The Stress Simulation Of Failure Casing In Water Injection Well

Along with ShengLi Oilfield entering the production tail, the failure of casing becomes very serious, especially the implementation of the high pressure water injection, which puts great impact on the oilfield development operation. Failure of large amount of casings in water injection well is an extremely severe threat to the stable yields of oilfield. Hence, the mechanism research about the failure of casing in water injection well is very important.The causes about the failure of casing are divided into two kinds: geologic factor and engineering factor. This article collects domestic and foreign newest documents about the research for the failure of casing, and judged that the layer dynamic property changes, caused by water injection's to geologic environment, increased the outer loading on the casing and seriously exceeded carrying capacity of the casing, so the casings were damaged. On the basis of the situation of casing failure in ShengLi Oilfield, we obtained the stress etching mechanism about the failure of the casing. At the same time, in order to get the affecting degree of some factors on casing failure, we adopted finite element analysis software ANSYS, aiming at the unique geology circumstance in ShengLi Oilfield, to analyze dynamics of the casing from clay stone creep, the pressure of the injection water, the temperature of the injection water and so on. The final results demonstrated the layer stress concentration caused by water injection and the inappropriate pressure of water injection are the main reason to the severe failure of the casing.On the casing failure mechanism and prevention measure, domestic and foreign researchers have done much work, and proposed some effective prevention methods. This article concretely studied the casing failure situation of ShengLi Oilfield water injection, proposed the corresponding preventive measure for the casing pressure change regarding the geologic factor, which could protect casing and lengthen casing's service life. The article could provide theory instructional value to prevent and slow down the failure phenomenon of casing in the similar geological situation.