Title : Development and field application of a flexible cement system for high temperature steam injection wells to enhance well integrity
Abstract:
The steam injection method is widely employed in heavy oil reservoirs to enhance production by reducing oil viscosity through high-temperature steam injections. These temperatures, reaching up to 400°C, induce cyclic thermal stresses on the wellbore, resulting in the expansion and contraction of the casing, which poses significant risks to cement sheath integrity. Such thermal cycling can lead to cement failures, including strength retrogression, shrinkage, and loss of zonal isolation, ultimately compromising the well's integrity and reducing operational lifespan. This paper presents the development and application of a novel flexible cementing system- termed the "Flex Cement System" - specifically engineered for high-temperature steam injection wells. The system incorporates advanced additives to counteract the detrimental effects of thermal stress and maintain the cement's mechanical properties under severe conditions. The design significantly mitigates strength retrogression while ensuring the system remains durable and flexible enough to endure cyclic casing deformation.
Field trials were conducted in approximately 25 steam injection wells in Kuwait, with the "Flex Cement system" demonstrating exceptional results in maintaining compressive strength and achieving excellent cement bond log (CBL) outcomes. Being a field proven design, the technology has been deployed for field application with over 80 wells completed till date. The study also explores the interaction between the cement matrix and casing during steam injection operations, highlighting how flexibility and reduced permeability prevent gas migration and cement failure over the well's lifecycle. This paper contributes to the growing body of knowledge on thermally resilient cementing solutions, offering valuable insights into the material design and the best operational practices required to ensure the long-term integrity of steam injection wells. The implications of this study extend beyond current applications, providing a framework for future developments in thermal cementing technology for high-temperature well environments.
Key Words: Cementing, Heavy Oil Reservoirs ; Well Integrity ; Thermal Stresses ; Cyclic Steam Injection
