Predicting the Flow ID of Water Injectors Identified with Obstruction in the Horizontal Section

Abstract This paper presents an automatic well performance method and advanced algorithm to estimate the size of any obstruction identified in the wellbore or in the horizontal wellbore section of injection wells. The advantageous feature of this analytical method is the ability to predict the size of obstruction without costly well intervention or injection shutdown. The method includes the determination of a calibrated well performance model with a simulated obstruction, using inflow performance and outflow performance relationships. The method calls for building the following two calibrated inflow performance models: a constant injectivity index model and a steady state Jushi model to take into account reservoir flow attributes such as permeability, anisotropy, and skin damage factor. On the other hand, the outflow performance model was constructed considering both gravitational and frictional pressure changes. Continuous surface flow measurements using Solar Flow Meter data were used to validate and calibrate the overall well performance model. An iterative algorithm was developed to estimate the obstruction size and generate its performance curve using surface injection data and single-phase choke flow equation. This has enabled the simulation of downhole obstruction effect on well injectivity. This method was used in determining the obstruction size within the horizontal section. The algorithm and the process were validated using actual case study with horizontal water injection well known with obstruction and palnned for well intervention.