Title : Optimizing transfer pipeline size to minimize backpressure
Abstract:
Objective: This paper provides a design guideline on determining an optimum transfer line size over the life of field with assumed length and flowrates / water cuts. Further, the purpose is also to establish mitigations required to overcome any bottleneck. Achieving optimal production levels while ensuring an efficient transportation of produced fluids to processing facilities is crucial and requires a comprehensive understanding of various operational constraints. In this article, steps involved in determining an ideal size for a pipeline between two different locations is presented. Requirements from flow assurance assessments to facilitate efficient transportation of produced fluids and mitigation of potential flow-related issues are discussed. This article also highlights the benefits of artificial lift systems for increasing deliverability.
Methodology: A thermo-hydraulic model is developed using a multiphase flow simulator. Critical model input parameters typically are pipeline elevation profiles, fluid compositions, ambient temperature, and pipeline specifications. The multiphase flow behaviour is simulated by specifying appropriate boundary conditions. The optimum line size is determined through a series of flow assurance simulations based on the assumed gas/oil rates and water cuts during the field life.
Result: Valuable insights into the hydraulic performance of system and corresponding backpressure characteristics are obtained through these flow assurance simulations. Various critical parameters including pressures, total liquid volumetric flow rates under actual operating conditions, presence of slugs, minimum and maximum liquid and gas velocities, and erosional velocity ratios (EVRs) are analyzed. Most significant factors influencing pipeline sizing decision and the optimum pipeline diameter capable of minimizing backpressure are identified.
Novelty: A novel workflow is proposed in this study to optimize the transfer line size. In this paper, a methodology to obtain an optimal transfer pipeline size whilst minimizing the backpressure at wellheads is presented. This innovative solution also enhances the efficiency of electric submersible pumps (ESPs) due to lower backpressure leading to fewer stages and reduced power demands.
