Reliable, Sustainable, and Innovative Workover (Cementing) Solution for Converting the Water Injector Well into Wag Injector

Abstract The accelerating global demand for energy is placing unprecedented pressure on the oil and gas industry to deliver reliable supply while upholding economic efficiency and environmental responsibility. As industrialization and urbanization continue to expand, operators are increasingly targeting deeper and more technically complex reservoirs. These developments present significant challenges—from advanced drilling requirements to the imperative of minimizing environmental impact. In response, the industry is aligning its operations with broader sustainability goals by investing in innovative technologies, low-carbon solutions, and responsible resource management. These initiatives are critical to ensuring long-term operational resilience, regulatory compliance, and alignment with global energy transition objectives. As the oil and gas industry advances toward more efficient and environmentally responsible operations, the continuous pursuit of optimal Enhanced Oil Recovery (EOR) solutions is essential. One strategic workover approach gaining traction is the conversion of aging water injector wells into Water Alternating Gas (WAG) injectors, which improves recovery rates and reservoir performance. This paper presents a reliable, sustainable and innovative cementing strategy integrated with a liner tie-back configuration as part of a comprehensive workover solution to convert existing water injector wells into Water Alternating Gas (WAG) injection wells. The design incorporates a 7-inch liner tie-back system equipped with an Orifice collar, annulus casing packer (ACP), Hydraulic stage tool, and landing collar with a non-shearable ball seat. This configuration eliminates the need for temporary suspension using Acid-soluble plug (ASP), Wait-on-cement (WOC) time, or the complex deployment of drillable Bridge plug (BP) to reach final target depth (TD). The cementing strategy includes an optimized spacer system and the use of flexible and expandable slurry formulations to meet well integrity objectives. By removing the need for extensive rig-based interventions, this solution delivers substantial cost savings—up to 10-15% compared to conventional workover methods—while significantly reducing operational time and environmental footprint. These benefits align with broader industry goals for sustainability, resource optimization, and low-carbon development, positioning this approach as a compelling option for future Enhanced Oil Recovery (EOR) strategies.