The Study Of Oil Casing Failure Mechanism And Stress Analysis

Casing failure phenomenon exists in most of the world oil. With the increasing years of exploitation,it is becoming more and more serious. Casing failure has become an important factor of limiting oil production. Major research topic of the subject is that casing has some deformation under several common external loads , and then we observe the changes of stress on the inner surface .At last can reache the purpose on detecting the casing failure.Based on a large number of domestic and foreign research datas, the types of the casing failure are caught. According to the form of casing failure and the rock strata activities of law, casing force models are established. With finite element analysis software, the models are meshed as finite element model. loading and calculation, the main research topics are summarized as follows:When one side is added constraints and the other side is free , the casing becomes bending deformation after loading . It take several paths on the inner surface of the casing. According to the path, draw the stress curves and observe the changes of stress, study variation law. Circumferential stress is presented as wave type, the change of each position is consistent, the axial stress change as a straight line, but the direction is not the same as a different path.It adds constraints in both ends of the casing when the rock slide, the casing becomes bending deformation. With the same method to take the stress path and to draw the curve, circumferential stress is wavy, but the variations of the force regional is different form nonforce regional. the axial stress is parabolic, the stress caves of different path have different directions. Detection and prevention.can be achieved under these laws .Under the effect of nonuniform loading the casing becomes necking and crowded flat deformation. according to the type and mudstone water law, it create finite element model under different loads,with loading and calculation. several stress paths are selected for analysis. In the non-uniform stress, damage to the casing always happens in those regions of small force. This prevention and detection can be achieved by this way.