Research On Anti-CO₂ Corrosion Cement Slurry System

In the process of oil and gas well production,cementing anti-corrosion of oil and gas field must be a serious production problem should be solved,must give rise to great importance of each big oil field,therefore,research on the law of corrosive medium like acid CO2 to cementing sheath and the influence regular pattern of different influence factors on the corrosion rate,at the same time,development of anticorrosive agent with good corrosion resistance and optimization of mineral admixture with corrosion resistance,have practical meaning to improve corrosion resistance of cementing sheath with rich CO2 formation,have extremely important significance to ensure the late stable production of the oil gas well and extend the life of development.Research on influence factors of cement corrosion such as different ages of corrosion,temperature,CO2 partial pressure has been carried on in this article firstly,Understanding the oil well cement stone corrosion mechanism of CO2,can provide theoretical guidance and direction for the optimization design for slurry system with anti-CO2 corrosion;then corrosion test of CO2 corrosion resistance admixture was done,screening inert mineral admixtures with good corrosion resistance and Polymer anticorrosive agent with environment response,optimal designing initial slurry formula with resistance of CO2 corrosion;Finally,experiments to slurry formulation with initial anti-CO2 corrosion was done,confirming the best slurry formulation with CO2 corrosion resistance,and evaluating the corrosion resistance of slurry formulation with best CO2 corrosion resistance,macro analyzing corrosion resistance mechanism with C02 corrosion resistance of cement stone by using modern analytical means such as electron microscope scanning,X-ray diffraction and energy spectrum.Experimental results show that the slurry formulation of CO2 corrosion resistance had good comprehensive performance,densification curve had a short transition time in temperature of 80,pressure of 40mpa,and temperature of 110,pressure of 55mpa,assumes the right-angle thickening,adjustable thickening time;corrosion experiment results show that fading rate of compressive strength of cement stone with adding mineral admixtures was 12.43%.growth rate of permeability was 8.52%;fading rate of compressive strength of cement stone with adding mineral admixtures and environmental response material were 12.29%and 9.11%,growth rate of penneability were 14.12%and 15.60%respectively,fading rate of compressive strength of cement stone with anti-CO2 corrosion and growth rate of permeability were less than blank cement,all above stated that slurry formulation involved in this subject had good CO2 corrosion resistance,reach the purpose of this subject.