Abstract
The steam injection method is widely deployed in heavy oil reservoirs to enhance production by reducing oil viscosity through high-temperature steam injections. These temperatures, reaching up to 500°F, 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, debonding ‘Inner-Outer’, cracking ‘compressional tensile’ leading to the loss of zonal isolation and ultimately compromising the well integrity and reducing operational lifespan.
This paper presents the development and application of a novel flexible cementing system- termed the "Thermal Cement System" – The system is specifically engineered for high-temperature steam injection wells, incorporates innovative additives to address the detrimental effects of thermal stresses 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 withstand cyclic casing deformation.
Field trials were conducted in approximately 75 steam injection wells in Kuwait, with the "Thermal Cement system" demonstrating exceptional results in maintaining compressive strength and achieving excellent cement bond log (CBL) outcomes. 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 design testing 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 environments.
