Research On The Corrosion Evaluation Method Of CO₂ On Cementing Cement Stone

Cementing cement are corrosive by CO2 of acid corrosion medium,it Will lead to lower the cement compressive strength and increase permeability and gradually lose the protective effect of the casing,carousing reduce the service life of oil and gas wells and bringing huge economic losses.At present,we do not have a relative standard and uniform CO2 corrosion of cement cementing evaluation methods at home and abroad,therefore,urgently need to work out a cement cementing evaluation methods of CO2 corrosion.From the experimental methods and evaluation,we establish the evaluation methods for CO2 corrosion cement cementing.From the experimental methods,we designed high temperature and pressure autoclave curing of anti-CO2 corrosion,at the same time,corrosive media and corrosion conditions were optimized;From the evaluation,it is preferable that the microstructure and composition of the etching depth analysis as CO2 and cement for cementing cement corrosion evaluation,and to establish a relationship with the compressive strength and permeability.Corrosion depth is the most intuitive comprehensive index evaluation of corrosion of cement,explaining the permeability of cement from corrosion before and after the micro,compressive strength and corrosion depth.From the CO2 partial pressure,temperature and corrosion etching time three main factors,we start to establish a cement corrosion depth affect relationship of mathematical expressions.cement corrosion depth change with CO2 partial pressure,temperature and time respectively with the square root,linear,logarithmic function of the form to indicate.Single factor linear superposition method established cement corrosion depth variation mathematical expression with CO2 partial pressure,temperature and corrosion time three main factors.By calculation,the corrosion depth and the relative error of theory etching depth measured values are less than 3%.Thus verifying the cement corrosion depth affect relationship of mathematical expressions can better assess and predict the condition and extent of corrosion of cement.