The strength and quality of the oil casing pipe
is always a concern for everyone, because the quality of the oil casing is one of the important factors affecting China's crude oil production. In fact, the causes of its damage include non-uniform stress, corrosion, and sand formation in the oil layer. And high pressure water injection. Regarding the strength of the oil casing, the API standard does not clearly point out the effects of non-uniform stress, geometric defects of the oil casing, and residual stress on the bearing capacity of the casing on the bearing capacity of the oil casing. Therefore, the impact of these unpredictable conditions makes it difficult for the designer to determine the impact of these factors on the strength of the oil casing.
Now, oil casing manufacturers understand that the existing data have analyzed the effects of geometric defects, residual stress, non-uniform ground stress and other factors on the strength of the oil casing. Most literature is limited to finite element numerical simulations. In actual engineering, the squeezing force of oil casing is unevenly distributed. The important point is that the formation of sand, slippage, swelling, cement channeling, etc. will cause uneven distribution of casing compression force. Therefore, in consideration of the non-uniform distribution of the load on the outer wall of the casing, a variety of non-uniform modes have been adopted. The following is an example, the non-uniform load is decomposed into two parts: uniform load and non-uniform load. In practice, the non-uniform bearing of oil casing and other factors greatly reduce the bearing capacity of the oil casing, thus showing these factors It is of great significance in the influence of the strength of oil casing.
When the load distribution of the outer wall of the oil casing is not uniform, the stresses at the points on the circumference of the same radius are different. The smaller the uniform compression pressure of the oil casing, the greater the degree of unevenness. These are the reasons that affect the strength of petroleum casing.