Successful Debottlenecking of a Surface Injection Facility

Abstract

This paper will present a dedicated field case study that shows effective optimization of injection facilities obtained by hydraulic simulation. Water Injection Plants (WIPs) in the fields under study are operated as a secondary oil recovery method by means of peripheral injection. Field production strategy dictates water injection requirements in a given field. A core area of Field-A was identified with a need for increased injection pressure support. However, existing injection facilities could not meet the demand of increased injection rates. The injection capacity constraints were discerned by conducting a selective injection system capacity test. The feasibility of future improvements to the injection system using hydraulic simulation forecasts provided valuable and vital inputs. Accordingly, the most reliable and cost effective option was implemented in the field. Hydraulic simulation along with network pipeline modelling was utilized on this case study with the objective of debottlenecking the overall injection system. Well performance models for the water injection wells to represent the reservoir inflow performance relationships (IPRs) were built. The most recent injectivity indices and static bottomhole pressures were used to construct the IPRs. Calibrations were then performed using current injection rates and wellhead pressures to history match the data and produce representative individual wells IPRs. On the other hand, piping network simulation incorporates surface injection lines sizes and ground elevation to account for pipe friction losses and gravitational pressure differences. Additionally, data from WIPs pump performance curves were inputted into the simulator to integrate surface and subsurface flow and capture the working mechanisms of the injection systems in this case study. Surface piping network optimizations were achieved using the outputs of the hydraulic simulator runs and sensitivity analysis based on proposed corrective scenarios. The effect of these scenarios to the existing system was forecasted in terms of the ability to achieve the required individual wells injection targets. The simulated options were conceived on the following basis: Utilizing an identified extra injection capacity from one of the WIPs. Looping the injected water through pipelines network connecting different WIPs. Constructing new injection lines to the field flanks that need additional injection.