Casing Damage Mechanism Of Mudstone Finite Element Analysis

With the adoption of various strengthened oil-extraction measures, the working conditions of casings of oil and gas wells have become more and more deteriorated; the casing failure of well is one important problem in oil engineering. Casing failure brings about enormous losses of manpower, material resources and financial resources to oilfields. Researches on the mechanism of casing failure have both theoretical and engineering significance.The data of casing failure wells indicates that the casing failure of mud-rock layer is a ubiquitous question in every large oil field at present. Under the development environment of water flooding, the mud-rock absorbs water and expands and the creep takes place, the displacement load emerges to act on the casing, meanwhile, make the non-uniform load of the casing distribute more serious , cause the casing to be damaged.The study developed the situation of casing failure of Dagang typical regions, the following major works were did: First, to put forward 4 factors to lead to Dagang casing failure, or geologic factor, engineering factor, high pressure water injection and chemical factors, we developed that the ground stress lead to casing to be pulled, pressured, squeezed and sheared. Second, creep curve, general characteristic of mud-rock to study and calculate casing load method through the creeping constitutive equation; According to the existing materials of casing failure of oil field, use deformation of the artificial simulated test casing of the computer and destruction course, analyze the mechanism of the casing failure with the finite element, this help assurance of quantization study the influence degree of the influencing factor of the casing failure, for prevent and slow down similar stratum terms oil well casing failure supply the theoretical supervise worth consulting.