Casing Damage Mechanism And Preventive Measures Study

With the progressing of the oil field development and changing of exploring program, due to various geological, engineering and managing condition, the working conditions of oil, gas, and water injection wells gets worse or even damaged. As a result, the wells can not work normally and affects the steady production of oil field. Extremely since more and more action for strengthening oil recovery were taken, such as high pressure water injection, fracturing, mega-acidization, steam injection, the working condition of casings gets more serious though apparent economic goals were achieved, the outer loads on casing are increased continually, but for many years the primary methodology for casing strength designing has aimed mainly at the well completion, the influences of oil recovering, water injection and ground stress has less considered or hasn't been considered. Because of all above, understanding the mechanism and factors relates to casing damage, finding out casing damage precautions fits well site will absolutely have significant economic value for the development of oil and gas reservoir.By reading enough documents and papers, along with producing practice of 8th oil recovery company of DaQing, the author analyzed the various causes of casing damage, using multi-professional and multi-subjects methods, introducing statistics of spot casing damage, mechanical experiment, indoor and theoretical analysis and computation methods, thoroughly and systematically study the mechanism of casing damage, put forward the mechanical model of casing damage and precautions for alleviate the casing damage.The main researches and computation of this paper focus on: ground stress, breakdown pressure, the relation between casing failure and injection pressure, mechanical model of casing damage.