Fast and accurate prediction method about productivities of horizontal wells in merged overseas oilfields

Incomplete data in merged oilfields in international cooperation may lead to significant error in predicting productivities of horizontal wells. In extreme cases, such error may lead to big difference in economic performances during merging process. In the concerned study impacts of “four-dimensional” factors including water production, de-gassing, sand production, etc. for productivity prediction of horizontal wells were reviewed in reservoir space and time, then on the base of the Joshi Equation, the model for predicting the productivity of horizontal wells in different production stages was built with consideration of the effect of de-gassing and sand production on dramatic changes of relative permeability, and finally the impact of various factors on the productivity of horizontal wells at different bottom-hole flow pressures was clarified, and quantitative evaluation on the impact of individual and multiple factors was performed. The new model was used to determine the productivity of some horizontal wells in a merged overseas oilfield. Compared with the conventional model, the new model can enhance calculation accuracy for up to 34.66% in productivity prediction for horizontal wells. Reliability of the model has been verified through field applications.