Water injection is by far the most popular method used in the secondary recovery phase of field development for oil displacement and pressure maintenance. Proactive reservoir management is important to validate the efficiency of the existing water injection schemes and to assess field development strategies to prolong oil production plateau and improve the recovery factor (RF). The main challenges arise in stretching the reservoir target whilst ensuring stabilized or reduced water cut (WCT), minimizing by-passed oil volumes and preventing wells from becoming inactive due to high WCT.
In order to mitigate premature water flooding issues, mainly two options are available: (1) artificial lift techniques to activate producers suffering early and rapid water breakthrough; and (2) optimized completion designs via preventive or corrective controls. Preventive (i.e. proactive) approach involves segmenting the wellbore using sliding sleeves, influx control equipment, limited-perforated liners, while corrective (i.e. reactive) methods attempt to divert/remedy unwanted water influx via water-shut off (WSO) interventions. None of these alternatives can be fully pursued as full-field development strategies without realizing the technical limitations as well as their economic benefits.
The objective of this paper is to determine the value of applying subsurface water control strategies in the context of enhancing reservoir management and develop a novel framework to assess potential remediation opportunities. The technical evaluation was supported by a robust Integrated Reservoir Management (IRM) process. This process identified the rig/rigless jobs opportunities to intervene inactive wells due to high WCT and rank all possible mitigation methods in an automated economic manner.
The findings have also proved the value of installing autonomous inflow control devices (AICDs) to control water production along horizontal sections. In effect, it controlled water slumping without jeopardizing oil production of wells awaiting gas lifting. A case scenario of combined Gas-lift and ICD deployments suggested a net incremental value of $66 million (or 106%). Field test results of the horizontal well's production and WCT were found to be within 10% of the expected planned rates, and the oil gain is expected to further improve by 50% when gas-lift is commenced.