfield
The horizontal wells of Chang7 continental shale reservoirs in Yanchang Oilfield decline rapidly in the early stage and slowly in the late stage.On the basis of fitting monthly and cumulative production data with YM-SEPD and Duong method,a new improved Duong model is proposed by defining"intercept cumulative production",introducing new intermediate variables,and changing monthly production fitting to cumulative production fitting when fitting the linear intermediate variables,and compared with another improved Duong model(WK-Duong model).The results show that:1)YM-SEPD and Duong models are greatly affected by the fluctuation of monthly production data,wherein the positive and negative values of YM-SEPD fitting errors change with the increase of time,while the Duong model fitting errors gradually increase.2)When the key parameter q1 is fitted by the WK-Duong model,the intercept of the fitting line is considered to be 0,which is inconsistent with the actual production of continental shale oil in Yanchang Oilfield and affects the fitting accuracy.3)The new improved Duong method reduces the influence of monthly yield data fluctuation on linear fitting by fitting the relationship between cumulative yield and related parameters,and optimizes the subsequent solving process,with the highest fitting accuracy compared with other methods.The new improved Duong method can be used to accurately fit and predict the production of horizontal wells of Chang7 shale oil in Yanchang Oilfield,which has reference significance for the production evaluation of continental shale oil.
Yanchang OilfieldChang7continental shale oilproduction predictionempirical modelimproved Duong model
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