Based on the analyses of the situation and distribution of casing damage in the Tarim Oilfield, it was considered that there are six major factors causing the casing damage: (1) There are flowing rock or highly permeable formation around the casing; (2) The well bore structure is unreasonable; (3) The up hole elevation of cement in the drilling design is not high enough, or the cementing quality does not conform to the rules; (4) The quality of casing grading hoop is not up to the required standard; (5) Collapse resistance decreased due to the corrosion, wear, and special down hole operation; (6) The unreasonable development factors. According to the present situation of the casing damage, the comprehensive countermeasures of “defense”, “diagnosis”, “treatment” for repairing the casing-damaged wells were developed. For the casing-damaged wells, 3 ways, taking underground work sit sealing to suppress, engineering logging and static temperature gradient, were used to find a leakage. During 1998-2009, casing damages happened in 71 wells, and 87 places were damaged in total. After determining the position of the casing damages, 3 ways were employed to repair the casing-damaged wells, cement squeezing, using packer to the selected segment, tube expanding subsidies. Fifty-seven casing-damaged wells were repaired, of which, 46 wells were recovered on production. The success ratio is 80.70%.
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