Effect of polymer emulsion and calcium sulfate whisker on an-corrosion of cement stone for CO₂ multiple gas injection and production wells

Abstract An oilfield in the South China Sea will be developed by CO 2 injection to enhance oil recovery and carbon sequestration. It is challenging to prevent corrosion in the cementing operation of injection wells, and high requirements are put forward for the anti-corrosion performance of cementing slurry. In this paper, aiming at the sealing problem of the cement ring, which is easy to corrode under the condition of stratified gas injection, the rheological properties and thickening properties of cement slurry, as well as the tensile strength, compressive strength, elastic modulus, and porosity permeability of the cement slurry system, are simulated under the condition of an underground field with polymer emulsion and calcium sulfate whiskers as the research objects. Through experimental and theoretical comparison, the results show that the addition of polymer emulsion and calcium sulfate whisker can significantly improve the tensile strength and tensile strength and reduce porosity and permeability, elastic modulus has been controlled below 7.5 GPa, and the performance has been dramatically improved. In addition, according to electron microscope scanning and other experimental methods, it is found that the cement stone cured by cement slurry with polymer emulsion and calcium sulfate whisker is more compact and compact in structure and has higher strength and toughness, which fully meets the requirements of stratified gas injection conditions, providing theoretical basis and data support for the corrosion prevention of cementing cement slurry in oil fields. Promoting the safe and efficient development of oil and gas resources is of great significance.