The Influence of the Production Lines Pressure Drop in the Definition of the Oilfield Drainage Strategy

Abstract

Abstract The success of an oil field drainage project depends on the production strategy, defined by an optimization process that maximizes the project Net Present Value (NPV). Considering the complexity of the process, the industry tends to simplify the numerical simulations used, mainly by separating behaviour analysis of the reservoir and production facilities. The pressure drop in the production facilities, for instance, is not generally considered in the selection of number and position of the wells. The main objective of this work is to verify if these simplifications have significant influence on the final result of the production strategy selection process. For this purpose, three studies have been done, with different operational conditions and fluid types. For each case, two production optimization processes of an oil field drainage project have been made, considering a simplified and a dynamic pressure drop calculation. The simplified pressure drop analysis consists in a bottom-hole pressure definition that allows the fluid to rise to the platform. In the dynamic option, it is necessary to define the production line geometry and the fluid conditions to calculate the bottom-hole pressure for each configuration, and the pressure drop is calculated dynamically, at each time step. With the result of both processes, the number and position of wells and performance of the optimized production strategies were compared. Significant differences were observed in the two cases tested, showing that the pressure drop influences the definition of the production strategy, although this influence should be minimized by operational conditions. It was also observed that the greater influence occurs on the heavy oil reservoir and that the locations are more influenced by the reservoir particularities.