First Low-Carbon, Geopolymer Cement-Free Primary Cementing in the Middle East: A Case Study in Oman

Abstract A crucial step in the decarbonization of well cementing operations is the replacement of conventional cement with a cement-free system. One metric ton of carbon dioxide (CO2) is released to the environment for every metric ton of Portland cement manufactured. A geopolymer cement-free system, customized for downhole temperature and pressure conditions, was implemented in Oman. This case study presents an innovative, at-scale application of geopolymers in oilfield well cementing. In addition, it represents the first well cemented in the Middle East using the low-carbon geopolymer cement-free system. The geopolymer cement-free system uses aluminosilicates as raw material activated in an alkali environment to produce a set material with similar or better properties than Portland cement. This provides a sustainable alternative to conventional cement with a comparable performance while contributing to efforts to decarbonize cementing operations. This approach also considered the use of local raw materials to minimize the transportation-related carbon footprint. Several Omani raw material sources were evaluated until a suitable material was identified to meet the performance criteria. The laboratory pilot tests performed included full sensitivities to produce a robust cement-free slurry that was suitable for cementing the candidate well successfully. This case study confirms that the low-carbon geopolymer cement-free system integrates seamlessly into standard oilfield cementing workflows without requiring changes to the design process, onsite execution, or post-job evaluation. Following the cementing jobs using the geopolymer cement-free system, a wireline evaluation log was performed, and zonal isolation was confirmed. This first primary casing cementing in an oil well using the low-carbon geopolymer cement-free system designed using local Omani raw materials represents the first step, paving the path toward decarbonization cementing operations in Oman and across the Middle East. In this manuscript we will present the methodology used for the planning, execution, and evaluation of these cementing jobs. Close collaboration between the operator and cementing service company was fundamental to the success of this job. Details regarding the fluid selection, software simulation, laboratory testing, and final evaluation will be presented in this paper. Prior to field application, a yard test was performed to confirm the handling (bulking) and transfer of the new cement-free blend and its mixing and pumping with a standard high-pressure cementing unit. Furthermore, the implementation of this innovative solution was complemented by a quantification of the carbon footprint using a sustainability assessment tool based on life-cycle analysis.