Successful Selection Methodology for Down-Hole Flow Control, Orchard Field Waterflood Injectors

Abstract

This contribution elaborates on a successful selection methodology for best alternative for Down Hole Flow Control (DHFC) for Orchard field injectors. Situated in central Sumatera, Orchard field holds a key role in maintaining strong production performance to its operating company. In 2016, the field reached a recovery factor of 33%, solely from a primary recovery. First waterflood injection in Orchard field was started in September 2017. A combination of four new and eight conversion peripheral injectors are designed to deliver a total injection of 120,000 BWIPD through commingle injections into all three main reservoirs (R-, S-, and T-sand).
Implementation of robust methodology consisting of fit-to-purpose selection criteria and workover-on-paper exercise with the slick-line operator was a key enabler. At the beginning of the evaluation, only two selection criteria were applied: technical and economic. However, the interim result did not show a clear distinction between a preferred alternative and the two other options. A new criterion, long term operability, was introduced to the evaluation process, with main role to assess the risk profile of each DHFC alternative during initial and future job interventions. Application of the workover-on-paper exercise played a significant role in this evaluation step. The on-paper exercise managed to simulate every step of future intervention jobs, which helped to identify operational strengths and weaknesses of each alternative, and provide theoretical evidence on doability. In the end, the decision on preferred alternative was taken at right confidence level due to clear trade- off between alternatives based on the outcome of workover-on-paper exercise. 
This approach used less evaluation time and cost, compared to if it was done by performing real pilot installations for all DHFC alternatives. Paper exercise was very successful to establish right confidence level to take decision and make cost savings at least $ 100,000 for pilot installations.