PERFORMANCE PROPERTIES OF CASING UNDER LOAD CONDITIONS
Casing is subjected to different loads during landing, cementing, drilling, and production operations. The most important loads which it must withstand are: tensile, burst and collapse loads. Accordingly, tensile, burst and collapse strengths of casing are defined by the API as minimal performance properties (API Bui. 5C2, 1987; API Bui. 5C3, 1989). There are other loads, however, that may be of equal or greater importance and are often limiting factors in the selection of casing grades. These loads include: wear, corrosion, vibration and pounding by drillpipe, the effects of gun perforating and erosion. In this chapter, the sources and characteristics of the loads which are important to the casing design and the formulas to compute them are discussed.
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Fig. 2.1: Elastoplastic material behavior with transition range. |
